Increase Centralized Composting

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Industry, Materials & Waste
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Cut Emissions
Cluster
Use Waste as a Resource
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Centralized composting facility
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Summary

A composting system diverts organic waste (OW) from landfills, reducing the production of methane and other GHG emissions. OW is defined as the combination of food waste and green waste, composed of yard and garden trimmings. Composting transforms it into a nutrient-rich soil supplement.

Our focus is on centralized (city- or regional-level) composting systems for the OW components of municipal solid waste (MSW). Decentralized (home- and community-level) and on-farm composting are also valuable climate actions, but are not included here due to limited data availability at the global level (see Increase Decentralized Composting).

Income & work,Health,Equality
Land resources,Water resources,Air quality
Description for Social and Search
Increase Centralized Composting reduces methane and other GHG emissions by diverting organic waste from landfills to facilities that turn it into soil supplements.
Overview

There are many stages involved in a composting system to convert organic MSW into finished compost that can be used to improve soil health (Figure 1). Within this system, composting is the biochemical process that transforms OW into a soil amendment rich in nutrients and organic matter. 

Figure 1. Stages of a composting system. Solution boundaries exclude activities upstream and downstream of centralized MSW composting such as waste collection and compost application. Modified from Kawai et al. (2020) and Manea et al. (2024).

Diagram demonstrating process steps for landfill and compost materials.

Sources: Kawai, K., Liu, C., & Gamaralalage, P. J. D. (2020). CCET guideline series on intermediate municipal solid waste treatment technologies: Composting. United Nations Environment Programme; Manea, E. E., Bumbac, C., Dinu, L. R., Bumbac, M., & Nicolescu, C. M. (2024). Composting as a sustainable solution for organic solid waste management: Current practices and potential improvements.  Sustainability, 16(15), Article 6329.

The composting process is based on aerobic decomposition, driven by complex interactions among microorganisms, biodegradable materials, and invertebrates and mediated by water and oxygen (see the Appendix). Without the proper balance of oxygen and water, anaerobic decomposition occurs, leading to higher methane emissions during the composting process (Amuah et al., 2022; Manea et al., 2024). Multiple composting methods can be used depending on the amounts and composition of OW feedstocks, land availability, labor availability, finances, policy landscapes, and geography. Some common methods include windrow composting, bay or bin systems, and aerated static piles (Figure 2; Amuah et al., 2022; Ayilara et al., 2020; Cao et al., 2023).

Figure 2. Examples of commonly used centralized composting methods. Bay systems (left) move organics between different bays at different stages of the composting process. Windrows (center) are long, narrow piles that are often turned using large machinery. Aerated static piles (right) can be passively aerated as shown here or actively aerated with specialized blowing equipment.

Decentralized composting examples

Credit: Bays, iStock | nikolay100; Windrows, iStock | Jeremy Christensen; Aerated static pile, iStock | AscentXmedia

Centralized composting generally refers to processing large quantities (>90 t/week) of organic MSW (Platt, 2017). Local governments often manage centralized composting as part of an integrated waste management system that can also include recycling non-OW, processing OW anaerobically in methane digesters, landfilling, and incineration (Kaza et al., 2018). 

Organic components of MSW include food waste and garden and yard trimmings (Figure 2). In most countries and territories, these make up 40–70% of MSW, with food waste as the largest contribution (Ayilara et al., 2020; Cao et al., 2023; Food and Agriculture Organization [FAO], 2019; Kaza et al., 2018; Manea et al., 2024; U.S. Environmental Protection Agency [U.S. EPA], 2020; U.S. EPA, 2023). 

Diverting OW, particularly food waste, from landfill disposal to composting reduces GHG emissions (Ayilara et al., 2020; Cao et al., 2023; FAO, 2019). Diversion of organics from incineration could also have emissions and pollution reduction benefits, but we did not include incineration as a baseline disposal method for comparison since it is predominantly used in high-capacity and higher resourced countries and contributes less than 1% to annual waste-sector emissions (Intergovernmental Panel On Climate Change [IPCC], 2023; Kaza et al., 2018). 

Disposal of waste in landfills leads to methane emissions estimated at nearly 1.9 Gt CO₂‑eq (100-yr basis) annually (International Energy Agency [IEA], 2024). Landfill emissions come from anaerobic decomposition of inorganic waste and OW and are primarily methane with smaller contributions from ammonia, nitrous oxide, and CO₂ (Cao et al., 2023; Kawai et al., 2020; Manea et al., 2024). Although CO₂, methane, and nitrous oxide are released during composting, methane emissions are up to two orders of magnitude lower than emissions from landfilling for each metric ton of waste (Ayilara et al., 2020; Cao et al, 2023; FAO, 2019; IEA, 2024; Nordahl et al., 2023; Perez et al., 2023). GHG emissions can be minimized by fine-tuning the nutrient balance during composting. 

Depending on the specifics of the composting method used, the full transformation from initial feedstocks to finished compost can take weeks or months (Amuah et al., 2022; Manea et al., 2024; Perez et al., 2023). Finished compost can be sold and used in a variety of ways, including application to agricultural lands and green spaces as well as for soil remediation (Gilbert et al., 2020; Platt et al., 2022; Ricci-Jürgensen et al., 2020a; Sánchez et al., 2025). 

Abedin, T., Pasupuleti, J., Paw, J.K.S., Tak, Y. C., Islam, M. R., Basher, M. K., & Nur-E-Alam, M. (2025). From waste to worth: Advances in energy recovery technologies for solid waste management. Clean Technologies and Environmental Policy, 27, 5963–5989. Link to source: https://doi.org/10.1007/s10098-025-03204-x

Alves Comesaña, D., Villar Comesaña, I., & Mato de la Iglesia, S. (2024). Community composting strategies for biowaste treatment: Methodology, bulking agent and compost quality. Environmental Science and Pollution Research, 31(7), 9873–9885. Link to source: https://doi.org/10.1007/s11356-023-25564-x 

Amuah, E. E. Y., Fei-Baffoe, B., Sackey, L. N. A., Douti, N. B., & Kazapoe, R. W. (2022). A review of the principles of composting: Understanding the processes, methods, merits, and demerits. Organic Agriculture, 12(4), 547–562. Link to source: https://doi.org/10.1007/s13165-022-00408-z

Ayilara, M., Olanrewaju, O., Babalola, O., & Odeyemi, O. (2020). Waste management through composting: Challenges and potentials. Sustainability, 12(11), Article 4456. Link to source: https://doi.org/10.3390/su12114456

Bekchanov, M., & Mirzabaev, A. (2018). Circular economy of composting in Sri Lanka: Opportunities and challenges for reducing waste related pollution and improving soil health. Journal of Cleaner Production, 202, 1107–1119. Link to source: https://doi.org/10.1016/j.jclepro.2018.08.186

Bell, B., & Platt, B. (2014). Building healthy soils with compost to protect watersheds. Institute for Local Self-Reliance. Link to source: https://ilsr.org/wp-content/uploads/2013/05/Compost-Builds-Healthy-Soils-ILSR-5-08-13-2.pdf 

Brown, S. (2015, July 14). Connections: YIMBY. Biocycle. Link to source: https://www.biocycle.net/connections-yimby/

Cai, B., Lou, Z., Wang, J., Geng, Y., Sarkis, J., Liu, J., & Gao, Q. (2018). CH4 mitigation potentials from China landfills and related environmental co-benefits. Science Advances, 4(7), Article eaar8400. Link to source: https://doi.org/10.1126/sciadv.aar8400

Cao, X., Williams, P. N., Zhan, Y., Coughlin, S. A., McGrath, J. W., Chin, J. P., & Xu, Y. (2023). Municipal solid waste compost: Global trends and biogeochemical cycling. Soil & Environmental Health, 1(4), Article 100038. Link to source: https://doi.org/10.1016/j.seh.2023.100038

Casey, J. A., Cushing, L., Depsky, N., & Morello-Frosch, R. (2021). Climate justice and California’s methane superemitters: Environmental equity Assessment of community proximity and exposure intensity. Environmental Science & Technology, 55(21), 14746–14757. Link to source: https://doi.org/10.1021/acs.est.1c04328

Coker, C. (2020, March 3). Composting business management: Revenue forecasts for composters. Biocycle. Link to source: https://www.biocycle.net/composting-business-management-revenue-forecasts-composters/

Coker, C. (2020, March 10). Composting business management: Capital cost of composting facility construction. Biocycle. Link to source: https://www.biocycle.net/composting-business-management-capital-cost-composting-facility-construction/

Coker, C. (2020, March 17). Composting business management: Composting facility operating cost estimates. Biocycle. Link to source: https://www.biocycle.net/composting-business-management-composting-facility-operating-cost-estimates/ 

Coker, C. (2022, August 23). Compost facility planning: Composting facility approvals and permits. Biocycle. Link to source: https://www.biocycle.net/composting-facility-approval-permits/

Coker, C. (2022, September 27). Compost facility planning: Composting facility cost estimates. Biocycle. Link to source: https://www.biocycle.net/compost-facility-planning-cost/

Coker, C. (2024, August 20). Compost market development. Biocycle. Link to source: https://www.biocycle.net/compost-market-development/

European Energy Agency. (2024). Greenhouse gas emissions by source sector. (Last Updated: April 18, 2024). Eurostat. [Data set and codebook]. Link to source: https://ec.europa.eu/eurostat/databrowser/view/env_air_gge__custom_16006716/default/table 

Farhidi, F., Madani, K., & Crichton, R. (2022). How the US economy and environment can both benefit from composting management. Environmental Health Insights, 16. Link to source: https://doi.org/10.1177/11786302221128454

Food and Agriculture Organization of the United Nations. (2024). The state of food and agriculture 2024 – Value-driven transformation of agrifood systems. Link to source: https://doi.org/10.4060/cd2616en

Finlay, K. (2024). Turning down the heat: how the U.S. EPA can fight climate change by cutting landfill emissions. Industrious Labs. Link to source: https://cdn.sanity.io/files/xdjws328/production/657706be7f29a20fe54692a03dbedce8809721e8.pdf

Global Alliance for Incinerator Alternatives. (2019). Pollution and health impacts of waste-to-energy incineration [Fact sheet]. Link to source: https://www.cms.gov/newsroom/fact-sheets/delivering-service-school-based-settings-comprehensive-guide-medicaid-services-and-administrative

González, D., Barrena, R., Moral-Vico, J., Irigoyen, I., & Sánchez, A. (2024). Addressing the gaseous and odour emissions gap in decentralised biowaste community composting. Waste Management, 178, 231–238. Link to source: https://doi.org/10.1016/j.wasman.2024.02.042 

International Energy Agency. (2024), Global Methane Tracker 2024. Link to source: https://www.iea.org/reports/global-methane-tracker-2024

Intergovernmental Panel On Climate Change. (2023). Climate change 2022 – Impacts, adaptation and vulnerability: Working Group II contribution to the sixth assessment report of the Intergovernmental Panel on Climate Change (1st ed.). Cambridge University Press. Link to source: https://doi.org/10.1017/9781009325844

Intergovernmental Panel On Climate Change. (2019). 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Calvo. Buendia, E., Tanabe, K., Kranjc, A., Baasansuren, J., Fukuda, M., Ngarize S., Osako, A., Pyrozhenko, Y., Shermanau, P. and Federici, S. (eds). Link to source: https://www.ipcc-nggip.iges.or.jp/public/2019rf/index.html 

Jamroz, E., Bekier, J., Medynska-Juraszek, A., Kaluza-Haladyn, A., Cwielag-Piasecka, I., & Bednik, M. (2020). The contribution of water extractable forms of plant nutrients to evaluate MSW compost maturity: A case study. Scientific Reports, 10(1), Article 12842. Link to source: https://doi.org/10.1038/s41598-020-69860-9

Kawai, K., Liu, C., & Gamaralalage, P. J. D. (2020). CCET guideline series on intermediate municipal solid waste treatment technologies: Composting. United Nations Environment Programme. Link to source: https://www.unep.org/ietc/resources/publication/ccet-guideline-series-intermediate-municipal-solid-waste-treatment

Kaza, S., Yao, L. C., Bhada-Tata, P., Van Woerden, F., (2018). What a waste 2.0: A global snapshot of solid waste management to 2050. Urban Development. World Bank. Link to source: http://hdl.handle.net/10986/30317 

Krause, M., Kenny, S., Stephenson, J., & Singleton, A. (2023). Quantifying methane emissions from landfilled food waste (Report No. EPA-600-R-23-064). U.S. Environmental Protection Agency Office of Research and Development. Link to source: https://www.epa.gov/system/files/documents/2023-10/food-waste-landfill-methane-10-8-23-final_508-compliant.pdf 

Liu, K-. M., Lin, S-. H., Hsieh, J-., C., Tzeng, G-., H. (2018). Improving the food waste composting facilities site selection for sustainable development using a hybrid modified MADM model. Waste Management, 75, 44–59. Link to source: https://doi.org/10.1016/j.wasman.2018.02.017

Liu, H., Zhang, X., & Hong, Q. (2021). Emission characteristics of pollution gases from the combustion of food waste. Energies, 14(19), Article 6439. Link to source: https://doi.org/10.3390/en14196439

Maalouf, A., & Agamuthu, P. (2023). Waste management evolution in the last five decades in developing countries – A review. Waste Management & Research: The Journal for a Sustainable Circular Economy, 41(9), 1420–1434. Link to source: https://doi.org/10.1177/0734242X231160099

Manea, E. E., Bumbac, C., Dinu, L. R., Bumbac, M., & Nicolescu, C. M. (2024). Composting as a sustainable solution for organic solid waste management: Current practices and potential improvements. Sustainability, 16(15), Article 6329. Link to source: https://doi.org/10.3390/su16156329

Martínez-Blanco, J., Lazcano, C., Christensen, T. H., Muñoz, P., Rieradevall, J., Møller, J., Antón, A., & Boldrin, A. (2013). Compost benefits for agriculture evaluated by life cycle assessment. A review. Agronomy for Sustainable Development, 33(4), 721–732. Link to source: https://doi.org/10.1007/s13593-013-0148-7

Martuzzi, M., Mitis, F., & Forastiere, F. (2010). Inequalities, inequities, environmental justice in waste management and health. The European Journal of Public Health, 20(1), 21–26. Link to source: https://doi.org/10.1093/eurpub/ckp216

Nordahl, S. L., Devkota, J. P., Amirebrahimi, J., Smith, S. J., Breunig, H. M., Preble, C. V., Satchwell, A. J., Jin, L., Brown, N. J., Kirchstetter, T. W., & Scown, C. D. (2020). Life-Cycle greenhouse gas emissions and human health trade-offs of organic waste management strategies. Environmental Science & Technology, 54(15), 9200–9209. Link to source: https://doi.org/10.1021/acs.est.0c00364 

Nordahl, S. L., Preble, C. V., Kirchstetter, T. W., & Scown, C. D. (2023). Greenhouse gas and air pollutant emissions from composting. Environmental Science & Technology, 57(6), 2235–2247. Link to source: https://doi.org/10.1021/acs.est.2c05846 

Nubi, O., Murphy, R., & Morse, S. (2024). Life cycle sustainability assessment of waste to energy systems in the developing world: A review. Environments, 11(6), 123. Link to source: https://doi.org/10.3390/environments11060123

Organisation for Economic Co-operation and Development. (2021). Waste - Municipal waste: generation and treatment. (Downloaded: March 20, 2025) [Data set]. Link to source: https://data-explorer.oecd.org/vis?lc=en&df[ds]=dsDisseminateFinalDMZ&df[id]=DSD_MUNW%40DF_MUNW&df[ag]=OECD.ENV.EPI&dq=.A.INCINERATION_WITHOUT%2BLANDFILL.T&pd=2014%2C&to[TIME_PERIOD]=false&vw=ov 

Pérez, T., Vergara, S. E., & Silver, W. L. (2023). Assessing the climate change mitigation potential from food waste composting. Scientific Reports, 13(1), Article 7608. Link to source: https://doi.org/10.1038/s41598-023-34174-z

Platt, B., Bell, B., & Harsh, C. (2013). Pay dirt: Composting in Maryland to reduce waste, create jobs, & protect the bay. Institute for Local Self-Reliance. Link to source: https://ilsr.org/wp-content/uploads/2013/05/Pay-Dirt-Report.pdf

Platt, B. (2017, April 4). Hierarchy to Reduce Food Waste & Grow Community, Institute for Local Self-Reliance. Link to source: https://ilsr.org/articles/food-waste-hierarchy/

Platt, B., and Fagundes, C. (2018). Yes! In my backyard: A home composting guide for local government. Institute for Local Self-Reliance. Link to source: https://ilsr.org/articles/yimby-compost/

Platt, B., Libertelli, C., & Matthews, M. (2022). A growing movement: 2022 community composter census. Institute for Local Self-Reliance. Link to source: https://ilsr.org/articles/composting-2022-census/ 

Ricci-Jürgensen, M., Gilbert, J., & Ramola, A.. (2020a). Global assessment of municipal organic waste production and recycling. International Solid Waste Association. Link to source: https://www.altereko.it/wp-content/uploads/2020/03/Report-1-Global-Assessment-of-Municipal-Organic-Waste.pdf 

Ricci-Jürgensen, M., Gilbert, J., & Ramola, A.. (2020b). Benefits of compost and anaerobic digestate when applied to soil. International Solid Waste Association. Link to source: https://www.altereko.it/wp-content/uploads/2020/03/Report-2-Benefits-of-Compost-and-Anaerobic-Digestate.pdf 

Rynk, R., Black, G., Biala, J., Bonhotal, J., Cooperband, L., Gilbert, J., & Schwarz, M. (Eds.). (2021). The composting handbook. Compost Research & Education Foundation and Elsevier. Link to source: https://www.compostingcouncil.org/store/viewproduct.aspx?id=19341051

Sánchez, A., Gea, T., Font, X., Artola, A., Barrena, R., & Moral-Vico, J. (Eds.). (2025). Composting: Fundamentals and Recent Advances: Chapter 1. Royal Society of Chemistry. Link to source: https://doi.org/10.1039/9781837673650 

Searchinger, T., Peng, L., Zionts, J., & Waite, R. (2024). The global land squeeze: Managing the growing competition for land. World Resources Institute. Link to source: https://www.wri.org/research/global-land-squeeze-managing-growing-competition-land

Souza, M. A. d., Gonçalves, J. T., & Valle, W. A. d. (2023). In my backyard? Discussing the NIMBY effect, social acceptability, and residents’ involvement in community-based solid waste management. Sustainability, 15(9), Article 7106. Link to source: https://doi.org/10.3390/su15097106

The Environmental Research & Education Foundation. (2024). Analysis of MSW landfill tipping fees — 2023. Link to source: https://erefdn.org/product/analysis-of-msw-landfill-tipping-fees-2023/

U.S. Composting Council. (2008). Greenhouse gases and the role of composting: A primer for compost producers [Fact sheet]. Link to source: https://cdn.ymaws.com/www.compostingcouncil.org/resource/resmgr/documents/GHG-and-Role-of-Composting-a.pdf 

U.S. Environmental Protection Agency. (2020). 2018 wasted food report (EPA Publication No. EPA 530-R-20-004). Office of Resource Conservation and Recovery. Link to source: https://www.epa.gov/system/files/documents/2025-02/2018_wasted_food_report-v2.pdf 

U.S. Environmental Protection Agency. (2023). 2019 Wasted food report (EPA Publication No. 530-R-23-005). National Institutes of Health. Link to source: https://www.epa.gov/system/files/documents/2024-04/2019-wasted-food-report_508_opt_ec_4.23correction.pdf

U.S. Environmental Protection Agency. (2023). Documentation for Greenhouse Gas Emission and Energy Factors Used in the Waste Reduction Model (WARM): Organic Materials Chapters (EPA Publication No. EPA-530-R-23-019). Office of Resource Conservation and Recovery. Link to source: https://www.epa.gov/system/files/documents/2023-12/warm_organic_materials_v16_dec.pdf

U.S. Environmental Protection Agency. (2025, January). Approaches to composting. Link to source: https://www.epa.gov/sustainable-management-food/approaches-composting

U.S. Environmental Protection Agency. (2025, April). Benefits of using compost. Link to source: https://www.epa.gov/sustainable-management-food/benefits-using-compost

United Nations Environment Programme. (2023). Towards Zero Waste: A Catalyst for delivering the Sustainable Development Goals. Link to source: https://doi.org/10.59117/20.500.11822/44102

United Nations Environment Programme. (2024). Global Waste Management Outlook 2024 Beyond an age of waste: Turning rubbish into a resource. Link to source: https://www.unep.org/resources/global-waste-management-outlook-2024 

Urra, J., Alkorta, I., & Garbisu, C. (2019). Potential benefits and risks for soil health derived from the use of organic amendments in agriculture. Agronomy, 9(9), 542. Link to source: https://doi.org/10.3390/agronomy9090542

Wilson, D. C., Paul, J., Ramola, A., & Filho, C. S. (2024). Unlocking the significant worldwide potential of better waste and resource management for climate mitigation: With particular focus on the Global South. Waste Management & Research: The Journal for a Sustainable Circular Economy, 42(10), 860–872. Link to source: https://doi.org/10.1177/0734242X241262717

World Bank. (2018). What a waste global database: Country-level dataset. (Last Updated: June 4, 2024) [Data set]. World Bank. Link to source: https://datacatalogfiles.worldbank.org/ddh-published/0039597/3/DR0049199/country_level_data.csv 

Yasmin, N., Jamuda, M., Panda, A. K., Samal, K., & Nayak, J. K. (2022). Emission of greenhouse gases (GHGs) during composting and vermicomposting: Measurement, mitigation, and perspectives. Energy Nexus, 7, Article 100092. Link to source: https://doi.org/10.1016/j.nexus.2022.100092

Zaman, A. U. (2016). A comprehensive study of the environmental and economic benefits of resource recovery from global waste management systems. Journal of Cleaner Production, 124, 41–50. Link to source: https://doi.org/10.1016/j.jclepro.2016.02.086

Zero Waste Europe & Bio-based Industries Consortium. (2024). Bio-waste generation in the EU: Current capture levels and future potential (Second edition). LIFE Programme of the European Union. Link to source: https://zerowasteeurope.eu/library/bio-waste-generation-in-the-eu-current-capture-levels-and-future-potential-second-edition/ 

Zhu, J., Luo, Z., Sun, T., Li, W., Zhou, W., Wang, X., Fei, X., Tong, H., & Yin, K. (2023). Cradle-to-grave emissions from food loss and waste represent half of total greenhouse gas emissions from food systems. Nature Food, 4(3), 247–256. Link to source: https://doi.org/10.1038/s43016-023-00710-3

Credits

Lead Fellow

  • Megan Matthews, Ph. D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Ted Otte

  • Sarah Gleeson, Ph. D.

  • Amanda D. Smith, Ph.D.

  • Paul C. West, Ph.D.

Effectiveness

We estimated that composting reduces emissions by 3.9 t CO₂‑eq /t OW (9.3 t CO₂‑eq /t OW, 20-yr basis) based on avoided landfill emissions minus the emissions during composting of MSW OW (Table 1). In our analysis, composting emissions were an order of magnitude lower than landfill emissions.

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Table 1. Effectiveness at reducing emissions. 

Unit: t CO₂‑eq (100-yr basis)/t OW

25th percentile 2.5
Mean 3.2
Median (50th percentile) 3.9
75th percentile 4.3
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Emissions data from composting and landfilling OW are geographically limited, but our analysis includes three global reports and studies from the U.S., China, Denmark, and the EU (European Energy Agency [EEA], 2024; Industrious Labs, 2024; Perez et al., 2023; U.S. EPA, 2020; Yang et al., 2017, Yasmin et al., 2022). We assumed OW was 39.6% of MSW in accordance with global averages (Kaza et al., 2018; World Bank, 2018).

We estimated that landfills emit 4.3 t CO₂‑eq /t OW (9.9 t CO₂‑eq /t OW, 20-yr basis). We estimated composting emissions were 10x lower at 0.4 t CO₂‑eq /t OW (0.6 t CO₂‑eq /t OW, 20-yr basis). We quantified emissions from a variety of composting methods and feedstock mixes (Cao et al., 2023; Perez et al., 2023; Yasmin et al., 2022). Consistent with Amuah et al. (2022), we assumed a 60% moisture content by weight to convert reported wet waste quantities to dry waste weights. We based effectiveness estimates only on dry OW weights. For adoption and cost, we did not distinguish between wet and dry OW.

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Cost

Financial data were geographically limited. We based cost estimates on global reports with selected studies from the U.K., U.S., India, and Saudi Arabia for landfilling and the U.S. and Sri Lanka for composting. Transportation and collection costs can be significant in waste management, but we did not include them in this analysis. We calculated amortized net cost for landfilling and composting by subtracting revenues from operating costs and amortized initial costs over a 30-yr facility lifetime.

Landfill initial costs are one-time investments, while operating expenses, which include maintenance, wages, and labor, vary annually. Environmental costs, including post-closure operations, are not included in our analysis, but some countries impose taxes on landfilling to incentivize alternative disposal methods and offset remediation costs. Landfills generate revenue through tip fees and sales of landfill gas (Environmental Research & Education Foundation [EREF], 2023; Kaza et al., 2018). We estimated that landfilling is profitable, with a net cost of –US$30/t OW. 

Initial and operational costs for centralized composting vary depending on method and scale (IPCC, 2023; Manea et al., 2024), but up-front costs are generally cheaper than landfilling. Since composting is labor-intensive and requires monitoring, operating costs can be higher, particularly in regions that do not impose landfilling fees (Manea et al., 2024). 

Composting facilities generate revenue through tip fees and sales of compost products. Compost sales alone may not be sufficient to recoup costs, but medium- to large-scale composting facilities are economically viable options for municipalities (Kawai et al., 2020; Manea et al., 2024). We estimated the net composting cost to be US$20/t OW. The positive value indicates that composting is not globally profitable; however, decentralized systems that locally process smaller waste quantities can be profitable using low-cost but highly efficient equipment and methods (see Increase Decentralized Composting). 

We estimated that composting costs US$50/t OW more than landfilling. Although composting systems cost more to implement, the societal and environmental costs are greatly reduced compared to landfilling (Yasmin et al., 2022). The high implementation cost is a barrier to adoption in lower-resourced and developing countries (Wilson et al., 2024). 

Combining effectiveness with the net costs presented here, we estimated a cost per unit climate impact of US$10/t CO₂‑eq (US$5/t CO₂‑eq , 20-yr basis) (Table 2). 

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Table 2. Cost per unit climate impact.

Unit: US$ (2023)/t CO₂‑eq (100-yr basis)

Median 10
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Methods and Supporting Data

Methods and Supporting Data

Learning Curve

Global cost data on composting are limited, and costs can vary depending on composting methods, so we did not quantify a learning rate for centralized composting.

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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Increase Centralized Composting is an EMERGENCY BRAKE climate solution. It has the potential to deliver a more rapid impact than nominal and delayed solutions. Because emergency brake solutions can deliver their climate benefits quickly, they can help accelerate our efforts to address dangerous levels of climate change. For this reason, they are a high priority.

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Caveats

The composting process has a low risk of reversal since carbon is stored stably in finished compost instead of decaying and releasing methane in a landfill (Ayilara et al., 2020; Manea et al., 2024). However, a composting system, from collection to finished product, can be challenging to sustain. Along with nitrogen-rich food and green waste, additional carbon-rich biomass, called bulking material, is critical for maintaining optimal composting conditions that minimize GHG emissions. Guaranteeing the availability of sufficient bulking materials can challenge the success of both centralized and decentralized facilities.

Financially and environmentally sustainable composting depends not only on the quality of incoming OW feedstocks, but also on the quality of the final product. Composting businesses require a market for sales of compost products (in green spaces and/or agriculture), and poor source separation could lead to low-quality compost and reduced demand (Kawai et al., 2020; Wilson et al., 2024). Improvements in data collection and quality through good feedback mechanisms can also act as leverage for expanding compost markets, pilot programs, and growing community support.

If composting facilities close due to financial or other barriers, local governments may revert to disposing of organics in landfills. Zoning restrictions also vary broadly across geographies, affecting how easily composting can be implemented (Cao et al., 2023). In regions where centralized composting is just starting, reversal could be more likely without community engagement and local government support (Kawai et al., 2020; Maalouf & Agamuthu, 2023); however, even if facilities close, the emissions savings from past operation cannot be reversed.

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Current Adoption

We estimated global composting adoption at 78 million t OW/yr, as the median between two datasets (Table 3). The most recent global data on composting were compiled in 2018 from an analysis from 174 countries and territories (World Bank, 2018). We also used an Organisation for Economic Co-operation and Development (OECD) analysis from 45 countries (OECD, 2021). However, there were still many countries and territories that did not report composting data in one or both datasets. Although the World Bank dataset is comprehensive, it is based on data collected in 2011–2018, so more recent, high-quality, global data on composting are needed.

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Table 3. Current adoption level (2021).

Unit: t OW composted/yr

25th percentile 67,000,000
Mean 78,000,000
Median (50th percentile) 78,000,000
75th percentile 89,000,000
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Globally in 2018, nearly 40% of all waste was disposed of in landfills, 19% was recovered through composting and other recovery and recycling methods, and the remaining waste was either unaccounted for or disposed of through open dumping and wastewater (Kaza et al., 2018)

We calculated total tonnage composted using the reported composting percentages and the total MSW tonnage for each country. Composting percentages were consistently lower than the total percentage of OW present in MSW, suggesting there is ample opportunity for increased composting, even in geographies where it is an established disposal method. In 2018, 26 countries/territories had a composting rate above 10% of MSW, and 15 countries/territories had a composting rate above 20% of MSW. Countries with the highest composting rates were Austria (31%), the Netherlands (27%), and Switzerland (21%) (World Bank, 2018).

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Adoption Trend

We used OECD data to estimate the composting adoption trend from 2014–2021 (OECD, 2021), which fluctuated significantly from year to year (Table 4). Negative rates indicate less OW was composted globally than in the previous year. Taking the median composting rate across seven years, we estimate the global composting trend as 260,000 t OW/yr/yr. However, the mean composting trend is –1.3 Mt OW/yr/yr, suggesting that on average, composting rates are decreasing globally. 

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Table 4. Adoption trend (2014–2021).

Unit: t OW composted/yr/yr

25th percentile -1,200,000
Mean -1,300,000
Median (50th percentile) 260,000
75th percentile 4,300,000
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Although some regions are increasing their composting capacity, others are either not composting or composting less over time. Germany, Italy, Spain, and the EU overall consistently show increases in composting rates year-to-year, while Greece, Japan, Türkiye, and the U.K. show decreasing composting rates. In Europe, the main drivers for consistent adoption were disposal costs, financial penalties, and the landfill directive (Ayilara et al., 2020). 

Lack of reported data could also contribute to a negative global average composting rate over the past seven years. A large decline in composting rates from 2018–2019 was driven by a lack of data in 2019 for the U.S. and Canada. If we assumed that the U.S. composted the same tonnage in 2019 as in 2018, instead of no tonnage as reported in the data, then the annual trend for 2018–2019 is much less negative (–450,000 t OW/yr/yr) and the overall mean trend between 2014–2019 would be positive (1,400,000 t OW/yr/yr).

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Adoption Ceiling

We estimate the global adoption ceiling for Increase Centralized Composting to be 1.35 billion t OW/yr (Table 5). In 2016, 2.01 Gt of MSW were generated, and generation is expected to increase to 3.4 Gt by 2050 (Kaza et al., 2018). Due to limited global data availability on composting infrastructure or policies, we estimated the adoption ceiling based on the projected total MSW for 2050 and assumed the OW fraction remains the same over time.

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Table 5. Adoption ceiling. upper limit for adoption level.

Unit: t OW composted/yr

Median (50th percentile) 1,350,000,000
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In reality, amounts of food waste within MSW are also increasing, suggesting that there are sufficient global feedstocks to support widespread composting adoption (Zhu et al., 2023). 

We assume that all OW could be processed via composting, but this ceiling is unlikely to be reached. In practice, organics could also be processed via methane digesters (see Deploy Methane Digesters), incinerated, or dumped, but these waste management treatments have similar environmental risks to landfilling. 

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Achievable Adoption

Since the global annual trend fluctuates, we used country-specific composting rates and organic fractions of MSW from 2018 to estimate the achievable range of composting adoption (see Appendix for an example). In our analysis, achievable increases in country-specific composting rates cannot exceed the total organic fraction of 2018 MSW. 

For the 106 countries/territories that did not report composting rates, we defined achievable levels of composting relative to the fraction of OW in MSW. When countries also did not report OW percentages, the country-specific composting rate was kept at zero. For the remaining 86 countries/territories, we assumed that 25% of organic MSW could be diverted to composting for low achievable adoption and that 50% could be diverted for high achievable adoption. 

For the 68 countries/territories with reported composting rates, we define low and high achievable adoption as a 25% or 50% increase to the country-specific composting rate, respectively. If the increased rate for either low or high adoption exceeded the country-specific OW fraction of MSW, we assumed that all organic MSW could be composted (see Appendix for an example). Our Achievable – Low adoption level is 201 Mt OW/yr, or 15% of our estimated adoption ceiling (Table 6). Our Achievable – High adoption level is 301 Mt OW/yr, or 22% of our estimated adoption ceiling. 

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Table 6. Range of achievable adoption levels.

Unit: t OW composted/yr

Current adoption 78,000,000
Achievable – low 201,000,000
Achievable – high 301,000,000
Adoption ceiling 1,350,000,000
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Our estimated adoption levels are conservative because some regions without centralized composting of MSW could have subnational decentralized composting programs that aren’t reflected in global data.

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Although our achievable range is conservative compared to the estimated adoption ceiling, increased composting has the potential to reduce GHG emissions from landfills (Table 7). We estimated that current adoption reduces annual GHG emissions by 0.3 Gt CO₂‑eq/yr (0.73 Gt CO₂‑eq/yr, 20-yr basis). Our estimated low and high achievable adoption levels reduce 0.78 and 1.2 Gt CO₂‑eq/yr (1.9 and 2.8 Gt CO₂‑eq/yr, 20-yr basis), respectively. Using the adoption ceiling, we estimate that annual GHG reductions increase to 5.2 Gt CO₂‑eq/yr (12.6 Gt CO₂‑eq/yr, 20-yr basis).

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Table 7. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq (100-yr basis)/yr

Current adoption 0.30
Achievable – low 0.78
Achievable – high 1.2
Adoption ceiling 5.2
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The IPCC estimated in 2023 that the entire waste sector accounted for 3.9% of total global GHG emissions, and solid waste management represented 36% of total waste sector emissions (IPCC, 2023). Disposal of waste in landfills leads to methane emissions estimated at nearly 1.9 Gt CO₂‑eq (100-yr basis) annually (IEA, 2024). Based on these estimates, current composting adoption reduces annual methane emissions from landfills more than 16%. 

Increasing adoption to low and high achievable levels could reduce the amount of OW going to landfills by up to 40% and avoid 32–50% of landfill emissions. Reaching our estimated adoption ceilings for Increase Centralized Composting and reduction-focused solutions like Reduce Food Loss and Waste could avoid all food-related landfill emissions.

These climate impacts can be considered underestimates of beneficial mitigation from increased composting since we did not quantify the carbon sequestration benefits of compost application and reduced synthetic fertilizer use. Our estimated climate impacts from composting are also an underestimate because we didn’t include decentralized composting. 

In addition to OW from MSW, large-scale composting also requires agricultural biomass as a feedstock. Multiple climate solutions, in addition to Increase Centralized Composting, require biomass, and projected demand across solutions greatly exceeds supply. The deforestation that would be required to meet demand would produce emissions far greater than any mitigation gains from full deployment of these solutions (Searchinger, 2024). In addition to deforestation, there would also be costs and emissions incurred to transport biomass from where it is produced to where it can be processed and used. Thus, the estimated climate impacts presented here are only possible if feedstocks are prioritized for this solution. If feedstocks are instead prioritized for other climate solutions (see Interactions for examples), adoption and impact will be lower for this solution. It is not possible to set all biomass-dependent solutions to high adoption levels, add up their impacts, and determine an accurate combined emissions impact.

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Additional Benefits

Income and Work

Composting creates more jobs than landfills or incinerators and can save money compared with other waste management options (Bekchanov & Mirzabaev, 2018; Farhidi et al., 2022; Platt et al., 2013; Zaman, 2016). It is less expensive to build and maintain composting plants than incinerators (Kawai et al., 2020). According to a survey of Maryland waste sites, composting creates twice as many jobs as landfills and four times as many jobs as incineration plants (Platt et al., 2013). Composting also indirectly sustains jobs in the distribution and use of compost products (Platt et al., 2013). Compost is rich in nutrients and can also reduce costs associated with synthetic fertilizer use in agriculture (Farhidi et al., 2022).

Health

Odors coming from anaerobic decomposition landfills, such as ammonia and hydrogen sulfide, are another source of pollutants that impact human well-being, which can be reduced by aerobic composting (Cai et al., 2018).

Equality

Reducing community exposure to air pollution from landfills through composting has implications for environmental justice (Casey et al., 2021; Nguyen et al., 2023). A large review of waste sites in the United States and Europe found that landfills are disproportionately located near populations with low socioeconomic status and near racially and ethnically marginalized neighborhoods (Marzutti et al., 2010). Reducing disproportionate exposures to air pollution from landfills may mitigate poor health outcomes in surrounding communities (Brender et al., 2011)

Land Resources

Compost provides an important soil amendment that adds organic matter and nutrients to soil, reducing the need for synthetic fertilizers (Urra et al., 2019; U.S. EPA, 2025). Healthy soils that are rich in organic matter can benefit the surrounding ecosystem and watershed and lead to more plant growth through improved water retention and filtration, improved soil quality and structure, and reduced erosion and nutrient runoff (Bell & Platt, 2014; Martinez-Blanco et al., 2013; U.S. EPA, 2025). By reducing the need for synthetic fertilizers and by improving soils’ ability to filter and conserve water, compost can also reduce eutrophication of water bodies (U.S. EPA, 2025). These soil benefits are partially dependent on how compost is sorted because there may be risks associated with contamination of microplastics and heavy metals (Manea et al., 2024; Urra et al., 2019).

Water Resources

For a description of water resources benefits, please see Land Resources above. 

Air Quality

Composting can reduce air pollution such as CO₂, methane, volatile organic compounds, and particulate matter that is commonly released from landfills and waste-to-energy systems (Kawai et al., 2020; Nordahl et al., 2020; Siddiqua et al., 2022). An analysis comparing emissions from MSW systems found composting to have lower emissions than landfilling and other waste-to-energy streams (Nordahl et al., 2020). Composting can also reduce the incidence of landfill fires, which release black carbon and carbon monoxide, posing risks to the health and safety of people in nearby communities (Nguyen et al., 2023).

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Risks

Before the composting process can start, feedstocks are sorted to remove potential contaminants, including nonbiodegradable materials such as metal and glass as well as plastics, bioplastics, and paper products (Kawai et al., 2020; Perez et al., 2023; Wilson et al., 2024). While most contaminants can be removed through a variety of manual and mechanical sorting techniques, heavy metals and microplastics can become potential safety hazards or reduce finished compost quality (Manea et al., 2024). Paper and cardboard should be separated from food and green waste streams because they often contain contaminants such as glue or ink, and they degrade more slowly than other OW, leading to longer processing time and lower-quality finished compost (Kawai et al., 2020; Krause et al., 2023).

Successful and safe composting requires careful monitoring of compost piles to avoid anaerobic conditions and ensure sufficient temperatures to kill pathogens and weed seeds (Amuah et al., 2022; Ayilara et al., 2020; Cao et al., 2023; Kawai et al., 2020; Manea et al., 2024). Anaerobic conditions within the compost pile increase GHGs emitted during composting. Poorly managed composting facilities can also pose safety risks for workers and release odors, leading to community backlash (Cao et al., 2023; Manea et al., 2024; UNEP, 2024). Regional standards, certifications, and composter training programs are necessary to protect workers from hazardous conditions and to guarantee a safe and effective compost product (Kawai et al., 2020). Community outreach and education on the benefits of separating waste and composting prevent “not-in-my-backyard” attitudes or “NIMBYism” (Brown, 2015; Platt & Fagundes 2018) that may lead to siting composting facilities further from the communities they serve (Souza, et al., 2023; Liu et al., 2018).

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Interactions with Other Solutions

Reinforcing

Increased composting could positively impact annual cropping by providing consistent, high-quality finished compost that can reduce dependence on synthetic fertilizers and improve soil health and crop yields. 

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High-quality sorting systems also allow for synergies that benefit all waste streams and create flexible, resilient waste management systems. Improving waste separation programs for composting can have spillover effects that also improve other waste streams, such as recyclables, agricultural waste, or e-waste. Access to well-sorted materials can also help with nutrient balance for various waste streams, including agricultural waste.

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Composting facilities require a reliable source of carbon-rich bulking material. Agricultural waste can be diverted to composting rather than burning to reduce emissions from crop residue burning. 

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Competing

Diverting OW from landfills will lead to lower landfill methane emissions and, therefore, less methane available to be captured and resold as revenue.

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Composting uses wood, crop residues, and food waste as feedstocks (raw material). Because the total projected demand for biomass feedstocks for climate solutions exceeds the supply, not all solutions will be able to achieve their potential adoption. This solution is in competition with other climate solutions for raw material.

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Dashboard

Solution Basics

t organic waste

t CO₂-eq (100-yr)/unit
02.53.9
units/yr
Current 7.8×10⁷ 02.009×10⁸3.01×10⁸
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.3 0.781.2
US$ per t CO₂-eq
10
Emergency Brake

CO₂,  CH₄

Trade-offs

Robust collection networks and source separation of OW are vital for successful composting, but they also increase investment costs. However, well-sorted OW can reduce the need for separation equipment and allow for simpler facility designs, leading to lower operational costs. The emissions from transporting OW are not included here, but are expected to be significantly less than the avoided landfill emissions. Composting facilities are typically located close to the source of OW (Kawai et al., 2020; U.S. Composting Council [USCC], 2008), but since centralized composting facilities are designed to serve large communities and municipalities, there can be trade-offs between sufficient land availability and distance from waste sources.

We also exclude emissions from onsite vehicles and equipment such as bulldozers and compactors, assuming that those emissions are small compared to the landfill itself.

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t/person/yr
≤ 0.17
0.18–0.32
0.33–0.5
> 0.5
No Data

Per capita MSW generation, 2018

Annual generation of MSW per capita. Total global MSW generation exceeded 2 Gt/yr.

World Bank Group (2021). What a waste global database (Version 3) [Data set]. WBG. Retrieved March 6, 2025, from Link to source: https://datacatalog.worldbank.org/search/dataset/0039597

t/person/yr
≤ 0.17
0.18–0.32
0.33–0.5
> 0.5
No Data

Per capita MSW generation, 2018

Annual generation of MSW per capita. Total global MSW generation exceeded 2 Gt/yr.

World Bank Group (2021). What a waste global database (Version 3) [Data set]. WBG. Retrieved March 6, 2025, from Link to source: https://datacatalog.worldbank.org/search/dataset/0039597

Maps Introduction

Globally, 17 countries reported composting more than 1 Mt each of organic waste in 2018, with India, China, Germany, and France reporting more than 5 Mt each (World Bank, 2018). With the exception of Austria, which composted nearly all organic waste generated, even countries with established centralized composting could divert more organic waste to composting. 

The fate from which composting diverts organic waste varies from region to region, but globally over 40% of all waste ends up in landfills. Since organic waste makes up the largest percentage of MSW in most regions, excluding North America, parts of East Asia and the Pacific, and parts of Europe and Central Asia, there is ample opportunity to increase composting. In East Asia and the Pacific, South Asia, and sub-Saharan Africa, diverting organics to composting also avoids disposal in waterways and open dumps, which reduces pollution. In North America and Europe and Central Asia, 15–20% of MSW is incinerated (Kaza et al., 2018), so diverting all organic waste to composting would avoid harmful incineration emissions including CO, NOx, and VOCs (Abedin et al., 2025; Global Alliance for Incinerator Alternatives, 2019; Liu et al., 2021; Nubi et al., 2024).

Diversion of organic waste requires separation of waste streams, and cities with better collection and tracking networks often have more robust composting programs. Higher quality and more frequent reporting on waste generation and disposal worldwide could improve source separation and increase composting. Additionally, city-level and decentralized pilot programs allow for better control over feedstock collection and can bolster support for larger scale, centralized operations. 

Multiple cities in Latin America and the Caribbean represent a resurgence in composting markets . In the 1960s and 1970s, composting facilities were built in cities across Mexico, El Salvador, Ecuador, Venezuela, and Brazil, but many closed due to high operational costs (Ricci-Jürgensen et al., 2020a). In 2018, 15% of waste was recycled or composted in Montevideo, Uruguay, and Bogotá and Medellín, Colombia, and 10% of waste was composted in Mexico City, Mexico, and Rosario, Argentina (Kaza et al., 2018).  

Waste generation is increasing globally, with the largest increases projected to occur in sub-Saharan Africa, South Asia, and the Middle East and North Africa (Kaza et al., 2018). As waste generation doubles or triples in these regions, sustainable disposal methods will become more critical for human health and well-being. 

In 2018, Ethiopia reported the highest organic waste percentage in sub-Saharan Africa at 85% of MSW, but no composting (World Bank, 2018). Organic waste percentages are high in other countries in the region, so composting could be a valuable method to handle the growing waste stream. In the Middle East & North Africa, 43% of countries reported composting as of 2018 (Kaza et al., 2018), indicating the presence of infrastructure that could be scaled up to handle increased waste in the future.

Action Word
Increase
Solution Title
Centralized Composting
Classification
Highly Recommended
Lawmakers and Policymakers
  • Establish zero waste and OW diversion goals; incorporate them into local or national climate plans and soil health and conservation policies.
  • Ensure public procurement uses local compost when possible.
  • Participate in consultations with farmers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Establish or improve existing centralized composting facilities, collection networks, and storage facilities.
  • Establish incentives and programs to encourage both centralized and decentralized composting.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Invest in source separation education and waste separation technology that enhances the quality of final compost products.
  • Regulate the use of waste separation technologies to prioritize source separation of waste and the quality of compost products.
  • Ensure low- and middle-income households are served by composting programs with particular attention to underserved communities such as multi-family buildings and rural households.
  • Enact extended producer responsibility approaches that hold producers accountable for waste.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Ensure composting plants are placed as close to farmland as possible and do not adversely affect surrounding communities.
  • Streamline permitting processes for centralized compost facilities and infrastructure.
  • Establish laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Establish zoning policies that support both centralized and decentralized composting efforts, including at the industrial, agricultural, community, and backyard scales.
  • Establish fees or fines for OW going to landfills; use funds for composting programs.
  • Use financial instruments such as taxes, subsidies, or exemptions to support infrastructure, participation, and waste separation.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why it’s important.
  • If composting is not possible or additional infrastructure is needed, consider methane digesters as alternatives to composting.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Practitioners
  • Work with policymakers and local communities to establish zero-waste and OW diversion goals for local or national climate plans.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to create quality supply streams and develop markets for compost.
  • Invest in source separation education and waste separation technology that enhances the quality of final compost products.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why that’s important.
  • Ensure low- and middle-income households are served by composting programs with particular attention to underserved communities such as multi-family buildings and rural households.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Ensure composting plants are placed as close to farmland as possible and do not adversely affect surrounding communities.
  • Take advantage of financial incentives such as subsidies or exemptions to set up centralized composting infrastructure, increase participation, and improve waste separation.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Consider partnerships through initiatives such as sister cities to share innovation and develop capacity.
  • If additional infrastructure is needed, consider methane digesters as alternatives to composting.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Business Leaders
  • Establish zero-waste and OW diversion goals; incorporate the goals into corporate net-zero strategies.
  • Ensure procurement uses strategies to reduce FLW at all stages of the supply chain; consider using the Food Loss and Waste Protocol.
  • Ensure corporate procurement and facilities managers use local compost when possible.
  • Participate in consultations with farmers, policymakers, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Offer employee pre-tax benefits on materials to compost at home or participate in municipal composting programs.
  • Offer financial services, including low-interest loans, microfinancing, and grants, to support composting initiatives.
  • Support extended producer responsibility approaches that hold producers accountable for waste.
  • Educate employees on the benefits of composting, include them in companywide waste diversion initiatives, and encourage them to use and advocate for municipal composting in their communities. Clearly label containers and signage for composting.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Nonprofit Leaders
  • Help policymakers establish zero-waste and OW diversion goals; help incorporate them into local or national climate plans.
  • Ensure organizational procurement uses local compost when possible.
  • Help administer, fund, or promote local composting programs.
  • Help gather data on local OW streams, potential markets, and comparisons of alternative uses such as methane digesters.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Help ensure low- and middle-income households are served by composting programs with particular attention to underserved communities such as multi-family buildings and rural households.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Advocate for laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why that’s important.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Investors
  • Ensure relevant portfolio companies separate waste streams, contribute to compost programs, and/or use finished compost.
  • Invest in companies developing composting programs or technologies that support the process, such as equipment, circular supply chains, and consumer products.
  • Fund start-ups or existing companies that are improving waste separation technology that enhances the quality of final compost products.
  • Offer financial services, including low-interest loans, microfinancing, and grants, to support composting initiatives.
  • Invest in companies that adhere to extended producer responsibility or encourage portfolio companies to adopt the policies.

Further information:

Philanthropists and International Aid Agencies
  • Help policymakers establish zero-waste and OW diversion goals; help incorporate them into local or national climate plans.
  • Advocate for businesses to establish time-bound and transparent zero-waste and OW diversion goals.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Provide financing and capacity building for low- and middle-income countries to establish composting infrastructure and programs.
  • Help administer, fund, or promote composting programs.
  • Invest in companies developing composting programs or technologies that support the process, such as equipment, circular supply chains, and consumer products.
  • Fund startups or existing companies that are improving waste separation technology that enhances the quality of final compost products.
  • Incubate and fund mission-driven organizations and cooperatives that are advancing OW composting.
  • Offer financial services, including low-interest loans, microfinancing, and grants, to support composting initiatives.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Help ensure low- and middle-income households are served by composting programs, with particular attention to underserved communities such as multifamily buildings and rural households.
  • Advocate for laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Research and enact effective composting promotional strategies.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why that’s important.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Thought Leaders
  • Participate in and promote centralized, community, or household composting programs, if available, and carefully sort OW from other waste streams.
  • If no centralized composting system exists, work with local experts to establish household and community composting systems.
  • Help policymakers establish zero-waste and OW diversion goals; help incorporate them into local or national climate plans.
  • Start cooperatives that provide services and/or equipment for composting.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Help gather data on local OW streams, potential markets, and comparisons of alternative uses such as methane digesters.
  • Help develop waste separation technology that enhances the quality of final compost products and/or improve educational programs on waste separation.
  • Develop innovative governance models for local composting programs; publicly document your experiences.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Advocate for laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Create, support, or join certification programs that verify the quality of compost.
  • Research various governance models for local composting programs and outline options for communities to consider.
  • Research and enact effective composting campaign strategies.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Technologists and Researchers
  • Quantify estimates of OW both locally and globally; estimate the associated potential compost output.
  • Improve waste separation technology to improve the quality of finished compost.
  • Create tracking and monitoring software for OW streams, possible uses, markets, and pricing.
  • Research the application of AI and robotics for optimal uses of OW streams, separation, collection, distribution, and uses.
  • Research various governance models for local composting programs and outline options for communities to consider.
  • Research effective composting campaign strategies and how to encourage participation from individuals.

Further information:

Communities, Households, and Individuals
  • Participate in and promote centralized composting programs, if available, and carefully sort OW from other waste.
  • If no centralized composting system exists, work with local experts to establish household and community composting systems.
  • Participate in consultations with farmers, policymakers, and businesses to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Take advantage of educational programs, financial incentives, employee benefits, and other programs that facilitate composting.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Advocate for laws or regulations that require waste separation, ensuring the rules are effective and practical.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Sources
Evidence Base

Consensus of effectiveness as a climate solution: High

Composting reduces OW, prevents pollution and GHG emissions from landfilled OW, and creates soil amendments that can reduce the use of synthetic fertilizers (Kaza et al., 2018; Manea et al., 2024). Although we do not quantify carbon sequestration from compost use in this analysis, a full life-cycle analysis that includes application could result in net negative emissions for composting (Morris et al., 2013).

Globally, the waste sector was responsible for an estimated 3.9% of total global GHG emissions in 2023, and solid waste management represented 36% of those emissions (IPCC, 2023; UNEP, 2024). Emissions estimates based on satellite and field measurements from landfills or direct measurements of carbon content in food waste can be significantly higher than IPCC Tier 1-based estimates. Reviews of global waste management estimated that food loss and food waste account for around 6% of global emissions or approximately 2.8 Gt CO₂‑eq/yr (Wilson et al., 2024; Zhu et al., 2023). Facility-scale composting reduces emissions 38–84% relative to landfilling (Perez et al., 2023), and monitoring and managing the moisture content, aeration, and carbon to nitrogen ratios can further reduce emissions (Ayilara et al., 2020).

Unclear legislation and regulation for MSW composting can prevent adoption, and there is not a one-size-fits-all approach to composting (Cao et al., 2023). Regardless of the method used, composting converts OW into a nutrient-rich resource and typically reduces incoming waste volumes 40–60% in the process (Cao et al., 2023; Kaza et al., 2018). A comparative cost and energy analysis of MSW components highlighted that while composting adoption varies geographically and economically, environmental benefits also depend on geography and income (Zaman, 2016). Food and green waste percentages of MSW are higher in lower-resourced countries than in high-income countries due to less packaging, and more than one-third of waste in high-income countries is recovered through recycling and composting (Kaza et al., 2018).

The results presented in this document summarize findings from 22 reports, 31 reviews, 12 original studies, two books, nine web articles, one fact sheet, and three data sets reflecting the most recent evidence for more than 200 countries and territories. 

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Appendix

Global MSW Generation and Disposal

Analysis of MSW in this section is based on the 2018 What a Waste 2.0 global dataset and report as well as the references cited in the report (Kaza et al., 2018; World Bank 2018). In 2018, approximately 2 Gt of waste was generated globally. Most of that went to landfills (41%) and open dumps (22%). Out of 217 countries and territories, 24 sent more than 80% of all MSW to landfills and 3 countries reported landfilling 100% of MSW. The average across all countries/territories was 28% of MSW disposed of in landfills. Both controlled and sanitary landfills with gas capture systems are included in the total landfilled percentage.

Approximately 13% of MSW was treated through recycling and 13% through incineration, but slightly more waste was incinerated than recycled per year. Incineration was predominately used in upper-middle and high-income countries with negligible amounts of waste incinerated in low- and lower-middle income countries.

Globally, only about 5% of MSW was composted and nearly no MSW was processed via methane digestion. However, OW made up nearly 40% of global MSW, so most OW was processed through landfilling, open dumping, and incineration all of which result in significant GHG emissions and pollution. There is ample opportunity to divert more OW from polluting disposal methods toward composting. Due to lack of data on open dumping, and since incineration only accounts for 1% of global GHG emissions, we chose landfilling as our baseline disposal method for comparison.

In addition to MSW, other waste streams include medical waste, e-waste, hazardous waste, and agricultural waste. Global agricultural waste generation in 2018 was more than double total MSW (Kaza et al., 2018). Although these specialized waste streams are treated separately from MSW, integrated waste management systems with high-quality source separation programs could supplement organic MSW with agricultural waste. Rather than being burned or composted on-farm, agricultural waste can provide bulking materials that are critical for maintaining moisture levels and nutrient balance in the compost pile, as well as scaling up composting operations. 

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Details of a Composting System and Process

Successful centralized composting starts with collection and separation of OW from other waste streams, ideally at the source of waste generation. Financial and regulatory barriers can hinder creation or expansion of composting infrastructure. Composting systems require both facilities and robust collection networks to properly separate OW from nonbiodegradable MSW and transport OW to facilities. Mixed waste streams increase contamination risks with incoming feedstocks, so separation of waste materials at the source of generation is ideal. 

Establishing OW collection presents a financial and logistical barrier to increased composting adoption (Kawai et al., 2020; Kaza et al., 2018). However, when considering a full cost-chain analysis that includes collection, transportation, and treatment, systems that rely on source-separated OW can be more cost-effective than facilities that process mixed organics. 

OW and inorganic waste can also be sorted at facilities manually or mechanically with automated techniques including electromagnetic separation, ferrous metal separation, and sieving or screening (Kawai et al., 2020). Although separation can be highly labor-intensive, it’s necessary to remove potential contaminants, such as plastics, heavy metals, glass, and other nonbiodegradable or hazardous waste components (Kawai et al., 2020; Manea et al., 2024). After removing contaminants, organic materials are pre-processed and mixed to achieve the appropriate combination of water, oxygen, and solids for optimal aerobic conditions during the composting process. 

Regardless of the specific composting method used, aerobic decomposition is achieved by monitoring and balancing key parameters within the compost pile. Key parameters are moisture content, temperature, carbon-to-nitrogen ratio, aeration, pH, and porosity (Cao et al., 2023; Kawai et al., 2020; Manea et al., 2024). The aerobic decomposition process can be split into distinct stages based on whether mesophilic (active at 20–40 oC) or thermophilic (active at 40–70 oC) bacteria and fungi dominate. Compost piles are constructed to allow for sufficient aeration while optimizing moisture content (50–60%) and the initial carbon-to-nitrogen ratio (25:1–40:1), depending on composting method and feedstocks (Amuah et al., 2022; Manea et al, 2024). Optimal carbon-to-nitrogen ratios are achieved through appropriate mixing of carbon-rich “brown” materials, such as sawdust or dry leaves, with nitrogen-rich “green” materials, such as food waste or manure (Manea et al., 2024). During the thermophilic stage, temperatures exceeding 62 oC are necessary to kill most pathogens and weed seeds (Amuah et al., 2022; Ayilara et al., 2020).

Throughout the composting process key nutrients (nitrogen, phosphorus, potassium, calcium, magnesium, and sodium), are mineralized and mobilized and microorganisms release GHGs and heat as by-products of their activity (Manea et al., 2024; Nordahl et al., 2023). Water is added iteratively to maintain moisture content and temperature in the optimal ranges, and frequent turning and aeration are necessary to ensure microorganisms have enough oxygen. Without the proper balance of oxygen and water, anaerobic conditions can lead to higher methane emissions (Amuah et al., 2022; Manea et al., 2024). Although CO₂, methane, and nitrous oxide are released during the process, these emissions are significantly lower than associated emissions from landfilling (Ayilara et al., 2020; Cao et al., 2023; FAO, 2019; Perez et al., 2023).

Once aerobic decomposition is completed, compost goes through a maturation stage where nutrients are stabilized before finished compost can be sold or used as a soil amendment. In stable compost, microbial decomposition slows until nutrients no longer break down, but can be absorbed by plants. Longer maturation phases reduce the proportion of soluble nutrients that could potentially leach into soils. 

The baseline waste management method of landfilling OW is cheaper than composting; however it also leads to significant annual GHG emissions. Composting, although more expensive due to higher labor and operating costs, reduces emissions and produces a valuable soil amendment. Establishing a composting program can have significant financial risks without an existing market for finished compost products (Bogner et al., 2007; Kawai et al., 2020; UNEP, 2024).

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Example Calculation of Achievable Adoption

In 2018, Austria had the highest composting rate of 31.2%, and Vietnam composted 15% of MSW (World Bank, 2018). 

For low adoption, we assumed composting increases by 25% of the existing rate or until all OW in MSW is composted. In Austria, OW made up 31.4% of MSW in 2018, so the Adoption – Low composting rate was 31.4%. In Vietnam, the Adoption – Low composting rate came out to 18.75%, which is still less than the total OW percentage of MSW (61.9%).

For high adoption, we assumed that composting rates increase by 50% of the existing rate or until all OW in MSW is composted. So high adoption in Austria remains 31.4% (i.e., all OW generated in Austria is composted). In Vietnam, the high adoption composting rate increases to 22.5% but still doesn’t capture all OW generated (61.9% of MSW).

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Updated Date

Improve Refrigerant Management

Submitted by Drawdown Admin on
Sector
Buildings & Industry
Mode
Cut Emissions
Cluster
Cut Fugitive Emissions
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Refrigerant controls
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Description for Social and Search
The Improve Refrigerant Management solution is coming soon.
Methods and Supporting Data

Methods and Supporting Data

Action Word
Improve
Solution Title
Refrigerant Management
Classification
Highly Recommended
Updated Date

Deploy Industrial Green Hydrogen

Submitted by Drawdown Admin on
Sector
Industry, Materials & Waste
Mode
Cut Emissions
Cluster
Improve Processes
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Industrial Green Hydrogen Feedstock
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Summary

In this solution, green hydrogen replaces fossil fuel–based hydrogen for use as a feedstock in the production of more complex molecules such as ammonia for fertilizers and methanol for the production of other commodity chemicals. Green hydrogen production in this solution uses on-site renewable electricity or off-site renewable electricity that directly supplies the facility. It replaces hydrogen produced from fossil fuels. This solution does not include the use of green hydrogen as a fuel or as a feedstock in the production of hydrogen-based fuels.

Income & work,Health
Water resources,Air quality
Description for Social and Search
Green hydrogen is a Highly Recommended climate solution. It cuts GHG emissions by replacing hydrogen made from fossil fuels for use as an industrial feedstock.
Overview

Green hydrogen in this solution is hydrogen produced from water by electrolysis using renewable electricity generated on-site or directly supplied from an off-site location. It can reduce emissions when replacing hydrogen made from fossil fuels as an industrial feedstock. 

Today, most hydrogen is produced through a chemical reaction of methane or coal with water that generates hydrogen and CO₂. Green hydrogen, made by splitting water into hydrogen and oxygen using electricity generated from renewables, accounts for less than 1% of current production (International Energy Agency [IEA], 2025a). The process of making green hydrogen generates no direct GHGs. Therefore, replacing fossil fuel–derived hydrogen with green hydrogen avoids all direct GHGs from the hydrogen production process. 

Hydrogen prolongs the lifespan and abundance of GHGs in the atmosphere when it leaks, and so can indirectly contribute to climate change. However, because this solution substitutes one source of hydrogen for another, it will have little to no effect on this indirect climate impact. 

The manufacture of industrial hydrogen from fossil fuels for all applications was responsible for 680 Mt of emissions in 2023 (IEA, 2024), nearly all of which could be eliminated by substituting green hydrogen.

In 2023, roughly 60% of industrial feedstock hydrogen was used to produce ammonia, a vital ingredient in nitrogen fertilizers while 30% was used to produce methanol (IEA, 2024), an ingredient in the manufacture of a wide range of chemicals, including plastics, building materials, and car parts (International Renewable Energy Agency [IRENA] & Methanol Institute, 2021). Although alternative low-carbon pathways exist for ammonia and methanol, these are difficult to scale, still under development, or reliant on biomass, which is a finite resource associated with potential land-use change and competing demand (IRENA & Methanol Institute, 2021; Rodriguez, 2025). 

While there are other ways to make low-carbon hydrogen, none has demonstrated potential to cut emissions from hydrogen production as effectively as this solution. For example, harvesting naturally occurring hydrogen is a nascent industry with lots of uncertainties (The Royal Society, 2025), and hydrogen made from biomass must compete for biomass with other hard-to-abate sectors. 

The greatest hurdle to green hydrogen deployment is cost. Green hydrogen is one-and-a-half to six times more expensive to produce than hydrogen from fossil fuels (IEA, 2024). Regulatory and demand uncertainty, licensing and permitting issues, and challenges with operational scale-up are also barriers to green hydrogen projects (IEA, 2024). Nevertheless, production capacity has started to grow: installed electrolyzer capacity doubled in 2023, supported by policies and incentives (Pavan et al., n.d.). 

Ademollo, A., Calabrese, M., & Carcasci, C. (2025). An up-to-date perspective of levelized cost of hydrogen for PV-based grid-connected power-to-hydrogen plants across all Italy. Applied Energy, 379, 124958. Link to source: https://doi.org/10.1016/j.apenergy.2024.124958  

Anand, C., Chandraja, B., Nithiya, P., Akshaya, M., Tamizhdurai, P., Shoba, G., Subramani, A., Kumaran, R., Yadav, K. K., Gacem, A., Bhutto, J. K., Alreshidi, M. A., & Alam, M. W. (2025). Green hydrogen for a sustainable future: A review of production methods, innovations, and applications. International Journal of Hydrogen Energy, 111, 319–341. Link to source: https://doi.org/10.1016/j.ijhydene.2025.02.257  

Cho, H. H., Strezov, V., & Evans, T. J. (2022). Environmental impact assessment of hydrogen production via steam methane reforming based on emissions data. Energy Reports, 8, 13585–13595. Link to source: https://doi.org/10.1016/j.egyr.2022.10.053  

Douglas, M., Trilho, M., & Pellegrinelli, T. (2025). Hydrogen: The outlook to 2050. Wood Mackenzie. Link to source: https://www.woodmac.com/news/opinion/hydrogen-the-outlook-to-2050/  

Du, L., Yang, Y., Bai, X., Xu, S., Lin, L., & Liu, M. (2024). Water scarcity footprint and water saving potential for large-scale green hydrogen generation: Evidence from coal-to-hydrogen substitution in China. Science of The Total Environment, 940, 173589. Link to source: https://doi.org/10.1016/j.scitotenv.2024.173589  

European Parliament, & Council of the European Union. (2023). Directive (EU) 2023/2413 of the European Parliament and of the Council of 18 October 2023 amending directive (EU) 2018/2001, regulation (EU) 2018/1999 and directive 98/70/EC as regards the promotion of energy from renewable sources, and repealing council directive (EU) 2015/652 (No. 2023/2413). Link to source: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L_202302413 

Ganter, A., Lonergan, K. E., Büchi, H. M., & Sansavini, G. (2024). Shifting to low-carbon hydrogen production supports job creation but does not guarantee a just transition. One Earth, 7(11), 1981–1993. Link to source: https://doi.org/10.1016/j.oneear.2024.10.009  

Gasparotto, J., & Da Boit Martinello, K. (2021). Coal as an energy source and its impacts on human health. Energy Geoscience, 2(2), 113–120. Link to source: https://doi.org/10.1016/j.engeos.2020.07.003  

Gulli, C., Heid, B., Noffsinger, J., Waardenburg, M., & Wilthaner, M. (2024). Global energy perspectives 2023: Hydrogen outlook. McKinsey & Company. Link to source: https://www.mckinsey.com/industries/oil-and-gas/our-insights/global-energy-perspective-2023-hydrogen-outlook  

Henneman, L., Choirat, C., Dedoussi, I., Dominici, F., Roberts, J., & Zigler, C. (2023). Mortality risk from United States coal electricity generation. Science, 382(6673), 941–946. Link to source: https://doi.org/10.1126/science.adf4915  

Henriksen, M. S., Matthews, H. S., White, J., Walsh, L., Grol, E., Jamieson, M., & Skone, T. J. (2024). Tradeoffs in life cycle water use and greenhouse gas emissions of hydrogen production pathways. International Journal of Hydrogen Energy, 49, 1221–1234. Link to source: https://doi.org/10.1016/j.ijhydene.2023.08.079  

Hermesmann, M., & Müller, T. E. (2022). Green, turquoise, blue, or grey? Environmentally friendly hydrogen production in transforming energy systems. Progress in Energy and Combustion Science, 90, 100996. Link to source: https://doi.org/10.1016/j.pecs.2022.100996  

International Energy Agency. (2023). Towards hydrogen definitions based on their emissions intensity. Link to source: https://iea.blob.core.windows.net/assets/acc7a642-e42b-4972-8893-2f03bf0bfa03/Towardshydrogendefinitionsbasedontheiremissionsintensity.pdf  

International Energy Agency. (2024). Global hydrogen review 2024. Link to source: https://iea.blob.core.windows.net/assets/89c1e382-dc59-46ca-aa47-9f7d41531ab5/GlobalHydrogenReview2024.pdf 

International Energy Agency. (2025a). Global hydrogen review 2025. Link to source: https://iea.blob.core.windows.net/assets/12d92ecc-e960-40f3-aff5-b2de6690ab6b/GlobalHydrogenReview2025.pdf  

International Energy Agency. (2025b). Hydrogen production and infrastructure projects database March 2025 [Dataset]. Link to source: https://www.iea.org/data-and-statistics/data-product/hydrogen-production-and-infrastructure-projects-database  

International Energy Agency. (2025c). Hydrogen production and infrastructure projects database September 2025 [Dataset]. Link to source: https://www.iea.org/data-and-statistics/data-product/hydrogen-production-and-infrastructure-projects-database  

Irarrazaval, F., Albornoz, C., & Bogolasky, F. (2026). The troubled geography of green jobs: Examining the estimations and expectations of green hydrogen development in regional labor markets in Chile. Applied Geography, 186, 103828. Link to source: https://doi.org/10.1016/j.apgeog.2025.103828 

International Renewable Energy Agency, & Bluerisk. (2023). Water for hydrogen production. Link to source: https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2023/Dec/IRENA_Bluerisk_Water_for_hydrogen_production_2023.pdf  

International Renewable Energy Agency & Methanol Institute. (2021). Innovation outlook: Renewable methanol. International Renewable Energy Agency. Link to source: https://www.methanol.org/wp-content/uploads/2020/04/IRENA_Innovation_Renewable_Methanol_2021.pdf  

Iyer, R. K., Prosser, J. H., Kelly, J. C., James, B. D., & Elgowainy, A. (2024). Life-cycle analysis of hydrogen production from water electrolyzers. International Journal of Hydrogen Energy, 81, 1467–1478. Link to source: https://doi.org/10.1016/j.ijhydene.2024.06.355  

Johnson, N., Liebreich, M., Kammen, D. M., Ekins, P., McKenna, R., & Staffell, I. (2025). Realistic roles for hydrogen in the future energy transition. Nature Reviews Clean Technology, 1(5), 351–371. Link to source: https://doi.org/10.1038/s44359-025-00050-4  

Kim, H., Song, G., & Ha, Y. (2025). Green hydrogen export potential in each Southeast Asian country based on exportable volumes and levelized cost of hydrogen. Applied Energy, 383, 125371. Link to source: https://doi.org/10.1016/j.apenergy.2025.125371  

Li, Y., Hao, J., & Zhou, Y. (2025). Economic analysis of different hydrogen production routes under a CO2 pricing mechanism – A levelized cost of hydrogen based study. International Journal of Hydrogen Energy, 128, 47–67. Link to source: https://doi.org/10.1016/j.ijhydene.2025.04.185  

National Renewable Energy Laboratory. (2021). Life cycle greenhouse gas emissions from electricity generation: update. Link to source: https://docs.nlr.gov/docs/fy21osti/80580.pdf  

Odenweller, A., & Ueckerdt, F. (2025). The green hydrogen ambition and implementation gap. Nature Energy, 10(1), 110–123. Link to source: https://doi.org/10.1038/s41560-024-01684-7  

Paardekooper, S., Lund, H., Chang, M., Nielsen, S., Moreno, D., & Thellufsen, J. Z. (2020). Heat Roadmap Chile: A national district heating plan for air pollution decontamination and decarbonisation. Journal of Cleaner Production, 272, 122744. Link to source: https://doi.org/10.1016/j.jclepro.2020.122744  

Pavan, F., Bermudez, J. M., Pizarro, A., Remme, U., & Blanco, H. (n.d.). Electrolysers. International Energy Agency. Retrieved October 10, 2025 from Link to source: https://www.iea.org/energy-system/low-emission-fuels/electrolysers  

Rodriguez, E. (2025, January 30). Low-carbon ammonia technology: Blue, green, and beyond. Rocky Mountain Institute. Link to source: https://rmi.org/low-carbon-ammonia-technology-blue-green-and-beyond/  

Smolinka, T., Bergmann, H., Garche, J., & Kusnezoff, M. (2022). The history of water electrolysis from its beginnings to the present. In Smolinka & Garche (Eds.), Electrochemical power sources: Fundamentals, systems, and applications (pp. 83–164). Elsevier. Link to source: https://doi.org/10.1016/B978-0-12-819424-9.00010-0  

The Royal Society. (2025). Natural hydrogen: Future energy and resources Policy briefing. Link to source: https://royalsociety.org/-/media/policy/projects/natural-hydrogen/natural-hydrogen-policy-briefing.pdf  

U.S. Department of Energy. (n.d.). Hydrogen production: Electrolysis. Retrieved October 10, 2025, from Link to source: https://www.energy.gov/eere/fuelcells/hydrogen-production-electrolysis  

US Environmental Protection Agency. (2025). Power sector programs—Progress report. Link to source: https://www.epa.gov/power-sector/progress-report  

Vartiainen, E., Breyer, C., Moser, D., Román Medina, E., Busto, C., Masson, G., Bosch, E., & Jäger-Waldau, A. (2022). True cost of solar hydrogen. Solar RRL, 6(5), 2100487. Link to source: https://doi.org/10.1002/solr.202100487  

Credits

Lead Fellow

  • Heather McDiarmid, Ph.D. 

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Nina-Francesca Farac, Ph.D.

  • James Gerber, Ph.D.

  • Amanda D. Smith, Ph.D.

Effectiveness

Our analysis showed that replacing hydrogen made from fossil fuels with green hydrogen made using renewable electricity can reduce 0.012 t CO₂‑eq /kg hydrogen (20-yr and 100-yr basis, Table 1). 

This analysis does not include the emissions associated with manufacturing and installing electrolyzer equipment or the energy and emissions impacts of storing or transporting hydrogen if needed. 

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq /kg green hydrogen, 100-yr basis

25th percentile 0.010
Mean 0.014
Median (50th percentile) 0.012
75th percentile 0.016
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Cost

Our estimates put the levelized cost of making hydrogen (LCOH) from coal and natural gas without any form of carbon emissions capture at US$1.90/kg hydrogen, while we estimated the LCOH of green hydrogen from renewable electricity at US$3.60/kg green hydrogen. LCOH represents the average cost to make a kilogram of hydrogen over the facility’s lifetime and includes all installation, operating, and equity costs. These values are in line with the IEA’s estimate that renewable hydrogen costs one-and-a-half to six times more than unabated fossil-fuel based production (IEA, 2024), with most of the higher cost attributed to the upfront costs (IEA, 2025a). 

The LCOH for green hydrogen shows significant variability, ranging from US$1.40/kg for hydrogen from solar in Chile (Vartiainen et al., 2022) to US$10.60/kg for hydrogen from solar in Italy (Ademollo et al., 2025). This reflects geographic differences in renewable energy generation potential and costs as well as differences in electrolyzer technologies, financing terms, and project scales (Kim et al., 2025; Li et al., 2025). Variation also arises from how renewable electricity is produced. Some modeled green hydrogen LCOH values may be underestimates due to the higher cost of operating electrolyzers at less than full capacity when intermittent renewable generation is used (Ademollo et al., 2025). 

We do not report the cost per climate impact because most of our cost data are based on theoretical values, not real projects, and because LCOH values do not include revenues. 

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Methods and Supporting Data

Methods and Supporting Data

Learning Curve

Our data show a median learning rate of 18% for the electrolyzer technologies used to make green hydrogen (Table 2) based on five studies. In other words, for every doubling of electrolyzer capacity, the equipment costs decrease by 18%. This is a median value for many electrolyzer types, each of which varies in its technological maturity and rate of cost decline. Research is ongoing to reduce the capital cost of electrolyzers, improve the energy efficiency of the process, and increase operational lifetimes of the equipment (U.S. Department of Energy, n.d.). While these studies consistently indicate declining electrolyzer costs with cumulative electrolyzer capacity, IEA (2025a) reported that costs have recently risen, largely due to inflation. 

The fundamental technology for splitting water into hydrogen and oxygen using electricity was developed more than 230 years ago (Smolinka et al., 2022). The process is simple enough that it is used in high school science classes around the world, but more complex equipment is needed to make and collect hydrogen on an industrial scale. 

The production of green hydrogen requires additional equipment beyond electrolyzers, such as renewable power generators, water purification plants, and equipment to process hydrogen, all of which have their own learning rates. 

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Table 2. Learning rate: drop in cost per doubling of installed electrolyzer.

Unit: %

25th percentile 15
Mean 20
Median (50th percentile) 18
75th percentile 24
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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Deploy Industrial Green Hydrogen Feedstock is a GRADUAL climate solution. It has a steady, linear impact on the atmosphere. 

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Caveats

This analysis defines green hydrogen as hydrogen made through electrolysis using onsite renewable electricity. However, many sources only provide data for electrolytic hydrogen, clean hydrogen, or low-carbon hydrogen. Each of these includes green hydrogen but may also include electrolytic hydrogen made using grid electricity, hydrogen made from biomass, or hydrogen made from fossil fuels with carbon capture and storage. We have clearly labeled when the data refer to the more generalized low-carbon electrolytic hydrogen rather than green hydrogen.

Adoption of green hydrogen as a feedstock depends on policy support for green hydrogen, regulations to drive demand for low-carbon end products made from hydrogen (Odenweller & Ueckerdt, 2025), and standardized certification for green hydrogen, including methodologies for GHG emissions monitoring (IEA, 2025a). Regulation and permitting issues can also delay green hydrogen projects and increase overall costs. 

We assumed that manufacture of methanol, ammonia, and other industrial products currently using hydrogen as a feedstock will not shift to new processes (e.g., biological) for their production. We also assumed that naturally occurring hydrogen (sometimes called white hydrogen) and other forms of very-low-carbon hydrogen will not compete with green hydrogen for use as an industrial feedstock. 

Green hydrogen requires a supply of purified water. Removing impurities, minerals, and ions from water has a carbon footprint (Henriksen et al., 2024); that cost is not included in this analysis. 

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Current Adoption

Based on IEA (2025c), we estimate that operational projects are currently making 130 million kg of green hydrogen for use as an industrial feedstock per year (Table 3). This represents less than 1% (55 Mt) of all industrial hydrogen demand in 2024 (IEA, 2025a). It may be an underestimate because we only included projects that we were able to confirm to use on-site renewable electricity or off-site renewable electricity that directly supplies the facility. 

The higher cost of green hydrogen relative to hydrogen made from fossil fuels is a major barrier to adoption, along with uncertain demand and regulatory environments (IEA, 2025a). 

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Table 3. Current (2025) adoption level of green hydrogen as feedstock.

Unit: kg green hydrogen/yr

Estimate (from IEA (2025c)) 130,000,000
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Adoption Trend

The IEA (2025a) has historical data on the production of low-carbon hydrogen using electrolysis for industrial applications; this includes green hydrogen but could also include hydrogen made from grid electricity. The data give an average annual rate of increase of 8.1 million kg/yr electrolytic hydrogen for use as an industrial feedstock and are likely an overestimate for purely green hydrogen (Table 4). Much of the added industrial low-carbon hydrogen from electrolysis was produced in China (IEA, 2025a). 

This rate of adoption is slower than expected; only 7% of anticipated 2023 projects have materialized, owing in part to high costs, limited demand, and lack of supportive policies (Odenweller & Ueckerdt, 2025). However, while there has been a decline overall in hydrogen offtake agreements, more than half of agreements signed are dedicated to the manufacture of ammonia and methanol, the two main industrial products that rely on hydrogen as a feedstock (IEA, 2025a). Between March 2025 and September 2025, the estimated production volume from operational industrial green hydrogen feedstock projects increased from 32 million kg/yr to 130 million kg/yr (data extracted from IEA, 2025b, 2025c).

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Table 4. Low-carbon electrolytic hydrogen as feedstock, 2021–2024 adoption trend.

Unit: kg low-carbon electrolytic hydrogen/yr/yr

Estimate (from IEA 2025a) 8,100,000
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Adoption Ceiling

Current demand for hydrogen as an industrial feedstock is 50 billion kg/yr (Table 5), all of which technically could be supplied with green hydrogen. This value is based on the IEA (2025a)’s estimate of 2024 industrial hydrogen demand, with 90% allocated to its use as a feedstock for ammonia and methanol production. Since demand for industrial hydrogen for ammonia production increased by 3.4% and for methanol production by 2.0% in 2023 (IEA, 2025a), the actual adoption ceiling will increase as the production of industrial hydrogen increases. 

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Table 5. Green hydrogen as a feedstock adoption ceiling.

Unit: kg green hydrogen/yr

Estimate (from IEA 2025a) 50,000,000,000
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Achievable Adoption

We estimated that 26–50 billion kg/yr of fossil-based hydrogen could be replaced with green hydrogen as an industrial feedstock by 2050, which is 53–100% of today’s total demand (Table 6).

The Achievable – Low adoption level is an average of McKinsey & Company and Wood Mackenzie’s estimated percent of hydrogen supplied by “clean” or “low-carbon” hydrogen in 2050, which presumably includes hydrogen made from fossil fuels with capture of carbon emissions (Douglas et al., 2025; Gulli et al., 2024). Wood Mackenzie projects that only 33% of traditional carbon-intensive hydrogen will be replaced with low-carbon hydrogen, while McKinsey & Company expects at least 73% of hydrogen demand to be met with clean hydrogen. These estimates may be low, given that the EU has committed to deriving 42% of industrial hydrogen from renewable sources by 2030 and 60% by 2035 (European Parliament & Council of the European Union, 2023). 

The Achievable – High adoption level is set at 100% of today’s industrial feedstock hydrogen, consistent with McKinsey & Company’s upper-end projection that all hydrogen demand could be met by clean hydrogen by 2050 (Gulli et al., 2024). 

Table 6. Green hydrogen as a feedstock range of achievable adoption levels (kg hydrogen/yr).

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Table 6. Green hydrogen as a feedstock range of achievable adoption levels.

Unit: kg green hydrogen/yr

Current adoption 130,000,000
Achievable – low 26,000,000,000
Achievable – high 50,000,000,000
Adoption ceiling 50,000,000,000
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Current adoption of green hydrogen as an alternative is too low to have a globally meaningful climate impact (less than 0.002 Gt CO₂‑eq/yr estimated on both 20- and 100-year basis). We estimate that green hydrogen could reduce 0.31 Gt CO₂‑eq/yr (100- and 20-year basis) of emissions at the Achievable – Low level and 0.60 Gt CO₂‑eq/yr (100- and 20-year basis) at the Achievable – High level (Table 7). This outcome is closely aligned with the IEA’s estimate that in 2023, industrial hydrogen use was responsible for 680 Mt CO₂‑eq/yr, 90% (0.61 Gt CO₂‑eq/yr ) of which is used as a feedstock for ammonia and methanol production (IEA, 2024). 

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Table 7. Green hydrogen as a feedstock climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current adoption 0.00
Achievable – low 0.31
Achievable – high 0.60
Adoption ceiling 0.60
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Additional Benefits

Income and Work

Research on the direct linkages of green hydrogen with employment is limited; however, the development and adoption of this technology is expected to create jobs (Anand et al., 2025). One study of the expansion of green hydrogen in Europe projected that by 2050, shifting to low-carbon hydrogen would directly create 18,000–50,000 jobs (Ganter et al., 2024). This is mostly driven by the higher labor demand of the electrolysis process. Some jobs associated with green hydrogen are in the construction sector and would not be permanent (Irarrazaval et al., 2026).

Health

Reducing air pollution by switching from fossil fuels to renewable energy decreases exposure to pollutants such as lead and fine particulate matter generated when hydrogen is made from fossil fuels, thereby improving the health of nearby communities (Cho et al., 2022; U.S. Environmental Protection Agency [U.S. EPA], 2025). These pollutants have been linked to increased morbidity from cardiovascular and respiratory disease, asthma, infections, and cancer (Gasparotto & Martinello, 2021) and to increased risk of premature mortality (Henneman et al., 2023).

Water Resources

Green hydrogen production is more water-efficient than most other types of hydrogen production, but water resource benefits can vary based on geography and renewable energy source (IRENA & Bluerisk, 2023; Du et al., 2024).

Air Quality

Displacing fossil fuel–based hydrogen with renewable energy–based hydrogen will reduce climate and air pollutants associated with burning higher-carbon fuels, such as CO₂, nitrogen oxides, methane, lead, and fine particulate matter (Anand et al., 2025; Cho et al., 2022; Paardekooper et al., 2020; U.S. EPA, 2025).

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Risks

Investments in green hydrogen policies and programs to support its use as a feedstock can also support its use as a fuel. Many potential applications for green hydrogen as a fuel, however, are less practical, cost-effective, and efficient than direct electrification, and investments in green hydrogen infrastructure risk diverting efforts away from these better alternatives (Johnson et al., 2025). 

Green hydrogen production requires a water supply. Many existing and planned green hydrogen projects are in water-stressed regions, including China, India, the Gulf States, and parts of the European Union (IRENA & Bluerisk, 2023). However, hydrogen production by other processes also requires a water supply and can exceed the water demand for green hydrogen (Henriksen et al., 2024). 

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Interactions with Other Solutions

Competing

Methanol made from industrial green hydrogen could compete with biomass-derived methanol, a product of the Deploy Low-Emission Industrial Feedstocks solution, thereby reducing that solution’s impact. 

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Dashboard

Solution Basics

kg of hydrogen produced

t CO₂-eq (100-yr)/unit/yr
00.010.012
units/yr
Current 1.3×10⁸ 02.6×10¹⁰5.0×10¹⁰
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0 0.310.6
Gradual

CO₂ ,CH₄, N₂O, BC

Trade-offs

There are embodied emissions associated with manufacturing and installing any industrial equipment, including the equipment used to make hydrogen of all kinds and renewable energy. Such emissions are not included in the analysis here, but they can be significant and their value depends on a variety of factors (Hermesmann & Müller, 2022; Iyer et al., 2024, National Renewable Energy Laboratory [NREL], 2021).

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Action Word
Deploy
Solution Title
Industrial Green Hydrogen
Classification
Highly Recommended
Lawmakers and Policymakers
  • Evaluate and implement green hydrogen feedstock proposals and policies independently of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Before approval, conduct thorough reviews of project proposals to ensure statistical rigor and feasibility of business plans; consider requiring beneficiaries of public incentives to have offtake agreements in place; create legal tools to claw back financial incentives if products fail to achieve targeted emissions intensities.
  • Ensure laws and regulations related to green hydrogen use as a feedstock are data-driven and adaptive with short review cycles to remain timely and relevant to the markets; avoid delays leading to loss of investments and project failures.
  • Use both demand- and supply-side interventions to help create stable markets for products made from green hydrogen, ensuring those products are suitable uses for green hydrogen given the alternatives available.
  • Seek to streamline permitting processes while aligning regulations with social and environmental safeguards.
  • Set into place policies to develop strong domestic renewable energy industries concurrently with policies promoting green hydrogen as a feedstock.
  • Offer incentives to relevant actors such as subsidies, grants, guarantees, concessional finance, public investments, tax credits, and contracts for difference for green hydrogen production for use as a feedstock and their derivatives; as the market matures and becomes competitive, gradually reduce these incentives to create long-term market stability.
  • Set into place demand-side policies such as sectoral quotas and mandates for products such as ammonia and methanol made with green hydrogen, but avoiding subsidies for uses that are better served by other low-carbon solutions.
  • Create or improve robust certification schemes for green hydrogen; include clear governance models, standards for how hydrogen would be tested, systems and timelines for evaluation, and enforcement and verification mechanisms.
  • Set deadlines for the retirement of fossil-fuel hydrogen plants for ammonia and methanol production.
  • Work with industry to develop domestic and/or diverse supply chains for electrolyzers and related components.
  • Help establish robust certification systems for low-carbon versions of common hydrogen products such as ammonia and methanol; develop information campaigns to help foster demand.
  • Design incentives and policies to stimulate local or regional production and advance R&D – particularly, to reduce costs and boost efficiency of commercial-scale electrolyzers.
  • Carefully conduct water supply and stress analyses for potential green hydrogen production sites to determine the impact a plant might have on the surrounding communities before approving; require green hydrogen facilities to regularly report on water use metrics.
  • Seek to locate green hydrogen plants near end users to facilitate transport and reduce costs.
  • Implement carbon taxes and remove subsidies from fossil fuel hydrogen.
  • Create regulations that limit the potential for hydrogen leaks and institute monitoring systems to reduce and/or eliminate leakage from infrastructure.
  • Consider creating market platforms and digital product passports that coordinate supply and demand and facilitate uptake for products made with green hydrogen such as ammonia and methanol.

Further information:

Practitioners
  • Design green hydrogen feedstock proposals independent of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Stay abreast of policies, regulations, developments to the enabling infrastructure, and the cost-competitiveness of green hydrogen to ensure your company is well positioned to take advantage of incentives, stays in compliance, and is able to respond to changing market conditions.
  • Take advantage of government incentives such as subsidies, grants, guarantees, concessional loans, public investments, tax credits, and contracts for difference; as the market matures and becomes competitive, gradually reduce your reliance on these incentives to create long-term market stability.
  • Take advantage of demand-side policies such as sectoral quotas and mandates.
  • Consider using green bonds to finance public projects or to de-risk markets.
  • Seek long-term flexible offtake agreements with both public and private actors; aim to establish the agreement before seeking publicly offered financial incentives.
  • Carefully conduct water supply and stress analyses for potential green hydrogen production sites to determine the impact a plant might have on the surrounding communities before approving; regularly report on water use metrics.
  • Seek to locate green hydrogen feedstock plants near end users to facilitate transport and reduce costs.
  • Identify and help foster markets in which consumers are willing to pay a premium for low-emissions products made from green hydrogen.
  • Establish programs to detect and repair leaks; invest in R&D to better detect, mitigate, and repair leaks.
  • Ensure project proposals are data-driven and statistically rigorous; do not announce green hydrogen feedstock projects prematurely or without commitments to follow through.
  • Join, help create, or improve existing certification schemes for green hydrogen, include clear governance models, standards for how hydrogen would be tested, systems and timelines for evaluation, and enforcement and verification mechanisms; voluntarily certify your operations if it is not required.
  • Commit to transparent business practices and provide publicly available data on aspects of production such as emissions intensity, cost, compliance, product life cycle, and other relevant components to facilitate policy and investment; help create open databases for hydrogen producers to share this information; verify data with third-party auditors.
  • Work with policymakers to develop domestic and/or diverse supply chains for electrolyzers and related components.
  • Invest in R&D, particularly to reduce costs and boost efficiency of commercial-scale electrolyzers.
  • Regularly monitor impacts of production facilities, – especially when using seawater for cooling, to minimize risks and harms to human well-being and/or nature.
  • Help standardize analysis for life-cycle impacts of green hydrogen to improve global comparisons.
  • Voluntarily use market platforms and digital product passports to coordinate supply and demand and facilitate uptake for products made with green hydrogen, such as ammonia and methanol.

Further information:

Business Leaders
  • Evaluate and implement green hydrogen feedstock proposals and policies independently of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Set realistic goals for green hydrogen as a feedstock, if relevant; incorporate them into corporate net-zero strategies.
  • Enter into long-term offtake agreements with green hydrogen producers or manufacturers that use green hydrogen; consider forming consortia to allow offtakers to act as equity partners.
  • Help cultivate demand by advertising the use of green hydrogen in your products, including end-use products such as food grown with fertilizers produced by green hydrogen.
  • Seek to de-risk green hydrogen production by investing in domestic and/or diverse supply chains, supportive infrastructure, and related equipment such as renewable energy production.
  • Take advantage of government incentives such as tax credits, if possible; seek to gradually reduce reliance on these incentives to create long-term market stability.
  • Join, help create, or improve existing certification schemes for green hydrogen, include clear governance models, standards for how hydrogen would be tested, systems and timelines for evaluation, and enforcement and verification mechanisms; voluntarily certify your operations and supply chain if certification is not required.

Further information:

Nonprofit Leaders
  • Propose green hydrogen feedstock programs and policies independent of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Operate or help with equipment testing and certification systems, market information disclosures, and onsite monitoring.
  • Urge governments to set into place long-term regulations, using both demand- and supply-side interventions to help create stable markets for products made from green hydrogen; when possible, urge policymakers to align regulations with international standards to facilitate trade – particularly for equipment needed to produce green hydrogen.
  • Advocate for policies that develop strong domestic renewable energy industries concurrently with policies promoting green hydrogen as a feedstock.
  • Join, help create, or improve existing certification schemes for green hydrogen, include clear governance models, standards for how hydrogen would be tested, systems and timelines for evaluation, and enforcement and verification mechanisms.
  • Advocate for financial incentives and favorable policies for products such as ammonia and methanol made from green hydrogen; urge policymakers to gradually reduce subsidies and replace them with market mechanisms such as fixed pricing or contracts for difference as the market matures.
  • Advocate for deadlines for the retirement of fossil-fuel hydrogen plants.
  • Help establish robust certification systems for common products such as ammonia and methanol; develop information campaigns to help foster demand.
  • Advocate for public incentives and policies to advance R&D, particularly to reduce costs and boost efficiency of commercial-scale electrolyzers; carry out open-access research on relevant topics to improve adoption, safety, cost, and efficiency.
  • Conduct water supply and stress analyses for potential green hydrogen production sites to determine the impact a plant might have on the surrounding communities.
  • Regularly monitor impacts of production facilities, especially when using seawater for cooling, to minimize risks and harms to human well-being and/or nature.
  • Advocate for carbon taxes and the removal of subsidies from fossil fuel hydrogen.
  • Create requirements, standards, and programs for digital product passports that coordinate supply and demand and facilitate uptake for products such as ammonia and methanol made with green hydrogen.

Further information:

Investors
  • Invest in green hydrogen feedstock projects independently of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Invest directly in the development of green hydrogen feedstock projects.
  • Offer low-interest loans, guarantees, and concessional financing for manufacturers, developers, and operators of green hydrogen feedstock projects; extend these investments to related technology such as renewable energy and water purification; offer these investments to products such as ammonia and methanol made from green hydrogen feedstock.
  • Directly invest in companies that produce end-use products such as food produced with fertilizers made from green hydrogen.
  • Invest in R&D, component technology, and related science, especially in areas that reduce costs, boost efficiency, improve longevity, and decrease material inputs; invest in projects or companies that improve the modularity for electrolyzers and related components to improve mass production.
  • Help de-risk green hydrogen feedstock production in low- and middle-income countries by offering low-interest loans, concessional financing, and/or favorable terms.
  • Align investments with existing voluntary agreements or voluntary guidance that might apply in the location of the investment (including those that apply to biodiversity).

Further information:

Philanthropists and International Aid Agencies
  • Provide financing directly for the development of green hydrogen feedstock projects and ensure they are independent of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Help de-risk green hydrogen feedstock production in low- and middle-income countries (LMICs) by offering grants or access to concessional financing for green hydrogen feedstock production.
  • Offer similar grants and financing for related technologies such as renewable energy and water purification; offer the same support for production of end-use products such as ammonia and methanol.
  • Operate or support efforts for equipment testing and certification systems, market information disclosures, and onsite monitoring.
  • Enter into long-term offtake agreements with manufacturers that use green hydrogen.
  • Urge governments to set into place long-term regulations, using both demand- and supply-side interventions to help create stable markets for products of green hydrogen; when possible, urge policymakers to align regulations with international standards to facilitate trade – particularly for equipment needed to produce green hydrogen.
  • Advocate for policies that develop strong domestic renewable energy industries concurrently with policies promoting green hydrogen as a feedstock.
  • Join, help create, or improve existing certification schemes for green hydrogen, include clear governance models, standards for how hydrogen would be tested, systems and timelines for evaluation, and enforcement and verification mechanisms.
  • Advocate for financial incentives and favorable policies for equipment needed to produce green hydrogen such as renewable power generators and water purification plants.
  • Advocate for financial incentives and favorable policies for products such as ammonia and methanol made from green hydrogen; urge policymakers to gradually reduce subsidies and replace them with market mechanisms such as fixed pricing or contracts for difference as the market matures.
  • Advocate for deadlines for the retirement of fossil-fuel hydrogen plants.
  • Help establish robust certification systems for common products such as ammonia and methanol; develop information campaigns to help foster demand.
  • Advocate for public incentives and policies to advance R&D, particularly to reduce costs and boost efficiency of commercial-scale electrolyzers; carry out open-access research on relevant topics to improve adoption, safety, cost, and efficiency.
  • Fund projects that provide water supply and stress analysis for potential green hydrogen production sites to determine the impact a plant might have on the surrounding communities.
  • Provide funding or assistance to projects that regularly monitor impacts of production facilities, especially when using seawater for cooling, to minimize risks and harms to human well-being and/or nature.
  • Advocate for carbon taxes and the removal of subsidies from fossil-fuel hydrogen.
  • Help establish international standards for measuring hydrogen leaks and help collect related data.
  • Create requirements, standards, and programs for digital product passports that coordinate supply and demand and facilitate uptake of products made with green hydrogen such as ammonia and methanol.

Further information:

Thought Leaders
  • Promote green hydrogen feedstock programs and policies independently of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Operate or help with equipment testing and certification systems, market information disclosures, and onsite monitoring.
  • Urge governments to set into place long-term regulations, using both demand- and supply-side interventions to help create stable markets for products of green hydrogen; when possible, urge policymakers to align regulations with international standards to facilitate trade – particularly for equipment needed to produce green hydrogen.
  • Advocate for policies that develop strong domestic renewable energy industries concurrently with policies promoting green hydrogen as a feedstock.
  • Join, help create, or improve existing certification schemes for green hydrogen, include clear governance models, standards for how hydrogen would be tested, systems and timelines for evaluation, and enforcement and verification mechanisms.
  • Advocate for financial incentives and favorable policies for equipment needed to produce green hydrogen feedstocks such as renewable power generators and water purification plants.
  • Advocate for financial incentives and favorable policies for products such as ammonia and methanol made from green hydrogen; urge policymakers to gradually reduce subsidies and replace them with market mechanisms such as fixed pricing or contracts for difference as the market matures.
  • Advocate for deadlines for the retirement of fossil-fuel hydrogen plants.
  • Help establish robust certification systems for common products such as ammonia and methanol; develop information campaigns to help foster demand.
  • Advocate for public incentives and policies to advance R&D, particularly to reduce costs and boost efficiency of commercial-scale electrolyzers; carry out open-access research on relevant topics to improve adoption, safety, cost, and efficiency.
  • Advocate for and/or conduct water supply and stress analysis for potential green hydrogen production sites and advocate for measures to avoid or redress harm to surrounding communities.
  • Regularly monitor impacts of production facilities, especially when using seawater for cooling, to minimize risks and harms to human well-being and/or nature.
  • Advocate for carbon taxes and removal of subsidies from fossil-fuel hydrogen.
  • Help standardize analysis for life-cycle impacts of green hydrogen to improve global comparisons.
  • Create requirements, standards, and programs for digital product passports that coordinate supply and demand and facilitate uptake for products such as ammonia and methanol made with green hydrogen.

Further information:

Technologists and Researchers
  • Develop electrolyzer technology for commercial-scale equipment to reduce costs, boost efficiency, improve longevity, and decrease material inputs; help improve modularity for electrolyzers and related components to improve mass production.
  • Improve cooling technology to increase water efficiency, reduce costs, and mitigate impacts on human well-being and the environment.
  • Develop and further improve upon air-cooling technologies.
  • Develop more sensitive leak detection equipment to identify smaller leaks that often go undetected by current technology.

Further information:

Communities, Households, and Individuals
  • Promote green hydrogen feedstock programs and policies independently of other green hydrogen solutions, such as green hydrogen fuels (see Mobilize Green Hydrogen for Aviation and Trucking).
  • Advocate for thorough reviews of project proposals to ensure statistical rigor and feasibility of business plans; consider requiring beneficiaries of public incentives to have offtake agreements in place; suggest legal tools to claw back financial incentives if products fail to achieve targeted emissions intensities.
  • Advocate for policies that develop strong domestic renewable energy industries concurrently with policies promoting green hydrogen as a feedstock.
  • Advocate for financial incentives and favorable policies for equipment needed to produce green hydrogen such as renewable power generators and water purification plants.
  • Advocate for deadlines for the retirement of fossil-fuel hydrogen plants.
  • Advocate for carbon taxes and removal of subsidies for fossil fuel hydrogen.

Further information:

Sources
Evidence Base

Consensus of effectiveness in reducing emissions: High

Green hydrogen that replaces fossil fuel–based hydrogen is widely regarded as an important approach for reducing emissions from this industrial feedstock. Blue hydrogen, made from fossil fuels with carbon capture and storage, competes with green hydrogen as a feedstock. However, incomplete carbon capture alongside methane leaks from natural gas extraction and transportation give blue hydrogen a notably higher carbon footprint (IEA, 2023). 

The IEA publishes an annual report on global hydrogen, including updates to global demand for hydrogen by sector, production routes, trade, investments, and policies (IEA, 2024, 2025a). These reports highlight how low-carbon electrolytic hydrogen production is increasing, albeit at a slower pace than previously expected. With 65 countries now having a hydrogen strategy and new policies being implemented in key regions, low-carbon hydrogen demand is expected to grow, with most new investments focused on low-carbon hydrogen as an industrial feedstock. 

Accelerating this growth is critically important to meet established GHG emission targets. Odenweller and Ueckerdt (2025) highlighted how plans for green hydrogen should focus on hard-to-electrify sectors, including industrial hydrogen feedstocks. They also emphasized the need for policymakers to use demand-side policies such as quotas and mandates along with developing plans to transition subsidies to market mechanisms such as fixed pricing mechanisms for green hydrogen and contracts for difference. 

The results presented in this document summarize findings from four reviews and meta-analyses, two databases, three reports, and 11 original studies reflecting current evidence from 10 countries, primarily China and the United States. We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Updated Date

Increase Industrial Electrification

Submitted by Drawdown Admin on
Sector
Industry, Materials & Waste
Mode
Cut Emissions
Cluster
Improve Processes
Image
Industrial electrification
Coming Soon
On
Description for Social and Search
The Increase Industrial Electrification solution is coming soon.
Methods and Supporting Data

Methods and Supporting Data

Action Word
Increase
Solution Title
Industrial Electrification
Classification
Highly Recommended
Updated Date

Deploy Low-Emission Industrial Feedstocks

Submitted by Drawdown Admin on
Sector
Industry, Materials & Waste
Mode
Cut Emissions
Cluster
Improve Materials
Image
Low-emission industrial feedstocks
Coming Soon
On
Description for Social and Search
The Deploy Low-Emission Industrial Feedstocks solution is coming soon.
Methods and Supporting Data

Methods and Supporting Data

Action Word
Deploy
Solution Title
Low-Emission Industrial Feedstocks
Classification
Highly Recommended
Updated Date

Improve Other Building Materials

Submitted by Drawdown Admin on
Sector
Industry, Materials & Waste
Mode
Cut Emissions
Cluster
Improve Materials
Image
Peatland
Coming Soon
On
Description for Social and Search
The Improve Other Building Materials solution is coming soon.
Methods and Supporting Data

Methods and Supporting Data

Action Word
Improve
Solution Title
Other Building Materials
Classification
Highly Recommended
Updated Date

Deploy Alternative Refrigerants

Submitted by Drawdown Admin on
Sector
Buildings & Industry
Mode
Cut Emissions
Cluster
Improve Materials
Image
Supermarket refrigerator
Coming Soon
Off
Summary

This solution involves reducing the use of high-global warming potential (GWP) refrigerants, instead deploying lower-GWP refrigerants. High-GWP (>800 on a 100-yr basis) fluorinated gases (F-gases) are currently used as refrigerants in refrigeration, air conditioning, and heat pump systems. Over the lifetime of this equipment, refrigerants escape into the atmosphere where they contribute to climate change. 

Leaked lower-GWP refrigerant gases trap less heat in the atmosphere than do higher-GWP gases, so using lower-GWP gases reduces the climate impact of refrigerant use. In our analysis, this solution is only deployed as new equipment replaces decommissioned equipment because alternative refrigerants cannot typically be retrofitted into existing systems.

Income & work
Land resources,Air quality
Description for Social and Search
Deploy Alternative Refrigerants is a Highly Recommended climate solution. Many refrigerants are potent greenhouse gases. Alternatives can reduce climate impacts.
Overview

Refrigerants are chemicals that can absorb and release heat as they move between gaseous and liquid states under changing pressure. In this solution, we considered their use in six applications: residential, commercial, industrial, and transport refrigeration as well as stationary and mobile air conditioning. Heat pumps double as heating sources, though they are included here with air conditioning appliances. Refrigerants are released to the atmosphere during manufacturing, transport, installation, operation, repair, and disposal of refrigerants and equipment. Deploy Alternative Insulation Materials covers the use of refrigerant chemicals to produce foams.

Climate impacts of emissions of refrigerants can be reduced by:

  • using lower-GWP refrigerants
  • reducing leaks during equipment manufacturing, transport, installation, use, and maintenance
  • reclaiming refrigerant at end-of-life and destroying or recycling it
  • using less refrigerant through efficiency improvements or reduction in demand.

This solution evaluated the use of lower-GWP refrigerants alone. Leak reduction and responsible disposal are covered in Improve Refrigerant Management. Lowering use of and demand for refrigerants – while outside the scope of these assessments – is the most effective way to reduce emissions.

Most refrigerants used in new equipment today are a group of F-gases called hydrofluorocarbons (HFCs) (Figure 1). HFCs are GHGs and are typically hundreds to thousands of times more potent than CO₂  (Smith et al., 2021). Since high-GWP refrigerants are usually short-lived climate pollutants, their negative climate impacts tend to be concentrated in the near term (Shah et al., 2015). High-GWP HFC production and consumption are being phased down under the Kigali Amendment to the Montreal Protocol, but existing stock and production remains high worldwide (Amendment to the Montreal Protocol on Substances That Deplete the Ozone Layer, 2016; United Nations Framework Convention on Climate Change [UNFCCC], 2023). Other types of refrigerants that deplete the ozone layer – including chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) — are also being phased out of new production and use globally (Montreal Protocol on Substances That Deplete the Ozone Layer, 1987; Figure 1).

Figure 1. Examples of common refrigerants and their climate and environmental impacts

High-GWP: red; Medium-GWP: yellow; Low-GWP: green

Type GWP
(20-yr)		 GWP
(100-yr)		 Lifetime
(yr)		 Ozone
Depleting?		 PFAS? Safety
Class*
R11CFC8,3206,23052YesA1
R12CFC12,70012,500102YesA1
R22HCFC5,6901,96011.9YesA1
R141bHCFC2,7108609.4Yes
R125HFC6,7403,74030NoYesA1
R134aHFC4,1401,53014NoYesA1
R143aHFC7,8405,81051NoYesA2L
R404AHFC
blend		7,2084,728NoYesA1
R407CHFC
blend		4,4571,908NoYesA1
R410AHFC
blend		4,7152,256NoYesA1
R452AHFC/HFO
blend		4,2732,292NoYesA1
R32HFC2,6907715.4NoNoA2L
R452BHFC/HFO
blend		2,275779NoYesA2L
R454AHFC/HFO
blend		943270NoYesA2L
R513AHFC/HFO
blend		1,823673NoYesA1
R290
(Propane)		Natural0.0720.020.036NoNoA3
R600a
(Isobutane)		Natural< 1< 10.019NoNoA3
R717
(Ammonia)		Natural< 1< 1< 1NoNoB2L
R744
(CO₂)		Natural11NoNoA1
R1234yfHFO1.810.5010.033NoYesA2L
R1234ze(E)HFO4.941.370.052NoYesA2L

*Safety classes based on ASHRAE Standard 34: 

A1: non-flammable, lower toxicity

A2L: lower flammability, lower toxicity

A3: higher flammability, lower toxicity

B2L: lower flammability, higher toxicity

 

Sources:

Baha, M., & Dupont, J.-L. (2023, September 15). Global warming potential (GWP) of HFC refrigerants. International Institute of Refrigeration. 

Behringer, D., Heydel, F., Gschrey, B., Osterheld, S., Schwarz, W., Warncke, K., Freeling, F., Nödler, K., Henne, S., Reimann, S., Blepp, M., Jörß, W., Liu, R., Ludig, S., Rüdenauer, I., & Gartiser, S. (2021). Persistent degradation products of halogenated refrigerants and blowing agents in the environment: Type, environmental concentrations, and fate with particular regard to new halogenated substitutes with low global warming potential. Final report. Umweltbundesamt [German Environment Agency]. 

Burkholder, J. B., Hodnebrog, Ø., McDonald, B. C., Orkin, V., Papadimitriou, V. C., & Van Hoomissen, D. (2023). Annex: Summary of abundances, lifetimes, ODPs, REs, GWPs, and GTPs. Scientific Assessment of Ozone Depletion 2022. 

Garry, M. (2021, June 23). Certain HFCs and HFOs are in PFAS group that five EU countries intend to restrict. 

Smith, C., Nicholls, Z. R. J., Armour, K., Collins, W., Forster, P., Meinshausen, M., Palmer, M. D., & Watanabe, M. (2021). The Earth’s energy budget, climate feedbacks, and climate sensitivity supplementary material. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. 

Trevisan, T. (2023, July 3). Overview of PFAS refrigerants used in HVAC&R and relevance of refrigerants in the PFAS Restriction Intention. UN Montreal Protocol 45th OEWG, Bangkok. 

United Nations Environment Programme. (2023). Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee: 2022 assessment report. 

United Nations Environment Programme & ASHRAE. (2025). Update on new refrigerants designations and safety classifications June 2025. 

In this solution, production and consumption of high-GWP refrigerants (which we defined as GWP>800, 100-yr basis) are avoided by the use of lower-GWP refrigerants in new equipment. These alternative refrigerants can still leak to the atmosphere, but their heat-trapping effect is much lower. Some promising alternatives have low GWPs (<5, 100-yr basis), including some hydrofluoroolefins (HFOs) as well as natural refrigerants, which include CO₂, ammonia, propane, and isobutane. (Figure 1). However, the adoption of these low-GWP refrigerants comes with challenges, including flammability, cost, building codes, and technical limitations (see Risks and Take Action sections below).

Refrigerants with medium GWPs (<800, 100-yr basis; <2,700, 20-yr basis (Smith et al., 2021)) can also be near-term alternatives that increase adoption while providing a climate benefit. In our analysis, we separately considered medium-GWP alternatives in applications where low-GWP alternatives are less common (Figure 2).

Figure 2. Alternative refrigerants used to calculate the low-GWP and medium-GWP scenarios. The low-GWP scenario assumed equipment using high-GWP refrigerants is replaced at end-of-life with equipment using alternative refrigerants with GWP<5. The medium-GWP calculations assumed GWP<800 (100-yr basis) and GWP<2,700 (20-yr basis) alternatives in applications where low-GWP replacements are currently less common (commercial refrigeration, transport refrigeration, stationary air conditioning) and assumed low-GWP replacements for the remaining applications where they are more developed technologies (residential refrigeration, industrial refrigeration, mobile air conditioning). The alternative refrigerants in the table are used for effectiveness and/or cost calculations. 

Application Scenario 1: Low-GWP only
(low GWP: < 5, 100-year basis) 		Scenario 2: Medium-GWP when low-GWP alternatives are less common, otherwise low-GWP
(medium GWP: < 800, 100-year basis)
Residential refrigeration Isobutane
Commercial refrigeration Propane, CO₂ Medium-GWP HFC and HFO blends
Industrial refrigeration Ammonia, CO₂, propane
Transport refrigeration Propane, propene, ammonia, CO₂,
low-GWP HFOs		 Medium-GWP HFC and HFO blends
Mobile air conditioning CO₂, low-GWP HFOs
Stationary air conditioning Propane, CO₂,
ammonia, low-GWP HFOs		 Medium-GWP HFC and HFO blends

Sources:

Purohit, P., & Höglund-Isaksson, L. (2017). Global emissions of fluorinated greenhouse gases 2005–2050 with abatement potentials and costs. Atmospheric Chemistry and Physics, 17(4), 2795–2816. 

Sustainable Purchasing Leadership Council Climate Friendly Refrigerant Action Team. (2021). Recommendations for climate friendly refrigerant management and procurement. 

United Nations Environment Programme. (2023). Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee: 2022 assessment report. 

United Nations Framework Convention on Climate Change. (2023). National inventory submissions, Annex 1 parties [Data set]. 

U.S. Environmental Protection Agency. (2011). Transitioning to low-GWP alternatives in transport refrigeration. 

There is currently no single refrigerant that perfectly fits the climate, safety, and performance requirements for all applications. Instead, the optimal alternative refrigerant will vary depending on equipment type and location (United Nations Environment Programme [UNEP], 2023). 

Generating electricity to run heating, ventilation, air conditioning, and refrigeration (HVAC&R) equipment also produces high levels of emissions (mostly CO₂ ) at power plants – more than twice the emissions from direct release of refrigerants (United Nations Development Programme [UNDP], 2022). Using alternative refrigerants can impact efficiency, changing these electricity-related emissions. However, indirect emissions are not quantified in this solution.

Air-Conditioning, Heating, and Refrigeration Institute. (n.d.-a). A2L refrigerant building code map - Canada. Link to source: https://www.ahrinet.org/a2l-refrigerant-building-code-map-canada 

Air-Conditioning, Heating, and Refrigeration Institute. (n.d.-b). A2L refrigerant building code map - US. Link to source: https://www.ahrinet.org/a2l-refrigerant-building-code-map-us 

Amendment to the Montreal Protocol on substances that deplete the ozone layer. (2016, October 15). Link to source: https://treaties.un.org/doc/Treaties/2016/10/20161015%2003-23%20PM/Ch_XXVII-2.f-English%20and%20French.pdf 

Arp, H. P. H., Gredelj, A., Glüge, J., Scheringer, M., & Cousins, I. T. (2024). The global threat from the irreversible accumulation of trifluoroacetic acid (TFA). Environmental Science & Technology, 58(45), 19925–19935. Link to source: https://doi.org/10.1021/acs.est.4c06189 

ASHRAE. (2009). ASHRAE position document on natural refrigerants. Link to source: https://www.epa.gov/sites/default/files/documents/ASHRAE_PD_Natural_Refrigerants_2011.pdf 

Babiker, M., Berndes, G., Blok, K., Cohen, B., Cowie, A., Geden, O., Ginzburg, V., Leip, A., Smith, P., Sugiyama, M., & Yamba, F. (2022). Cross-sectoral perspectives. In P. R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, & J. Malley (Eds.), Climate change 2022: Mitigation of climate change. Contribution of working group III to the sixth assessment report of the intergovernmental panel on climate change (pp. 1245–1354). Cambridge University Press. Link to source: https://doi.org/10.1017/9781009157926.014 

Baha, M., & Dupont, J.-L. (2023, September 15). Global warming potential (GWP) of HFC refrigerants. International Institute of Refrigeration. Link to source: https://iifiir.org/en/encyclopedia-of-refrigeration/global-warming-potential-gwp-of-hfc-refrigerants 

Behringer, D., Heydel, F., Gschrey, B., Osterheld, S., Schwarz, W., Warncke, K., Freeling, F., Nödler, K., Henne, S., Reimann, S., Blepp, M., Jörß, W., Liu, R., Ludig, S., Rüdenauer, I., & Gartiser, S. (2021). Persistent degradation products of halogenated refrigerants and blowing agents in the environment: Type, environmental concentrations, and fate with particular regard to new halogenated substitutes with low global warming potential. Final report. Umweltbundesamt [German Environment Agency]. Link to source: https://www.umweltbundesamt.de/sites/default/files/medien/5750/publikationen/2021-05-06_texte_73-2021_persistent_degradation_products.pdf 

Blumberg, K., Isenstadt, Taddonio, K. N., Andersen, S. O., & Sherman, N. J. (2019). Mobile air conditioning: The life-cycle costs and greenhouse-gas benefits of switching to alternative refrigerants and improving system efficiencies. Link to source: https://theicct.org/wp-content/uploads/2021/06/ICCT_mobile-air-cond_CBE_201903.pdf 

Bolaji, B. O., & Huan, Z. (2013). Ozone depletion and global warming: Case for the use of natural refrigerant – a review. Renewable and Sustainable Energy Reviews, 18, 49–54. Link to source: https://doi.org/10.1016/j.rser.2012.10.008 

Booten, C., Nicholson, S., Mann, M., & Abdelaziz, O. (2020). Refrigerants: Market trends and supply chain assessment. Link to source: https://www.nrel.gov/docs/fy20osti/70207.pdf 

Burkholder, J. B., Hodnebrog, Ø., McDonald, B. C., Orkin, V., Papadimitriou, V. C., & Van Hoomissen, D. (2023). Annex: Summary of abundances, lifetimes, ODPs, REs, GWPs, and GTPs. Scientific Assessment of Ozone Depletion 2022. Link to source: https://csl.noaa.gov/assessments/ozone/2022/downloads/Annex_2022OzoneAssessment.pdf 

California Public Utilities Commission. (2022). Refrigerant avoided cost calculator [Data set]. Link to source: https://www.cpuc.ca.gov/dercosteffectiveness 

Campbell, I., Kalanki, A., & Sachar, S. (2018). Solving the global cooling challenge: How to counter the climate threat from room air conditioners. Rocky Mountain Institute. Link to source: https://rmi.org/wp-content/uploads/2018/11/Global_Cooling_Challenge_Report_2018.pdf 

Chele, F. S., Salvador, C., Stevenson, L., Dolislager, F., Armstrong, A., Power, S., Mathews, T., & Yana Motta, S. F. (2024). Critical literature review of low global warming potential (GWP) refrigerants and their environmental impact. Oak Ridge National Laboratory. Link to source: https://www.osti.gov/servlets/purl/2528023 

CLASP. (2025, December). Mepsy: The appliance & equipment climate impact calculator (Version 1.15.0). Link to source: https://clasp.shinyapps.io/mepsy

CLASP & ATMOsphere. (2022). Global refrigerant impact from 6 appliances in 22 countries. Link to source: https://www.clasp.ngo/wp-content/uploads/2022/05/Refrigerant-Modeling-Interim-Report-APR142022.pdf 

Climate and Ozone Protection Alliance. (2025). Global banks of ozone depleting substances (ODS) and hydrofluorocarbons (HFCs). Link to source: https://www.copalliance.org/imglib/publications/2025-04_COPA_Global%20Banks%20ODS%20HFC_update.pdf 

Colbourne, D., Croiset, I., Ederberg, L., Heubes, J., Martin, M., Narayan, C., Oppelt, D., Papst, I., Usinger, J., & Gschrey, B. (2013). NAMAs in the refrigeration, air conditioning and foam sectors: A technical handbook. Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH [German Agency for International Cooperation] . Link to source: https://transparency-partnership.net/sites/default/files/e-bruochure-20131015-neu.pdf 

Copernicus Climate Change Service. (2023). ERA5 hourly data on single levels from 1940 to present [Data set]. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). Retrieved January 13, 2026 from Link to source: https://doi.org/10.24381/cds.adbb2d47

Crippa, M., Guizzardi, D., Pagani, F., Banja, M., Muntean, M., Schaaf, E., Quadrelli, R., Risquez Martin, A., Taghavi-Moharamli, P., Köykkä, J., Grassi, G., Rossi, S., Melo, J., Oom, D., Branco, A., Suárez-Moreno, M., Sedano, F., San-Miguel, J., Manca, G., … Pekar, F. (2025). GHG emissions of all world countries - 2025 Report (JRC143227). Publications Office of the European Union. Link to source: https://data.europa.eu/doi/10.2760/9816914

Denzinger, P. (2023, December 9). Context and global mitigation potential of “green” ACs. COP28 UAE. Link to source: https://www.green-cooling-initiative.org/fileadmin/user_upload/Final_02_COP28_Side_Event_Green_ACs_Final_Final.pdf 

Dimitrakopoulou, M.-E., Karvounis, M., Marinos, G., Theodorakopoulou, Z., Aloizou, E., Petsangourakis, G., Papakonstantinou, M., & Stoitsis, G. (2024). Comprehensive analysis of PFAS presence from environment to plate. npj Science of Food, 8, 80. Link to source: https://doi.org/10.1038/s41538-024-00319-1 

Dong, Y., Coleman, M., & Miller, S. A. (2021). Greenhouse gas emissions from air conditioning and refrigeration service expansion in developing countries. Annual Review of Environment and Resources, 46, 59–83. Link to source: https://doi.org/10.1146/annurev-environ-012220-034103 

Dräger. (n.d.). Cooling with ammonia: What you should keep in mind. Link to source: https://www.draeger.com/Content/Documents/Content/ammoniak-fa-pdf-8110-en.pdf  

Dreyfus, G., Borgford-Parnell, N., Christensen, J., Fahey, D. W., Motherway, B., Peters, T., Picolotti, R., Shah, N., & Xu, Y. (2020). Assessment of climate and development benefits of efficient and climate-friendly cooling. Link to source: https://www.ccacoalition.org/resources/assessment-climate-and-development-benefits-efficient-and-climate-friendly-cooling 

European Chemicals Agency. (2023). Annex XV restriction report: Per- and polyfluoroalkyl substances (PFASs). Link to source: https://echa.europa.eu/documents/10162/f605d4b5-7c17-7414-8823-b49b9fd43aea 

European Environmental Bureau. (2025). Universal PFAS restriction under REACH: Briefing on fluorinated gases in the universal PFAS restriction—The F-lephant in the room. Link to source: https://eeb.org/wp-content/uploads/2025/02/EEB_EURENI_F-gas_Policy-Brief.pdf 

Fabris, F., Fabrizio, M., Marinetti, S., Rossetti, A., & Minetto, S. (2024). Evaluation of the carbon footprint of HFC and natural refrigerant transport refrigeration units from a life-cycle perspective. International Journal of Refrigeration, 159, 17–27. Link to source: https://doi.org/10.1016/j.ijrefrig.2023.12.018 

Fenton, S. E., Ducatman, A., Boobis, A., DeWitt, J. C., Lau, C., Ng, C., Smith, J. S., & Roberts, S. M. (2021). Per- and polyfluoroalkyl substance toxicity and human health review: Current state of knowledge and strategies for informing future research. Environmental Toxicology and Chemistry, 40(3), 606–630. Link to source: https://doi.org/10.1002/etc.4890 

Food and Agriculture Organization of the United Nations. (2019). The state of food and agriculture 2019: Moving forward on food loss and waste reduction. Link to source: https://openknowledge.fao.org/server/api/core/bitstreams/11f9288f-dc78-4171-8d02-92235b8d7dc7/content 

Garavagno, M. d. l. A., Holland, R., Khan, M. A. H., Orr-Ewing, A. J., & Shallcross, D. E. (2024). Trifluoroacetic acid: Toxicity, sources, sinks and future prospects. Sustainability, 16(6), Article 2382. Link to source: https://doi.org/10.3390/su16062382 

Garry, M. (2021, June 23). Certain HFCs and HFOs are in PFAS group that five EU countries intend to restrict. Link to source: https://naturalrefrigerants.com/certain-hfcs-and-hfos-are-in-pfas-group-that-five-eu-countries-intend-to-restrict/  

Goetzler, W., Guernsey, M., Young, J., Fuhrman, J., & Abdelaziz, O. (2016). The future of air conditioning for buildings. U.S. Department of Energy. Office of Energy Efficiency and Renewable Energy. Building Technologies Office. Link to source: https://www.energy.gov/sites/prod/files/2016/07/f33/The%20Future%20of%20AC%20Report%20-%20Full%20Report_0.pdf 

Gradient. (2015). Risk assessment of refrigeration systems using A2L flammable refrigerants. Link to source: https://www.ahrinet.org/system/files/2023-08/AHRI-8009_Final_Report.pdf 

Green Cooling Initiative. (n.d.). Global greenhouse gas emissions from the RAC sector. Retrieved April 15, 2025, from Link to source: https://www.green-cooling-initiative.org/country-data 

Hanson, M. L., Madronich, S., Solomon, K., Sulbaek Andersen, M. P., & Wallington, T. J. (2024). Trifluoroacetic acid in the environment: Consensus, gaps, and next steps. Environmental Toxicology and Chemistry, 43, 2091–2093. Link to source: https://doi.org/10.1002/etc.5963 

Hayes, C., Stausholm, T., Ilana, K., & Devin, Y. (2023). Natural refrigerants: State of the industry. ATMOsphere. Link to source: https://atmosphere.cool/marketreport-2022/ 

Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz‐Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmins, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., … Thépaut, J. N. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. Link to source: https://doi.org/10.1002/qj.3803

Heubes, J., Martin, M., & Oppelt, D. (2012). Refrigeration, air conditioning and foam blowing sectors technology roadmap. GIZ Proklima. Link to source: https://unfccc.int/ttclear/misc_/StaticFiles/gnwoerk_static/TEM_tec_cfi_rm/993ecdfa67144e68b88b4735ea50fcf0/647faaa714484a2983fe6851111ab9aa.pdf 

Höglund-Isaksson, L., Purohit, P., Amann, M., Bertok, I., Rafaj, P., Schöpp, W., & Borken-Kleefeld, J. (2017). Cost estimates of the Kigali Amendment to phase-down hydrofluorocarbons. Environmental Science & Policy, 75, 138–147. Link to source: https://doi.org/10.1016/j.envsci.2017.05.006 

Holland, R., Khan, M. A. H., Driscoll, I., Chhantyal-Pun, R., Derwent, R. G., Taatjes, C. A., Orr-Ewing, A. J., Percival, C. J., & Shallcross, D. E. (2021). Investigation of the production of trifluoroacetic acid from two halocarbons, HFC-134a and HFO-1234yf and its fates using a global three-dimensional chemical transport model. ACS Earth and Space Chemistry, 5(4), 849–857. Link to source: https://doi.org/10.1021/acsearthspacechem.0c00355 

Imamura, T., Kamiya, K., & Sugawa, O. (2015). Ignition hazard evaluation on A2L refrigerants in situations of service and maintenance. Journal of Loss Prevention in the Process Industries, 36, 553–561. Link to source: https://doi.org/10.1016/j.jlp.2014.12.018 

Inforum, JMS Consulting, The Alliance for Responsible Atmospheric Policy, & Air-Conditioning, Heating, and Refrigeration Institute. (2019, December 12). Economic & consumer impacts of HFC phasedown. Link to source: https://www.congress.gov/116/meeting/house/110388/documents/HHRG-116-IF18-20200114-SD003.pdf 

International Energy Agency. (2023, July 12). Space cooling. Link to source: https://www.iea.org/energy-system/buildings/space-cooling 

Intergovernmental Panel on Climate Change. (2023). Climate change 2022: Mitigation of climate change. Working Group III Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. Link to source: https://doi.org/10.1017/9781009157926 

JMS Consulting & Inforum. (2018). Consumer cost impacts of U.S. ratification of the Kigali Amendment. Link to source: https://www.alliancepolicy.org/site/usermedia/application/10/Consumer_Costs_Final_InforumJMS_20181109.pdf 

Kim, B., Lee, S. H., Lee, D., & Kim, Y. (2020). Performance comparison of heat pumps using low global warming potential refrigerants with optimized heat exchanger designs. Applied Thermal Engineering, 171, Article 114990. Link to source: https://doi.org/10.1016/j.applthermaleng.2020.114990 

Montreal protocol on substances that deplete the ozone layer. (1987, September 16). Link to source: https://treaties.un.org/doc/publication/unts/volume%201522/volume-1522-i-26369-english.pdf 

The North American Sustainable Refrigeration Council. (n.d.). HFC policies & refrigerant regulations by state. Link to source: https://nasrc.org/hfc-policy-tracker/ 

Ozone Secretariat. (2017, February 17). Frequently asked questions relating to the Kigali Amendment to the Montreal Protocol. United Nations, United Nations Environment Programme. Link to source: https://ozone.unep.org/sites/default/files/FAQs_Kigali_Amendment.pdf 

Ozone Secretariat. (2020). Treaties. United Nations, United Nations Environment Programme. Link to source: https://ozone.unep.org/classification-parties 

Ozone Secretariat. (n.d.). Country data. United Nations, United Nations Environment Programme. Link to source: https://ozone.unep.org/countries/data 

Petri, Y., & Caldeira, K. (2015). Impacts of global warming on residential heating and cooling degree-days in the United States. Scientific Reports, 5(1), Article 12427. Link to source: https://doi.org/10.1038/srep12427 

Purohit, P., & Höglund-Isaksson, L. (2017). Global emissions of fluorinated greenhouse gases 2005–2050 with abatement potentials and costs. Atmospheric Chemistry and Physics, 17(4), 2795–2816. Link to source: https://doi.org/10.5194/acp-17-2795-2017 

Salvador, C. M., Chele, F. S., Stevenson, L., Dolislager, F., Armstrong, A., Mathews, T., & Yana Motta, S. (2024). Atmospheric transformation of refrigerants: Current research developments and knowledge gaps. International Refrigeration and Air Conditioning Conference, USA, Paper 2671. Link to source: https://docs.lib.purdue.edu/iracc/2671 

Secop. (2018). Practical application of refrigerants R600a and R290 in small hermetic systems. Link to source: https://www.secop.com/fileadmin/user_upload/technical-literature/guidelines/application_guideline_r600a_r290_02-2018_desa610a202.pdf 

Shah, N., Khanna, N., Karali, N., Park, W. Y., Qu, Y., & Zhou, N. (2017). Opportunities for simultaneous efficiency improvement and refrigerant transition in air conditioning. Lawrence Berkeley National Laboratory. Link to source: https://cooling.lbl.gov/publications/opportunities-simultaneous-efficiency 

Shah, N., Wei, M., Letschert, V., & Phadke, A. (2015). Benefits of leapfrogging to superefficiency and low global warming potential refrigerants in room air conditioning. Lawrence Berkeley National Laboratory. Link to source: https://www.osti.gov/servlets/purl/1235571 

Shah, N., Wei, M., Letschert, V., & Phadke, A. (2019). Benefits of energy efficient and low-global warming potential refrigerant cooling equipment. Lawrence Berkeley National Laboratory. Link to source: https://cooling.lbl.gov/publications/benefits-energy-efficient-and-low 

Sherry, D., Nolan, M., Seidel, S., & Andersen, S. O. (2017). HFO-1234yf: An examination of projected long-term costs of production. Nolan Sherry & Associates, Center for Climate and Energy Solutions, Institute for Governance and Sustainable Development. Link to source: https://www.c2es.org/wp-content/uploads/2017/04/hfo-1234yf-examination-projected-long-term-costs-production.pdf 

Smith, C., Nicholls, Z. R. J., Armour, K., Collins, W., Forster, P., Meinshausen, M., Palmer, M. D., & Watanabe, M. (2021). The Earth’s energy budget, climate feedbacks, and climate sensitivity supplementary material. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Link to source: https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07_SM.pdf 

Sustainable Purchasing Leadership Council Climate Friendly Refrigerant Action Team. (2021). Recommendations for climate friendly refrigerant management and procurement. Link to source: https://www.igsd.org/publications/recommendations-for-climate-friendly-refrigerant-management-and-procurement/ 

Trevisan, T. (2023, July 3). Overview of PFAS refrigerants used in HVAC&R and relevance of refrigerants in the PFAS Restriction Intention. UN Montreal Protocol 45th OEWG, Bangkok. Link to source: https://ozone.unep.org/system/files/documents/OEWG45_ATMO_sidevent.pdf 

United Nations Development Programme. (2022). Guidance note: Assessing greenhouse gas emissions from refrigerants use in UNDP operations. Link to source: https://www.undp.org/sites/g/files/zskgke326/files/2022-07/Refrigerants%20methodology%20version%20July%202022.pdf 

United Nations Environment Programme. (2022). Medical and Chemical Technical Options Committee: 2022 assessment report. Link to source: https://ozone.unep.org/system/files/documents/MCTOC-Assessment-Report-2022.pdf 

United Nations Environment Programme. (2023). Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee: 2022 assessment report. Link to source: https://ozone.unep.org/system/files/documents/RTOC-assessment%20-report-2022.pdf 

United Nations Environment Programme & ASHRAE. (2025). Update on new refrigerants designations and safety classifications June 2025. Link to source: https://www.ashrae.org/file%20library/professional%20development/ashrae-unep/unep---ashrae-factsheet--english.pdf 

United Nations Framework Convention on Climate Change. (2023). National inventory submissions, Annex 1 parties [Data set]. Link to source: https://unfccc.int/ghg-inventories-annex-i-parties/2023  

U.S. Environmental Protection Agency. (2011). Transitioning to low-GWP alternatives in transport refrigeration. Link to source: https://www.epa.gov/sites/default/files/2015-07/documents/transitioning_to_low-gwp_alternatives_in_transport_refrigeration.pdf 

U.S. Environmental Protection Agency. (2025). Frequent questions on the phasedown of hydrofluorocarbons. Link to source: https://www.epa.gov/climate-hfcs-reduction/frequent-questions-phasedown-hydrofluorocarbons 

Velders, G. J. M., Daniel, J. S., Montzka, S. A., Vimont, I., Rigby, M., Krummel, P. B., Muhle, J., O’Doherty, S., Prinn, R. G., Weiss, R. F., & Young, D. (2022). Projections of hydrofluorocarbon (HFC) emissions and the resulting global warming based on recent trends in observed abundances and current policies. Atmospheric Chemistry and Physics, 22(9), 6087–6101. Link to source: https://doi.org/10.5194/acp-22-6087-2022 

Velders, G. J. M., Fahey, D. W., Daniel, J. S., Andersen, S. O., & McFarland, M. (2015). Future atmospheric abundances and climate forcings from scenarios of global and regional hydrofluorocarbon (HFC) emissions. Atmospheric Environment, 123, 200–209. Link to source: https://doi.org/10.1016/j.atmosenv.2015.10.071 

World Meteorological Organization. (2018). Executive summary: Scientific assessment of ozone depletion: 2018 (Report No. 58). Link to source: https://ozone.unep.org/sites/default/files/2019-04/SAP-2018-Assessment-report-ES-rev%20%281%29.pdf 

Zaelke, D., & Borgford-Parnell, N. (2015). The importance of phasing down hydrofluorocarbons and other short-lived climate pollutants. Journal of Environmental Studies and Sciences, 5(2), 169–175. Link to source: https://doi.org/10.1007/s13412-014-0215-7 

Zanchi, V., Boban, L., & Soldo, V. (2019). Refrigerant options in the near future. Journal of Sustainable Development of Energy, Water and Environment Systems, 7(2), 293–304. Link to source: https://doi.org/10.13044/j.sdewes.d6.0250 

Credits

Lead Fellow

  • Sarah Gleeson, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • James Gerber, Ph.D.

  • Hannah Henkin

  • Heather McDiarmid, Ph.D.

  • Ted Otte

  • Amanda D. Smith, Ph.D.

Effectiveness

For every kt high-GWP refrigerant phased out in favor of low-GWP refrigerant, approximately 460,000 t CO₂‑eq/yr of F-gas emissions will be mitigated on a 100-yr basis (Table 1). If medium-GWP refrigerants are instead adopted in certain applications (Figure 2), the effectiveness decreases to 400,000 t CO₂‑eq (100-yr)/kt high-GWP refrigerant phased out/yr (Table 1). Effectiveness is based on average GWP of the high-, low-, and medium-GWP refrigerants; the difference in refrigerant charge; and the expected percent released to the atmosphere.

Since F-gases are short-lived climate pollutants, the effectiveness of this solution on a 20-yr basis is higher than on a 100-yr basis. Switching to low-GWP refrigerants saves 860,000 t CO₂‑eq /kt high-GWP refrigerant phased out/yr on a 20-yr basis. Medium-GWP refrigerants in certain applications reduces the effectiveness to 700,000 t CO₂‑eq (20-yr)/kt high-GWP refrigerant phased out/yr.

Using low-GWP refrigerants mitigates almost all CO₂‑eq emissions from direct release of high-GWP refrigerants. Medium-GWP refrigerants potentially offer a faster path to adoption in certain applications, but yield a smaller reduction in CO₂‑eq emissions. Switching to the lowest possible GWP refrigerant appropriate for a given application will have the highest effectiveness at cutting emissions.

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Table 1. Effectiveness at reducing emissions using low-GWP refrigerants only or medium-GWP refrigerants in some applications and low-GWP alternatives otherwise

Unit: t CO₂‑eq /kt high-GWP refrigerant phased out/yr, 100-yr basis

Average – low GWP only 460000
Average – medium & low GWP 400000
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Cost

We estimated the cost of purchasing and using low-GWP alternative refrigerants and equipment by taking a weighted average across all application types, averaging to US$23 million/kt high-GWP refrigerant phased out/yr. A kt of refrigerant goes a long way; a typical residential air conditioner requires only 0.6–3 kg refrigerant, depending on the country and refrigerant type (CLASP & ATMOsphere, 2022). On average across all applications, the emissions abatement cost for this solution is only US$50/t CO₂‑eq on a 100-yr basis (Table 2), or US$27/t CO₂‑eq on a 20-yr basis.

We separately evaluated the net costs of using medium-GWP refrigerants in some applications (Figure 2). Using medium-GWP refrigerants brought average costs down to US$9.4 million/kt high-GWP refrigerant phased out/yr. The emissions abatement cost is US$24/t CO₂‑eq (100-yr basis) or US$13/t CO₂‑eq (20-yr basis).

We calculated cost using values of initial cost and annual operation and maintenance costs from Purohit and Höglund-Isaksson (2017). The overall net cost is a weighted average of the average net costs of switching to alternative refrigerants for each of the six refrigerant applications (Figure 2). Costs are likely to change as the HFC phase-down continues under the Kigali Amendment. We did not evaluate external costs such as those to manufacturers. 

Although our calculated costs are averages, costs varied widely depending on the specific equipment, refrigerant type, and geographic location. Using ammonia in industrial refrigeration yields net savings of US$24 million/kt high-GWP refrigerant/yr. Low-GWP alternative refrigerants for transport refrigeration lead to cost savings over high- or medium-GWP refrigerants, as do hydrocarbons in residential and commercial air conditioning.

We did not consider energy cost differences due to changes in efficiency. Since electricity costs are the majority of the life-cycle costs for certain equipment, these changes in energy costs may be significant (Goetzler et al., 2016).

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Table 2. Cost per unit of climate impact for low-GWP refrigerants.

Unit: 2023 US$/t CO₂‑eq , 100-yr basis

Average 50.00
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Methods and Supporting Data

Methods and Supporting Data

Learning Curve

We did not find a learning rate for this solution, although there is evidence that costs of equipment and refrigerant decrease as more alternative refrigerants are deployed. Zanchi et al. (2019) claim that after regulations limiting emissions from F-gases and capping allowable refrigerant GWP were enacted in Europe, component prices for natural refrigerant equipment – particularly in commercial refrigeration – became comparable with lower HFC unit prices. Equipment prices have trended downwards through other similar technological transitions in the past (JMS Consulting & Inforum, 2018).

The cost of refrigerants can change with adoption as well as the cost of equipment. Natural refrigerants tend to be inexpensive, but cost premiums for expensive HFO refrigerants could drop by more than 75% as production volumes increase (Booten et al., 2020). Certain expensive-to-produce alternative refrigerants like HFO-1234yf have limited information about possible future price reductions, but other refrigerant transitions have indicated that prices should decrease due to increased production experience, capacity, and number of producers – especially as patents expire (Sherry et al., 2017). 

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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Deploy Alternative Refrigerants is an EMERGENCY BRAKE climate solution. It has the potential to deliver a more rapid impact than gradual and delayed solutions. Because emergency brake solutions can deliver their climate benefits quickly, they can help accelerate our efforts to address dangerous levels of climate change. For this reason, they are a high priority.

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Caveats

Permanence

There is a low risk of the emissions reductions for this solution being reversed. Each kt high-GWP refrigerant phased out for a lower-GWP alternative reduces the emissions from refrigerant release during manufacturing, transport, installation, operation, repair, and disposal of equipment. 

Additionality

This solution is additional when alternative refrigerant is used in applications that would have used HFCs or other high-GWP refrigerants in recent history. HFCs are not the baseline refrigerant in every scenario: hydrocarbons, for example, have been widely used in residential refrigeration and ammonia in industrial refrigeration for many years. 

In our analysis, we considered any path to adoption of alternative refrigerants to be part of its effectiveness at reducing GHG emissions. For example, we considered all HFC reductions mandated by policy to be considered additional over baseline HFC usage. However, some GHG accounting or crediting organizations would consider this regulatory additionality; the only emissions reductions that count as additional would be those not mandated by international, regional, and application-specific policy limits.

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Current Adoption

We estimated that 440 kt high-GWP refrigerants already have been phased out in favor of low-GWP alternative refrigerants worldwide (Table 3). For adoption, we did not differentiate between low- and medium-GWP alternative refrigerants due to insufficient data. 

There are limited recent and global data available to quantify the adoption of alternative refrigerants. For this reason, our approach to quantifying adoption is a simplified approximation. We used projected 2022 HFC emissions from Velders et al. (2015) as our baseline. These projections were made before any Kigali Amendment phase-down began, and we assumed they represent a reasonable 2022 emissions picture in the absence of policy-regulated HFC reductions. 

To calculate current adoption, we analyzed a Velders et al. (2022) model of 2022 HFC emissions accounting for current policies. Projected 2022 emissions in the current model were 6.4% lower than the 2015-projected baseline, which we assumed to be proportional to the amount of high-GWP HFC phased out and replaced with low-GWP alternatives. We estimated current adoption by applying this assumption to an estimated 6,480 kt bank of existing refrigerants (Climate and Ozone Protection Alliance, 2025). That bank includes all HFC and ozone-depleting refrigerants in new, in-use, and end-of-life equipment, and represents the potential refrigerant that could be replaced by alternative refrigerants. Since some alternative refrigerants were adopted before our 2015 baseline, the current adoption value is likely an underestimate.

Some applications are known to have higher levels of current adoption than others. For example, 800 million domestic refrigerators are estimated to use isobutane refrigerant globally, and most of the market for commercial supermarket plug-in cases in Europe, the United States, and Japan use hydrocarbons such as propane (Hayes et al., 2023; UNEP, 2023).

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Table 3. Current (2022 modeled) adoption level of low-GWP alternative refrigerants relative to 2015 baseline levels.

Unit: kt high-GWP refrigerant phased out

Estimate 440
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Adoption Trend

We estimated that 77 kt high-GWP refrigerants are phased out for alternative low-GWP refrigerants each year (Table 4). Using the same method as current adoption, we compared baseline and policy-adjusted projections of HFC emissions from Velders et al. (2015, 2022) for 2019–2022. The difference between the projections increased by a median 1.2% year-over-year.

We applied this percent change directly to the 2022 HFC refrigerant bank estimate to determine the tonnage of high-GWP refrigerant that will be phased out as new equipment replaces decommissioned stock. We assumed the replacements all use low-GWP refrigerants.

Although more HFC is being phased out each year, the bank and associated emissions of HFCs are also growing as refrigeration and cooling equipment are more heavily used globally. Alternative refrigerant adoption will need to outpace market growth before net emissions reductions occur. The adoption trend is likely higher today than what is reflected by the data used in our calculations (prior to 2023), since 2024 was a Kigali-mandated increase in HFC phase-down for certain countries. We expect adoption trend to continue to increase as HFC restrictions tighten further in the future.

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Table 4. 2019–2022 adoption trend of low-GWP alternative refrigerants.

Unit: kt high-GWP refrigerant phased out/yr

Estimate 77
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Adoption Ceiling

The adoption ceiling for this solution is phasing out all high-GWP refrigerants, or 6,900 kt globally (Table 5). This value represents the entire current bank of HFCs and ozone-depleting refrigerants added to the current adoption of low-GWP refrigerants (Climate and Ozone Protection Alliance, 2025).

This quantity assumes no increase in the total refrigerant bank above 2022 levels, while in reality the bank is projected to increase substantially as demand for cooling and refrigeration grows worldwide (International Energy Agency [IEA], 2023). Consumption of refrigerants in stationary air conditioning applications alone is projected to increase 3.5-fold between 2020–2050 (Denzinger, 2023). Additionally, new equipment that uses refrigerants (such as heat pump water heaters) is expected to replace non-refrigerant equipment, adding to future refrigerant demand. However, projecting future refrigerant demand was not part of this assessment.

We assumed that in all future cases, high-GWP refrigerants can be phased out for low-GWP alternatives. While ambitious, this ceiling is possible across all applications as new refrigerants, blends, and equipment are developed and commercialized. Since we considered implementation in new equipment, it comes with an adoption delay as existing equipment with high-GWP refrigerants finish their lifespans, which can last 10–20 years (California Public Utilities Commission, 2022; CLASP & ATMOsphere, 2022). 

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Table 5. Adoption ceiling for low-GWP refrigerants.

Unit: kt high-GWP refrigerant phased out

Estimate 6,900
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Achievable Adoption

The achievable adoption range is clearly laid out by the Kigali Amendment schedule for reduction in HFC consumption and production. The Achievable – Low adoption assumes that worldwide, all countries meet the Kigali phase-down schedule and collectively reach 80% reduction from baseline emissions by 2045. Under the Kigali Amendment, all participating countries are expected to meet at least this standard by this date. It is achievable that this adoption level could be reached collectively across all nations (including higher-adopting countries and non-Kigali signatories). This comes to 5,500 kt reduction in high-GWP refrigerants, calculated as 80% of the sum of net bank and current adoption (Table 6). 

Achievable – High assumes that all countries average the highest Kigali-mandated HFC reduction levels for any country (85% reduction from baseline), which comes to 5,900 kt high-GWP refrigerant phased out when applied to our adoption ceiling. If countries continue to follow the Kigali Amendment phase-down schedule, most production and use of HFCs will be eliminated over the coming decades. Other high-GWP ozone-depleting refrigerants are mostly phased out of new production under the Montreal Protocol, although large quantities still exist in refrigerant banks (Montreal Protocol on Substances That Deplete the Ozone Layer, 1987). 

Our achievable adoption values do not account for growth in the refrigerant bank over 2022 levels. Although refrigerant use is expected to grow substantially in the coming decades (IEA, 2023), we did not project future demand as part of our assessment. If HFC phaseout does not outpace refrigerant demand growth, emissions can increase despite more widespread adoption of this solution. Lowering the demand for refrigerant while ensuring that all people have access to refrigeration, heating, and cooling will be challenging.

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Table 6. Range of achievable adoption levels for low-GWP refrigerants.

Unit: kt high-GWP refrigerant phased out

Current adoption 440
Achievable – low 5500
Achievable – high 5900
Adoption ceiling 6900
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This solution has high potential climate impact due to both the quantity and high GWP of many current refrigerants. High-GWP refrigerant already phased out for low-GWP alternatives has an estimated current climate impact of 0.20 Gt CO₂‑eq/yr on a 100-yr basis (Table 7). If the Kigali Amendment HFC phasedown schedule is followed globally, we expect the achievable-adoption climate impact to be 2.5–2.7 Gt CO₂‑eq (100-yr)/yr. Reaching the adoption ceiling could potentially mitigate 3.2 Gt CO₂‑eq (100-yr)/yr. 

Due to the short lifetime of most high-GWP refrigerants, the climate benefit of phasing them out for alternatives is higher on a 20-year time horizon, making this solution highly impactful in the short-term. The use of low-GWP refrigerants currently saves an estimated 0.38 Gt CO₂‑eq (20-yr)/yr. The achievable 20-year impact is 4.7–5.0 Gt CO₂‑eq/yr, with a ceiling of 5.9 Gt CO₂‑eq/yr.

Since medium-GWP refrigerants are less effective at reducing emissions, the climate impacts are lower. If the same achievable adoption scenarios are reached but the effectiveness is calculated for medium-GWP refrigerants in commercial refrigeration, transport refrigeration, and stationary air conditioning applications, the climate impact reduces to 2.2–2.4 Gt CO₂‑eq (100-yr)/yr or 3.9–4.1 Gt CO₂‑eq (20-yr)/yr.

Our findings for impact are higher than many estimates of the scale of current refrigerant emissions. This is because other reports of F-gas emissions typically do not include high-GWP ozone-depleting refrigerants such as CFCs and HCFCs. The IPCC Sixth Assessment (2023) estimates 1.4 ± 0.41 GtCO₂‑eq/yr of 2019 emissions were F-gases from all sources, but this value does not include CFCs or HCFCs. The UNEP (2022) estimates that CFCs and HCFCs stored in equipment produce almost twice as many CO₂‑eq emissions as HFCs do. Our calculated achievable climate impact accounts for all major high-GWP refrigerant chemicals (CFCs, HCFCs, and HFCs), and therefore an achievable climate impact much higher than 1.4 GtCO₂‑eq/yr is reasonable.

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Table 7. Climate impact at different levels of adoption of low-GWP alternative refrigerants.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current adoption 0.20
Achievable – low 2.50
Achievable – high 2.70
Adoption ceiling 3.20
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Additional Benefits

Income and Work

Transitioning from HFCs to refrigerants with lower GWP can increase jobs (Colbourne et al., 2013; U.S. EPA, 2025). Reports from the Alliance for Responsible Atmospheric Policy and collaborators found that moving toward lower GWP refrigerants in the United States would increase jobs, increase manufacturing outputs of alternative refrigerants, and create more exports, strengthening the United States’ trade position (Inforum et al., 2019; JMS Consulting & Inforum, 2018). It is possible that using alternative refrigerants could lead to consumer savings on energy bills, depending on the alternative refrigerant, application, and equipment design (Colbourne et al., 2013; Purohit & Höglund-Isaksson, 2017; Shah et al., 2019; Zaelke & Borgford-Parnell, 2015). For example, an analysis of mobile air conditioning found that switching to an alternative refrigerant, such as R152a, can lead to high cost savings over its lifetime, and consumers in hotter climates would see the savings benefits (Blumberg et al., 2019). Since efficiency improvements are possible but not guaranteed in all cases, we do not consider this a guaranteed additional benefit. 

Land Resources

For a description of the benefits to land resources, please refer to Air Quality below. 

Air Quality

Some F-gases such as HFCs are considered per- and polyfluoroalkyl substances (PFAS) and can persist in the environment for centuries, posing serious human and ecosystem health risks (Figure 1) (Dimitrakopoulou et al., 2024; Fenton et al., 2021). PFAS can decompose in the atmosphere to produce trifluoroacetic acid (TFA), which can harm the environment and human health (UNEP, 2023). Possible impacts of high atmospheric TFA concentrations include acid rain, accumulation in terrestrial ecosystems in water and plant matter, and harmful effects on the environment and organisms (Chele et al., 2024; Hanson et al., 2024). Non-fluorinated alternative refrigerants would reduce the amount of PFAS pollution and reduce atmospheric TFA formation, lessening these harmful impacts. Some of these air quality benefits would also benefit indoor air quality because most refrigerants are used in buildings. Using alternative refrigerants avoids release of ozone-depleting substances such as HCFCs that can harm the ozone layer (Bolaji & Huan, 2013).

These benefits depend on the alternative refrigerant used – some low-GWP F-gas refrigerants such as HFOs are highly reactive, can be classified as PFAS, and can form TFA and other degradation products (Salvador et al., 2024). Therefore, the type of alternative refrigerant affects whether this is a benefit or a risk (see Risks below for more information). The thresholds at which these impacts occur are not well understood, and more research is needed to understand the potential harmful effects of TFA (Arp et al., 2024). 

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Risks

Some alternative refrigerants – including propane and ammonia – can react in the atmosphere to form polluting or toxic compounds (Chele et al., 2024). Low- and medium-GWP HFO or HFC refrigerants degrade into TFA, which is considered by some regulating bodies to be a PFAS, a class of chemicals with a proposed ban in Europe (European Chemicals Agency, 2023; European Environmental Bureau, 2025; Garavagno et al., 2024). Although TFA concentrations are currently low and impacts are minimal, increased HFO use could lead to greater accumulation, making it important to further study the potential risks (Chele et al., 2024; European Environmental Bureau, 2025; Hanson et al., 2024; Holland et al., 2021). Moreover, HFOs are made from high-GWP feedstocks, perpetuating the production and release of high-GWP chemicals (Booten et al., 2020; Chele et al., 2024). The use of other alternative refrigerant chemistries will reduce these risks (see Figure 1 and Additional Benefits).

Alternative refrigerants can be flammable (e.g., propane, ammonia) and toxic (e.g., ammonia). This potentially risks the well-being of people or property due to ignition, explosion, or refrigerant leaks (Shah et al., 2017). Minimizing leaks, reducing proximity to ignition sources, enhancing leak sensing, regulating safe charge sizes, and training installation and maintenance professionals are ways to lower this risk (Secop, 2018). Many alternative refrigerants are classified in ASHRAE safety group A2L, and these refrigerants have a low risk of ignition (Gradient, 2015; Imamura et al., 2015). Many countries have updated their standards in recent years to ensure safe use of low-GWP refrigerants, but adoption can be slowed if building codes do not allow for adoption (Heubes et al., 2012; UNEP, 2023).

Some specific technological solutions are required to avoid risks – for example, ammonia corrodes copper (Dräger, n.d.), and CO₂ refrigerant requires equipment and safety mechanisms that can handle its high operating pressure (Zanchi et al., 2019).

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Interactions with Other Solutions

Reinforcing

Decreasing food loss and waste could require increases in cold storage capacity, especially in commercial, residential, and transport refrigeration (Babiker, 2017; Food and Agriculture Organization of the United Nations, 2019). Alternative refrigerants will lead to reduced GHG emissions from this new food refrigeration equipment, particularly for high-leakage systems such as supermarket refrigeration. However, if less food is produced to better manage food loss, this could lead to a decreased demand for cold storage (Dong et al., 2021).

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Competing

Alternative refrigerants require design changes (Kim et al., 2020) that could increase the up-front cost of heat pumps.

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Using alternative refrigerants will decrease the CO₂‑eq emissions from released refrigerants. This means that management practices to reduce refrigerant release will save fewer CO₂‑eq emissions.

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Dashboard

Solution Basics

kt high-GWP refrigerant phased out

t CO₂-eq (100-yr)/unit/yr
460,000
units
Current 440 05,5005,900
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.2 2.52.7
US$ per t CO₂-eq
50
Emergency Brake

F-gases

Trade-offs

For particular alternative refrigerants and applications, switching to a lower-GWP refrigerant can reduce equipment efficiency (ASHRAE, 2009). Such a switch would decrease direct emissions due to reduction in refrigerant GWP, but would increase emissions associated with electricity generation.

Less efficient refrigerants may also require larger equipment and heavier masses of refrigerants, increasing the emissions for producing and transporting appliances. Fabris et al. (2024) reported that transport refrigeration systems using CO₂ refrigerant are heavier, leading to a 9.3% increase in emissions from fuel consumption during transport.

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°C days
03500

Space cooling demand (21 °C basis)

This map shows the annual average cooling degree days (CDD) for the decade ending in 2025. CDD are a measure of how much the temperature in a location exceeds 21 °C each day, summed cumulatively over a year. Regions with greater cooling degree days will likely have higher demand for space cooling equipment to maintain a comfortable indoor air temperature in buildings and vehicles.

Copernicus Climate Change Service. (2023). ERA5 hourly data on single levels from 1940 to present [Data set]. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). Retrieved January 13, 2026 from Link to source: https://doi.org/10.24381/cds.adbb2d47 

Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz‐Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmins, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., … Thépaut, J. N. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. Link to source: https://doi.org/10.1002/qj.3803

°C days
03500

Space cooling demand (21 °C basis)

This map shows the annual average cooling degree days (CDD) for the decade ending in 2025. CDD are a measure of how much the temperature in a location exceeds 21 °C each day, summed cumulatively over a year. Regions with greater cooling degree days will likely have higher demand for space cooling equipment to maintain a comfortable indoor air temperature in buildings and vehicles.

Copernicus Climate Change Service. (2023). ERA5 hourly data on single levels from 1940 to present [Data set]. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). Retrieved January 13, 2026 from Link to source: https://doi.org/10.24381/cds.adbb2d47 

Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz‐Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmins, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., … Thépaut, J. N. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. Link to source: https://doi.org/10.1002/qj.3803

Maps Introduction

Deploy Alternative Refrigerants is most effective at mitigating climate change in regions with high levels of current refrigerant use. Unfortunately, there are no comprehensive data available at the country level to estimate the quantity of high-GWP or alternative refrigerants stored in equipment. Countries report HFC stocks and emissions for refrigeration and air conditioning to the UNFCCC, but these do not include high-GWP ozone-depleting substances such as CFCs and HCFCs (UNFCCC, 2023). Since national emissions estimates such as the Emissions Database for Global Atmospheric Research (EDGAR) do not report high-GWP ozone-depleting F-gases, we do not include these data in this analysis (Crippa et al., 2025). The UNEP does track CFC, HCFC, and HFC production and consumption, but this does not provide a comprehensive use or emissions picture since many current emissions are from stock already contained in existing equipment (Ozone Secretariat, n.d.). 

Regions with greater cooling demand are likely to require more refrigerant use for refrigeration and air conditioning. Regional patterns of where this solution is most important may evolve in the future as cooling appliances become more widespread and the climate warms. 

International, national, and local policies have a large impact on the adoption of alternative refrigerants. The Kigali Amendment to the Montreal Protocol mandates HFC phasedown schedules for participating countries through 2047. Additionally, local building codes and policies influence the use of alternative refrigerants. The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) and The North American Sustainable Refrigeration Council (NASRC) give region-specific information in North America about such policies (AHRI, n.d.-a, n.d.-b; NASRC, n.d.). 

CLASP found that in 2025, China and the United States had the highest numbers of both residential air conditioners and refrigerator-freezers (CLASP, 2025). This suggests that residential refrigerant use and emissions are likely to be highest in these countries. 

Emissions from producing refrigerants will be higher in locations with more refrigerant manufacturing. Refrigerant manufacturing is more common in locations that are close to chemical feedstocks, have financial incentives, and have experienced and cheap labor (Booten et al., 2020).

Action Word
Deploy
Solution Title
Alternative Refrigerants
Classification
Highly Recommended
Lawmakers and Policymakers
  • Develop national cooling plans and integrate them into national climate plans.
  • Enact comprehensive policies that incentivize the lowest possible GWP refrigerants, penalize high-GWP refrigerants, and provide updated building code requirements.
  • Create government procurement policies that become stricter over time to mandate the use of alternative refrigerants or implement refrigerant GWP limits in government buildings and cooling systems.
  • Offer financial incentives such as subsidies, tax credits, and grants for using alternative refrigerants.
  • Implement the transition to alternative refrigerants while simultaneously working to improve equipment energy efficiency.
  • Implement an array of safety regulations that reduce the risk of leaks and exposure, such as restricting charge sizes, improving ventilation and leak sensors, and requiring certification for professionals.
  • Create free workforce training programs to improve safety around installation and maintenance.
  • Invest in R&D to improve availability, compatibility with existing equipment, and safety of alternative refrigerants.
  • Require detailed recordkeeping for vendors, contractors, and technicians to track and report on refrigerant types and amounts in use.
  • Develop refrigerant audit programs similar to energy audit programs.
  • Conduct consultations with national and local government agencies, businesses, schools, universities, farmers, healthcare professionals, research institutions, nonprofits, and the public to determine how best to transition local supply chains to alternative refrigerants.
  • Create certification schemes to identify which businesses utilize alternative refrigerants.
  • Offer educational resources, creating one-stop shops for information on alternative refrigerants and energy efficiency; offer demonstrations, highlighting their cost savings and climate benefits.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Practitioners
  • Use alternative refrigerants and equipment that uses the lowest possible GWP refrigerant, and phase in alternative refrigerants throughout the rest of your supply chain.
  • Advocate for comprehensive policy plans that incentivize the lowest possible GWP refrigerants, penalize high-GWP refrigerants, and provide updated building code requirements.
  • Avoid venting or intentional releases of high-GWP refrigerants and conduct regular maintenance on equipment.
  • Maintain detailed records to track and report on refrigerant types and amounts in use.
  • Improve building, operations, and cooling designs to reduce demand for refrigerants.
  • Implement an array of safety protocols to reduce the risk of leaks and exposure, such as restricting charge sizes, improving ventilation and leak sensors, and ensuring only trained professionals service the equipment.
  • Take advantage of financial incentives such as subsidies, tax credits, and grants for using alternative refrigerants.
  • Participate in consultations with national and local government agencies, businesses, universities, farmers, healthcare professionals, research institutions, nonprofits, and the public to determine how best to transition local supply chains to alternative refrigerants.
  • Stay abreast of changing regulations, identify authoritative and trustworthy sources of legal and policy information, and invest in technology that stays ahead of the refrigerant transition curve.
  • Participate in certification schemes that identify which businesses utilize alternative refrigerants.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Business Leaders
  • Establish time-bound, transparent targets for transitioning to alternative refrigerants.
  • Use alternative refrigerants and equipment that uses the lowest possible GWP refrigerant; pressure or incentivize suppliers to phase in and report on alternative refrigerants throughout your supply chain.
  • Take advantage of financial incentives such as subsidies, tax credits, and grants for using alternative refrigerants.
  • Maintain detailed records to track and report on refrigerant types and amounts in use within operations; request and maintain records from suppliers.
  • Improve building, operations, and cooling designs to reduce demand for refrigerants.
  • Participate in consultations with national and local government agencies, businesses, universities, farmers, healthcare professionals, research institutions, nonprofits, and the public to determine how best to transition local supply chains to alternative refrigerants.
  • Participate in certification schemes that identify which businesses utilize alternative refrigerants.
  • Advocate for comprehensive policy plans that incentivize the lowest possible GWP refrigerants, penalize high-GWP refrigerants, and provide updated building code requirements.
  • Advocate for bans on venting or intentional releases of high-GWP refrigerants, requirements for regular maintenance, and refrigerant or equipment tracking programs to help enforcement.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Nonprofit Leaders
  • Ensure operations use alternative refrigerants and equipment that uses the lowest possible GWP refrigerant, if relevant.
  • Advocate for comprehensive policy plans that incentivize the lowest possible GWP refrigerants, penalize high-GWP refrigerants, and provide updated building code requirements.
  • Advocate for bans on venting or intentional releases of high-GWP refrigerants, requirements for regular maintenance, and refrigerant or equipment tracking programs to help enforcement.
  • Help develop national cooling plans and integrate them into national climate plans.
  • Work with public schools, health facilities, and other public venues to deploy alternative refrigerants.
  • Create free workforce training programs to improve safety around installation and maintenance.
  • Assist with technology transfer to low- and middle-income countries to help improve low-cost adoption.
  • Create public campaigns to advocate against dumping inefficient equipment in local markets – especially in low- and middle-income countries.
  • Help develop refrigerant audit programs similar to energy audit programs.
  • Participate in consultations with national and local government agencies, businesses, universities, farmers, healthcare professionals, research institutions, nonprofits, and the public to determine how best to transition local supply chains to alternative refrigerants.
  • Offer educational resources, creating one-stop shops for information on alternative refrigerants and energy efficiency; offer demonstrations, highlighting their cost savings and climate benefits.
  • Administer or participate in certification schemes that identify which businesses utilize alternative refrigerants.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Investors
  • Ensure portfolio companies use or have a credible plan to use alternative refrigerants and phase in alternative refrigerants throughout the rest of their supply chain.
  • Ensure infrastructure investment projects leverage building, operations, and cooling designs that reduce demand for refrigerants.
  • Invest in start-ups working to improve and deploy alternative refrigeration technologies and refrigerant recycling.
  • Offer preferential loan agreements for developers utilizing alternative refrigerants and other climate-friendly practices.
  • Offer innovative financing methods such as microloans and green bonds to invest in projects that use alternative refrigerants.
  • Invest in R&D to improve availability, cost, compatibility with existing equipment, and safety of alternative refrigerants.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Philanthropists and International Aid Agencies
  • Ensure operations use alternative refrigerants and equipment that uses the lowest possible GWP refrigerant, if relevant.
  • Advocate for comprehensive policy plans that incentivize the lowest possible GWP refrigerants, penalize high-GWP refrigerants, and provide updated building code requirements.
  • Advocate for bans on venting or intentional releases of high-GWP refrigerants, requirements for regular maintenance, and refrigerant or equipment tracking to help enforcement.
  • Invest in start-ups working to improve and deploy alternative refrigeration technologies.
  • Set requirements for alternative refrigerants when funding new construction.
  • Offer financing options such as grants, microloans, and green bonds to invest in projects that use alternative refrigerants.
  • Invest in R&D to improve availability, cost, compatibility with existing equipment, and safety of alternative refrigerants.
  • Help develop national cooling plans and integrate them into national climate plans.
  • Work with public schools, health facilities, and other public venues to deploy alternative refrigerants.
  • Create free workforce training programs to improve safety around installation and maintenance.
  • Assist with technology transfer to low- and middle-income countries to help improve adoption.
  • Create public campaigns to advocate against dumping inefficient equipment in local markets – especially in low- and middle-income countries.
  • Help develop refrigerant audit programs similar to energy audit programs.
  • Research other traditional methods of cooling and food storage, develop means of scaling relevant methods, and find practical means of integrating traditional methods with modern lifestyles.
  • Participate in consultations with national and local government agencies, businesses, universities, farmers, healthcare professionals, research institutions, nonprofits, and the public to determine how best to transition local supply chains to alternative refrigerants.
  • Offer educational resources, creating one-stop shops for information on alternative refrigerants and energy efficiency; offer demonstrations, highlighting their cost savings and climate benefits.
  • Participate in certification schemes that identify which businesses utilize alternative refrigerants.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Thought Leaders
  • Advocate for comprehensive policy plans that incentivize the lowest possible GWP refrigerants, penalize high-GWP refrigerants, and provide updated building code requirements.
  • Advocate for bans on venting or intentional releases of high-GWP refrigerants, requirements for regular maintenance, and refrigerant or equipment tracking to help enforcement.
  • Help develop national cooling plans and integrate them into national climate plans.
  • Work with public schools, health facilities, and other public venues to deploy alternative refrigerants.
  • Assist with technology transfer to low- and middle-income countries to help improve adoption.
  • Create public campaigns to advocate against dumping inefficient equipment in local markets – especially in low- and middle-income countries.
  • Help develop refrigerant audit programs similar to energy audit programs.
  • Research other traditional methods of cooling and food storage, develop means of scaling relevant methods, and find practical means of integrating traditional methods with modern lifestyles.
  • Participate in consultations with national and local government agencies, businesses, universities, farmers, healthcare professionals, research institutions, nonprofits, and the public to determine how best to transition local supply chains to alternative refrigerants.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Technologists and Researchers
  • Research and develop new low- and medium-GWP alternative refrigerants.
  • Find ways to optimize the charge size, cooling performance, and end-of-life management of alternative refrigerants.
  • Design better cooling and heat pump systems to reduce cost of installation and maintenance.
  • Develop software to track types and quantities of refrigerants in use.
  • Conduct R&D on improving cost-effectiveness, safety, and compatibility with existing equipment of alternative refrigerants.
  • Develop software for companies to model and simulate alternative refrigerants within various system configurations.
  • Find opportunities to achieve higher equipment efficiencies or other energy-saving designs, such as recovering and utilizing waste heat from CO₂ refrigerant systems.
  • Improve gas detection systems to improve safety protocols around alternative refrigerants.
  • Research other traditional methods of cooling and food storage; develop means of scaling relevant methods; find practical means of integrating traditional methods with modern lifestyles.

Further information:

Communities, Households, and Individuals
  • Use alternative refrigerants and equipment that uses the lowest possible GWP.
  • Explore and integrate other traditional methods of cooling and food storage, if relevant.
  • Advocate for comprehensive policy plans that incentivize the lowest possible GWP refrigerants, penalize high-GWP refrigerants, and provide updated building code requirements.
  • Advocate for bans on venting or intentional releases of high-GWP refrigerants, requirements for regular maintenance, and refrigerant or equipment tracking to help enforcement.
  • Work with public schools, health facilities, and other public venues to deploy alternative refrigerants.
  • Take advantage of financial incentives such as subsidies, tax credits, and grants for using alternative refrigerants.
  • Participate in consultations with national and local government agencies, businesses, universities, farmers, healthcare professionals, research institutions, nonprofits, and the public to determine how best to transition local supply chains to alternative refrigerants.
  • Create, support, or join networks or partnerships dedicated to advancing and deploying alternative refrigerants.

Further information:

Sources
Evidence Base

Consensus of effectiveness in reducing emissions: High

Phasing out high-GWP refrigerants for low or medium-GWP refrigerants is unquestionably effective at reducing emissions from refrigerant use.

In a report from two U.S. national laboratories, Booten et al. (2020) claim that systems using F-gas refrigerants for refrigeration and air conditioning are “the most difficult and impactful” innovation spaces for refrigerants. Zaelke and Borgford-Parnell (2015) asserted that reducing short-lived climate pollutants including HFCs “is the most effective strategy for constraining warming and associated impacts in the near term.” Utilizing low-GWP alternative refrigerants is a proven means to achieve this.

The IPCC Sixth Assessment (2023) cites the World Meteorological Organization (2018) and Höglund-Isaksson et al. (2017) in claiming that worldwide compliance with the Kigali Amendment schedule would reduce HFC emissions by 61% over baseline emissions by 2050. Velders et al. (2022) modeled future HFC emissions under the Kigali Amendment and found that these HFC reductions could save 3.1–4.4 Gt CO₂‑eq , 100-yr basis/yr by 2050. Dreyfus et al. (2020) estimate possible cumulative savings of 33–47 Gt CO₂‑eq (100-yr) through 2050, with an additional 53 Gt CO₂‑eq (100-yr) through 2060 if HFC phase-down is immediate.

Expert consensus is that the potential impact of alternative refrigerants will increase as a warming climate and increased population and development drive demand for higher use of cooling equipment (Campbell et al., 2018; Dreyfus et al., 2020; Petri & Caldeira, 2015). This will particularly be true for developing countries in already warm climates (Dong et al., 2021). 

The results presented in this document summarize findings from one review article, six original studies, two reports, one international treaty, two industry guidelines, one conference proceeding, and eight national GHG inventory submissions to the United Nations. This reflects current evidence from 34 countries, primarily Annex 1 countries as identified by the United Nations as well as China. We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Updated Date

Deploy Alternative Insulation Materials

Submitted by Drawdown Admin on
Sector
Buildings & Industry
Mode
Cut Emissions
Cluster
Improve Materials
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Worker sprays insulation in building frame.
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Summary

Deploy Alternative Insulation Materials is defined as using alternative building insulation materials in place of conventional ones. In particular, we highlight the impact of using cellulose instead of glass, mineral, or plastic insulation in new and retrofit buildings. Cellulose insulation manufacture and installation emits fewer GHGs to reach the same operational insulating performance than does manufacture and installation of conventional materials.

Income & work,Health
Water resources
Description for Social and Search
Deploy Alternative Insulation Materials is a Highly Recommended climate solution. It reduces GHGs emitted during insulation manufacturing and installation.
Overview

Thermal insulation materials are used in the walls, roofs, and floors of buildings to help maintain comfortable indoor temperatures. However, manufacture and installation of insulation materials produces GHG emissions. These are called embodied emissions because they occur before the insulation is used in buildings. Insulation embodied emissions offset a portion of the positive climate impacts from using insulation to reduce heating and cooling demand. A Canadian study found that over 25% of residential embodied emissions from manufacturing building materials can be due to insulation (Magwood et al., 2022). Using cellulose insulation made primarily from recycled paper avoids some embodied emissions associated with conventional insulation.

Insulation is manufactured in many different forms, including continuous blankets or boards, loose fill, and sprayed foam (Types of Insulation, n.d.). Most conventional insulation materials are nonrenewable inorganic materials such as stone wool and fiberglass. These require high temperatures (>1,300 °C) to melt the raw ingredients, consuming thermal energy and releasing CO₂ from fossil fuel combustion or grid power generation (Schiavoni et al., 2016). Other common insulations are plastics, including expanded polystyrene (EPS), extruded polystyrene (XPS), polyurethane (PUR), and polyisocyanurate (PIR). Producing these plastics requires the extraction of fossil fuels – primarily petroleum – for feedstocks, as well as high amounts of energy for processing (Harvey, 2007). 

F-gases are often used as blowing agents to manufacture rigid foam board insulation or install sprayed foam insulation. F-gases are GHGs with GWPs that can be hundreds or thousands of times higher than CO₂. High-GWP F-gases used in foam production are released into the atmosphere during all subsequent stages of the foam’s life cycle (Biswas et al., 2016; Waldman et al., 2023). The climate benefits of this solution during the installation stage are primarily due to avoiding these blowing agents. 

Alternative insulation is produced from plant or animal biomass (bio-based materials) or waste products (recycled materials). Alternative insulation materials provide climate benefits by consuming less manufacturing energy, using renewable materials in place of fossil fuels, and eliminating high-GWP blowing agents (Sustainable Traditional Buildings Alliance, 2024). 

Figure 1 compares a variety of conventional and alternative insulation materials. While many bio-based and recycled materials could be used as alternatives to these conventional materials, this solution focuses on cellulose due to its effectiveness in avoiding emissions, low cost, and wide availability. Cellulose insulation is made primarily from recycled paper fibers, newsprint, and cardboard. These products are made into fibers and blended with fire retardants to produce loose or batt cellulose insulation (Waldman et al., 2023; Wilson, 2021).

Figure 1. Properties and adoption of conventional and alternative insulation materials. Costs and emissions will vary from the values here depending on the insulation form (board, blanket, loose-fill, etc.).

Category Material High-GWP F-gases used? Median manufacturing and installation emissions* Mean product and installation cost** Estimated market share
(% by mass)
Conventional materials Stone wool No 0.31 623 20
Glass wool (fiberglass) No 0.29 508 34
EPS No 0.38 678 22
XPS Yes, sometimes 9.44 702 7
PUR/PIR Yes, sometimes 6.14 1,000 11
Alternative materials Cellulose No 0.05 441 2–13
Cork No 0.30 1,520 Commercially available, not widely used
Wood fiber No 0.13 814 Commercially available, not widely used
Plant fibers (kenaf, hemp, jute) No 0.18 467 Commercially available, not widely used
Sheep’s wool No 0.14 800 Commercially available, not widely used
Recycled PET plastic No 0.12 2,950 Commercially available, not widely used

*t CO₂‑eq (100-yr) to insulate 100m² to 1m²·K/W

**2023 US$ to insulate 100m² to 1m²·K/W. We use mean values for cost analysis to better capture the limited data and wide range of reported costs.

Although we are estimating the impact of using cellulose insulation in all buildings, the unique circumstances of each building are important when choosing the most appropriate insulation material. In this solution, we do not distinguish between residential and commercial buildings, retrofit or new construction, different building codes, or different climates, but these would be important areas of future study.

In this solution, the effectiveness, cost, and adoption are calculated over a specified area (100 m²) and thermal resistance (1 m²·K/W). The chosen adoption unit ensures that all data are for materials with the same insulating performance. Due to limited material information, we assumed that insulation mass scales linearly with thermal resistance.

To better understand the adoption unit, a one-story residential building of 130 m² floor area would require approximately 370 m² of insulation area (RSMeans, & The Gordian Group, 2023). For a cold climate like Helsinki, Finland, code requires insulation thermal resistance of 11 m²·K/W (The World Bank Group, n.d.). For a warm climate like Jerusalem, Israel, envelope thermal resistance requirements average 1.1 m²·K/W (The World Bank Group, n.d.). Therefore, depending on the location, anywhere from approximately 4–40 adoption units insulating 100 m² to 1 m²·K/W may be needed to insulate a small single-story home to the appropriate area and insulation level.

Take Action Intro

Would you like to help deploy alternative insulation? Below are some ways you can make a difference, depending on the roles you play in your professional or personal life.

These actions are meant to be starting points for involvement and may or may not be the most important, impactful, or doable actions you can take. We encourage you to explore, get creative, and take a step that is right for you!

Adams, M., Burrows, V., & Richardson, S. (2019). Bringing embodied carbon upfront: Coordinated action for the building and construction sector to tackle embodied carbon. World Green Building Council, Advancing Net Zero, Ramboll, & C40 Cities. Link to source: https://worldgbc.s3.eu-west-2.amazonaws.com/wp-content/uploads/2022/09/22123951/WorldGBC_Bringing_Embodied_Carbon_Upfront.pdf 

Amendment to the Montreal Protocol on substances that deplete the ozone layer. (2016, October 15). Link to source: https://treaties.un.org/doc/Treaties/2016/10/20161015%2003-23%20PM/Ch_XXVII-2.f-English%20and%20French.pdf 

Andersen, B., & Rasmussen, T. V. (2025). Biobased building materials: Moisture characteristics and fungal susceptibility. Building and Environment, 112720. Link to source: https://doi.org/10.1016/j.buildenv.2025.112720 

Asdrubali, F., D’Alessandro, F., & Schiavoni, S. (2015). A review of unconventional sustainable building insulation materials. Sustainable Materials and Technologies, 4, 1–17. Link to source: https://doi.org/10.1016/j.susmat.2015.05.002 

Biswas, K., Shrestha, S. S., Bhandari, M. S., & Desjarlais, A. O. (2016). Insulation materials for commercial buildings in North America: An assessment of lifetime energy and environmental impacts. Energy and Buildings, 112, 256–269. Link to source: https://doi.org/10.1016/j.enbuild.2015.12.013 

Cabeza, L. F., Boquera, L., Chàfer, M., & Vérez, D. (2021). Embodied energy and embodied carbon of structural building materials: Worldwide progress and barriers through literature map analysis. Energy and Buildings, 231, 110612. Link to source: https://doi.org/10.1016/j.enbuild.2020.110612 

Carbon Removals Expert Group Technical Assistance. (2023, December). Review of certification methodologies for long-term biogenic carbon storage in buildings. European Commission. Link to source: https://climate.ec.europa.eu/system/files/2023-12/policy_carbon_expert_biogenic_carbon_storage_in_buildings_en.pdf 

Deer et al. (2007). Alaska Residential Building Manual. Alaska Housing Finance Corporation. Link to source: https://www.ahfc.us/application/files/2813/5716/1325/building_manual.pdf 

Esau et al. (2021). Reducing Embodied Carbon in Buildings: Low-Cost, High-Value Opportunities. RMI. Link to source: http://www.rmi.org/insight/reducing-embodied-carbon-in-buildings 

The Freedonia Group. (2024). Global insulation report. Link to source: https://www.freedoniagroup.com/industry-study/global-insulation 

Fabbri, M., Rapf, O., Kockat, J., Fernández Álvarez, X., Jankovic, I., & Sibileau, H. (2022). Putting a stop to energy waste: How building insulation can reduce fossil fuel imports and boost EU energy security. Buildings Performance Institute Europe. Link to source: https://www.bpie.eu/wp-content/uploads/2022/05/Putting-a-stop-to-energy-waste_Final.pdf 

Forestry production and trade. (2023). [Dataset]. FAOSTAT. Link to source: https://www.fao.org/faostat/en/#data/FO 

Füchsl, S., Rheude, F., & Röder, H. (2022). Life cycle assessment (LCA) of thermal insulation materials: A critical review. Cleaner Materials, 5, 100119. Link to source: https://doi.org/10.1016/j.clema.2022.100119 

Gelowitz, M. D. C., & McArthur, J. J. (2017). Comparison of type III environmental product declarations for construction products: Material sourcing and harmonization evaluation. Journal of Cleaner Production, 157, 125–133. Link to source: https://doi.org/10.1016/j.jclepro.2017.04.133 

Global Alliance for Buildings and Construction, International Energy Agency, and the United Nations Environment Programme. (2020). GlobalABC roadmap for buildings and construction: Towards a zero-emission, efficient and resilient buildings and construction sector. International Energy Agency. Link to source: https://www.iea.org/reports/globalabc-roadmap-for-buildings-and-construction-2020-2050 

Grazieschi, G., Asdrubali, F., & Thomas, G. (2021). Embodied energy and carbon of building insulating materials: A critical review. Cleaner Environmental Systems, 2, 100032. Link to source: https://doi.org/10.1016/j.cesys.2021.100032 

Harvey, L. D. D. (2007). Net climatic impact of solid foam insulation produced with halocarbon and non-halocarbon blowing agents. Building and Environment, 42(8), 2860–2879. Link to source: https://doi.org/10.1016/j.buildenv.2006.10.028 

Insulation choices revealed in new study. (2019, June 19). Home Innovation Research Labs. Link to source: https://www.homeinnovation.com/trends_and_reports/trends/insulation_choices_revealed_in_new_study 

International Energy Agency. (2023). Building envelopes. Link to source: https://www.iea.org/energy-system/buildings/building-envelopes 

International Energy Agency, International Renewable Energy Agency, & United Nations Climate Change High-Level Champions. (2023). Breakthrough agenda report 2023. Link to source: https://www.iea.org/reports/breakthrough-agenda-report-2023 

Jelle, B. P. (2011). Traditional, state-of-the-art and future thermal building insulation materials and solutions – Properties, requirements and possibilities. Energy and Buildings, 43(10), 2549–2563. Link to source: https://doi.org/10.1016/j.enbuild.2011.05.015 

Kumar, D., Alam, M., Zou, P. X. W., Sanjayan, J. G., & Memon, R. A. (2020). Comparative analysis of building insulation material properties and performance. Renewable and Sustainable Energy Reviews, 131, 110038. Link to source: https://doi.org/10.1016/j.rser.2020.110038 

Magwood et al. (2022). Emissions of materials benchmark assessment for residential construction report. Passive Buildings Canada and Builders for Climate Action.

Malhotra, A., & Schmidt, T. S. (2020). Accelerating Low-Carbon Innovation. Joule, 4(11), 2259–2267. Link to source: https://doi.org/10.1016/j.joule.2020.09.004

Mályusz, L., & Pém, A. (2013). Prediction of the learning curve in roof insulation. Automation in Construction, 36, 191–195. Link to source: https://doi.org/10.1016/j.autcon.2013.04.004 

Maskell, D., Da Silva, C., Mower, K., Rana, C., Dengel, A., Ball, R., Ansell, M., Walker, P., & Shea, A. (2015, June 22). Properties of bio-based insulation materials and their potential impact on indoor air quality. First International Conference on Bio-based Building Materials, Clermont-Ferrand, France.

McGrath et al. (2023). Embodied carbon and material health in insulation. Healthy Building Network, Perkins&Will. Link to source: https://habitablefuture.org/wp-content/uploads/2024/03/96-Carbon-Health-Insulation.pdf 

Naldzhiev, D., Mumovic, D., & Strlic, M. (2020). Polyurethane insulation and household products: A systematic review of their impact on indoor environmental quality. Building and Environment, 169, 106559. Link to source: https://doi.org/10.1016/j.buildenv.2019.106559 

Northeast Bio-based Materials Collective 2023 summit proceedings. (2023). Link to source: https://massdesigngroup.org/sites/default/files/file/2024/Northeast%20Bio-Based%20Materials%20Collective%202023%20Summit%20Proceedings.pdf 

Petcu et al. (2023). Research on thermal insulation performance and impact on indoor air quality of cellulose-based thermal insulation materials. Materials, 16(15), Article 15. Link to source: https://doi.org/10.3390/ma16155458 

Rabbat, C., Awad, S., Villot, A., Rollet, D., & Andrès, Y. (2022). Sustainability of biomass-based insulation materials in buildings: Current status in France, end-of-life projections and energy recovery potentials. Renewable and Sustainable Energy Reviews, 156, 111962. Link to source: https://doi.org/10.1016/j.rser.2021.111962 

Riverse. (2024, August). Methodology: Biobased construction materials. Link to source: https://www.riverse.io/methodologies/biobased-construction-materials 

RSMeans, & The Gordian Group. (2023, September). Installed cost of residential siding comparative study – September 2023 [Report]. The Brick Industry Association. Link to source: https://www.gobrick.com/content/userfiles/files/RSMeans%20Residential%20Siding%20Comparative%20Cost%20Wall%20System%20Study%20Final%202023-09-15.pdf

SaravanaPrabhu et al. (2021). Comparative analysis of learning curve models on construction productivity of diaphragm wall and pile. IOP Conference Series: Materials Science and Engineering, 1197(1), 012004. Link to source: https://doi.org/10.1088/1757-899X/1197/1/012004 

Schiavoni, S., D׳Alessandro, F., Bianchi, F., & Asdrubali, F. (2016). Insulation materials for the building sector: A review and comparative analysis. Renewable and Sustainable Energy Reviews, 62, 988–1011. Link to source: https://doi.org/10.1016/j.rser.2016.05.045 

Schulte, M., Lewandowski, I., Pude, R., & Wagner, M. (2021). Comparative life cycle assessment of bio-based insulation materials: Environmental and economic performances. GCB Bioenergy, 13(6), 979–998. Link to source: https://doi.org/10.1111/gcbb.12825 

Searchinger, T., Peng, L., Zionts, J., & Waite, R. (2024). The global land squeeze: Managing the growing competition for land. World Resources Institute. Link to source: https://www.wri.org/research/global-land-squeeze-managing-growing-competition-land

Stamm et al. (2022). Chemical and environmental justice impacts in the life cycle of building insulation. Energy Efficiency for All, Healthy Building Network. Link to source: https://informed.habitablefuture.org/resources/research/20-chemical-and-environmental-justice-impacts-in-the-life-cycle-of-building-insulation-report-brief 

Sustainable Traditional Buildings Alliance. (2024, March). The use of natural insulation materials in retrofit. Link to source: https://stbauk.org/wp-content/uploads/2024/03/The-use-of-natural-insulation-materials-in-retrofit.pdf 

The World Bank Group. (n.d.). Mapping energy efficiency: A global dataset on building code effectiveness and compliance: Country profiles. Link to source: https://www.worldbank.org/content/dam/sites/buildinggreen/doc/building_green_country_profile.pdf

Types of insulation. (n.d.). U.S. Department of Energy. Link to source: https://www.energy.gov/energysaver/types-insulation 

Waldman et al. (2023). 2023 Carbon Leadership Forum North American material baselines. Carbon Leadership Forum, University of Washington. Link to source: https://carbonleadershipforum.org/clf-material-baselines-2023/ 

Wang et al. (2023). Can paper waste be utilised as an insulation material in response to the current crisis. Sustainability, 15(22), Article 22. Link to source: https://doi.org/10.3390/su152215939 

Wi, S., Kang, Y., Yang, S., Kim, Y. U., & Kim, S. (2021). Hazard evaluation of indoor environment based on long-term pollutant emission characteristics of building insulation materials: An empirical study. Environmental Pollution, 285, 117223. Link to source: https://doi.org/10.1016/j.envpol.2021.117223 

Wilson. (2021). The BuildingGreen guide to thermal insulation: What you need to know about performance, health, and environmental considerations. BuildingGreen, Inc.

Zabalza Bribián, I., Valero Capilla, A., & Aranda Usón, A. (2011). Life cycle assessment of building materials: Comparative analysis of energy and environmental impacts and evaluation of the eco-efficiency improvement potential. Building and Environment, 46(5), 1133–1140. Link to source: https://doi.org/10.1016/j.buildenv.2010.12.002 

Credits

Lead Fellow

  • Sarah Gleeson, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Yusuf Jameel, Ph.D. 

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Ted Otte

  • Amanda D. Smith, Ph.D.

  • Christina Swanson, Ph.D.

Effectiveness

To insulate 100 m² to a thermal resistance of 1 m²·K/W using entirely cellulose insulation in place of the current baseline mix of insulation materials is expected to avoid 1.59 t CO₂‑eq on a 100-yr basis (Table 1). Since many of the avoided emissions are F-gases, the 20-yr effectiveness is higher, avoiding 4.07 t CO₂‑eq per unit of insulation. Effectiveness for this solution measures the one-time reduced emissions from manufacturing and installing insulation. Insulation also reduces the energy used while a building is operating, but those emissions are addressed separately in the Improve Building Envelopes solution. 

Conventional insulation effectiveness was considered to be a weighted average effectiveness of the current baseline insulation mix, including a small amount of cellulose insulation currently in use.

The largest contributor to conventional insulation embodied emissions is using high-GWP blowing agents to manufacture or install XPS, PUR, or PIR foam. We assumed the use of F-gas blowing agents for all foams, although these are already being regulated out of use globally (Amendment to the Montreal Protocol on Substances That Deplete the Ozone Layer, 2016) and an unknown amount of low-GWP blowing agents are currently used (such as hydrocarbons or CO₂). Therefore, we anticipate the effectiveness of this solution will decrease as F-gases are used less in the future. We assumed that 100% of blowing agents are emitted over the product lifetime.

Cellulose has the greatest avoided emissions of all of the alternative materials we evaluated (Figure 1). The next most effective materials were recycled PET, wood fibers, and sheep’s wool. Conventional materials like XPS, PUR, and PIR that are foamed with F-gases had the highest GHG emissions. For bio-based materials, we did not consider biogenic carbon as a source of carbon sequestration due to quantification and permanence concerns. 

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq /insulation required to insulate 100 m² to a thermal resistance of 1 m²·K/W, 100-yr basis

25th percentile 0.98
Mean 1.34
Median (50th percentile) 1.59
75th percentile 1.81
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Cost

Available cost data are variable for all materials, particularly those in early-stage commercialization. The mean cost of purchasing and installing cellulose insulation is less than that of any other conventional or alternative insulation material (Figure 1). Compared with the average cost of conventional insulation, the mean cost savings for cellulose insulation is US$193/100 m² insulated to a thermal resistance of 1 m²·K/W. Since most buildings are insulated over greater areas to higher thermal resistances, these savings would quickly add up. When considering the mean cost per median climate impact, cellulose insulation saves US$121/t CO₂‑eq (100-yr basis), making it an economically and environmentally beneficial alternative (Table 2).

We considered conventional insulation cost to be a weighted average cost of the current baseline insulation mix, including a small amount of cellulose insulation currently in use.

For conventional insulation, material costs of purchasing the insulation are higher than costs for installation (US$540 and US$97, respectively, to insulate 100 m2 to a thermal resistance of 1 m²·K/W). Cellulose has a lower product cost and comparable installation costs to conventional materials. We considered all costs to be up front and not spread over the lifetime of the material or building. For each material type, cost will vary based on the form of the insulation (board, loose, etc.), and this should be accounted for when comparing insulation options for a particular building. 

We determined net costs of insulation materials by adding the mean cost to purchase the product and the best estimation of installation costs based on available information. Installation costs were challenging to find data on and therefore represent broad assumptions of installation type and labor. Cost savings were determined by subtracting the weighted average net cost of conventional materials to the net cost of an alternative material. Although we used median values for other sections of this assessment, the spread of data was large for product cost estimates and the mean value was more appropriate in the expert judgment of our reviewers. 

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Table 2. Cost per unit of climate impact.

Unit: 2023 US$/t CO₂‑eq, 100-yr basis

Estimate -121
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Methods and Supporting Data

Methods and Supporting Data

Learning Curve

Little information is available about the learning rate for new insulation materials. Mályusz and Pém (2013) evaluated how labor time decreased with repetitive cycles for installing roof insulation. They found a learning rate of ~90%, but only for this specific insulation scenario, location, and material. Additionally, this study does not include any product or manufacturing costs that may decrease with scale.

In general, labor time for construction projects decreases with repetitive installation, including improved equipment and techniques and increased construction crew familiarity with the process (SaravanaPrabhu & Vidjeapriya, 2021). However, Malhotra and Schmidt (2020) classify building envelope retrofits as technologies that are highly customized based on user requirements, regulations, physical conditions, and building designs, likely leading to learning rates that are slow globally but where local expertise could reduce installation costs.

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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Deploy Alternative Insulation Materials is an EMERGENCY BRAKE climate solution. It has the potential to deliver a more rapid impact than gradual and delayed solutions. Because emergency brake solutions can deliver their climate benefits quickly, they can help accelerate our efforts to address dangerous levels of climate change. For this reason, they are a high priority.

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Caveats

Manufacturing and installation emissions reductions due to the use of alternative building thermal insulation materials are both permanent and additional. 

Permanence

There is a low risk of the emissions reductions for this solution being reversed. By using cellulose insulation instead of inorganic or plastic-based insulation, a portion of the manufacturing and installation emissions are never generated in the first place, making this a permanent reduction. Emissions from high-temperature manufacturing, petroleum extraction, and blowing agent use are all reduced through this approach.

Additionality

The GHG emissions reductions from alternative insulation materials are additional because we calculated them relative to a baseline insulation case. This includes a small amount of cellulose materials included in baseline building insulation. Therefore, avoided emissions represent an improvement of the current emissions baseline that would have occurred in the absence of this solution. 

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Current Adoption

Adoption data are extremely limited for alternative insulation materials. All adoption data and estimates are assumed to apply to both residential and commercial buildings, although in reality the uptake of alternative insulation materials will vary by building type due to differences in structures, climate, use type, and regulations. We assume that future uptake of alternative insulation is used only during retrofit or new construction, or when existing insulation is at the end of its functional lifetime.

European sources report that 2–13% of the insulation market is alternative materials. Depending on the source, this could include renewable materials, bio-based insulation, or recycled materials. In 2018 in the United States, 5% of total insulation area in new single-family homes was insulated with cellulose (Insulation Choices Revealed in New Study, 2019).

To convert estimated cellulose adoption percentage into annual insulation use, we estimated 26 Mt of all installed global insulation materials in 2023 based on a report from The Freedonia Group (2024). We calculated an annual use of approximately 1.7 billion insulation units of 100 m² at a thermal resistance of 1 m²·K/W. Therefore, the median cellulose adoption is 14 million units/yr at 100 m² at 1 m²·K/W, calculated from the median of the 2–13% adoption range. 

Since this calculation is based on more alternative materials than just cellulose and is heavily reliant on European data where we assume adoption is higher, this estimate of current adoption (Table 3) is most likely an overestimate.

The little adoption data that were considered in this section are mostly for Europe, and some for the United States. We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Table 3. Current (2017–2022) adoption level.

Unit: units of insulation/yr installed to insulate 100 m² to a thermal resistance of 1 m²·K/W

25th percentile 9000000
Mean 13000000
Median (50th percentile) 14000000
75th percentile 17000000
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Adoption Trend

Very few data are available that quantify adoption trends. In a regional study of several bio-based insulation materials, Rabbat et al. (2022) estimated French market annual growth rates of 4–10%, with cellulose estimated at 10%. Petcu et al. (2023) estimated the European adoption of recycled plastic and textile insulation, biomass fiber insulation, and waste-based insulation to have increased from 6% to 10% between 2012 and 2020.

When accounting for the calculated current adoption, these growth rates mean a median estimated annual increase of 500,000 insulation units/yr required to insulate 100 m² to a thermal resistance of 1 m²·K/W. The increasing adoption of bio-based insulation decreases the use of conventional insulation materials in those regions.

This adoption trend (Table 4) is likely an overestimate, as it is biased by high European market numbers and based on the likely high estimate we made for current adoption. 

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Table 4. 2012–2020 adoption trend.

Unit: annual change in units of insulation/yr installed to insulate 100 m² to a thermal resistance of 1 m²·K/W

25th percentile 500000
Mean 800000
Median (50th percentile) 500000
75th percentile 1300000
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Adoption Ceiling

No estimates have been found for the adoption ceiling of this solution, although we expect it to be high given low rates of current adoption and projected increases in building construction in the coming decades (International Energy Agency [IEA], International Renewable Energy Agency, & United Nations Climate Change High-Level Champions, 2023). Two physical factors that could influence adoption are availability of alternative materials and thickness of insulation.

For cellulose insulation, availability does not seem to limit adoption. The Food and Agriculture Organization of the United Nations (2023) reports that there is a much higher annual production of cellulose-based materials (>300 Mt annually of cartonboard, newsprint, and recycled paper) than the overall demand for insulation globally (>25 Mt annual demand; Global Insulation Report, 2024). However, other uses for cellulose products may create competition for this supply.

Increased thickness of insulation could also be a limiting factor because this would reduce adoption by decreasing building square footage, in particular making retrofits more challenging and expensive. Deer et al. (2007) reported that the average cellulose thermal resistance is similar to mineral and glass wool, and lower than plastic insulations made of polystyrene and other foams. If we assume that 50% of plastic insulation cannot be replaced with cellulose due to thickness limitations, this would represent ~20% of current insulation that could not be replaced without structural changes to the building. Therefore, we calculated the adoption ceiling to be 80% of the current insulation that would be reasonably replaceable, or 140 million units/yr required to insulate 100 m² to a thermal resistance of 1 m²·K/W (Table 5).

Uptake of cellulose insulation could also be limited by its susceptibility to absorbing moisture, limiting its use in wet climates or structures that retain moisture, such as flat roofs. Commercialization of alternative insulation materials beyond cellulose and in many different forms (e.g., board, loose-fill) will increase the adoption ceiling across more building types.

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Table 5. Adoption ceiling.

Unit: units of insulation/yr installed to insulate 100 m² to a thermal resistance of 1 m²·K/W

25th percentile N/A
Mean N/A
Estimate 140000000
75th percentile N/A
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Achievable Adoption

We found no estimates for feasible global adoption of this solution. Rabbat et al. (2022) estimated the adoption levels of several bio-based insulation materials in France in 2050. For cellulose wadding, this was estimated to be 2.1 times the commercialized volume in France in 2020. Although we do not expect France to be representative of the rest of the world, if the predicted adoption trend holds across the world then we expect low adoption in 2050 to be 2.1 times greater than 2023 adoption. This is 29 million units/yr to insulate 100 m² to a thermal resistance of 1 m²·K/W (Table 6).

The IEA (2023) claims that building envelopes need to have their retrofit rate increase by 2.5 times over the current rate in order to meet net zero targets (2023). This is a reasonable high-adoption scenario. Assuming that more retrofits of buildings occur and greater amounts of alternative insulation are installed in new buildings, we estimate that high future adoption of new insulation could occur at 2.5 times the rate of the low-adoption scenario. This is 73 million units/yr to insulate 100 m² to a thermal resistance of 1 m²·K/W (Table 6).

Adoption will be facilitated or limited by local regulations around the world. Building codes will determine the location and extent of use of cellulose or other bio-based insulation. We expect uptake to be different between residential and commercial buildings, but due to insufficient data, we have grouped them in our adoption estimates.

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Table 6. Range of achievable adoption levels.

Unit: units of insulation/yr installed to insulate 100 m² to a thermal resistance of 1 m²·K/W

Current adoption 14000000
Achievable – low 29000000
Achievable – high 73000000
Adoption ceiling 140000000
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The climate impacts for this solution are modest compared to current global GHG emissions. Not all conventional insulations have a high environmental impact due to the use of a wide range of materials, forms, and installation methods as well as the recent adoption of lower-GWP blowing agents. Therefore, the potential for further emissions savings is limited.

We quantified the effectiveness and adoption of cellulose insulation, which has the lowest emissions and, therefore, the highest climate impacts of the insulation materials we evaluated. With high adoption, 1.2 Gt CO₂‑eq on a 100-yr basis could be avoided over the next decade (Table 7).

While we only considered the adoption of cellulose insulation in this analysis, a realistic future for lowering the climate impact of insulation may include other bio-based materials, too. Utilizing a greater range of materials should increase adoption and climate impact due to more available forms, sources, and thermal resistance values of bio-based insulation.

Producing and deploying cellulose and other bio-based insulation requires the use of biomass as a feedstock. Multiple climate solutions, in addition to alternative insulation materials, require biomass, and projected demand across solutions greatly exceeds supply. The deforestation that would be required to meet demand would produce emissions far greater than any mitigation gains from full deployment of these solutions (Searchinger, 2024). In addition to deforestation, there would also be costs and emissions incurred to transport biomass from where it is produced to where it can be processed and used. Thus, the achievable climate impacts presented here is only possible if feedstocks are prioritized for this solution. If feedstocks are instead prioritized for other climate solutions (see Interactions for examples), adoption and impact will be lower for this solution. It is not possible to set all biomass-dependent solutions to high adoption levels, add up their impacts, and determine an accurate combined emissions impact.

Note that we calculated the current climate impact using a current materials baseline that includes a small fraction of cellulose. This means that the reported current adoption impact is a slight underestimate compared with the impacts for replacing entirely conventional insulation with the current amount of cellulose insulation in use.

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Table 7. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current adoption 0.022
Achievable – high 0.046
Achievable – low 0.12
Achievable ceiling 0.22
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Additional Benefits

Income and Work

Some alternative insulations can be cheaper than conventional materials. Although there is large variation in evaluation methods and reported costs, our analysis found that cellulose and plant fibers are cheaper than conventional insulation materials such as stone wool, glass wool, and EPS (Figure 1). Depending on the applicable climate conditions and insulation form, switching to alternative insulation materials can result in cost savings for consumers, including homeowners and business owners.

Health

Conventional insulation materials may contribute to poor indoor air quality, especially during installation, and contribute to eye, skin, and lung irritation (Naldzhiev et al., 2020; Stamm et al., 2022; Wi et al., 2021). Additionally, off-gassing of flame retardants and other volatile organic compounds and by-products of conventional insulation can occur shortly after installation (Naldzhiev et al., 2020). Using bio-based alternative insulation products can minimize the health risks during and after installation (McGrath et al., 2023).

Water Resources

Although there is not a scientifically consistent approach to compare the environmental impacts of conventional and alternative insulation materials, a review analysis of 47 studies on insulation concluded that bio-based insulation materials generally have lower impacts as measured through acidification, eutrophication, and photochemical ozone creation potentials than do conventional materials (Füchsl et al., 2022). Other alternative materials such as wood fiber and miscanthus also tend to have a lower environmental footprint (Schulte et al., 2021). The water demand for wood and cellulose is significantly lower than that for EPS (about 2.8 and 20.8 l/kg respectively compared with 192.7 l/kg for EPS) (Zabalza Bribián et al., 2011). While the limited evidence suggests that the alternative material tends to be better environmentally, there is an urgent need to conduct life cycle assessments using a consistent approach to estimate the impact of these materials.

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Risks

Cellulose insulation is susceptible to water absorption, which can lead to mold growth in wet or humid environments (Andersen & Rasmussen, 2025; Petcu et al., 2023). Reducing this risk either requires an antifungal treatment for the material or limits adoption to particular climates. The thermal performance of cellulose insulation can decrease over time due to water absorption, settling, or temperature changes, but installing it as dense-packed or damp-spray can alleviate this problem (Wang & Wang, 2023; Wilson, 2021).

Bio-based insulation materials tend to be combustible, meaning they contribute more to the spread of a fire than non-combustible stone or glass insulation. Some bio-based materials are classified as having minimal contribution to a fire, such as some cellulose forms, rice husk, and flax (Kumar et al., 2020). These materials are less likely to contribute to a fire than very combustible plastic insulation such as EPS, XPS, and PUR. Fire codes – as well as other building and energy codes – could limit adoption, risking a lack of solution uptake due to regulatory setbacks (Northeast Bio-Based Materials Collective 2023 Summit Proceedings, 2023). 

Additives such as fire retardants and anti-fungal agents are added to bio-based insulation along with synthetic binders, which can lead to indoor air pollution from organic compounds, although likely in low concentrations (Maskell et al., 2015; Rabbat et al., 2022).

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Interactions with Other Solutions

Reinforcing

Upgrading insulation to lower-cost and lower-emitting alternative materials should increase the adoption of other building envelope solutions as they can be installed simultaneously to optimize cost and performance. 

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Increasing the manufacturing of cellulose insulation, which contains large amounts of recycled paper, could increase the revenues for paper recycling.

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Competing

This solution uses wood as a feedstock (raw material), including wood, and crop residues. Because the total projected demand for woody biomass for climate solutions exceeds the supply, not all of these solutions will be able to achieve their potential adoption. This solution is in competition with the following solutions for raw material:

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Reducing the demand for conventional insulation products and instead making insulation that produces fewer GHGs during manufacturing would slightly reduce the global climate impact of other industrial manufacturing solutions. This is because less energy overall would be used for manufacturing, and therefore other technologies for emissions reductions would be less impactful for insulation production.

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Dashboard

Solution Basics

insulation units of 100 m² and 1 m²·K/W

t CO₂-eq (100-yr)/unit
00.981.59
units/yr
Current 1.4×10⁷ 02.9×10⁷7.3×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.022 0.0460.12
US$ per t CO₂-eq
-121
Emergency Brake

CO₂, F-gas

Trade-offs

Bio-based insulation materials including cellulose often have lower thermal resistance than some conventional insulation materials. In particular, bio-based materials may require a thicker layer than plastic insulation to reach the same insulating performance (Esau et al., 2021; Rabbat et al., 2022). Usable floor area within a building would need to be sacrificed to accommodate thicker insulation, which would potentially depreciate the structure or impact the aesthetic value (Jelle, 2011). This would be a more significant trade-off for retrofit construction and buildings in densely developed urban areas.

Sourcing bio-based materials has environmental trade-offs that come from cultivating biomass, such as increased land use, fertilizer production, and pesticide application (Schulte et al., 2021). Using waste or recycled materials could minimize these impacts. Binders and flame-retardants may also be required in the final product, leading to more processing and material use (Sustainable Traditional Buildings Alliance, 2024).

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Maps Introduction

The effectiveness of deploying alternative insulation is not inherently dependent on geographic factors since it addresses emissions embodied in the manufacture and deployment of insulation materials. However, due to a lack of related data, we assumed a consistent global breakdown of currently used insulation materials when in reality, the exact mix of insulation currently used in different geographic locations will affect the emissions impact of switching to alternative materials.

Building insulation is used in higher quantities in cold or hot climates, so deploying alternative insulation is more likely to be relevant and adopted in such climates. Other geographic factors also impact adoption: Areas with higher rates of new construction will be better able to design for cellulose or other alternative insulation materials, and drier climates will face a lower risk of mold growth on these materials. Local building codes, including fire codes, can also affect the adoption of alternative materials.

There are no maps for the Deploy Alternative Insulation Materials solution. It is intended to address emissions embodied in the manufacture and deployment of insulation materials and has no intrinsic dependence on geographic factors.

Action Word
Deploy
Solution Title
Alternative Insulation Materials
Classification
Highly Recommended
Lawmakers and Policymakers
  • Enact comprehensive policy plans that utilize all levers, including financial incentives, improved building and fire code regulations, and educational programs to advance the transition to alternative insulation.
  • Create government procurement policies that become stricter over time and mandate the use of alternative insulation or implement GWP limits in government buildings.
  • Update insulation installation regulations to encourage more sustainable practices and materials.
  • Offer financial incentives such as subsidies, tax credits, and grants for manufacturers, start-ups, and alternative insulation installers.
  • Remove financial and regulatory incentives for conventional insulation.
  • Create and enforce embodied carbon disclosure requirements for new commercial construction.
  • Create energy efficiency standards that periodically increase for insulation materials and buildings.
  • Regulate demolition of old buildings to require proper disposal of conventional insulation to ensure emissions are avoided and gases are destroyed.
  • Create reference standards for the performance and properties of alternative insulation materials.
  • Invest in R&D to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Create green building certification schemes and/or public-private partnerships that offer information, training, and general support for alternative insulation.
  • Offer educational resources, one-stop shops for retrofitting and weatherization, installation demonstrations, and tours of model builds for commercial and private developers, highlighting the cost savings, environmental benefits, and health benefits of alternative insulation.

Further information:

Practitioners
  • Finance or develop only new construction and retrofits that use alternative insulation and other low-carbon practices.
  • Take advantage of financial incentives such as subsidies, tax credits, and grants for installing alternative insulation.
  • Seek or negotiate preferential loan agreements for developers using alternative insulation and other climate-friendly practices.
  • Whenever possible, install insulation that does not use F-gas blowing agents.
  • During demolition, ensure proper disposal of conventional insulation to avoid emissions and destroy residual F-gases.
  • Integrate alternative insulation materials into construction databases, listing prices, and environmental benefits.
  • Enact company policies that disclose embodied carbon of commercial construction.
  • Create new contractual terms that require embodied emissions data from materials and methods from suppliers.
  • Advocate for financial incentives, improved building and fire codes, and educational programs for alternative insulation.
  • Use educational resources, one-stop shops for retrofitting and weatherization, installation demonstrations, and tours of model builds.
  • Conduct research to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Create or join green building certification schemes, green building councils, and/or public-private partnerships that offer information, training, and general support for alternative insulation.

Further information:

Business Leaders
  • Finance only new construction and retrofits that utilize alternative insulation and other low-carbon practices.
  • Expand product lines to include alternative insulation materials.
  • Integrate alternative insulation materials into construction databases, listing prices and environmental benefits.
  • Create new contractual terms that require embodied emissions data from materials and methods.
  • Invest in R&D to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Advocate for financial incentives, improved building and fire codes, and educational programs for alternative insulation.
  • Join green building certification schemes and/or public-private partnerships that offer information, training, and general support for alternative insulation.
  • Create long-term purchasing agreements with alternative insulation manufacturers to support stable demand and improve economies of scale.

Further information:

Nonprofit Leaders
  • Advocate for financial incentives, improved building and fire codes, and educational programs for alternative insulation.
  • Conduct research to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Offer educational resources, one-stop shops for retrofitting and weatherization, installation demonstrations, and tours of model builds for commercial and private developers, highlighting the cost savings and environmental benefits of alternative insulation.
  • Create, join, or administer green building certification schemes and/or public-private partnerships that offer information, training, and general support for alternative insulation.

Further information:

Investors
  • Finance only new construction and retrofits that utilize alternative insulation and other low-carbon practices.
  • Invest in R&D and start-ups to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Issue green bonds to invest in projects that use alternative insulation.
  • Offer preferential loan agreements for developers utilizing alternative insulation and other climate-friendly practices.
  • Create new contractual terms that require embodied emissions data from materials and methods.
  • Join green building certification schemes and/or public-private partnerships that offer information, training, and general support for alternative insulation.

Further information:

Philanthropists and International Aid Agencies
  • Finance only new construction and retrofits that utilize alternative insulation and other low-carbon practices.
  • Offer grants for developers using alternative insulation and other climate-friendly practices.
  • Create financing programs for private construction in low-income or under-resourced communities.
  • Create new contractual terms that require embodied emissions data from materials and methods.
  • Advocate for financial incentives, improved building and fire codes, and educational programs for alternative insulation.
  • Fund research to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Offer educational resources, one-stop shops for retrofitting and weatherization, installation demonstrations, and tours of model builds for commercial and private developers, highlighting the cost savings and environmental benefits of alternative insulation.
  • Create or join green building certification schemes and/or public-private partnerships that offer information, training, and general support for alternative insulation.

Further information:

Thought Leaders
  • Advocate for financial incentives, improved building and fire codes, and educational programs for alternative insulation.
  • Conduct research to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Offer or amplify educational resources, one-stop shops for retrofitting and weatherization, installation demonstrations, and tours of model builds for commercial and private developers, highlighting the cost savings and environmental benefits of alternative insulation.
  • Create, join, or administer green building certification schemes and/or public-private partnerships that offer information, training, and general support for alternative insulation.

Further information:

Technologists and Researchers
  • Develop and improve existing alternative insulation materials or innovate new materials with enhanced insulation performance.
  • Investigate ways to increase the durability of alternative insulation, such as resistance to moisture, pests, and fire.
  • Find uses for recycled materials in alternative insulation and ways to improve the circular economy.
  • Innovate new manufacturing methods that reduce electricity use and emissions.
  • Design new application systems for alternative insulation that can be done without much additional training or licensing/certification.
  • Create new methods of disposal for conventional insulation during demolitions.
  • Research adoption rates of alternative insulation materials across regions and environments.

Further information:

Communities, Households, and Individuals
  • Finance or develop only new construction and retrofits that utilize alternative insulation and other low-carbon practices.
  • Take advantage of financial incentives such as subsidies, tax credits, and grants for installing alternative insulation.
  • Whenever possible, install insulation that does not use F-gas blowing agents.
  • Advocate for financial incentives, improved building and fire codes, and educational programs for alternative insulation.
  • Conduct local research to improve alternative insulation materials’ manufacturing, adoption, supply chain access, and circularity.
  • Organize local “green home tours” and open houses to showcase climate-friendly builds and foster demand by highlighting cost savings and environmental benefits of alternative insulation.
  • Create or join green building certification schemes, green building councils, and/or public-private partnerships that offer information, training, and general support for alternative insulation.
  • Capture community feedback and share it with local policymakers to address barriers such as permitting logistics or upfront costs, helping to share policies that drive adoption.

Further information:

Sources
Evidence Base

Consensus of effectiveness in reducing building sector emissions: Mixed

There is scientific consensus that using building insulation with lower embodied emissions will reduce GHG emissions, but expert opinions about the magnitude of possible emissions reductions as well as the accuracy of determining these reductions are mixed. 

Biswas et al. (2016) determined that, for insulation, avoided emissions from reduced heating and cooling energy tend to outweigh the embodied emissions. However, others emphasize that as buildings become more energy-efficient, material embodied emissions become a larger factor in their carbon footprint (Cabeza et al., 2021; Grazieschi et al., 2021). Embodied emissions from insulation can be substantial: Esau et al. (2021) analyzed a mixed-use multifamily building and found that selecting low-embodied-carbon insulation could reduce building embodied emissions by 16% at no cost premium.

Multiple studies have found that some sustainable insulation materials have lower manufacturing emissions than traditional insulation materials (Asdrubali et al., 2015; Füchsl et al., 2022; Kumar et al., 2020; Schiavoni et al., 2016). However, researchers have highlighted the difficulty in evaluating environmental performance of different insulation materials (Cabeza et al., 2021; Grazieschi et al., 2021). Gelowitz and McArthur (2017) found that construction product Environmental Product Declarations contain many errors and discrepancies due to self-contradictory or missing data. Füschl et al. (2022) conducted a meta-analysis and cautioned that “it does not appear that a definitive ranking [of insulation materials] can be drawn from the literature.” In our analysis, we attempted to compare climate impact between materials, but we acknowledge that this can come from flawed and inconsistent data.

Despite the difficulties in comparing materials, there is high consensus that cellulose is a strong low-emissions insulation option due to its low embodied carbon, high recycled content, and good thermal insulating performance (Wilson, 2021).

The results presented in this document summarize findings from four reviews and meta-analyses, 14 original studies, three reports, 27 Environmental Product Declarations, and two commercial websites reflecting current evidence from eight countries as well as data representing global, North American, or European insulation materials. We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Updated Date

Improve Cement Production

Submitted by Drawdown Admin on
Sector
Industry, Materials & Waste
Mode
Cut Emissions
Cluster
Improve Materials
Image
Cement factory
Coming Soon
Off
Summary

Cement is a key ingredient of concrete, a manufactured material used in massive quantities around the world. Cement production generates high CO₂ emissions from the production of clinker, a binding ingredient. These emissions come from not only the chemical reaction that produces clinker, but also burning fossil fuels to provide heat for this reaction. We define the Improve Cement Production solution as reducing GHG emissions related to cement manufacturing by substituting other materials for clinker, using alternative fuels, and improving process efficiency.

Health
Air quality
Description for Social and Search
Improve Cement Production is a Highly Recommended climate solution. It involves using low GHG-emitting materials & reducing emissions from fossil-fuel burning.
Overview

Concrete production requires the manufacturing of 4 Gt of cement annually (U.S. Geological Survey, 2024). Roughly 85% of cement industry GHG emissions come from the production of a key cement component called clinker. Both the clinker formation chemical reaction and fuel combustion for high-temperature clinker kilns release GHGs (Goldman et al., 2023). Figure 1 illustrates the manufacturing steps responsible for these emissions and highlights how three approaches – clinker substitution, use of alternative fuels, and process efficiency upgrades – could mitigate emissions.

Figure 1. Cement production GHG emissions. Some 85% of GHGs emitted during cement production are released when clinker is produced in high-temperature kilns. The three approaches analyzed in this solution – clinker substitution, alternative fuels, and process efficiency upgrades – aim to mitigate such emissions. Modified from Goldman et al. (2023) via McKinsey.

Diagram of energy used in cement production process

Source: Goldman, S., Majsztrik, P., Sgro Rojas, I., Gavvalapalli, M., Gaikwad, R., Feric, T., Visconti, K., & McMurty, B. (2023). Pathways to commercial liftoff: Low-carbon cement. U.S. Department of Energy.

Clinker substitution replaces a portion of the clinker used in cement with alternative materials, thus reducing the amount of clinker manufactured. This decreases the amount of CO₂ emitted by the chemical reaction and fuel combustion. Clinker is made by heating limestone to convert it to lime. This reaction releases CO₂. Some of the CO₂ production can be eliminated by replacing some of the clinker with substitute materials such as industrial waste products, other cementitious compounds, or available minerals. Clinker substitution also reduces energy demand, lowering emissions from burning fossil fuels. Clinker fraction in cement is often expressed as a clinker-to-cement ratio, which ranges from 0 (no clinker) to 1 (entirely clinker). The most common type of cement, Portland cement, typically has a clinker-to-cement ratio of 0.95, meaning the cement is 95% clinker by mass.

Alternative fuels that can be used to heat cement kilns in place of fossil fuels are typically biomass and waste-based fuels. Cement production uses two kilns, one heated to ~700 °C and the other to ~1,400 °C (U.S. Department of Energy, 2022). The energy needed to provide this heat typically comes from burning fossil fuels such as oil, gas, or coal on-site, which emits CO₂ as well as small amounts of other GHGs, including methane and nitrous oxide, and air pollutants, including nitrogen oxides, sulfur oxides, and particulate matter (Hottle et al., 2022; Miller & Moore, 2020). Switching to alternative fuels decreases emissions by reducing the mining and combustion of fossil fuels and recovering energy from waste streams that would have otherwise released GHG during decomposition or incineration (Georgiopoulou & Lyberatos, 2018).

Efficiency upgrades include a broad suite of technologies such as improved controls, electrically efficient equipment (e.g., mills, fans, and motors), thermally efficient and multistage kilns, and waste heat recovery. These improvements lead to less wasted heat and input energy, and therefore require less fossil fuel burning during manufacturing. In particular, upgrading kilns has the potential for high emissions mitigation (Mokhtar & Nasooti, 2020; Morrow III et al., 2014). Kiln upgrades can include processing dry raw material (which is more efficient than expending energy to remove moisture from wet feedstock), adding a preheater that uses kiln exhaust gas to dry and preheat raw material, and adding a precalciner kiln that uses some of the fuel to partially calcine raw material at a lower temperature (European Cement Research Academy, 2022; Schorcht et al., 2013). Each study included in our analysis for effectiveness and cost included a set group of technologies that were considered to be process efficiency upgrades.

The cost and avoided emissions from each approach vary depending on the other technologies in use at a particular cement plant (Glenk et al., 2023). While coupling the impacts of the approaches would provide the most accurate representation of this solution, that analysis is complex and outside the scope of this assessment. Therefore, we will consider the three approaches separately. 

5.32%
of total global emissions
4.1 Billion

Worldwide, we make 4.1 billion metric tons of cement every year.

3.2 Gt

In the process, we produce more than 3 Gt CO₂‑eq of greenhouse gases – 5.32% of global annual emissions

Take Action Intro

Would you like to help reduce the climate impacts of cement production? Below are some ways you make a difference, depending on the roles you play in your professional or personal life.

These actions are meant to be starting points for involvement and may or may not be the most important, impactful, or doable actions you can take. We encourage you to explore, get creative, and take a step that is right for you!

Afsah, S. (2004). CDM potential in the cement sector: The challenge of demonstrating additionality. Performeks LLC. Link to source: https://www.performeks.com/media/downloads/CDM-Cement%20Sector_May%202004.pdf 

Cannon, C., Guido, V., & Wright, L. (2021). Concrete solutions guide: Mix it up: Supplementary cementitious materials (SCMs). RMI. Link to source: https://rmi.org/wp-content/uploads/2021/08/ConcreteGuide2.pdf 

Cao, Z., Masanet, E., Tiwari, A., and Akolawala, S. (2021). Decarbonizing concrete: Deep decarbonization pathways for the cement and concrete cycle in the United States, India, and China. Industrial Sustainability Analysis Laboratory. 

Cavalett, O., Watanabe, M. D. B., Voldsund, M., Roussanaly, S., & Cherubini, F. (2024). Paving the way for sustainable decarbonization of the European cement industry. Nature Sustainability, 7, 568–580. Link to source: https://doi.org/10.1038/s41893-024-01320-y 

CEMBUREAU. (n.d.) Clinker substitution. Retrieved August 7, 2024, from Link to source: https://lowcarboneconomy.cembureau.eu/5-parallel-routes/resource-efficiency/clinker-substitution/ 

Clark, G., Davis, M., Shibani, & Kumar, A. (2024). Assessment of fuel switching as a decarbonization strategy in the cement sector. Energy Conversion and Management, 312, 118585. Link to source: https://doi.org/10.1016/j.enconman.2024.118585 

ClimeCo. (2022). Low carbon cement production. Link to source: https://www.climateactionreserve.org/wp-content/uploads/2022/10/Low-Carbon-Cement-Issue-Paper-05-20-2022_final.pdf 

Daehn, K., Basuhi, R., Gregory, J., Berlinger, M., Somjit, V., & Olivetti, E. A. (2022). Innovations to decarbonize materials industries. Nature Reviews Materials, 7, 275–294. Link to source: https://doi.org/10.1038/s41578-021-00376-y 

de Puy Kamp, M. (2021, July 9). How marginalized communities in the South are paying the price for ‘green energy’ in Europe. CNN. Link to source: https://edition.cnn.com/interactive/2021/07/us/american-south-biomass-energy-invs/ 

European Cement Research Academy. (2022). The ECRA technology papers 2022: State of the art cement manufacturing, current technologies and their future development. Link to source: https://api.ecra-online.org/fileadmin/files/tp/ECRA_Technology_Papers_2022.pdf 

Georgiopoulou, M., & Lyberatos, G. (2018). Life cycle assessment of the use of alternative fuels in cement kilns: A case study. Journal of Environmental Management, 216, 224–234. Link to source: https://doi.org/10.1016/j.jenvman.2017.07.017 

Glenk, G., Kelnhofer, A., Meier, R., & Reichelstein, S. (2023). Cost-efficient pathways to decarbonizing Portland cement production. ZEW - Centre for European Economic Research Discussion Paper No. 23-023. Link to source: https://doi.org/10.2139/ssrn.4434830 

Global Cement and Concrete Association. (2021). Concrete future: The GCCA 2050 cement and concrete industry roadmap for net zero concrete. Link to source: https://gccassociation.org/concretefuture/wp-content/uploads/2021/10/GCCA-Concrete-Future-Roadmap-Document-AW.pdf 

Goldman, S., Majsztrik, P., Sgro Rojas, I., Gavvalapalli, M., Gaikwad, R., Feric, T., Visconti, K., & McMurty, B. (2023). Pathways to commercial liftoff: Low-carbon cement. U.S. Department of Energy. 

Gómez, D. R., & Watterson, J. D., et al. (2006). Stationary combustion. In S. Eggelston, L. Buendia, K. Miwa, T. Ngara, & K. Tanabe (Eds.), 2006 IPCC guidelines for national greenhouse gas inventories (Vol. 2). Institute for Global Environmental Strategies (IGES) for the IPCC. Link to source: https://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_2_Ch2_Stationary_Combustion.pdf 

Griffiths, S., Sovacool, B. K., Furszyfer Del Rio, D. D., Foley, A. M., Bazilian, M. D., Kim, J., & Uratani, J. M. (2023). Decarbonizing the cement and concrete industry: A systematic review of socio-technical systems, technological innovations, and policy options. Renewable and Sustainable Energy Reviews, 180, 113291. Link to source: https://doi.org/10.1016/j.rser.2023.113291 

Habert, G., Miller, S. A., John, V. M., Provis, J. L., Favier, A., Horvath, A., & Scrivener, K. L. (2020). Environmental impacts and decarbonization strategies in the cement and concrete industries. Nature Reviews Earth & Environment, 1, 559–573. Link to source: https://doi.org/10.1038/s43017-020-0093-3 

Hottle, T., Hawkins, T. R., Chiquelin, C., Lange, B., Young, B., Sun, P., Elgowainy, A., & Wang, M. (2022). Environmental life-cycle assessment of concrete produced in the United States. Journal of Cleaner Production, 363, 131834. Link to source: https://doi.org/10.1016/j.jclepro.2022.131834 

International Energy Agency. (2018). Technology roadmap: Low-carbon transition in the cement industry. Link to source: https://www.iea.org/reports/technology-roadmap-low-carbon-transition-in-the-cement-industry 

International Energy Agency. (2023a). CO2 emitted and captured in the cement sector and clinker-to-cement ratio in the Net Zero Scenario, 2015–2030. Link to source: https://www.iea.org/data-and-statistics/charts/co2-emitted-and-captured-in-the-cement-sector-and-clinker-to-cement-ratio-in-the-net-zero-scenario-2015-2030 

International Energy Agency. (2023b). Global cement production in the Net Zero Scenario, 2010–2030. Link to source: https://www.iea.org/data-and-statistics/charts/global-cement-production-in-the-net-zero-scenario-2010-2030-5260 

International Energy Agency. (2023c). Global thermal energy intensity of clinker production by fuel in the Net Zero Scenario, 2010–2030. Link to source: https://www.iea.org/data-and-statistics/charts/global-thermal-energy-intensity-of-clinker-production-by-fuel-in-the-net-zero-scenario-2010-2030 

Isabirye, A., & Sinha, A. (2023). Manufacturing sector: Cement manufacturing emissions. ClimateTRACE. Link to source: https://github.com/climatetracecoalition/methodology-documents/blob/main/2023/Manufacturing/Manufacturing%20and%20Industrial%20Processes%20sector-%20Cement%20Manufacturing%20Emissions%20methodology.docx.pdf 

Juenger, M. C. G., Snellings, R., & Bernal, S. A. (2019). Supplementary cementitious materials: New sources, characterization, and performance insights. Cement and Concrete Research, 122, 257–273. Link to source: https://doi.org/10.1016/j.cemconres.2019.05.008 

Miller, S. A., & Moore, F. C. (2020). Climate and health damages from global concrete production. Nature Climate Change, 10(5), 439–443. Link to source: https://doi.org/10.1038/s41558-020-0733-0

Mokhtar, A., & Nasooti, M. (2020). A decision support tool for cement industry to select energy efficiency measures. Energy Strategy Reviews, 28, 100458. Link to source: https://doi.org/10.1016/j.esr.2020.100458 

Morrow III, W. R., Hasanbeigi, A., Sathaye, J., & Xu, T. (2014). Assessment of energy efficiency improvement and CO2 emission reduction potentials in India's cement and iron & steel industries. Journal of Cleaner Production, 65, 131–141. Link to source: https://doi.org/10.1016/j.jclepro.2013.07.022 

Rissman, J., Bataille, C., Masanet, E., Aden, N., Morrow III, W. R., Zhou, N., Elliott, N., Dell, R., Heeren, N., Huckestein, B., Cresko, J., Miller, S. A., Roy, J., Fennell, P., Cremmins, B., Blank, T. K., Hone, D., Williams, E. D., de la Rue du Can, S., …Helseth, J. (2020). Technologies and policies to decarbonize global industry: Review and assessment of mitigation drivers through 2070. Applied Energy, 266, 114848. Link to source: https://doi.org/10.1016/j.apenergy.2020.114848 

Schorcht, F., Kourti, I., Scalet, B. M., Roudier, S., & Delgado Sancho L. (2013). Best available techniques (BAT) reference document for the production of cement, lime and magnesium oxide – Industrial Emissions Directive 2010/75/EU (integrated pollution prevention and control) (Joint Research Center publication JRC 83006). European Commission, Joint Research Centre, Institute for Prospective Technological Studies. Link to source: https://doi.org/10.2788/12850 

Searchinger, T., Peng, L., Zionts, J., & Waite, R. (2024). The global land squeeze: Managing the growing competition for land. World Resources Institute. Link to source: https://www.wri.org/research/global-land-squeeze-managing-growing-competition-land

Shah, I. H., Miller, S. A., Jiang, D., & Myers, R. J. (2022). Cement substitution with secondary materials can reduce annual global CO2 emissions by up to 1.3 gigatons. Nature Communications, 13, 5758. Link to source: https://doi.org/10.1038/s41467-022-33289-7 

Sinha, A., and Crane, V. (2024). Manufacturing and industrial processes sector: Cement manufacturing emissions. TransitionZero, UK, Climate TRACE Emissions Inventory. Link to source: https://climatetrace.org

Snellings, R. (2016). Assessing, understanding and unlocking supplementary cementitious materials. RILEM Technical Letters, 1, 50–55. Link to source: https://doi.org/10.21809/rilemtechlett.2016.12 

Snellings, R., Suraneni, P., & Skibsted, J. (2023). Future and emerging supplementary cementitious materials. Cement and Concrete Research, 171, 107199. Link to source: https://doi.org/10.1016/j.cemconres.2023.107199

U.S. Department of Energy. (2022). Industrial decarbonization roadmap. Link to source: https://www.energy.gov/sites/default/files/2022-09/Industrial%20Decarbonization%20Roadmap.pdf 

U.S. Environmental Protection Agency. (2016). Greenhouse gas inventory guidance: Direct emissions from stationary combustion sources. Link to source: https://www.epa.gov/sites/default/files/2016-03/documents/stationaryemissions_3_2016.pdf 

U.S. Federal Highway Administration. (n.d.). Use of supplementary cementitious materials (SCMs) in concrete mixtures (FHWA-HIF-19-054). U.S. Department of Transportation. Link to source: https://www.fhwa.dot.gov/pavement/concrete/trailer/resources/hif19054.pdf 

U.S. Geological Survey. (2024). Mineral commodity summaries 2024. https://doi.org/10.3133/mcs2024 

Yang, X., Teng, F., & Wang, G. (2013). Incorporating environmental co-benefits into climate policies: A regional study of the cement industry in China. Applied Energy, 112, 1446–1453. Link to source: https://doi.org/10.1016/j.apenergy.2013.03.040

Zhang, S., Ren, H., Zhou, W., Yu, Y., & Chen, C. (2018). Assessing air pollution abatement co-benefits of energy efficiency improvement in cement industry: A city level analysis. Journal of Cleaner Production, 185, 761–771. Link to source: https://doi.org/10.1016/j.jclepro.2018.02.293

Zhang, S., Worrell, E., & Crijns-Graus, W. (2015). Evaluating co-benefits of energy efficiency and air pollution abatement in China’s cement industry. Applied Energy, 147, 192–213. Link to source: https://doi.org/10.1016/j.apenergy.2015.02.081

Zhang, S., Xie, Y., Sander, R., Yue, H., & Shu, Y. (2021). Potentials of energy efficiency improvement and energy–emission–health nexus in Jing-Jin-Ji’s cement industry. Journal of Cleaner Production, 278, 123335. Link to source: https://doi.org/10.1016/j.jclepro.2020.123335

Credits

Lead Fellow

  • Sarah Gleeson, Ph.D.

Contributors

  • James Gerber, Ph.D.

  • Yusuf Jameel, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Ted Otte

  • Amanda D. Smith, Ph.D.

  • Christina Swanson, Ph.D.

Effectiveness

Cement production currently emits 760,000 t CO₂‑eq /Mt cement produced, based on our analysis. With global cement production exceeding 4 Gt/yr (U.S. Geological Survey, 2024), the scale of emissions to be mitigated is large.

Clinker substitution is the most effective of the three approaches at reducing emissions, eliminating approximately 240,000 t CO₂‑eq /Mt cement produced. This is equivalent to 690,000 t CO₂‑eq /Mt clinker avoided (Table 1a). This estimate is based on expert predictions of GHG savings for realistic target levels of clinker replacement with material substitutes.

Alternative fuels and efficiency upgrades have carbon abatement potentials of 96,000 and 90,000 t CO₂‑eq /Mt cement produced, respectively, when calculated based on production levels (Table 1b). Since the units of adoption for process efficiency upgrades are GJ thermal energy input, when calculating climate impact we used an effectiveness per GJ of thermal energy, calculated using an emission factor for fuel combustion. This effectiveness is 0.0847 t CO₂ /GJ thermal energy input (Table 1c; Gómez & Watterson et al., 2006; International Energy Agency [IEA], 2023c). 

We calculated the effectiveness of these three approaches separately. Because the implementation of each affects the effectiveness potential of the others (Glenk et al., 2023), the actual effectiveness will be lower when the approaches are implemented together.

Emissions reductions from these approaches can be directly related to how the approach impacts GHG emissions from clinker production and fossil fuel burning. However, sourcing, processing, and transporting clinker substitutes and alternative fuels also produces GHGs. Our data sources did not always report whether such indirect emissions were accounted for, so our analysis primarily focuses on direct emissions. Further analysis of other life-cycle emissions considerations would be valuable in future research; however, indirect emission levels for both clinker substitutes and alternative fuels are reportedly small compared to direct emissions (European Cement Research Academy, 2022; Shah et al., 2022).

Additionally, cement industry members sometimes assume that there are no direct emissions from burning biomass fuels (Goldman et al., 2023). As a result, we assume that direct emissions from biomass are not fully accounted for in the data and therefore that the climate benefit of using alternative fuels may be exaggerated.

While other GHGs, including methane and nitrous oxide, are also released during cement manufacturing, these gases represent a small fraction (<3% combined) of overall CO₂‑eq emissions so we considered them negligible in our calculations (U.S. Environmental Protection Agency, 2016; Hottle et al., 2022). 

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq /Mt clinker avoided, 100-year basis

25th percentile 540,000
Mean 710,000
Median (50th percentile) 690,000
75th percentile 860,000

Unit: t CO₂‑eq /Mt cement produced (100-year basis)

25th percentile 77,000
Mean 94,000
Median (50th percentile) 96,000
75th percentile 99,000

Unit: t CO₂‑eq /GJ thermal energy input (100-year basis)

Calculated value 0.0847
Cost

All three approaches to mitigating cement emissions result in cost savings by our analysis. Despite high initial costs, when considering the long technology lifetime and annual operational savings, the net lifetime and annualized costs are lower than conventional cement production.

Clinker substitution has the highest net savings of the three approaches, with US$7 million/Mt cement produced generating savings of US$30/t CO₂‑eq (Table 2a). While initial and operating costs may vary between different substitute materials, we averaged all material types for each cost estimate. Goldman et al. (2023) and the European Cement Research Academy (2022) offer breakdowns of cost by material type.

Alternative fuels generate savings of US$5 million/Mt cement, or US$50/t CO₂‑eq mitigated (Table 2b). For both clinker substitution and alternative fuels, cost and emissions will vary based on local material availability (Cannon et al., 2021). We assumed equivalent costs for all alternative fuel types.

Efficiency upgrades save US$6 million/Mt cement and have the highest cost savings per unit climate impact (US$60/t CO₂‑eq ). While process efficiency upgrades encompass many different technologies, this cost estimate incorporates the costs of two of the technologies yielding high avoided emissions – replacing long kilns with preheater/precalciner kilns and implementing efficient clinker cooler technology. Between these technologies, upgrading to preheater/precalciner kilns represents most of the initial cost increase and the operational cost savings (European Cement Research Academy, 2022).

The costs of each approach (Table 2) were calculated as amortized initial costs of upgrading plants, added to the expected changes in annual operational costs. Only very limited data are available for price premiums on low-carbon cement. Therefore, we did not include any revenues for low-carbon cement. 

While we calculated these costs separately, in reality the cost for implementing multiple approaches will be different due to interactions between technologies (Glenk et al., 2023). For example, material processing equipment could change based on the type of clinker substitute materials. We do not expect the costs to be additive as we assumed in our analysis, and limited cost data means that this estimate is based on limited sources.

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Table 2: Cost per unit climate impact.

Unit: 2023 US$/t CO₂‑eq , 100-yr basis

Clinker substitution –30

Negative values reflect cost savings.

Unit: 2023 US$/t CO₂‑eq , 100-yr basis

Alternative fuels –50

Negative values reflect cost savings.

Unit: 2023 US$/t CO₂‑eq , 100-yr basis

Process efficiency upgrades –60

Negative values reflect cost savings.

Methods and Supporting Data

Methods and Supporting Data

Learning Curve

The technologies needed for all approaches in this solution are well developed and ready to deploy at scale, so we did not consider learning curves. 

We did not find any global data on cost changes related to adoption levels for equipment, including energy-efficient processing technologies, dry-process kilns, or material storage. A portion of the solution’s initial costs come from plant downtimes, which would not be impacted by the technology learning curve. For feedstock components of the solution, including alternative fuels and clinker material substitutes, the costs will be subject to material availability, market prices, and transportation, and therefore will not necessarily decrease with adoption.

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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Improve Cement Production is a GRADUAL climate solution. It has a steady, linear impact on the atmosphere. The cumulative effect over time builds as a straight line.

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Caveats

Manufacturing emissions reductions due to clinker substitution, alternative fuels, and process efficiency upgrades are both permanent and additional. 

Permanence 

There is a low risk that the emission reductions this solution generates will be reversed in the next 100 years. This approach calls for reduced burning of fossil fuels and less calcination of limestone into clinker, thereby avoiding emissions from these activities. Meanwhile, carbon that is not released as CO₂ due to these technologies will remain stable in limestone or fossil fuel reserves indefinitely, making the emissions mitigation permanent.

Additionality 

These cement emissions reductions are additional if they are adopted in amounts higher than what is currently required and used in local or regional cement manufacturing. Afsah (2004) assessed additionality based on whether it represents “not common practice” from a national standpoint of market share or adoption. ClimeCo (2022) suggested that for clinker material substitutes to be considered additional, the substitute needs to meet two criteria: The replacement is not mandated by law, and new or emerging materials are used.

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Current Adoption

Few global data are available for current adoption. Most data are from regional sources, typically the United States or Europe. As a result, we do not expect these data to be representative at the global level – China and India alone produce more than 60% of the world’s cement (U.S. Geological Survey, 2024). Therefore, we quantified adoption only from a limited number of worldwide sources, using the adoption units listed in Figure 2.

Clinker substitution is challenging to assess for adoption, since it is implemented with a broad range of materials and replacement fractions. We therefore simplified adoption in this analysis by quantifying it as the amount of global cement material that is not clinker. The adoption tonnage (Table 3a) represents Mt of clinker production avoided, using conventional Portland cement (5% non-clinker) as a baseline (CEMBUREAU, n.d.). Note that this is different from the way we considered cement tonnage for effectiveness and cost. There, we calculated emissions reductions for a Mt of cement produced including substituted material. For adoption, however, we considered tonnage to be clinker avoided (based on amount replaced with other materials).

The IEA (2023a) and the European Cement Research Academy (2022) estimated the global clinker-to-cement ratio to be approximately 0.72, meaning that 28% of cement composition is material other than clinker. This correlates to 980 Mt clinker avoided/yr used over the Portland cement baseline.

Alternative fuels are currently used to replace approximately 7% of fossil fuels in global cement production (Global Cement and Concrete Association, 2021; IEA, 2023c). We assumed this means approximately 300 Mt cement/yr are currently produced with biomass and waste fuels (Table 3b).

Efficiency upgrades encompass dozens of technological improvements, which – along with a paucity of available data – make adoption levels challenging to assess. To estimate the current state of energy usage in the cement industry, we used the IEA (2023c) estimate of 3,550,000 GJ/Mt clinker as the 2022 benchmark thermal energy input for clinker production. This value does not include electrical efficiency and can vary based on fuel mix, but approximates the current state of energy use. We converted it to GJ/yr using amounts of annual clinker production, yielding 10.5 billion GJ thermal energy consumed each year for clinker production. Since there is no baseline for efficiency, we consider this value to be the zero adoption scenario and the current adoption to be not determined (Table 3c).

For the other approaches, there is a clear baseline case of “zero adoption” where no substitutes or alternative fuels are in use. However, thermal energy input is an energy use indicator that represents a continuum with no clear baseline. We therefore had to benchmark future energy savings against an initial value, which we chose as 2022 since it provided the most recent available data. All future estimates represent annual GHG savings relative to global cement production’s 2022 GHG emissions levels.

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Table 3. Current adoption level (2022).

Unit: Mt clinker avoided/yr

Median (50th percentile) 980

Unit: Mt cement produced using alternative fuels/yr

Median (50th percentile) 300

Unit: GJ thermal energy input/yr saved

Median (50th percentile) not determined
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Adoption Trend

Clinker substitution has experienced relatively unchanged adoption worldwide in recent years (Table 4a). Since 2016, there has been a small increase in clinker-to-cement ratio, indicating a slight decrease in adoption of this approach (IEA, 2023a). This corresponds to 40 Mt fewer clinker material substitutes being used each year, on average. 

Alternative fuels adoption is slowly on the rise as percent of fuel mix (Table 4b). According to the IEA (2023c), the percentage of global clinker produced by bioenergy and waste fuels increased from 6.5% in 2015 to 8.5% in 2022. This corresponds to a median annual increase of 12 Mt cement/yr produced by alternative fuels. 

The IEA (2023c) reported efficiency upgrades to have led to a median annual decrease of 5,000 GJ/Mt clinker from 2011 to 2022, representing a –0.14% annual change in energy input. This indicates that processes consuming thermal energy have become slightly more efficient in recent years. When converted to GJ/yr, this is 15 million fewer GJ thermal energy consumed each year (Table 4c).

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Table 4. Adoption trend.

Unit: annual change in Mt clinker avoided/yr

Median (50th percentile) –40

2016–2022 adoption trend

Unit: annual change in Mt cement produced using alternative fuels/yr

Median (50th percentile) 12

2015–2022 adoption trend

Unit: annual change in GJ thermal energy input/yr

Median (50th percentile) –15,000,000

2011–2022 adoption trend

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Adoption Ceiling

The adoption ceiling (Table 5) is high for all approaches within this solution.

Clinker substitution adoption is likely to be limited primarily by material standards and availability. Across literature, the median adoption ceiling is considered to be 3,000 Mt clinker avoided/yr beyond the Portland cement baseline, yielding a clinker-to-cement ratio of 0.2. Snellings (2016) calculated the worldwide amount of clinker materials substitutes and found that a maximum of ~2,000 Mt/yr would be available, which would result in a clinker-to-cement ratio of approximately 0.5. In the future, some waste materials – like fly ash and ground granulated blast furnace slag – are likely to be less available so increasing the possible substitute amounts would require research on new materials or cement properties.

Alternative fuels are typically assumed to be applicable to roughly 90% of cement production globally, or approximately 4,000 Mt cement/yr at 2022 global production levels (Daehn et al., 2022). In theory, kilns can use 100% alternative fuels, although composition of the fuel can influence the trace elements or calorific value (European Cement Research Academy, 2022). In particular, several analyses point to the lower calorific value of alternative fuels as an adoption-limiting factor. Cavalett et al. (2024) considered 90% to be the maximum. A separate analysis of Canadian cement production determined that 65% is the threshold due to lower-calorie fuels only being applicable in a precalciner kiln – the equipment where fuel is used to begin decomposing limestone through the calcination process (Clark et al., 2024).

Efficiency upgrades have their adoption ceiling limited by the minimum thermal energy demand needed to run cement kilns. The European Cement Research Academy estimates this lower threshold of energy input to be approximately 2,300,000 GJ/Mt clinker, considering chemical reaction and evaporation energy needs (European Cement Research Academy, 2022). This converts to 6.9 billion GJ thermal energy used each year, or 3.6 billion GJ/yr saved over current thermal energy efficiency levels (Table 5c).

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Table 5. Adoption ceiling.

Unit: Mt clinker avoided/yr

Median (50th percentile) 3,000

Unit: Mt cement produced using alternative fuels/yr

Median (50th percentile) 4,000

Unit: GJ thermal energy input/yr saved over current levels

Median (50th percentile) 3,600,000,000
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Achievable Adoption

Clinker substitution achievable adoption (Table 6a) is primarily limited by material availability and initial costs. Global estimates generally expect 30–50% of total substituted material to be reasonable, which correlates to a clinker-to-cement ratio of 0.4–0.6 and 1,000–2,000 Mt clinker avoided/yr (Habert et al., 2020; European Cement Research Academy, 2022). In a separate U.S.-specific analysis, the substitute amount was projected to vary from 5% to 45% depending on the availability and performance of the material substitute (Goldman et al., 2023).

Alternative fuels are projected to account for roughly 40% of the cement fuel mix in 2050 for both global and North American estimates. Taking the median of the global achievable adoption estimates, this correlates to 2,000 Mt cement/yr that would be produced using alternative kiln fuels. As a low estimate, if the current adoption trend holds, approximately 16% of global cement fuel (producing 610 Mt cement/yr) will come from biomass and waste (IEA, 2023c). A reasonable adoption range is 610–2,000 Mt cement/yr (Table 6b), although some European countries currently have ~80% adoption of alternative fuels, meaning that >40% adoption in an aggressive 2050 scenario may be feasible (Cavalett et al., 2024).

Little information exists on projected global adoption of efficiency upgrades between now and 2050. In an analysis of a fraction of cement plants in China, India, and the U.S., it was estimated that these three countries – which represent more than 70% of current cement production worldwide – could reach a thermal energy input of 3.15–3.25 million GJ/Mt clinker by 2060, or 9.30–9.59 billion GJ/yr, which is 0.886–1.18 billion GJ/yr saved over current adoption levels (Table 6c; Cao et al., 2021). Meanwhile, in a European analysis, the European Cement Research Academy (2022) found the same range to be possible by 2050. This is not significantly lower than the current state due to the fact that the highest-producing countries – China and India – have newer manufacturing facilities with more efficient equipment today. Countries with more room to improve in thermal energy efficiency – such as the U.S. – produce only a small fraction of the world’s cement. Approximately 92% of global plants are estimated to use more efficient dry kiln technology, indicating that some of the more energy-saving equipment upgrades are already highly adopted (Isabirye & Sinha, 2023). Therefore, there is less room for increased adoption in kiln technologies worldwide, although electrical efficiency measures could further improve these values.

 While the estimates for tonnage of cement impacted by these approaches are based on 2022 global production numbers, cement production will change through 2050, meaning the impacted mass of cement will also change as these emissions-reducing measures are adopted (IEA, 2023b).

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Table 6. Range of achievable adoption levels.

Unit: Mt clinker avoided/yr

Current adoption 980
Achievable – low 1,000
Achievable – high 2000
Adoption ceiling 3000

Unit: Mt cement produced using alternative fuels/yr

Current adoption 300
Achievable – low 610
Achievable – high 2,000
Adoption ceiling 4,000

Unit: GJ thermal energy input/yr saved over current adoption levels

Current adoption not determined
Achievable – low 886,000,000
Achievable – high 1,180,000,000
Adoption ceiling 3,600,000,000

Note: High adoption in this case results in lower energy use for each unit of cement produced, and thus better efficiency. 

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Improved cement production has high potential for climate impact. By our estimate, cement production is responsible for >5% of global GHG emissions, so mitigating even a portion of these emissions will meaningfully reduce the world’s carbon output.

Clinker substitution has the highest current and potential GHG emissions savings of the three approaches (Table 7a). To calculate the climate impact, we used effectiveness and adoption on the basis of Mt clinker avoided. Climate impact was calculated as:

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$$\frac{\textit{CO₂ abated}}{\textit{yr}} = \frac{\textit{CO₂ abated}}{\textit{clinker avoided}} \times \frac{\textit{clinker avoided}}{\textit{Year}}$$
  • Current GHG savings: 0.67 Gt CO₂‑eq/yr
  • GHG savings ceiling: 2 Gt CO₂‑eq/yr
  • Achievable GHG savings range: 0.7–1 Gt CO₂‑eq/yr

Alternative fuels have a low current climate impact but possess the potential to be adopted for a much greater fraction of the global kiln fuel mix (Table 7b). However, alternative fuels’ potential GHG emissions savings are lower than those for clinker substitutes because alternative fuels have a lower CO₂ mitigation effectiveness. Climate impact is calculated as:

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$$\frac{\textit{CO₂ abated}}{\textit{yr}} = \frac{\textit{CO₂ abated}}{\textit{cement produced}} \times \frac{\textit{cement produced}}{\textit{Year}}$$
  • Current GHG savings: 0.03 Gt CO₂‑eq/yr
  • GHG savings ceiling: 0.4 Gt CO₂‑eq/yr
  • Achievable GHG savings range: 0.06–0.2 Gt CO₂‑eq/yr

Switching to alternative fuels requires the use of biomass as a feedstock. Multiple climate solutions, in addition to improving cement production, require biomass, and projected demand across solutions greatly exceeds supply. The deforestation that would be required to meet demand would produce emissions far greater than any mitigation gains from full deployment of these solutions (Searchinger, 2024). In addition to deforestation, there would also be costs and emissions incurred to transport biomass from where it is produced to where it can be processed and used. Thus, the achievable GHG savings range presented here is only possible if feedstocks are prioritized for this solution. If feedstocks are instead prioritized for other climate solutions (see Interactions for examples), adoption and impact will be lower for this solution. It is not possible to set all biomass-dependent solutions to high adoption levels, add up their impacts, and determine an accurate combined emissions impact.

Efficiency upgrades are the most challenging to assess for climate impact because they represent a broad range of equipment upgrades with no clear baseline efficiency. We considered adoption to be energy savings from the current (2022) baseline in GJ thermal energy input/yr. We converted adoption to climate impact using the emission factor of 0.0847 t CO₂‑eq /GJ thermal energy input (calculated using data from Gómez & Watterson et al., 2006 and IEA, 2023c). The resulting calculation is as follows:

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$$\frac{\textit{CO₂ abated}}{\textit{yr}} = \frac{\textit{CO₂ emissions}}{\textit{thermal energy}} \times \frac{\textit{thermal energy savings from 2022 baseline}}{\textit{yr }}$$
  • Current GHG savings: N/A (we consider the current adoption to be the baseline)
  • GHG savings ceiling: 0.31 Gt CO₂‑eq/yr less than 2022
  • Achievable GHG savings range: 0.0760–0.101 Gt CO₂‑eq/yr less than 2022

While clinker substitution, alternative fuels, and efficiency upgrades are quantified separately here, the adoption of any of these approaches will reduce the climate impact of the others. In particular, the climate impacts for technologies that reduce emissions per Mt of clinker (such as alternative fuels and process efficiency upgrades) will be lower when implemented along with technologies that reduce the amount of clinker used (such as clinker substitution), and vice versa (Glenk et al., 2023). Therefore, these impacts will not be additive, although they will contribute to reduced emissions when implemented together.

While our analysis found clinker substitution to have the highest climate impact, cement manufacturers will have to prioritize these technologies depending on their plant’s existing equipment, local availability of materials, and regional cement standards.

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Table 7. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current adoption 0.67
Achievable – low 0.7
Achievable – high 1
Adoption ceiling 2

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current adoption 0.03
Achievable – low 0.06
Achievable – high 0.2
Adoption ceiling 0.4

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current adoption not determined
Achievable – low 0.075
Achievable – high 0.100
Adoption ceiling 0.31
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Additional Benefits

Health 

Miller & Moore (2020) estimated that the health damages associated with cement production amounted to approximately US$60 billion globally in 2015. These health damages are due to air pollutants produced during cement manufacturing, which would be reduced by this solution as described above. In China, one study estimated that improving energy efficiency in the Jing Jin Ji region’s cement industry could prevent morbidity in 17,000 individuals (Zhang et al., 2021). 

Air Quality 

Cement production is a major contributor to air pollution. Globally, concrete production accounts for approximately 8% of nitrogen oxide emissions, 5% of sulfur oxide emissions, and 5% of particulate matter emissions, with a significant portion of all these emissions stemming exclusively from cement production (Miller & Moore, 2020). Cement-related air pollution is especially acute in China, which produces over 50% of the world’s cement (U.S. Geological Survey, 2024). In 2009, China's cement industry emitted 3.59 Mt of particulate matter, making the industry the leading source of particulate matter emissions in the country (Yang et al., 2013). China also released 0.88 Mt of sulfur dioxide, accounting for about 4% of the national total, and emitted 1.7 Mt of nitrogen oxides (Yang et al., 2013). Process efficiency upgrades in cement manufacturing can reduce these harmful emissions. For example, implementing energy efficiency measures in China’s cement industry could reduce particulate matter by more than 3%, lower sulfur dioxide emissions by more than 15%, and decrease nitrogen oxide emissions by more than 12% by 2030 (Zhang et al., 2015). In Jiangsu province, which is the largest cement producer in China, energy and CO₂ reduction techniques could cut particulate matter and nitrogen oxide emissions by 30% and 56%, respectively, by 2030 (Zhang et al., 2018).

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Risks

According to the U.S. Federal Highway Administration (n.d.), the use of clinker material substitutes in cement slows concrete curing times. Additionally, some clinker material substitutes, such as fly ash, raise ecotoxicity concerns and require safe handling (U.S. Department of Energy, 2022). Robust research and development is needed for new compositions of cement to accelerate testing, standardization, and adoption (Griffiths et al., 2023). Since regional standards vary for cement and concrete, policy and regulatory support designed for specific locations will be necessary to influence adoption levels and rates.

Most clinker material substitutes have limited or regional availability, leading to shortages, high costs, and transportation emissions (Habert et al., 2020). Because some substitute materials are sourced from the waste streams of other industries, such as the coal and steel industries, the long-term feasibility of sourcing these materials is uncertain (Goldman et al., 2023; Juenger et al., 2019). However, one study found that most leading cement-producing countries have substitute materials available in sufficient quantities to replace at least half of their current clinker usage (Shah et al., 2022). 

In terms of risks associated with alternative fuels, they can be subject to regional scarcity. Lack of available waste fuel in particular could risk non-waste biomass burning, leading to deforestation and high net emissions (de Puy Kamp, 2021). In addition, waste fuels can have varying compositions that can lead to different heats of combustion, kiln compatibility, or emitted pollutants (Griffiths et al., 2023). Finally, the use of waste products requires cement plants to be situated near industrial waste sources, risking low adoption for cement plants that are not located near a waste source. 

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Interactions with Other Solutions

Reinforcing

Lower-carbon cement will improve the effectiveness and enhance the net climate impact of any solutions that might require new construction. The embodied emissions from the cement and concrete used for new built structures or roads will be reduced.

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Technological advancements and increased adoption of efficient cement manufacturing equipment will improve the rate and cost of scaling similar high-efficiency machinery.

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Industrial electrification in cement plants will be faster and easier to adopt if the plants’ energy demands are lowered via reduced clinker production and more efficient processes.

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Competing

This solution uses biomass as a feedstock (raw material) for kiln fuel or as a source of ash for clinker substitues, including wood, food, crop residues, and municipal waste.  Because the total projected demand for biomass feedstocks for climate solutions exceeds the supply, not all of these solutions will be able to achieve their potential adoption. This solution is in competition with the following solutions for raw material:

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Dashboard

Solution Basics

Mt clinker avoided

t CO₂-eq (100-yr)/unit
0540,000690,000
units/yr
Current 980 01,0002,000
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.67 0.71
US$ per t CO₂-eq
-30
Gradual

CO₂

Solution Basics

Mt cement produced using alternative fuels

t CO₂-eq (100-yr)/unit
077,00096,000
units/yr
Current 300 06102,000
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.03 0.060.2
US$ per t CO₂-eq
-50
Gradual

CO₂

Solution Basics

GJ thermal energy input reduced from current levels/yr

t CO₂-eq (100-yr)/unit
0.085
units/yr
Current Not Determined 08.86×10⁸1.18×10⁹
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current Not Determined 0.0760.1
US$ per t CO₂-eq
-60
Gradual

CO₂

Trade-offs

Wider adoption of clinker material substitutes, alternative fuels, and process efficiency upgrades could generate new GHG emissions, including emissions stemming from the transportation of clinker material substitutes and alternative fuels as well as embodied emissions from manufacturing and installing new cement plant equipment. Nevertheless, the overall solution effectiveness is not expected to be significantly impacted. In some of the largest cement-producing countries, the emissions from transport of clinker material substitutes has been calculated to be an order of magnitude less than the emissions savings from the use of those substitutes in place of clinker (Shah et al., 2022). 

In terms of environmental impact, some clinker substitutes such as calcined clays and natural pozzolans can increase water use (Juenger et al., 2019; Snellings et al., 2023). Additionally, the use of biomass as an alternative fuel source could lead to trade-offs – such as increased water use and land use, or diminished resource availability – although the risk of this outcome is low since biomass for kiln fuels tends to be agricultural by-products or other waste (Clark et al., 2024; Georgiopoulou & Lyberatos, 2018). 

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Mt CO2-eq
< 2
2 - 4
4 - 6
6 - 8
8 - 10
> 10

Annual cement plant emissions, 2024

Cement production emissions are partly due to burning fossil fuels to run kilns and partly due to CO2 emissions associated with the chemistry of producing clinker, a key component of cement.

Sinha, A. and Crane, V. (2024). Manufacturing and industrial processes sector: Cement manufacturing emissions [Data set]. TransitionZero, Climate TRACE Emissions Inventory. Retrieved February 11, 2025, from Link to source: https://climatetrace.org

Mt CO2-eq
< 2
2 - 4
4 - 6
6 - 8
8 - 10
> 10

Annual cement plant emissions, 2024

Cement production emissions are partly due to burning fossil fuels to run kilns and partly due to CO2 emissions associated with the chemistry of producing clinker, a key component of cement.

Sinha, A. and Crane, V. (2024). Manufacturing and industrial processes sector: Cement manufacturing emissions [Data set]. TransitionZero, Climate TRACE Emissions Inventory. Retrieved February 11, 2025, from Link to source: https://climatetrace.org

Maps Introduction

There are no location-specific constraints to the effectiveness of the Improve Cement Production solution as there are for solutions dependent on climatic factors. However, there is geographic variation associated with current uptake of solutions and feasibility/expense of future uptake. Moreover, the distribution of cement-producing facilities around the world is non-uniform, thus the solution set naturally has the greatest applicability in regions with the greatest concentration of cement production. China and India have particularly high production of cement at 51% and 8% of global totals in 2024, respectively (Sinha & Crane, 2024).

Newer cement plants are more likely to have high thermal efficiencies, and the age of cement plants varies around the world, with average ages of cement plants less than 20 years in much of Asia, and greater than 40 years in much of the U.S. and Europe.

Uptake of alternative fuels is relatively high in Europe and low in the Americas.  

While use of clinker substitutes is in principle possible anywhere, the materials themselves are not readily available everywhere, thus transportation costs and associated emissions can place constraints on their viability (Shah et al., 2022).

Action Word
Improve
Solution Title
Cement Production
Current State Introduction

Our analysis of the current state of solutions for improved cement production included three separate approaches to reducing emissions: clinker substitution, alternative fuels, and process efficiency upgrades. Each approach had adoption units chosen based on data availability and consistency between calculated values. Figure 2 summarizes the units and conversions used for all approaches.

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Figure 2. Units of quantification used in the Current State, Adoption, and Impacts analyses below.

Approach Clinker substitution Alternative fuels Process efficiency upgrades
Effectiveness

t CO₂-eq abated/Mt clinker avoided*

t CO₂ abated/Mt cement produced*

 t CO₂-eq abated/Mt cement produced

t CO₂-eq abated/GJ thermal energy input**

t CO₂-eq abated/Mt cement produced**
Cost US$/Mt cement produced US$/Mt cement produced US$/Mt cement produced
Adoption Mt clinker avoided/yr Mt cement/yr produced using alternative fuels GJ thermal energy input saved/yr
Climate impact Gt CO₂-eq/yr Gt CO₂-eq/yr Gt CO₂-eq/yr

*Clinker substitution effectiveness was calculated in two different adoption units using the same source data. Effectiveness in t CO₂‑eq abated/Mt cement produced was used to calculate cost per climate impact. Effectiveness was converted to t CO₂‑eq abated/Mt clinker avoided using the clinker-to-cement ratio for each individual study in the analysis, and this was used to calculate climate impact.

**Process efficiency upgrades effectiveness in units of t CO₂‑eq abated/Mt cement produced was used to calculate cost per climate impact. Separately, a calculated fuel emission factor effectiveness in units of t CO₂‑eq abated/GJ thermal energy was used to quantify climate impact.

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Classification
Highly Recommended
Lawmakers and Policymakers
  • Hold cement manufacturers accountable for safety standards.
  • Regulate clinker substitution, alternative fuel usage, and process efficiency upgrades.
  • Set standards for low-carbon cement and reporting on embodied carbon for new projects.
  • Provide financial incentives such as grants, subsidies, and/or carbon taxes.
  • Set low-carbon cement standards for public procurement.
  • Implement building codes and standards that allow for the safe, tested use of low-clinker cement while accounting for regional variability in cement compositions.
  • When possible integrate low-carbon cement standards into industry standards such as LEED certification or CALGreen.
  • Increase investment in research and development of clinker material substitutes.
  • Promote a circular economy by creating reverse supply chains to collect industrial and biomass waste to be used as feedstocks for cement kilns and products.
  • Require labels for low-carbon products and materials.
  • Engage impacted communities and incorporate public feedback into policy design.
  • Ensure permit processes for mining or collecting clinker substitutes allow local supply chains to develop.
  • Integrate water management into policy planning when adopting new cement technologies, especially in drought-prone areas.

Further information:

Practitioners
  • Increase the fraction of clinker substitutes in cement, which will reduce production costs.
  • Use alternative fuels as manufacturing energy sources, ideally from renewable sources when possible, which will reduce production costs.
  • Upgrade equipment and production process to be more efficient, which will reduce production costs.
  • Invest in research and development for clinker material substitutes and process improvements.
  • Work to form national and regional industrial strategies for low-carbon cement.
  • Engage with local community members and use their feedback to create safer and healthier production facilities.
  • Increase transparency and reporting around energy usage, fuel composition, and the material composition of cement products.
  • Integrate water management safeguards when adopting new cement technologies, especially in drought-prone areas.
  • Join, create, or participate in partnerships or certification programs dedicated to improving cement production.

Further information:

Business Leaders
  • Source from low-carbon cement producers.
  • Advocate for low-carbon cement during project design and construction.
  • Promote concrete alternatives in high-profile projects.
  • Purchase, promote, and/or invest in local manufacturing and supply chains not only for materials and equipment used to make low-carbon cement, but also for low-carbon cementitious products.
  • Create off-take agreements for emerging cement technologies.
  • Create training and capacity-building programs for industry professionals related to the use and benefits of low-carbon cement and concrete.
  • Launch education and awareness campaigns that share case studies and pilot projects with industry media and other key stakeholders.
  • Leverage carbon markets to help subsidize the cost of low-carbon cement.
  • Work with governments and financial institutions to establish standards and incentives for utilizing low-carbon materials.

Further information:

Nonprofit Leaders
  • Assist with monitoring and reporting related to energy usage, fuel composition, and the material composition of cement products.
  • Help design policies and regulations that support low-carbon cement production.
  • Educate the public about the urgent need for low-carbon cement while showcasing its many benefits.
  • Encourage policymakers to create ambitious targets and regulations.
  • Encourage cement manufacturers to improve their practices.
  • Join, create, or participate in partnerships or certification programs dedicated to improving cement production.

Further information:

Investors
  • Invest in low-carbon cement producers, low-carbon cement research and development, and shared recycling infrastructure for cement materials.
  • Invest in supply chains for new clinker substitutes, alternative fuels, and technologies that improve production efficiency.
  • Encourage portfolio companies to produce low-carbon cement or source from low-carbon cement producers, noting that low-carbon retrofits will save money for producers.
  • Seek impact investment opportunities, such as low-interest loans for construction or renovation projects that use low-carbon cement, or favorable loans for entities that set low-carbon cement policies or targets.

Further information:

Philanthropists and International Aid Agencies
  • Set low-carbon cement standards for construction-related grants, loans, and awards.
  • Provide capital for local supply chains and the acquisition or production of clinker material substitutes.
  • Support global, national, and local policies that promote low-carbon cement use.
  • Explore opportunities to fund low-carbon cement start-ups.
  • Advance awareness of the public health and climate benefits of low-carbon cement.
  • Join, create, or participate in partnerships or certification programs dedicated to improving cement production.

Further information:

Thought Leaders
  • Provide technical assistance (e.g., circular economy design) to producers, government agencies, and other entities working to reduce cement emissions.
  • Help design policies and regulations that support the adoption of low-carbon cement.
  • Educate the public through campaigns emphasizing the urgent need to reduce cement production emissions.
  • Encourage policymakers to create more ambitious targets and regulations.
  • Pressure the cement industry to improve its production practices.
  • Join, create, or participate in partnerships or certification programs dedicated to improving cement production.

Further information:

Technologists and Researchers
  • Develop new separation technology for recycling cement material.
  • Assess new clinker substitutes and improve supply chains for known substitutes.
  • Improve the efficiency of processing technology and equipment.
  • Increase the safety of extraction, transport, handling, and processing of clinker material substitutes.
  • Develop on-site testing and reporting methods for tracking the energy use of manufacturing processes, fuel composition, and the material composition of cement products.
  • Examine and refine understandings of the potential revenue and price premiums of low-carbon cement products.

Further information:

Communities, Households, and Individuals
  • Purchase low-carbon cement and concrete products when possible.
  • Document your experiences if harmful cement production practices impact you. Share documentation of harmful cement production practices and/or other key messages with policymakers, the media, and your community.
  • Encourage policymakers to improve regulations related to cement production.
  • Support public education efforts to raise awareness about the urgent need to make cement production practices more environmentally sustainable.
  • Pressure the cement industry to improve its production practices.

Further information:

Sources
Evidence Base

Consensus of effectiveness in reducing cement industry emissions: High

The U.S. Department of Energy reports that the cement industry produces an estimated 7–8% of global CO₂ emissions (Goldman et al., 2023), so this is an important area to target. There is high scientific consensus that clinker substitution, alternative fuels, and process efficiency upgrades can be immediately and effectively implemented. Other emissions reduction strategies – including hydrogen kiln fuel, electrification, and carbon capture and storage technologies – have generated mixed scientific opinions on their potential for immediate impact and were not considered in this analysis. 

The U.S. Department of Energy (2022) highlighted cement as one of five high-emitting industries with potential for mitigation. The technologies identified as having the highest level of maturity and market readiness were energy efficiency measures, biomass and natural gas fuels, material efficiency measures, and blended-material cements. 

An extensive review of industrial decarbonization points to four technologies that could be implemented in the near term across global industries: electrification, material efficiency, energy efficiency, and circularity (Rissman et al., 2020). The European Cement Research Academy (2022) classified the three cement industry approaches considered in this solution – clinker substitution, alternative fuels, and process efficiency upgrades – as meeting the highest technology readiness level.

Goldman et al. (2023) identified clinker substitution, alternative fuels, and efficiency improvements as deployable today, estimating that these three approaches could abate 30% of U.S. cement industry emissions by 2030. Habert et al. (2020) proposed technologies that could reduce emissions up to 50% in the next few decades, including “cement improvements” of supplementary clinker materials, alternative fuels, and more efficient technologies. The IEA (2018) estimated that clinker material replacement, alternative fuels, and efficiency improvements could provide 37%, 12%, and 3% of cement emissions savings by 2050, respectively.

The results presented in this document summarize findings from two reviews and meta-analyses, eight original studies, nine reports, and several data sets reflecting current evidence from 33 countries, primarily high cement-producing countries in North America, Europe, and Asia. We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Updated Date

Deploy Methane Digesters

Submitted by Drawdown Admin on
Sector
Industry, Materials & Waste
Mode
Cut Emissions
Cluster
Use Waste as a Resource
Image
Methane digesters
Coming Soon
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Summary

Methane digesters are specialized devices that use anaerobic digestion to convert agricultural, industrial, or municipal organic waste into biogas and digestate, a nutrient-rich material. Treating organic waste using a methane digester reduces emissions by capturing methane that would have been released during uncontrolled anaerobic decomposition in a landfill or manure lagoon. In addition, the biogas produced by a methane digester can be used as fuel for heat, electricity, or transportation. However, emissions reduction efficacy depends on the type of organic feedstock used and methane leakage rates, which can be high. Methane digesters have been deployed in many parts of the world at various scales, from household to centralized industrial-scale digesters. Capital and operational costs can be high, but the sale of biogas can provide additional sources of revenue for farmers or waste disposal facilities. However, this could also incentivize increased waste production to meet biogas demand, leading to higher emissions. Based on our assessment, methane digesters can reduce emissions under specific conditions. However, due to their high costs, uneven effectiveness, and risk of incentivizing waste production, we will “Keep Watching” this potential solution.

Description for Social and Search
The Deploy Methane Digesters solution is coming soon.
Overview

What is our assessment?

Based on our analysis, methane digesters can reduce emissions only under some conditions. However, because of high methane leakage rates, relatively high costs, and the risk that they may incentivize high-emission activities, methane digesters are not broadly applicable for large-scale deployment. We will “Keep Watching” this potential climate solution.

Plausible Could it work? Yes
Ready Is it ready? Yes
Evidence Are there data to evaluate it? Limited
Effective Does it consistently work? No
Impact Is it big enough to matter? No
Risk Is it risky or harmful? No
Cost Is it cheap? No

What is it?

Methane digesters are specialized devices that utilize anaerobic digestion to convert agricultural, industrial, or municipal organic waste into useful products, such as biogas and digestate, in a controlled environment. Using methane digesters to treat organic waste reduces emissions by capturing methane that would have otherwise been released during uncontrolled anaerobic decomposition in landfills, manure lagoons, or other waste facilities. Methane digester-produced biogas, which is roughly 50% methane and 50% CO₂, along with some trace gases, can be used directly as a fuel or refined further into biomethane to replace natural gas use for heat, electricity, transportation, or industrial processes. Biogas can potentially reduce emissions from electricity or heat generation if it is used to replace a more emissions-intensive fuel. Biomethane, also called renewable natural gas, can be used as a drop-in replacement anywhere natural gas is used, such as in industrial processes.

Does it work?

The effectiveness of methane digesters for reducing emissions varies depending on the type of feedstock used and the amount of methane that leaks from the digester and any associated tanks, valves, and pipes. For manure and municipal organic waste, which often degrade in anaerobic environments and can emit methane directly to the atmosphere, capturing that methane in a methane digester and using the resulting biogas to replace a fossil fuel energy source can result in a net emissions reduction if methane leakage rates are low. In contrast, using agricultural crop residues, which typically degrade aerobically and produce CO₂, as feedstock for a methane digester may yield little or no reduction in net GHG emissions, largely due to methane leaks. Use of biogas for energy can also reduce emissions if it replaces a more carbon-intensive fuel. 

Why are we excited?

Methane digesters have been deployed in many parts of the world at various scales, from household to centralized industrial-scale digesters. They can use a wide variety of organic feedstocks from the agricultural, municipal, and industrial sectors. For municipal organic waste and concentrated livestock manure, methane digesters are more effective at reducing emissions than landfilling or most other manure management strategies. The biogas produced can be stored and used for on-site energy needs or as a fuel source for dispatchable electricity that supports intermittent clean energy options such as solar and wind generation. It can also be sold to provide additional sources of revenue for farmers or waste disposal facilities. The use of methane digesters can reduce noxious odors from waste, and the digestate can be used as material for animal bedding or fertilizer, reducing demand for synthetic fertilizers. 

Why are we concerned?

The most serious problem with methane digesters is that they are a significant source of methane leaks. Few data are available on leakage rates; however, the International Energy Agency (IEA) reports that methane leakage from biogas production can range from 0% to 12%, which is significantly higher than the average global methane leakage rate for oil and gas production of 1.2% in 2024. Over a 20-year time frame, methane is more than 80 times more potent than CO₂ at trapping heat in the atmosphere. Therefore, using methane digesters to process waste material that would otherwise degrade aerobically in order to produce methane-rich biogas could, due to high methane leakage rates, have an even greater warming impact than if the waste were left alone. The collection, transportation, and processing of feedstocks and the operation of the methane digesters also produce GHG emissions from fuel use. 

Methane digesters have a high capital cost and are more expensive than other forms of manure methane abatement, such as covers, physical treatments, or chemical treatments. Financial support from governments can help with the upfront installation costs, while low-cost feedstocks and expensive conventional fuel prices could help create an environment where biogas production is economically viable. However, these economic incentives may encourage poor farming practices or increased waste production. For example, dairy farmers may consider increasing their herd size to capitalize on revenues from the outputs of methane digesters, an outcome that would increase total methane emissions from agriculture. There are also health and safety concerns, as there have been instances of digester explosions and leaks that have injured people or harmed the environment.

Brown, D. (2025). Anaerobic digesters must be tightly regulated. Huron River Watershed Council. Link to source: https://www.hrwc.org/anaerobic-digesters-must-be-tightly-regulated/ 

CCAC secretariat. (2022). Biogas, a climate and clean air solution with many benefits. Climate & Clean Air Coalition. Link to source: https://www.ccacoalition.org/news/biogas-climate-and-clean-air-solution-many-benefits 

International Energy Agency. (2021). Global methane tracker 2021: Methane abatement and regulation. Link to source: https://www.iea.org/reports/methane-tracker-2021/methane-abatement-and-regulation 

International Energy Agency. (2022). The role of biogas and biomethane in pathway to net zero. Link to source: https://task37.ieabioenergy.com/wp-content/uploads/sites/32/2023/05/2022_12_12-IEA_Bioenergy_position-paper_Final2.pdf 

International Energy Agency. (2025). Global methane tracker 2025. Link to source: https://www.iea.org/events/global-methane-tracker-2025 

Krause, M. Kenny, S., Stephensons, J. & Singleton, A (2023). Food waste management: Quantifying methane emissions from landfilled food waste. U.S. Environmental Protection Agency. Link to source: https://www.epa.gov/system/files/documents/2023-10/food-waste-landfill-methane-10-8-23-final_508-compliant.pdf

Liebetrau, J., Rensberg, N., Maguire, D., Archer, D., Wall, D., & Murphy, J. D. (2021). Renewable gas – discussion on the state of the industry and its future in a decarbonised world. International Energy Agency. Link to source: https://task37.ieabioenergy.com/wp-content/uploads/sites/32/2022/02/Renewable_Gas_Report_END.pdf 

Murphy, J. D., Rusmanis, D., Gray, N., & O’Shea, R. (2024). Circular economy approaches to integration of anaerobic digestion with power to X technologies. IEA Bioenergy Task 37. Link to source: https://task37.ieabioenergy.com/wp-content/uploads/sites/32/2024/03/IEA_power_to_Xreport_END.pdf 

Smith P., Reay D., & Smith J. (2021). Agricultural methane emissions and the potential for mitigation. Philosophical Transactions A. Link to source: https://doi.org/10.1098/rsta.2020.0451 

Toussaint, K. (2023). Renewable natural gas has become a climate darling - but there’s a catch. Fast Company. Link to source: https://www.fastcompany.com/90970432/renewable-natural-gas-has-become-a-climate-darling-but-theres-a-catch 

Williams, M. (2024). Dairy Digesters Promise to Cut Methane — Unfortunately, They Might Be an Inefficient Band-Aid. Sentient Climate. Link to source: https://sentientmedia.org/dairy-digesters-methane/ 

Zeniewski, P., Gould, T., McGlade, C., Hays, J., Hwang, G. Báscones, A. A., Minier, Q., StClair, N. & Takashiro, J. (2025). Outlook for biogas and biomethane: A global geospatial assessment. International Energy Agency. Link to source: https://www.iea.org/reports/outlook-for-biogas-and-biomethane 

Credits

Lead Fellow

  • Jason Lam

Internal Reviewer

  • Christina Swanson, Ph.D.
Action Word
Deploy
Solution Title
Methane Digesters
Classification
Keep Watching
Updated Date
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