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Improve Annual Cropping

Submitted by Drawdown Admin on
Sector
FALO & Nature-Based Carbon Removal
Mode
Cut Emissions
Cluster
Shift Agriculture Practices
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Summary

Farmers on much of the world’s 1.4 billion ha of cropland grow and harvest annual crops – crops like wheat, rice, and soybeans that live for one year or less. After harvest, croplands are often left bare for the rest of the year and sometimes tilled, exposing the soil to wind and rain. This keeps soil carbon levels low and can lead to soil erosion. There are many ways to improve annual cropping to protect or enhance the health of the soil and increase soil organic matter. Project Drawdown’s Improve Annual Cropping solution is a set of practices that protects soils by minimizing plowing (no-till/reduced tillage) and maintaining continuous soil cover (by retaining crop residues or growing cover crops). This increases soil carbon sequestration and reduces nitrous oxide emissions. These techniques are commonly used in conservation agriculture, regenerative, and agro-ecological cropping systems. Other annual cropping practices with desirable climate impacts – including compost application and crop rotations – are omitted here due to lack of data and much smaller scale of adoption. 

Extreme weather events
Income & work,Food security
Nature protection,Land resources,Water resources
Overview

The Improve Annual Cropping solution incorporates several practices that minimize soil disturbance and introduce a physical barrier meant to prevent erosion to fragile topsoils. Our definition includes two of the three pillars of conservation agriculture: minimal soil disturbance and permanent soil cover (Kassam et al., 2022).

Minimal Soil Disturbance

Soil organic carbon (SOC) – which originates from decomposed plants – helps soils hold moisture and provides the kinds of chemical bonding that allow nutrients to be stored and exchanged easily with plants. Soil health and productivity depend on microbial decomposition of plant biomass residues, which mobilizes critical nutrients in soil organic matter (SOM) and builds SOC. Conventional tillage inverts soil, buries residues, and breaks down compacted soil aggregates. This process facilitates microbial activity, weed removal, and water infiltration for planting. However, tillage can accelerate CO₂ fluxes as SOC is lost to oxidation and runoff. Mechanical disturbance further exposes deeper soils to the atmosphere, leading to radiative absorption, higher soil temperatures, and catalyzed biological processes – all of which increase oxidation of SOC (Francaviglia et al., 2023).

Reduced tillage limits soil disturbance to support increased microbial activity, moisture retention, and stable temperature at the soil surface. This practice can increase carbon sequestration, at least when combined with cover cropping. These effects are highly contextual, depending on tillage intensity and soil depth as well as the practice type, duration, and timing. Reduced tillage further reduces fossil fuel emissions from on-farm machinery. However, this practice often leads to increased reliance on herbicides for weed control (Francaviglia et al., 2023).

Permanent Soil Cover

Residue retention and cover cropping practices aim to provide permanent plant cover to protect and improve soils. This can improve aggregate stability, water retention, and nutrient cycling. Farmers practicing residue retention leave crop biomass residues on the soil surface to suppress weed growth, improve water infiltration, and reduce evapotranspiration from soils (Francaviglia et al., 2023).

Cover cropping includes growth of spontaneous or seeded plant cover, either during or between established cropping cycles. In addition to SOC, cover cropping can help decrease nitrous oxide emissions and bind nitrogen typically lost via oxidation and leaching. Leguminous cover crops can also fix atmospheric nitrogen, reducing the need for fertilizer. Cover cropping can further be combined with reduced tillage for additive SOC and SOM gains (Blanco-Canqui et al., 2015; Francaviglia et al., 2023).

Improved annual cropping practices can simultaneously reduce GHG emissions and improve SOC stocks. However, there are biological limits to SOC stocks – particularly in mineral soils. Environmental benefits are impermanent and only remain if practices continue long term (Francaviglia et al., 2023).

References

Abdalla, M., Hastings, A., Cheng, K., Yue, Q., Chadwick, D., Espenberg, M., Truu, J., Rees, R. M., & Smith, P. (2019). A critical review of the impacts of cover crops on nitrogen leaching, net greenhouse gas balance and crop productivity. Global Change Biology, 25(8), 2530–2543. https://doi.org/10.1111/gcb.14644 

Arslan, A., McCarthy, N., Lipper, L., Asfaw, S., Cattaneo, A., & Kokwe, M. (2015). Climate smart agriculture? Assessing the adaptation implications in Zambia. Journal of Agricultural Economics, 66(3), 753-780.

Bai, X., Huang, Y., Ren, W., Coyne, M., Jacinthe, P.-A., Tao, B., Hui, D., Yang, J., & Matocha, C. (2019). Responses of soil carbon sequestration to climate-smart agriculture practices: A meta-analysis. Global Change Biology, 25(8), 2591–2606. https://doi.org/10.1111/gcb.14658

Blanco‐Canqui, H., Shaver, T. M., Lindquist, J. L., Shapiro, C. A., Elmore, R. W., Francis, C. A., & Hergert, G. W. (2015). Cover crops and ecosystem services: Insights from studies in temperate soils. Agronomy journal, 107(6), 2449-2474.

Blanco-Canqui, H., & Francis, C. A. (2016). Building resilient soils through agroecosystem redesign under fluctuating climatic regimes. Journal of Soil and Water Conservation, 71(6), 127A-133A. https://doi.org/10.2489/jswc.71.6.127A 

Cai, A., Han, T., Ren, T., Sanderman, J., Rui, Y., Wang, B., Smith, P., Xu, M., & Li, Y. (2022). Declines in soil carbon storage under no tillage can be alleviated in the long run. Geoderma, 425, 116028. https://doi.org/10.1016/j.geoderma.2022.116028 

Clapp, J. (2021). Explaining growing glyphosate use: The political economy of herbicide-dependent agriculture. Global Environmental Change, 67, 102239.

Cui, Y., Zhang, W., Zhang, Y., Liu, X., Zhang, Y., Zheng, X., Luo, J., & Zou, J. (2024). Effects of no-till on upland crop yield and soil organic carbon: A global meta-analysis. Plant and Soil, 499(1), 363–377. https://doi.org/10.1007/s11104-022-05854-y

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Dupraz, C., and Liagre, F. (2011). Agroforesterie: des arbres et des cultures. France Agricole Editions, 2011. 

Fitton, N., Alexander, P., Arnell, N., Bajzelj, B., Calvin, K., Doelman, J., Gerber, J. S., Havlik, P., Hasegawa, T., Herrero, M., Krisztin, T., van Meijl, H., Powell, T., Sands, R., Stehfest, E., West, P. C., and Smith, P. (2019). The vulnerabilities of agricultural land and food production to future water scarcity. Global Environmental Change, 58:101944. https://doi.org/10.1016/j.gloenvcha.2019.101944 

Francaviglia, R., Almagro, M., & Vicente-Vicente, J. L. (2023). Conservation Agriculture and Soil Organic Carbon: Principles, Processes, Practices and Policy Options. Soil Systems, 7(1), 17. https://doi.org/10.3390/soilsystems7010017 

Griscom, B. W., Adams, J., Ellis, P. W., Houghton, R. A., Lomax, G., Miteva, D. A., ... & Fargione, J. (2017). Natural climate solutions. Proceedings of the National Academy of Sciences, 114(44), 11645-11650.

Hassan, M. U., Aamer, M., Mahmood, A., Awan, M. I., Barbanti, L., Seleiman, M. F., ... & Huang, G. (2022). Management strategies to mitigate N₂O emissions in agriculture. Life, 12(3), 439.

Hu, Q., Thomas, B. W., Powlson, D., Hu, Y., Zhang, Y., Jun, X., Shi, X., & Zhang, Y. (2023). Soil organic carbon fractions in response to soil, environmental and agronomic factors under cover cropping systems: A global meta-analysis. Agriculture, Ecosystems & Environment, 355, 108591. https://doi.org/10.1016/j.agee.2023.108591

Jat, H. S., Choudhary, K. M., Nandal, D. P., Yadav, A. K., Poonia, T., Singh, Y., Sharma, P. C., & Jat, M. L. (2020). Conservation Agriculture-based Sustainable Intensification of Cereal Systems Leads to Energy Conservation, Higher Productivity and Farm Profitability. Environmental Management, 65(6), 774–786. https://doi.org/10.1007/s00267-020-01273-w

Jayaraman, S., Dang, Y. P., Naorem, A., Page, K. L., & Dalal, R. C. (2021). Conservation Agriculture as a System to Enhance Ecosystem Services. Agriculture, 11(8), 718. https://doi.org/10.3390/agriculture11080718

Jian, J., Du, X., Reiter, M. S., & Stewart, R. D. (2020). A meta-analysis of global cropland soil carbon changes due to cover cropping. Soil Biology and Biochemistry, 143, 107735. https://doi.org/10.1016/j.soilbio.2020.107735

Joshi, D. R., Sieverding, H. L., Xu, H., Kwon, H., Wang, M., Clay, S. A., Johnson, J. M., Thapa, R., Westhoff, S., & Clay, D. E. (2023). A global meta-analysis of cover crop response on soil carbon storage within a corn production system. Agronomy Journal, 115(4), 1543–1556. https://doi.org/10.1002/agj2.21340

Kan, Z.-R., Liu, W.-X., Liu, W.-S., Lal, R., Dang, Y. P., Zhao, X., & Zhang, H.-L. (2022). Mechanisms of soil organic carbon stability and its response to no-till: A global synthesis and perspective. Global Change Biology, 28(3), 693–710. https://doi.org/10.1111/gcb.15968

Kassam, A., Friedrich, T., & Derpsch, R. (2022). Successful Experiences and Lessons from Conservation Agriculture Worldwide. Agronomy, 12(4), Article 4. https://doi.org/10.3390/agronomy12040769

Lal, R., Smith, P., Jungkunst, H. F., Mitsch, W. J., Lehmann, J., Nair, P. R., ... & Ravindranath, N. H. (2018). The carbon sequestration potential of terrestrial ecosystems. Journal of soil and water conservation, 73(6), 145A-152A.

Lessmann, M., Ros, G. H., Young, M. D., & de Vries, W. (2022). Global variation in soil carbon sequestration potential through improved cropland management. Global Change Biology, 28(3), 1162–1177. https://doi.org/10.1111/gcb.15954

Luo, Z., Wang, E., & Sun, O. J. (2010). Can no-tillage stimulate carbon sequestration in agricultural soils? A meta-analysis of paired experiments. Agriculture, Ecosystems & Environment, 139(1), 224–231. https://doi.org/10.1016/j.agee.2010.08.006

Martínez-Mena, M., Carrillo-López, E., Boix-Fayos, C., Almagro, M., García Franco, N., Díaz-Pereira, E., Montoya, I., & De Vente, J. (2020). Long-term effectiveness of sustainable land management practices to control runoff, soil erosion, and nutrient loss and the role of rainfall intensity in Mediterranean rainfed agroecosystems. CATENA, 187, 104352. https://doi.org/10.1016/j.catena.2019.104352

McClelland, S. C., Paustian, K., & Schipanski, M. E. (2021). Management of cover crops in temperate climates influences soil organic carbon stocks: A meta-analysis. Ecological Applications, 31(3), e02278. https://doi.org/10.1002/eap.2278

Moukanni, N., Brewer, K. M., Gaudin, A. C. M., & O’Geen, A. T. (2022). Optimizing Carbon Sequestration Through Cover Cropping in Mediterranean Agroecosystems: Synthesis of Mechanisms and Implications for Management. Frontiers in Agronomy, 4. https://doi.org/10.3389/fagro.2022.844166 

Mrabet, R., Singh, A., Sharma, T., Kassam, A., Friedrich, T., Basch, G., Moussadek, R., & Gonzalez-Sanchez, E. (2023). Conservation Agriculture: Climate Proof and Nature Positive Approach. In G. Ondrasek & L. Zhang (Eds.), Resource Management in Agroecosystems. IntechOpen. https://doi.org/10.5772/intechopen.108890

Nabuurs, G-J., R. Mrabet, A. Abu Hatab, M. Bustamante, H. Clark, P. Havlík, J. House, C. Mbow, K.N. Ninan, A. Popp, S. Roe, B. Sohngen, S. Towprayoon, 2022: Agriculture, Forestry and Other Land Uses (AFOLU). In IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [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.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. https://doi.org/10.1017/9781009157926.009

Nyagumbo, I., Mupangwa, W., Chipindu, L., Rusinamhodzi, L., & Craufurd, P. (2020). A regional synthesis of seven-year maize yield responses to conservation agriculture technologies in Eastern and Southern Africa. Agriculture, Ecosystems & Environment, 295, 106898. https://doi.org/10.1016/j.agee.2020.106898

Ogle, S. M., Alsaker, C., Baldock, J., Bernoux, M., Breidt, F. J., McConkey, B., Regina, K., & Vazquez-Amabile, G. G. (2019). Climate and Soil Characteristics Determine Where No-Till Management Can Store Carbon in Soils and Mitigate Greenhouse Gas Emissions. Scientific Reports, 9(1), 11665. https://doi.org/10.1038/s41598-019-47861-7

Paustian, K., Larson, E., Kent, J., Marx, E., & Swan, A. (2019). Soil C Sequestration as a Biological Negative Emission Strategy. Frontiers in Climate, 1, 8. https://doi.org/10.3389/fclim.2019.00008 

Pittelkow, C. M., Liang, X., Linquist, B. A., van Groenigen, K. J., Lee, J., Lundy, M. E., van Gestel, N., Six, J., Venterea, R. T., & van Kessel, C. (2015). Productivity limits and potentials of the principles of conservation agriculture. Nature, 517(7534), Article 7534. https://doi.org/10.1038/nature13809

Poeplau, C., & Don, A. (2015). Carbon sequestration in agricultural soils via cultivation of cover crops–A meta-analysis. Agriculture, Ecosystems & Environment, 200, 33-41.

Powlson, D. S., Stirling, C. M., Jat, M. L., Gerard, B. G., Palm, C. A., Sanchez, P. A., & Cassman, K. G. (2014). Limited potential of no-till agriculture for climate change mitigation. Nature Climate Change, 4(8), 678–683. https://doi.org/10.1038/nclimate2292

Prestele, R., Hirsch, A. L., Davin, E. L., Seneviratne, S. I., & Verburg, P. H. (2018). A spatially explicit representation of conservation agriculture for application in global change studies. Global Change Biology, 24(9), 4038–4053. https://doi.org/10.1111/gcb.14307

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Stavi, I., Bel, G., & Zaady, E. (2016). Soil functions and ecosystem services in conventional, conservation, and integrated agricultural systems. A review. Agronomy for Sustainable Development, 36(2), 32. https://doi.org/10.1007/s13593-016-0368-8

Su, Y., Gabrielle, B., Beillouin, D., & Makowski, D. (2021). High probability of yield gain through conservation agriculture in dry regions for major staple crops. Scientific Reports, 11(1), 3344. https://doi.org/10.1038/s41598-021-82375-1

Sun, W., Canadell, J. G., Yu, L., Yu, L., Zhang, W., Smith, P., Fischer, T., & Huang, Y. (2020). Climate drives global soil carbon sequestration and crop yield changes under conservation agriculture. Global Change Biology, 26(6), 3325–3335. https://doi.org/10.1111/gcb.15001 

Tambo, J. A., & Mockshell, J. (2018). Differential Impacts of Conservation Agriculture Technology Options on Household Income in Sub-Saharan Africa. Ecological Economics, 151, 95–105. https://doi.org/10.1016/j.ecolecon.2018.05.005

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Credits

Lead Fellows

  • Avery Driscoll

  • Erika Luna

  • Megan Matthews, Ph.D.

  • Eric Toensmeier

  • Aishwarya Venkat, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Yusuf Jameel, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Emily Cassidy, Ph.D.

  • James Gerber, Ph.D.

  • Hannah Henkin

  • Zoltan Nagy, Ph.D.

  • Ted Otte

  • Paul West, Ph.D.

Effectiveness

Based on seven reviews and meta-analyses, which collectively analyzed over 500 studies, we estimate that this solution’s SOC sequestration potential is 1.28 t CO₂‑eq/ha/yr. This is limited to the topsoil (>30 cm), with minimal effects at deeper levels (Sun et al., 2020; Tiefenbacher et al., 2021). Moreover, carbon sequestration potential isn't constant over time. The first two decades show the highest increase, followed by an equilibrium or SOC saturation (Cai, 2022; Sun et al., 2020).

The effectiveness of the Improve Annual Cropping solution heavily depends on local geographic conditions (e.g., soil properties, climate), crop management practices, cover crop biomass, cover crop types, and the duration of annual cropping production – with effects typically better assessed in the long term (Abdalla et al., 2019; Francaviglia et al., 2023; Moukanni et al., 2022; Paustian et al., 2019).

Based on reviewed literature (three papers, 18 studies), we estimated that improved annual cropping can potentially reduce nitrous oxide emissions by 0.51 t CO₂‑eq/ha/yr (Table 1). Cover crops can increase direct nitrous oxide emissions by stimulating microbial activity, but – compared with conventional cropping – lower indirect emissions allow for reduced net nitrous oxide emissions from cropland (Abdalla et al., 2019). 

Nitrogen fertilizers drive direct nitrous oxide emissions, so genetic optimization of cover crops to increase nitrogen-use efficiencies and decrease nitrogen leaching could further improve mitigation of direct nitrous oxide emissions (Abdalla et al., 2019). 

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Table 1. Effectiveness at reducing emissions and removing carbon.

Unit: t CO₂‑eq/ha/yr

25th percentile 0.29
median (50th percentile) 0.51
75th percentile 0.80

Unit: t CO₂‑eq/ha/yr

25th percentile 0.58
median (50th percentile) 1.28
75th percentile 1.72

Unit: t CO₂‑eq/ha/yr

25th percentile 0.88
median (50th percentile) 1.80
75th percentile 2.52
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Cost

Because baseline (conventional) annual cropping systems are already extensive and well established, we assume there is no cost to establish new baseline cropland. In the absence of global datasets on costs and revenues of cropping systems, we used data on the global average profit per ha of cropland from Damiana et al. (2023) to create a weighted average profit US$76.86/ha.

Based on 13 data points (of which seven were from the United States), the median establishment cost of the Improve Annual Cropping Solution is $329.78/ha. Nine data points (three from the United States) provided a median increase in profitability of US$86.01/ha. 

The net net cost of the Improve Annual Cropping solution is US$86.01. The cost per t CO2 -eq is US$47.80 (Table 2).

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Table 2. Cost per unit climate impact.

Unit: 2023 US$/t CO₂‑eq, 100-yr basis

median 47.80
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Learning Curve

We found limited information on this solution’s learning curve. A survey of farmers in Zambia found a reluctance to avoid tilling soils because of the increased need for weeding or herbicides and because crop residues may need to be used for livestock feed (Arslan et al., 2015; Searchinger et al., 2019).

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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 gradual, emergency brake, or delayed.

Improve Annual Cropping is a DELAYED climate solution. It works more slowly than nominal or emergency brake solutions. Delayed solutions can be robust climate solutions, but it’s important to recognize that they realize their full potential for some time.

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Caveats

As with other biosequestration solutions, carbon stored in soils via improved annual cropping is not permanent. It can be lost quickly through a return to conventional agriculture practices like plowing, and/or through a regional shift to a drier climate or other human- or climate change–driven disturbances. Carbon sequestration also only continues for a limited time, estimated at 20–50 years (Lal et al., 2018)).

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Current Adoption

Kassam et al. (2022) provided regional adoption from 2008–2019. We used a linear forecast to project 2025 adoption. This provided a figure of 267.4 Mha in 2025 (Table 3).

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Table 3. Current (2025) adoption level.

Unit: Mha of improved annual cropping installed

Drawdown estimate 267.4
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Adoption Trend

Between 2008–2009 and 2018–2019 (the most recent data available), the cropland area under improved annual cropping practices nearly doubled globally, increasing from 10.6 Mha to 20.5 Mha at an average rate of 1.0 Mha/yr (Kassam et al., 2022), equivalent to a 9.2% annual increase in area relative to 2008–2009 levels. Adoption slowed slightly in the latter half of the decade, with an average increase of 0.8 Mha/yr- between 2015–2016 and 2018–2019, equivalent to 4.6% annual increase in area relative to 2015–2016 levels. 

Median adoption is 1.11 ha/yr. The median, mean, and 25th and 75th percentiles are shown in Table 4.

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Table 4. 2008–2009 to 2018–2019 adoption trend.

Unit: Mha adopted/yr

25th percentile 0.54
mean 1.41
median (50th percentile) 1.11
75th percentile 2.04
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Adoption Ceiling

Griscom et al. (2017) estimate that 800 Mha of global cropland are suitable – but not yet used for – cover cropping, in addition to 168 Mha already in cover crops (Popelau and Don, 2015). We update the 168 Mha in cover crops to 267 Mha based on Kassam (2022). Griscom et al.’s estimate is based on their analysis that much cropland is unsuitable because it already is used to produce crops during seasons in which cover crops would be grown. Their estimate thus provides a maximum technical potential of 1,067 Mha (Table 5). 

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Table 5. Adoption ceiling.

Unit: Mha

Adoption ceiling 1,067
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Achievable Adoption

The 8th World Congress on Conservation Agriculture (8WCCA) set a goal to achieve adoption of improved annual cropping on 50% of available cropland by 2050 (WCCA 2021). That provides an adoption ceiling of 700 Mha – though this is not a biophysical limit. 

We used the 2008–2019 data from Kassam (2022) to calculate average annual regional growth rates. From these we selected the 25th percentile as our low achievable level (Table 6).

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Table 6. Range of achievable adoption levels.

Unit: Mha installed

Current Adoption 267.4
Achievable – Low 331.7
Achievable – High 700.0
Adoption Ceiling 1,067.0

Unit: Mha installed

Current Adoption 0.00
Achievable – Low 64.2
Achievable – High 432.6
Adoption Ceiling 868.6
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Carbon sequestration continues only for a period of decades; because adoption of improved annual cropping was already underway in the 1970s (Kassam et al., 2022), we could not assume that previously adopted hectares continue to sequester carbon indefinitely. Thus we make the conservative choice to calculate carbon sequestration only for newly adopted hectares. We use the same conservative assumption for nitrous oxide emissions. 

Combined effect is 0.0 Gt CO₂‑eq/yr for current adoption, 0.12 for Achievable – Low, 0.78 for Achievable – High, and 1.56 for our Adoption Ceiling.

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Table 8. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.00
Achievable – Low 0.03
Achievable – High 0.22
Adoption Ceiling 0.45

(from nitrous oxide)

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.00
Achievable – Low 0.08
Achievable – High 0.56
Adoption Ceiling 1.12

(from SOC)

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.00
Achievable – Low 0.12
Achievable – High 0.78
Adoption Ceiling 1.56
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Additional Benefits

Extreme weather events

The soil and water benefits of this solution can lead to agricultural systems that are more resilient to extreme weather events (Mrabet et al., 2023). These agricultural systems have improved uptake, conservation, and use of water, so they are more likely to successfully cope and adapt to drought and dry conditions (Su et al., 2021). Additionally, more sustained year-round plant cover can increase the capacity of cropping systems to adapt to high temperatures and extreme rainfall (Blanco-Canqui & Francis, 2016; Martinez-Mena et al., 2020).

Droughts

Increased organic matter due to improved annual cropping increases soil water holding capacity. This increases drought resilience (Su et al., 2021). 

Income & work

Conservation agriculture practices can reduce costs on fuel, fertilizer, and pesticides (Stavi et al., 2016). The highest revenues from improved annual cropping are often found in drier climates where higher yields are more likely. Nyagumbo et al. (2020) found that smallholder farms in sub-Saharan Africa using conservation agriculture had the highest returns on crop yields when rainfall was low. Tambo et al. (2018) found when smallholder farmers in sub-Saharan Africa jointly employed the three aspects of conservation agriculture – reduced tillage, cover crops, and crop rotation – households and individuals saw the largest income gains.

Food security

Improved annual cropping can improve food security by increasing the amount and the stability of crop yields. A meta-analysis of studies of South Asian cropping systems found that those following conservation agriculture methods had 5.8% higher mean yield than cropping systems with more conventional agriculture practices (Jat et al., 2020). Evidence supports that conservation agriculture practices especially improve yields in water scarce areas (Su et al., 2021). Nyagumbo et al. (2020) found that smallholder farmers in sub-Saharan Africa experienced reduced yield variability when using conservation agriculture practices.

Nature protection

Improved annual cropping can increase biodiversity below and above soils (Mrabet et al., 2023). Increased vegetation cover improves habitats for arthropods, which help with pest and pathogen management (Stavi et al., 2016).

Land resources

Improved annual cropping methods can lead to improved soil health through the increased stability of soil structure, increased soil nutrients, and improved soil water storage (Francaviglia et al., 2023). This can reduce soil degradation and erosion (Mrabet et al., 2023). Additionally, more soil organic matter can lead to additional microbial growth and nutrient availability for crops (Blanco-Canqui & Francis, 2016). 

Water quality

Runoff of soil and other agrochemicals can be minimized through conservation agricultural practices (Jayaraman et al., 2021), reducing the amount of nitrate and phosphorus that leach into waterways and contribute to algal blooms and eutrophication (Jayaraman et al., 2021). Abdalla et al. (2019) found that cover crops reduced nitrogen leaching.

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Risks

Herbicides – in place of tillage – are used in many but not all no-till cropping systems to kill (terminate) the cover crop. The large-scale use of herbicides in improved annual cropping systems can produce a range of environmental and human health consequences. Agricultural impacts can include development of herbicide-resistant weeds (Clapp, 2021). 

If cover crops are not fully terminated before establishing the main crop, there is a risk that cover crop can compete with the main crop (Quintarelli et al., 2022). 

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Interactions with Other Solutions

Improved annual cropping has competing interactions with several other solutions related to shifting annual practices. For each of these other solutions, the Improve Annual Cropping solution can reduce the area on which the solution can be applied or the nutrient excess available for improved management. 

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COMPETING

In no-till systems, cover crops are typically terminated with herbicides, often preventing incorporation of trees depending on the type of herbicide used.

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Land managed under the Improve Annual Cropping solution is not available for perennial crops.

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Improved annual cropping typically reduces fertilizer demand, reducing the scale of climate impact under improved nutrient management. 

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Our definition of improved annual cropping requires residue retention, limiting the additional area available for deployment of reduced burning.

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Dashboard

Solution Basics

1 ha of cropland

tCO2-eq/unit/yr
1.8
units
Current 06.42×10⁷4.33×10⁸
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 0 0.120.78
US$ per tCO2-eq
48
Delayed

CO₂, N₂O

Trade-offs

Some studies have found that conservation tillage without cover crops can reduce soil carbon stocks in deeper soil layers. They caution against overreliance on no-till as a sequestration solution in the absence of cover cropping. Reduced tillage should be combined with cover crops to ensure carbon sequestration (Luo et al., 2010; Ogle et al., 2019; Powlson et al., 2014).

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tCO2-eq/ha
0400

Millennia of agricultural land use have removed nearly 500 Gt CO2-eq from soils

Agriculture has altered the soil carbon balance around the world, resulting in changes (mostly losses) of soil carbon. Much of the nearly 500 Gt CO2-eq lost in the last 12,000 years is now in the atmosphere in the form of CO2.

Sanderman, J. et al. (2017). The soil carbon debt of 12,000 years of human land use [Data set]. PNAS 114(36): 9575–9580. doi:10.1073/pnas.1706103114

tCO2-eq/ha
0400

Millennia of agricultural land use have removed nearly 500 Gt CO2-eq from soils

Agriculture has altered the soil carbon balance around the world, resulting in changes (mostly losses) of soil carbon. Much of the nearly 500 Gt CO2-eq lost in the last 12,000 years is now in the atmosphere in the form of CO2.

Sanderman, J. et al. (2017). The soil carbon debt of 12,000 years of human land use [Data set]. PNAS 114(36): 9575–9580. doi:10.1073/pnas.1706103114

Geographic Guidance Introduction

Adoption of this solution varies substantially across the globe. Currently, improved annual cropping practices are widely implemented in Australia and New Zealand (74% of annual cropland) and Central and South America (69%), with intermediate adoption in North America (34%) and low adoption in Asia, Europe, and Africa (1–5%) (Kassam et al., 2022), though estimates vary (see also Prestele et al., 2018). Future expansion of this solution is most promising in Asia, Africa, and Europe, where adoption has increased in recent years. Large areas of croplands are still available for implementation in these regions, whereas Australia, New Zealand, and Central and South America may be reaching a saturation point, and these practices may be less suitable for the relatively small area of remaining croplands.

The carbon sequestration effectiveness of this solution also varies across space. Drivers of soil carbon sequestration rates are complex and interactive, with climate, initial soil carbon content, soil texture, soil chemical properties (such as pH), and other land management practices all influencing the effectiveness of adopting this solution. Very broadly, the carbon sequestration potential of improved annual cropping tends to be two to three times higher in warm areas than cool areas (Bai et al., 2019; Cui et al., 2022; Lessmann et al., 2021). Warm and humid conditions enable vigorous cover crop growth, providing additional carbon inputs into soils. Complicating patterns of effectiveness, however, arid regions often experience increased crop yields following adoption of this solution whereas humid regions are more likely to experience yield losses (Pittelkow et al., 2015). Yield losses may reduce adoption in humid areas and can lead to cropland expansion to compensate for lower production. 

Uptake of this solution may be constrained by spatial variation in places where cover cropping is suitable. In areas with double or triple cropping, there may not be an adequate interval for growth of a cover crop between harvests. In areas with an extended dry season, there may be inadequate moisture to grow a cover crop.

Action Word
Improve
Solution Title
Annual Cropping
Classification
Highly Recommended
Lawmakers and Policymakers
  • Provide local and regional institutional guidance for improving annual cropping that adapts to the socio-environmental context.
  • Integrate soil protection into national climate mitigation and adaptation plans.
  • Remove financial incentives, such as subsidies, for unsustainable practices and replace them with financial incentives for carbon sequestration practices.
  • Place taxes or fines on emissions and related farm inputs (such as nitrogen fertilizers).
  • Reform international agricultural trade, remove subsidies for emissions-intensive agriculture, and support climate-friendly practices.
  • Strengthen and support land tenure for smallholder farmers.
  • Mandate insurance schemes that allow farmers to use cover crops and reduce tillage.
  • Support, protect, and promote traditional and Indigenous knowledge of land management practices.
  • Set standards for measuring, monitoring, and verifying impacts on SOC accounting for varying socio-environmental conditions.
  • Develop economic budgets for farmers to adopt these practices.
  • Invest in or expand extension services to educate farmers and other stakeholders on the economic and environmental benefits of improved annual cropping.
  • Create, support, or join education campaigns and/or public-private partnerships that facilitate stakeholder discussions.

Further information:

Practitioners
  • Implement no-till practices and use cover crops.
  • Utilize or advocate for financial assistance and tax breaks for farmers to use improved annual cropping techniques.
  • Adjust the timing and dates of the planting and termination of the cover crops in order to avoid competition for resources with the primary crop.
  • Find opportunities to reduce initial operation costs of no-tillage and cover crops, such as selling cover crops as forage or grazing.
  • Take advantage of education programs, support groups, and extension services focused on improved annual cropping methods.
  • Create, support, or join stakeholder discussions, especially around standardized monitoring frameworks, ROI, and climate benefits.

Further information:

Business Leaders
  • Source from producers implementing improved annual cropping practices, create programs that directly engage and educate farmers, and promote inspiring case studies with the industry and wider public.
  • Create sustainability goals and supplier requirements that incorporate this solution and offer pricing incentives for compliant suppliers.
  • Invest in companies that utilize improved annual cropping techniques or produce the necessary inputs.
  • Promote and develop markets for products that employ improved annual cropping techniques and educate consumers about the importance of the practice.
  • Stay abreast of recent scientific findings and use third-party verification to monitor sourcing practices.
  • Offer financial services – including low-interest loans, micro-financing, and grants – to support low-carbon agriculture (e.g., sustainable land management systems).
  • Support high-integrity carbon markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Create, support, or join education campaigns and/or public-private partnerships that facilitate stakeholder discussions, especially around standardized monitoring frameworks, ROI, and climate benefits.

Further information:

Nonprofit Leaders
  • Start model farms to demonstrate techniques, conduct experiments, and educate local farmers.
  • Conduct and share research on improving annual cropping techniques and local policy options.
  • Advocate to policymakers for improving annual cropping techniques, incentives, and regulations.
  • Educate farmers on sustainable means of agriculture and support implementation.
  • Help integrate improved annual cropping practices as part of the broader climate agenda.
  • Engage with businesses to encourage corporate responsibility and/or monitor soil health.
  • Offer resources and training in financial planning and yield risk management to farmers adopting improved annual cropping approaches.
  • Partner with research institutions and businesses to co-develop and distribute region-specific best practices.
  • Create, support, or join stakeholder discussions, especially around standardized monitoring frameworks, ROI, and climate benefits.

Further information:

Investors
  • Integrate science-based due diligence on improved annual cropping techniques and soil health measures into all farming and agritech investments.
  • Encourage companies in your investment portfolio to adopt improved annual cropping practices.
  • Offer access to capital, such as low-interest loans, micro-financing, and grants to improve annual cropping.
  • Invest in companies developing technologies that improve annual cropping, such as soil management equipment and related software.
  • Create, support, or join stakeholder discussions, especially around standardized monitoring frameworks, ROI, and climate benefits.

Further information:

Philanthropists and International Aid Agencies
  • Start model farms to demonstrate techniques, conduct experiments, and educate local farmers.
  • Offer access to capital, such as low-interest loans, micro-financing, and grants to support improving annual cropping, (e.g., traditional land management).
  • Conduct and share research on improved annual cropping techniques and local policy options.
  • Advocate to policymakers for improved annual cropping techniques, incentives, and regulations.
  • Educate farmers on traditional means of agriculture and support implementation.
  • Help integrate improved annual cropping practices as part of the broader climate agenda.
  • Engage with businesses to encourage corporate responsibility and/or monitor soil health.
  • Offer resources and training in financial planning and yield risk management to farmers adopting improved annual cropping approaches.
  • Partner with research institutions and businesses to co-develop and distribute region-specific best practices.
  • Create, support, or join stakeholder discussions, especially around standardized monitoring frameworks, ROI, and climate benefits.
  • Invest in companies developing technologies that improve annual cropping, such as soil management equipment and related software.

Further information:

Thought Leaders
  • Start model farms to demonstrate techniques, conduct experiments, and educate local farmers.
  • Conduct and share research on improved annual cropping techniques and local policy options.
  • Advocate to policymakers for improved annual cropping techniques, incentives, and regulations.
  • Educate farmers on traditional means of agriculture and support implementation.
  • Engage with businesses to encourage corporate responsibility and/or monitor soil health.
  • Research the regional impacts of cover crops on SOC and SOM and publish the data.
  • Partner with research institutions and businesses to co-develop and distribute region-specific best practices.
  • Create, support, or join stakeholder discussions, especially around standardized monitoring frameworks, ROI, and climate benefits.
  • Work with farmers and other private organizations to improve data collection on uptake of improved annual cropping techniques, effectiveness, and regional best practices.

Further information:

Technologists and Researchers
  • Help develop standards for measuring, monitoring, and verifying impacts on SOC accounting for varying socio-environmental conditions.
  • Research the regional impacts of cover crops (particularly outside the United States) on SOC and SOM, and publish the data.
  • Create tracking and monitoring software to support farmers' decision-making.
  • Research the application of AI and robotics for crop rotation.
  • Improve data and analytics to monitor soil and water quality, assist farmers, support policymaking, and assess the impacts of policies.
  • Develop education and training applications to improve annual cropping techniques and provide real-time feedback.

Further information:

Communities, Households, and Individuals
  • Participate in urban agriculture or community gardening programs that implement these practices.
  • Engage with businesses to encourage corporate responsibility and/or monitor soil health.
  • Work with farmers and other private organizations to improve data collection on uptake of improved annual cropping techniques, effectiveness, and regional best practices.
  • Advocate to policymakers for improved annual cropping techniques, incentives, and regulations.
  • Start model farms to demonstrate techniques, conduct experiments, and educate local farmers.
  • Educate farmers on traditional means of agriculture and support implementation.
  • Create, support, or join stakeholder discussions, especially around standardized monitoring frameworks, ROI, and climate benefits.

Further information:

Sources
Evidence Base

Carbon sequestration from cover cropping: High consensus

The impacts of improved annual cropping practices on soil carbon sequestration have been extensively studied, and there is high consensus that adoption of cover crops can increase carbon sequestration in soils. However, estimates of how much carbon can be sequestered vary substantially, and sequestration rates are strongly influenced by factors such as climate, soil properties, time since adoption, and how the practices are implemented.

The carbon sequestration benefits of cover cropping are well established. They have been documented in reviews and meta-analyses including Hu et al. (2023) and Vendig et al. (2023). 

Carbon sequestration from reduced tillage: Mixed

Relative to conventional tillage, estimates of soil carbon gains in shallow soils under no-till management include average increases of 5–20% (Bai et al., 2019; Cui et al., 2022; Kan et al., 2022). Lessmann et al. (2021) estimated that use of no-till is associated with an average annual increase in carbon sequestration of 0.88 t CO₂‑eq /ha/yr relative to high-intensity tillage. 

Nitrous oxide reduction: Mixed

Consensus on nitrous oxide reductions from improved annual cropping is mixed. Several reviews have demonstrated a modest reduction in nitrous oxide from cover cropping (Abdalla et al., 2019; Xing & Wang, 2024). Reduced tillage can result in either increased or decreased nitrous oxide emissions (Hassan et al., 2022). 

The results presented in this document summarize findings from 10 reviews and meta-analyses reflecting current evidence at the global scale. Nonetheless, not all countries are represented. 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 Nutrient Management

Submitted by Drawdown Admin on
Sector
Food, Agriculture, Land & Ocean
Mode
Cut Emissions
Cluster
Shift Agriculture Practices
Image
Farm equipment applying fertilizer selectively
Coming Soon
Off
Summary

We define the Improve Nutrient Management solution as reducing excessive nitrogen use on croplands. Nitrogen is critical for crop production and is added to croplands as synthetic or organic fertilizers and through microbial activity. However, farmers often add more nitrogen to croplands than crops can use. Some of that excess nitrogen is emitted to the atmosphere as nitrous oxide, a potent GHG. 

Droughts
Income & work,Food security,Health
Nature protection
Overview

Agriculture is the dominant source of human-caused emissions of nitrous oxide (Figure 1; Tian et al., 2020). Nitrogen is critical for plant growth and is added to croplands in synthetic forms, such as urea, ammonium nitrate, or anhydrous ammonia; in organic forms, such as manure or compost; and by growing legume crops, which host microbes that capture nitrogen from the air and add it to the soil (Adalibieke et al., 2023; Ludemann et al., 2024). If more nitrogen is added than crops can use, the excess can be converted to other forms, including nitrous oxide, through microbial processes called denitrification and nitrification (Figure 2; Reay et al., 2012).

Figure 1. The agricultural nitrogen cycle represents the key pathways by which nitrogen is added to croplands and lost to the environment, including as nitrous oxide. The “4R” nutrient management principles – right source, right rate, right time, right place – increase the proportion of nitrogen taken up by the plant, therefore reducing nitrogen losses to the environment.

Diagram of agricultural nitrogen cycle.

Illustrations: BioRender CC-BY 4.0

Farmers can reduce nitrous oxide emissions from croplands by using the right amount and the right type of fertilizer at the right time and in the right place (Fixen, 2020; Gao & Cabrera Serrenho, 2023). Together, these four “rights” increase nitrogen use efficiency – the proportion of applied nitrogen that the crop uses (Congreves et al., 2021). Improved nutrient management is often a win-win for the farmer and the environment, reducing fertilizer costs while also lowering nitrous oxide emissions (Gu et al., 2023).

Improving nutrient management involves reducing the amount of nitrogen applied to match the crop’s requirements in areas where nitrogen is currently overapplied. A farmer can implement the other three principles – type, time, and place – in a number of ways. For example, fertilizing just before planting instead of after the previous season’s harvest better matches the timing of nitrogen addition to that of plant uptake, reducing nitrous oxide emissions before the crop is planted. Certain types of fertilizers are better suited for maximizing plant uptake, such as extended-release fertilizers, which allow the crop to steadily absorb nutrients over time. Techniques such as banding, in which farmers apply fertilizers in concentrated bands close to the plant roots instead of spreading them evenly across the soil surface, also reduce nitrous oxide emissions. Each of these practices can increase nitrogen use efficiency and decrease the amount of excess nitrogen lost as nitrous oxide (Gao & Cabrera Serrenho, 2023; Gu et al., 2023; Wang et al., 2024; You et al., 2023).

For this solution, we estimated a target rate of nitrogen application for major crops as the 20th percentile of the current rate of nitrogen application (in tN/t crop) in areas where yields are near a realistic ceiling. Excess nitrogen was defined as the amount of nitrogen applied beyond the target rate (see Adoption and Appendix for more details). Our emissions estimates include nitrous oxide from croplands, fertilizer runoff, and fertilizer volatilization. They do not include emissions from fertilizer manufacturing, which are addressed in the Deploy Low-Emission Industrial Feedstocks and Increase Industrial Efficiency solutions. We excluded nutrient management on pastures from this solution due to data limitations, and address nutrient management in paddy rice systems in the Improve Rice Management solution instead. 

References

Adalibieke, W., Cui, X., Cai, H., You, L., & Zhou, F. (2023). Global crop-specific nitrogen fertilization dataset in 1961–2020. Scientific Data, 10(1), 617. https://doi.org/10.1038/s41597-023-02526-z

Almaraz, M., Bai, E., Wang, C., Trousdell, J., Conley, S., Faloona, I., & Houlton, B. Z. (2018). Agriculture is a major source of NOx pollution in California. Science Advances, 4(1), eaao3477. https://doi.org/10.1126/sciadv.aao3477

Antil, R. S., & Raj, D. (2020). Integrated nutrient management for sustainable crop production and improving soil health. In R. S. Meena (Ed.), Nutrient Dynamics for Sustainable Crop Production (pp. 67–101). Springer. https://doi.org/10.1007/978-981-13-8660-2_3

Bijay-Singh, & Craswell, E. (2021). Fertilizers and nitrate pollution of surface and ground water: An increasingly pervasive global problem. SN Applied Sciences, 3(4), 518. https://doi.org/10.1007/s42452-021-04521-8

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Deng, J., Guo, L., Salas, W., Ingraham, P., Charrier-Klobas, J. G., Frolking, S., & Li, C. (2018). Changes in irrigation practices likely mitigate nitrous oxide emissions from California cropland. Global Biogeochemical Cycles, 32(10), 1514–1527. https://doi.org/10.1029/2018GB005961

Domingo, N. G. G., Balasubramanian, S., Thakrar, S. K., Clark, M. A., Adams, P. J., Marshall, J. D., Muller, N. Z., Pandis, S. N., Polasky, S., Robinson, A. L., Tessum, C. W., Tilman, D., Tschofen, P., & Hill, J. D. (2021). Air quality–related health damages of food. Proceedings of the National Academy of Sciences, 118(20), e2013637118. https://doi.org/10.1073/pnas.2013637118

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Fixen, P. E. (2020). A brief account of the genesis of 4R nutrient stewardship. Agronomy Journal, 112(5), 4511–4518. https://doi.org/10.1002/agj2.20315

Foley, J. A., Ramankutty, N., Brauman, K. A., Cassidy, E. S., Gerber, J. S., Johnston, M., Mueller, N. D., O’Connell, C., Ray, D. K., West, P. C., Balzer, C., Bennett, E. M., Carpenter, S. R., Hill, J., Monfreda, C., Polasky, S., Rockström, J., Sheehan, J., Siebert, S., … Zaks, D. P. M. (2011). Solutions for a cultivated planet. Nature, 478(7369), 337–342. https://doi.org/10.1038/nature10452

Gao, Y., & Cabrera Serrenho, A. (2023). Greenhouse gas emissions from nitrogen fertilizers could be reduced by up to one-fifth of current levels by 2050 with combined interventions. Nature Food, 4(2), 170–178. https://doi.org/10.1038/s43016-023-00698-w

Gerber, J. S., Carlson, K. M., Makowski, D., Mueller, N. D., Garcia de Cortazar-Atauri, I., Havlík, P., Herrero, M., Launay, M., O’Connell, C. S., Smith, P., & West, P. C. (2016). Spatially explicit estimates of nitrous oxide emissions from croplands suggest climate mitigation opportunities from improved fertilizer management. Global Change Biology, 22(10), 3383–3394. https://doi.org/10.1111/gcb.13341

Gerber, J. S., Ray, D. K., Makowski, D., Butler, E. E., Mueller, N. D., West, P. C., Johnson, J. A., Polasky, S., Samberg, L. H., & Siebert, S. (2024). Global spatially explicit yield gap time trends reveal regions at risk of future crop yield stagnation. Nature Food, 5(2), 125–135. https://doi.org/10.1038/s43016-023-00913-8 

Gong, C., Tian, H., Liao, H., Pan, N., Pan, S., Ito, A., Jain, A. K., Kou-Giesbrecht, S., Joos, F., Sun, Q., Shi, H., Vuichard, N., Zhu, Q., Peng, C., Maggi, F., Tang, F. H. M., & Zaehle, S. (2024). Global net climate effects of anthropogenic reactive nitrogen. Nature, 632(8025), 557–563. https://doi.org/10.1038/s41586-024-07714-4

Gu, B., Zhang, X., Lam, S. K., Yu, Y., van Grinsven, H. J. M., Zhang, S., Wang, X., Bodirsky, B. L., Wang, S., Duan, J., Ren, C., Bouwman, L., de Vries, W., Xu, J., Sutton, M. A., & Chen, D. (2023). Cost-effective mitigation of nitrogen pollution from global croplands. Nature, 613(7942), 77–84. https://doi.org/10.1038/s41586-022-05481-8

Hergoualc’h, K., Akiyama, H., Bernoux, M., Chirinda, N., del Prado, A., Kasimir, Å., MacDonald, J. D., Ogle, S. M., Regina, K., & van der Weerden, T. J. (2019). Chapter 11: nitrous oxide Emissions from managed soils, and CO₂ emissions from lime and urea application (2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories). Intergovernmental Panel on Climate Change. https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch11_Soils_nitrous oxide_CO₂. pdf

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Lawrence, N. C., Tenesaca, C. G., VanLoocke, A., & Hall, S. J. (2021). Nitrous oxide emissions from agricultural soils challenge climate sustainability in the US Corn Belt. Proceedings of the National Academy of Sciences, 118(46), e2112108118. https://doi.org/10.1073/pnas.2112108118

Ludemann, C. I., Wanner, N., Chivenge, P., Dobermann, A., Einarsson, R., Grassini, P., Gruere, A., Jackson, K., Lassaletta, L., Maggi, F., Obli-Laryea, G., van Ittersum, M. K., Vishwakarma, S., Zhang, X., & Tubiello, F. N. (2024). A global FAOSTAT reference database of cropland nutrient budgets and nutrient use efficiency (1961–2020): Nitrogen, phosphorus and potassium. Earth System Science Data, 16(1), 525–541. https://doi.org/10.5194/essd-16-525-2024

Menegat, S., Ledo, A., & Tirado, R. (2022). Greenhouse gas emissions from global production and use of nitrogen synthetic fertilisers in agriculture. Scientific Reports, 12(1), 14490. https://doi.org/10.1038/s41598-022-18773-w

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Pinder, R. W., Davidson, E. A., Goodale, C. L., Greaver, T. L., Herrick, J. D., & Liu, L. (2012). Climate change impacts of US reactive nitrogen. Proceedings of the National Academy of Sciences, 109(20), 7671–7675. https://doi.org/10.1073/pnas.1114243109

Porter, E. M., Bowman, W. D., Clark, C. M., Compton, J. E., Pardo, L. H., & Soong, J. L. (2013). Interactive effects of anthropogenic nitrogen enrichment and climate change on terrestrial and aquatic biodiversity. Biogeochemistry, 114(1), 93–120. https://doi.org/10.1007/s10533-012-9803-3

Qiao, C., Liu, L., Hu, S., Compton, J. E., Greaver, T. L., & Li, Q. (2015). How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input. Global Change Biology, 21(3), 1249–1257. https://doi.org/10.1111/gcb.12802

Qin, Z., Deng, S., Dunn, J., Smith, P., & Sun, W. (2021). Animal waste use and implications to agricultural greenhouse gas emissions in the United States. Environmental Research Letters, 16(6), 064079. https://doi.org/10.1088/1748-9326/ac04d7

Reay, D. S., Davidson, E. A., Smith, K. A., Smith, P., Melillo, J. M., Dentener, F., & Crutzen, P. J. (2012). Global agriculture and nitrous oxide emissions. Nature Climate Change, 2(6), 410–416. https://doi.org/10.1038/nclimate1458

Rockström, J., Williams, J., Daily, G., Noble, A., Matthews, N., Gordon, L., Wetterstrand, H., DeClerck, F., Shah, M., Steduto, P., de Fraiture, C., Hatibu, N., Unver, O., Bird, J., Sibanda, L., & Smith, J. (2017). Sustainable intensification of agriculture for human prosperity and global sustainability. Ambio, 46(1), 4–17. https://doi.org/10.1007/s13280-016-0793-6

Rurinda, J., Zingore, S., Jibrin, J. M., Balemi, T., Masuki, K., Andersson, J. A., Pampolino, M. F., Mohammed, I., Mutegi, J., Kamara, A. Y., Vanlauwe, B., & Craufurd, P. Q. (2020). Science-based decision support for formulating crop fertilizer recommendations in sub-Saharan Africa. Agricultural Systems, 180, 102790. https://doi.org/10.1016/j.agsy.2020.102790

Scavia, D., David Allan, J., Arend, K. K., Bartell, S., Beletsky, D., Bosch, N. S., Brandt, S. B., Briland, R. D., Daloğlu, I., DePinto, J. V., Dolan, D. M., Evans, M. A., Farmer, T. M., Goto, D., Han, H., Höök, T. O., Knight, R., Ludsin, S. A., Mason, D., … Zhou, Y. (2014). Assessing and addressing the re-eutrophication of Lake Erie: Central basin hypoxia. Journal of Great Lakes Research, 40(2), 226–246. https://doi.org/10.1016/j.jglr.2014.02.004

Selim, M. M. (2020). Introduction to the integrated nutrient management strategies and their contribution to yield and soil properties. International Journal of Agronomy, 2020(1), 2821678. https://doi.org/10.1155/2020/2821678

Shcherbak, I., Millar, N., & Robertson, G. P. (2014). Global metaanalysis of the nonlinear response of soil nitrous oxide (nitrous oxide) emissions to fertilizer nitrogen. Proceedings of the National Academy of Sciences, 111(25), 9199–9204. https://doi.org/10.1073/pnas.1322434111

Shindell, D. T., Faluvegi, G., Koch, D. M., Schmidt, G. A., Unger, N., & Bauer, S. E. (2009). Improved attribution of climate forcing to emissions. Science, 326(5953), 716–718. https://doi.org/10.1126/science.1174760

Sobota, D. J., Compton, J. E., McCrackin, M. L., & Singh, S. (2015). Cost of reactive nitrogen release from human activities to the environment in the United States. Environmental Research Letters, 10(2), 025006. https://doi.org/10.1088/1748-9326/10/2/025006

Tian, H., Xu, R., Canadell, J. G., Thompson, R. L., Winiwarter, W., Suntharalingam, P., Davidson, E. A., Ciais, P., Jackson, R. B., Janssens-Maenhout, G., Prather, M. J., Regnier, P., Pan, N., Pan, S., Peters, G. P., Shi, H., Tubiello, F. N., Zaehle, S., Zhou, F., … Yao, Y. (2020). A comprehensive quantification of global nitrous oxide sources and sinks. Nature, 586(7828), 248–256. https://doi.org/10.1038/s41586-020-2780-0

van Grinsven, H. J. M., Bouwman, L., Cassman, K. G., van Es, H. M., McCrackin, M. L., & Beusen, A. H. W. (2015). Losses of ammonia and nitrate from agriculture and their effect on nitrogen recovery in the European Union and the United States between 1900 and 2050. Journal of Environmental Quality, 44(2), 356–367. https://doi.org/10.2134/jeq2014.03.0102

Vanlauwe, B., Descheemaeker, K., Giller, K. E., Huising, J., Merckx, R., Nziguheba, G., Wendt, J., & Zingore, S. (2015). Integrated soil fertility management in sub-Saharan Africa: Unravelling local adaptation. SOIL, 1(1), 491–508. https://doi.org/10.5194/soil-1-491-2015

Wang, C., Shen, Y., Fang, X., Xiao, S., Liu, G., Wang, L., Gu, B., Zhou, F., Chen, D., Tian, H., Ciais, P., Zou, J., & Liu, S. (2024). Reducing soil nitrogen losses from fertilizer use in global maize and wheat production. Nature Geoscience, 17(10), 1008–1015. https://doi.org/10.1038/s41561-024-01542-x

Wang, Y., Li, C., Li, Y., Zhu, L., Liu, S., Yan, L., Feng, G., & Gao, Q. (2020). Agronomic and environmental benefits of Nutrient Expert on maize and rice in Northeast China. Environmental Science and Pollution Research, 27(22), 28053–28065. https://doi.org/10.1007/s11356-020-09153-w

Ward, M. H., Jones, R. R., Brender, J. D., de Kok, T. M., Weyer, P. J., Nolan, B. T., Villanueva, C. M., & van Breda, S. G. (2018). Drinking water nitrate and human health: an updated review. International Journal of Environmental Research and Public Health, 15(7), 1557. https://doi.org/10.3390/ijerph15071557

Withers, P. J. A., Neal, C., Jarvie, H. P., & Doody, D. G. (2014). Agriculture and eutrophication: where do we go from here? Sustainability, 6(9), Article 9. https://doi.org/10.3390/su6095853

You, L., Ros, G. H., Chen, Y., Shao, Q., Young, M. D., Zhang, F., & de Vries, W. (2023). Global mean nitrogen recovery efficiency in croplands can be enhanced by optimal nutrient, crop and soil management practices. Nature Communications, 14(1), 5747. https://doi.org/10.1038/s41467-023-41504-2

Zaehle, S., Ciais, P., Friend, A. D., & Prieur, V. (2011). Carbon benefits of anthropogenic reactive nitrogen offset by nitrous oxide emissions. Nature Geoscience, 4(9), 601–605. https://doi.org/10.1038/ngeo1207

Zhang, X., Fang, Q., Zhang, T., Ma, W., Velthof, G. L., Hou, Y., Oenema, O., & Zhang, F. (2020). Benefits and trade-offs of replacing synthetic fertilizers by animal manures in crop production in China: A meta-analysis. Global Change Biology, 26(2), 888–900. https://doi.org/10.1111/gcb.14826

Credits

Lead Fellow

  • Avery Driscoll, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Yusuf Jameel, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

  • Eric Toensmeier

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Ted Otte

Effectiveness

We relied on the 2019 IPCC emissions factors to calculate the emissions impacts of improved nutrient management. These are disaggregated by climate zone (“wet” vs. “dry”) and by fertilizer type (“organic” vs. “synthetic”). Nitrogen use reductions in wet climates, which include ~65% of the cropland area represented in this analysis (see Appendix for details), have the largest impact. In these areas, a 1 t reduction in nitrogen use reduces emissions by 8.7 t CO₂‑eq on average for synthetic fertilizers and by 5.0 t CO₂‑eq for organic fertilizers. Emissions savings are lower in dry climates, where a 1 t reduction in nitrogen use reduces emissions by 2.4 t CO₂‑eq for synthetic fertilizers and by 2.6 t CO₂‑eq for organic fertilizers. While these values reflect the median emissions reduction for each climate zone and fertilizer type, they are associated with large uncertainties because emissions are highly variable depending on climate, soil, and management conditions. 

Based on our analysis of the adoption ceiling for each climate zone and fertilizer type (see Appendix), we estimated that a 1 t reduction in nitrogen use reduces emissions by 6.0 t CO₂‑eq at the global average (Table 1). This suggests that ~1.4% of the applied nitrogen is emitted as nitrous oxide at the global average, which is consistent with existing estimates (IPCC, 2019). 

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq /tN, 100-yr basis

25th percentile 4.2
median (50th percentile) 6.0
75th percentile 7.7
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Cost

Improving nutrient management typically reduces fertilizer costs while maintaining or increasing yields, resulting in a net financial benefit to the producer. Gu et al. (2023) found that a 21% reduction in global nitrogen use would be economically beneficial, notably after accounting for increased fertilizer use in places that do not currently have adequate access. Using data from their study, we evaluated the average cost of reduced nitrogen application considering the following nutrient management practices: increased use of high-efficiency fertilizers, organic fertilizers, and/or legumes; optimizing fertilizer rates; altering the timing and/or placement of fertilizer applications; and use of buffer zones. Implementation costs depend on the strategy used to improve nutrient management. For example, optimizing fertilizer rates requires soil testing and the ability to apply different fertilizer rates to different parts of a field. Improving timing can involve applying fertilizers at two different times during the season, increasing labor and equipment operation costs. Furthermore, planting legumes incurs seed purchase and planting costs. 

Gu et al. (2023) estimated that annual reductions of 42 Mt of nitrogen were achievable globally using these practices, providing total fertilizer savings of US$37.2 billion and requiring implementation costs of US$15.9 billion, adjusted for inflation to 2023. A 1 t reduction in excess nitrogen application, therefore, was estimated to provide an average of US$507.80 of net cost savings, corresponding to a savings of US$85.21 per t CO₂‑eq of emissions reductions (Table 2).

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Table 2. Cost per unit of climate impact, 100-yr basis.

Unit: 2023 US$/t CO₂‑eq

mean -85.21
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Methods and Supporting Data

Abatzoglou, J. T., Dobrowski, S. Z., Parks, S. A., & Hegewisch, K. C. (2018). TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958–2015. Scientific Data, 5(1), 170191. https://doi.org/10.1038/sdata.2017.191

Adalibieke, W., Cui, X., Cai, H., You, L., & Zhou, F. (2023). Global crop-specific nitrogen fertilization dataset in 1961–2020. Scientific Data, 10(1), 617. https://doi.org/10.1038/s41597-023-02526-z

Gerber, J. S., Ray, D. K., Makowski, D., Butler, E. E., Mueller, N. D., West, P. C., Johnson, J. A., Polasky, S., Samberg, L. H., & Siebert, S. (2024). Global spatially explicit yield gap time trends reveal regions at risk of future crop yield stagnation. Nature Food, 5(2), 125–135. https://doi.org/10.1038/s43016-023-00913-8 

IPCC, 2019: Summary for Policymakers. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. Masson-Delmotte, H.-O. Pörtner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)].

Mehta, P., Siebert, S., Kummu, M., Deng, Q., Ali, T., Marston, L., Xie, W., & Davis, K. F. (2024). Half of twenty-first century global irrigation expansion has been in water-stressed regions. Nature Water, 2(3), 254–261. https://doi.org/10.1038/s44221-024-00206-9

Learning Curve

The improved nutrient management strategies considered for this solution are already well-established and widely deployed (Fixen, 2020). Large nitrogen excesses are relatively easy to mitigate through simple management changes with low implementation costs. As nitrogen use efficiency increases, further reductions may require increasingly complex mitigation practices and increasing marginal costs. Therefore, a learning curve was not quantified for this solution.

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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 gradual, emergency brake, or delayed.

Improve Nutrient Management 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

Emissions reductions from improved nutrient management are permanent, though they may not be additional in all cases.

Permanence

As this solution reduces emissions rather than enhancing sequestration, permanence is not applicable.

Additionality

Additionality requires that the emissions benefits of the practice are attributable to climate-related incentives and would not have occurred in the absence of incentives (Michaelowa et al., 2019). If they are not contingent on external incentives, fertilizer use reductions implemented solely to maximize profits do not meet the threshold for additionality. However, fertilizer reductions may be additional if incentives are required to provide access to the technical knowledge and soil testing required to identify optimal rates. Other forms of nutrient management (e.g., applying nitrification inhibitors, using extended-release or organic fertilizers, or splitting applications between two time points) may involve additional costs, substantial practice change, and technical expertise. Thus, these practices are likely to be additional.

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Current Adoption

Given that improved nutrient management takes a variety of forms and data on the adoption of individual practices are very limited, we leveraged several global datasets related to nitrogen use and yields to directly assess improvements in nitrogen use efficiency (see Appendix for details).

First, we calculated nitrogen use per t of crop produced using global maps of nitrogen fertilizer use (Adalibieke et al., 2023) and global maps of crop yields (Gerber et al., 2024) for 17 major crops (see Appendix). Next, we determined a target nitrogen use rate (t N/t crop) for each crop, corresponding to the 20th percentile of nitrogen use rates observed in croplands with yield gaps at or below the 20th percentile, meaning that actual yields were close to an attainable yield ceiling (Gerber et al., 2024). Areas with large yield gaps were excluded from the calculation of target nutrient use efficiency because insufficient nitrogen supply may be compromising yields (Mueller et al., 2012). Yield data were not available for a small number of crops; for these, we assumed reductions in nitrogen use to be proportional to those of other crops.

We considered croplands that had achieved the target rate and had yield gaps lower than the global median to have adopted the solution. We calculated the amount of excess nitrogen use avoided from these croplands as the difference in total nitrogen use under current fertilization rates relative to median fertilizer application rates. As of 2020, croplands that had achieved the adoption threshold for improved nutrient management avoided 10.45 Mt of nitrogen annually relative to the median nitrogen use rate (Table 3), equivalent to 11% of the adoption ceiling.

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Table 3. Current (2020) adoption level.

Unit: tN/yr

estimate 10,450,000
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Adoption Trend

Global average nitrogen use efficiency increased from 47.7% to 54.6% between 2000 and 2020, a rate of approximately 0.43%/yr (Ludemann et al., 2024). This increase accelerated somewhat in the latter decade, from an average rate of 0.38%/yr to 0.53%/yr. Underlying this increase were increases in both the amount of nitrogen used and the amount of excess nitrogen. Total nitrogen additions increased by approximately 2.64 Mt/yr, with the amount of nitrogen used increasing more rapidly (1.99 Mt/yr) than the amount of excess nitrogen (0.65 Mt/yr) between 2000 and 2020 (Ludemann et al., 2024). Although nitrogen use increased between 2000 and 2020 as yields increased, the increase in nitrogen use efficiency suggests uptake of this solution.

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Adoption Ceiling

We estimated the adoption ceiling of improved nutrient management to be 95.13 Mt avoided excess nitrogen use/year (Table 4), including current adoption. This value reflects our estimate of the maximum potential reduction in nitrogen application while avoiding large yield losses and consists of the potential to avoid 62.25 Mt of synthetic nitrogen use and 32.88 Mt of manure and other organic nitrogen use, in addition to current adoption. In total, this is equivalent to an additional 68% reduction in global nitrogen use. The adoption ceiling was calculated as the difference between total nitrogen use at the current rate and total nitrogen use at the target rate (as described in Current Adoption), assuming no change in crop yields. For nitrogen applied to crops for which yield data were not available, the potential reduction in nitrogen use was assumed to be proportional to that of crops for which full data were available.

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Table 4. Adoption ceiling.

Unit: tN/yr

estimate 105,580,000
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Achievable Adoption

We estimated that fertilizer use reductions of 69.85–91.06 Mt of nitrogen are achievable, reflecting current adoption plus nitrogen savings due to the achievement of nitrogen application rates equal to the median and 30th percentile of nitrogen application rates occurring in locations where yield gaps are small (Table 5).

This range is more ambitious than a comparable recent estimate by Gu et al. (2023), who found that reductions of approximately 42 Mt of nitrogen are avoidable via cost-effective implementation of similar practices. Differences in target nitrogen use efficiencies underlie differences between our estimates and those of Gu et al., whose findings correspond to an increase in global average cropland nitrogen use efficiency from 42% to 52%. Our estimates reflect higher target nitrogen use efficiencies. Nitrogen use efficiencies greater than 52% have been widely achieved through basic practice modification without compromising yields or requiring prohibitively expensive additional inputs. For instance, You et al. (2023) estimated that the global average nitrogen use efficiency could be increased to 78%. Similarly, cropland nitrogen use efficiency in the United States in 2020 was estimated to be 71%, and substantial opportunities for improved nitrogen use efficiency are still available within the United States (Ludemann et al., 2024), though Lu et al. (2019) and Swaney et al. (2018) report slightly lower estimates. These findings support our slightly more ambitious range of achievable nitrogen use reductions for this solution.

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Table 5. Range of achievable adoption levels.

Unit: tN/yr

Current Adoption 10,450,000
Achievable – Low 69,850,000
Achievable – High 91,060,000
Adoption Ceiling 105,580,000
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We estimated that improved nutrient management has the potential to reduce emissions by 0.63 Gt CO₂‑eq/yr, with achievable emissions reductions of 0.42–0.54 Gt CO₂‑eq/yr (Table 6). This is equivalent to an additional 56–76% reduction in total nitrous oxide emissions from fertilizer use, based on the croplands represented in our analysis.

We estimated avoidable emissions by multiplying our estimates of adoption ceiling and achievable adoption by the relevant IPCC 2019 emissions factors, disaggregated by climate zone and fertilizer type. Under the adoption ceiling scenario, approximately 70% of emissions reductions occurred in wet climates, where emissions per t of applied fertilizer are higher. Reductions in synthetic fertilizer use, which are larger than reductions in organic fertilizer use, contributed about 76% of the potential avoidable emissions. We estimated that the current implementation of improved nutrient management was associated with 0.06 Gt CO₂‑eq/yr of avoided emissions. 

Our estimates are slightly more optimistic but well within the range of the IPCC 2021 estimates, which found that improved nutrient management could reduce nitrous oxide emissions by 0.06–0.7 Gt CO₂‑eq/yr.

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Table 6. Climate impact at different levels of adoption.

Unit: Gt CO₂-eq/yr, 100-yr basis

Current Adoption 0.06
Achievable – Low 0.42
Achievable – High 0.54
Adoption Ceiling 0.63
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Additional Benefits

Food Security

While excessive nutrients cause environmental problems in some parts of the world, insufficient nutrients are a significant problem in others, resulting in lower agricultural yields (Foley et al., 2011). Targeted, site-specific, efficient use of fertilizers can improve crop productivity (Mueller et al., 2012; Vanlauwe et al., 2015), improving food security globally. 

Health

Domingo et al. (2021) estimated about 16,000 premature deaths annually in the United States are due to air pollution from the food sector and found that more than 3,500 premature deaths per year could be avoided through reduced use of ammonia fertilizer, a secondary particulate matter precursor. Better agriculture practices overall can reduce particulate matter-related premature deaths from the agriculture sector by 50% (Domingo et al., 2021). Nitrogen oxides from fertilized croplands is another source of agriculture-based air pollution, and improved management can lead to decreased respiratory and cardiovascular disease (Almarez et al., 2018; Sobota et al., 2015). 

Nitrate contamination of drinking water due to excessive runoff from agriculture fields has been linked to several health disorders, including methemoglobinemia and cancer (Patel et al., 2022; Ward et al., 2018). Reducing nutrient runoff through better management is critical to minimize these risks (Ward et al., 2018). 

Income and Work

Better nutrient management reduces farmers' input costs and increases profitability (Rurinda et al., 2020; Wang et al., 2020). It is especially beneficial to smallholder farmers in sub-Saharan Africa, where site-specific nutrient management programs have demonstrated a significant increase in yield (Chivenge et al., 2021). A review of 61 studies across 11 countries showed that site-specific nutrient management resulted in an average increase in yield by 12% and increased farmer’s’ income by 15% while improving nitrogen use efficiency (Chivenge et al., 2021). 

Nature protection

Nutrient runoff from agricultural systems is a major driver of water pollution globally, leading to eutrophication and hypoxic zones in aquatic ecosystems (Bijay-Singh & Craswell, 2021). Nitrogen pollution also harms terrestrial biodiversity through soil acidification and increases productivity of fast-growing species, including invasives, which can outcompete native species (Porter et al., 2013). Improved nutrient management is necessary to reduce nitrogen and phosphorus loads to water bodies (Withers et al., 2014; van Grinsven et al., 2019) and terrestrial ecosystems (Porter et al., 2013). These practices have been effective in reducing harmful algal blooms and preserving biodiversity in sensitive water systems (Scavia et al., 2014). 

Resilience to Drought

Balanced nutrient concentration contributes to long-term soil fertility and improved soil health by enhancing organic matter content, microbial diversity, and nutrient cycling (Antil & Raj, 2020; Selim, 2020). Healthy soil experiences reduced erosion and has higher water content, which increases its resilience to droughts and extreme heat (Rockström et al., 2017).

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Risks

Although substantial reductions in nitrogen use can be achieved in many places with no or minimal impacts on yields, reducing nitrogen application by too much can lead to yield declines, which in turn can boost demand for cropland, causing GHG-producing land use change. Reductions in only excess nitrogen application will prevent substantial yield losses.

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Some nutrient management practices are associated with additional emissions. For example, nitrification inhibitors reduce direct nitrous oxide emissions (Qiao et al., 2014) but can increase ammonia volatilization and subsequent indirect nitrous oxide emissions (Lam et al., 2016). Additionally, in wet climates, nitrous oxide emissions may be reduced through the use of manure instead of synthetic fertilizers (Hergoualc’h et al., 2019), though impacts vary across sites and studies (Zhang et al., 2020). Increased demand for manure could increase livestock production, which has high associated GHG emissions. Emissions also arise from transporting manure to the site of use (Qin et al., 2021).

Although nitrous oxide has a strong direct climate-warming effect, fertilizer use can cool the climate through emissions of other reactive nitrogen-containing compounds (Gong et al., 2024). First, aerosols from fertilizers scatter heat from the sun and cool the climate (Shindell et al., 2009; Gong et al., 2024). Moreover, other reactive nitrogen compounds from fertilizers shorten the lifespan of methane in the atmosphere, reducing its warming effects (Pinder et al., 2012). Finally, nitrogen fertilizers that leave farm fields through volatilization or runoff are ultimately deposited elsewhere, enhancing photosynthesis and sequestering additional carbon in plants and soils (Zaehle et al., 2011; Gong et al., 2024). Improved nutrient management would reduce these cooling effects.

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Interactions with Other Solutions

Reinforcing

Improved nutrient management will reduce emissions from the production phase of biomass crops, increasing their benefit.

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Competing

Improved nutrient management will reduce the GHG production associated with each calorie and, therefore, the impacts of the Improve Diets and Reduce Food Loss and Waste solutions will be reduced

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Each of these solutions could decrease emissions associated with fertilizer production, but improved nutrient management will reduce total demand for fertilizers.

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Dashboard

Solution Basics

t avoided excess nitrogen application/yr

tCO2-eq/unit
6
units
Current 1.05×10⁷6.99×10⁷9.11×10⁷
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 0.06 0.420.54
US$ per tCO2-eq
-85
Gradual

N₂O

tCO2-eq/ha
01

The Problem — Emissions of Nitrous Oxide Coming from Over-fertilized Soils

The world’s agricultural lands can emit high levels of nitrous oxide (N2O), the third most powerful greenhouse gas. These emissions stem from overusing nitrogen-based fertilizers, especially in regions in China, India, Western Europe, and central North America (in red). While crops absorb some of the nitrogen fertilizer we apply, much of what remains is lost to the atmosphere as nitrous oxide pollution or to local waterways as nitrate pollution. Using fertilizers more wisely can dramatically reduce greenhouse gas emissions and water pollution while maintaining high levels of crop production.

Analysis: Project Drawdown; Driscoll et al, In prep.

tCO2-eq/ha
01

The Problem — Emissions of Nitrous Oxide Coming from Over-fertilized Soils

The world’s agricultural lands can emit high levels of nitrous oxide (N2O), the third most powerful greenhouse gas. These emissions stem from overusing nitrogen-based fertilizers, especially in regions in China, India, Western Europe, and central North America (in red). While crops absorb some of the nitrogen fertilizer we apply, much of what remains is lost to the atmosphere as nitrous oxide pollution or to local waterways as nitrate pollution. Using fertilizers more wisely can dramatically reduce greenhouse gas emissions and water pollution while maintaining high levels of crop production.

Analysis: Project Drawdown; Driscoll et al, In prep.

Geographic Guidance Introduction

Improved nutrient management will have the greatest emissions reduction if it is targeted at areas with the largest excesses of nitrogen fertilizer use. In 2020, China, India, and the United States alone accounted for 52% of global excess nitrogen application (Ludemann et al., 2024). Improved nutrient management could be particularly beneficial in China and India, where nutrient use efficiency is currently lower than average (Ludemann et al., 2024). You et al. (2023) also found potential for large increases in nitrogen use efficiency in parts of China, India, Australia, Northern Europe, the United States Midwest, Mexico, and Brazil under standard best management practices. Gu et al. (2024) found that nitrogen input reductions are economically feasible in most of Southern Asia, Northern and Western Europe, parts of the Middle East, North America, and Oceania.

In addition to regional patterns in the adoption ceiling, greater nitrous oxide emissions reductions are possible in wet climates or on irrigated croplands compared to dry climates. Nitrous oxide emissions tend to peak when nitrogen availability is high and soil moisture is in the ~70–90% range (Betterbach-Bahl et al., 2013; Elberling et al., 2023; Hao et al., 2025; Lawrence et al., 2021), though untangling the drivers of nitrous oxide emissions is complex (Lawrence et al., 2021). Water management to avoid prolonged periods of soil moisture in this range is an important complement to nutrient management in wet climates and on irrigated croplands (Deng et al., 2018).

Importantly, improved nutrient management, as defined here, is not appropriate for implementation in areas with nitrogen deficits or negligible nitrogen surpluses, including much of Africa. In these areas, crop yields are constrained by nitrogen availability, and an increase in nutrient inputs may be needed to achieve target yields. Additionally, nutrient management in paddy (flooded) rice systems is not included in this solution but rather in the Improve Rice Production solution.

Action Word
Improve
Solution Title
Nutrient Management
Classification
Highly Recommended
Lawmakers and Policymakers
  • Focus policies and regulations on the four nutrient management principles – right rate, type, time, and place.
  • Create dynamic nutrient management policies that account for varying practices, environments, drainage, historical land use, and other factors that may require adjusting nutrient regulations.
  • Offer financial assistance responsive to local soil and weather conditions, such as grants and subsidies, insurance programs, and tax breaks, to encourage farmers to comply with regulations.
  • Mandate insurance schemes that allow farmers to reduce fertilizer use.
  • Mandate nutrient budgets or ceilings that are responsive to local yield, weather, and soil conditions.
  • Require farmers to formulate nutrient management and fertilizer plans.
  • Mandate efficiency rates for manure-spreading equipment.
  • Ensure access to and require soil tests to inform fertilizer application.
  • Invest in research on alternative organic nutrient sources.
  • Create and expand education programs and extension services that highlight the problems that arise from the overuse of fertilizers, benefits of soil management such as cost-savings, and penalties for non-compliance
  • Create ongoing support groups among farmers.

Further information:

Practitioners
  • Use the four nutrient management principles – right rate, type, time, and place – to guide fertilizer application.
  • Utilize or advocate for financial assistance and tax breaks for farmers to improve nutrient management techniques.
  • Create and adhere to nutrient and fertilizer management plans.
  • Conduct soil tests to inform fertilizer application.
  • Use winter cover crops, crop rotations, residue retention, and split applications for fertilizer.
  • Improve the efficiency of, and regularly calibrate, manure-spreading equipment.
  • Leverage agroecological practices such as nutrient recycling and biological nitrogen fixation.
  • Join, create, or participate in partnerships or certification programs dedicated to improving nutrient management.
  • Take advantage of education programs, support groups, and extension services focused on improved nutrient management.

Further information:

Business Leaders
  • Provide incentives for farmers in primary sourcing regions to adopt best management practices for reducing nitrogen application.
  • Invest in companies that use improved nutrient management techniques or produce equipment or research for fertilizer application and testing.
  • Advocate to policymakers for improved nutrient management techniques, incentives, and regulations.
  • Join, create, or participate in partnerships or certification programs dedicated to improving nutrient management practices.
  • Promote products produced with improved nutrient management techniques and educate consumers about the importance of the practice.
  • Create or support education programs and extension services that highlight the problems that arise from the overuse of fertilizers, benefits of soil management such as cost-savings, and penalties for non-compliance.
  • Create ongoing support groups among farmers.

Further information:

Nonprofit Leaders
  • Start model farms to demonstrate improved nutrient management techniques, conduct experiments, and educate local farmers.
  • Conduct and share research on improved nutrient management techniques, alternative organic fertilizers, or local policy options.
  • Advocate to policymakers for improved nutrient management techniques, incentives, and regulations.
  • Engage with businesses to encourage corporate responsibility and/or monitor water quality and soil health.
  • Join, create, or participate in partnerships or certification programs dedicated to improving nutrient management practices.
  • Create or support education programs and extension services that highlight the problems that arise from the overuse of fertilizers, benefits of soil management such as cost-savings, and penalties for non-compliance.
  • Create ongoing support groups among farmers.

Further information:

Investors
  • Invest in companies developing technologies that support improved nutrient management such as precision fertilizer applicators, alternative fertilizers, soil management equipment, and software.
  • Invest in ETFs and ESG funds that hold companies committed to improved nutrient management techniques in their portfolios.
  • Encourage companies in your investment portfolio to adopt improved nutrient management.
  • Provide access to capital at reduced rates for farmers adhering to improved nutrient management.

Further information:

Philanthropists and International Aid Agencies
  • Provide financing for farmers to improve nutrient management.
  • Start model farms to demonstrate nutrient management techniques, conduct experiments, and educate local farmers.
  • Conduct and share research on improved nutrient management, alternative organic fertilizers, or local policy options.
  • Advocate to policymakers for improved nutrient management techniques, incentives, and regulations.
  • Engage with businesses to encourage corporate responsibility and/or monitor water quality and soil health.
  • Join, create, or participate in partnerships or certification programs dedicated to improving nutrient management practices.
  • Create or support education programs and extension services that highlight the problems that arise from the overuse of fertilizers, benefits of soil management such as cost-savings, and penalties for non-compliance.
  • Create ongoing support groups among farmers.

Further information:

Thought Leaders
  • Start model farms to demonstrate techniques, conduct experiments, and educate local farmers.
  • Conduct and share research on improved nutrient management, alternative organic fertilizers, or local policy options.
  • Advocate to policymakers for improved nutrient management techniques, incentives, and regulations.
  • Engage with businesses to encourage corporate responsibility and/or monitor water quality and soil health.
  • Join, create, or participate in partnerships dedicated to improving nutrient management practices.
  • Create or support education programs and extension services that highlight the problems that arise from the overuse of fertilizers, benefits of soil management such as cost-savings, and penalties for non-compliance.
  • Create ongoing support groups among farmers.

Further information:

Technologists and Researchers
  • Improve technology and cost-effectiveness of precision fertilizer application, slow-release fertilizer, alternative organic fertilizers, nutrient recycling, and monitoring equipment.
  • Create tracking and monitoring software to support farmers' decision-making.
  • Research and develop the application of AI and robotics for precise fertilizer application.
  • Improve data and analytics to monitor soil and water quality, assist farmers, support policymaking, and assess the impacts of policies.
  • Develop education and training applications to promote improved nutrient management and provide real-time feedback.

Further information:

Communities, Households, and Individuals
  • Create or join community-supported agriculture programs that source from farmers who used improved nutrient management practices.
  • Conduct soil tests on your lawn and garden and reduce fertilizer use if you are over-fertilizing.
  • Volunteer for soil and water quality monitoring and restoration projects.
  • Start model farms to demonstrate techniques, conduct experiments, and educate local farmers.
  • Advocate to policymakers for improved nutrient management techniques, incentives, and regulations.
  • Engage with businesses to encourage corporate responsibility and/or monitor water quality and soil health.
  • Join, create, or participate in partnerships dedicated to improving nutrient management.
  • Create or support education programs and extension services that highlight the problems that arise from the overuse of fertilizers, benefits of soil management such as cost-savings, and penalties for non-compliance.
  • Create ongoing support groups among farmers.

Further information:

Sources
Evidence Base

There is high scientific consensus that reducing nitrogen surpluses through improved nutrient management reduces nitrous oxide emissions from croplands. 

Nutrient additions to croplands produce an estimated 0.9 Gt CO₂‑eq/yr (range 0.7–1.1 Gt CO₂ -e/yr) of direct nitrous oxide emissions from fields, plus approximately 0.3 Gt CO₂‑eq/yr of indirect emissions from fertilizers that runoff into waterways or erode (Tian et al., 2020). Nitrous oxide emissions from croplands are directly linked to the amount of nitrogen applied. Furthermore, the amount of nitrous oxide emitted per unit of applied nitrogen is well quantified for a range of different nitrogen sources and field conditions (Reay et al., 2012; Shcherbak et al., 2014; Gerber et al., 2016; Intergovernmental Panel on Climate Change [IPCC], 2019; Hergoualc’h et al., 2021). Tools to improve nutrient management have been extensively studied, and practices that improve nitrogen use efficiency through right rate, time, place, and type principles have been implemented in some places for several decades (Fixen, 2020; Ludemann et al., 2024).

Recently, Gao & Cabrera Serrenho (2023) estimated that fertilizer-related emissions could be reduced up to 80% by 2050 relative to current levels using a combination of nutrient management and new fertilizer production methods. You et al. (2023) found that adopting improved nutrient management practices would increase nitrogen use efficiency from a global average of 48% to 78%, substantially reducing excess nitrogen. Wang et al. (2024) estimated that the use of enhanced-efficiency fertilizers could reduce nitrogen losses to the environment 70–75% for maize and wheat systems. Chivenge et al. (2021) found comparable results in smallholder systems in Africa and Asia.

The results presented in this document were produced through analysis of global datasets. We recognize that geographic biases can influence the development of global datasets and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Appendix

In this analysis, we calculated the potential for reducing crop nitrogen inputs and associated nitrous oxide emissions by integrating spatially explicit, crop-specific data on nitrogen inputs, crop yields, attainable yields, irrigated extent, and climate. Broadly, we calculated a “target” yield-scaled nitrogen input rate based on pixels with low yield gaps and calculated the difference between nitrous oxide emissions under the current rate and under the hypothetical target emissions rate, using nitrous oxide emissions factors disaggregated by fertilizer type and climate. 

Emissions factors

We used Tier 1 emissions factors from the IPCC 2019 Refinement to the 2006 Guidelines for National Greenhouse Gas Inventories, including direct emissions factors as well as indirect emissions from volatilization and leaching pathways. Direct emissions factors represent the proportion of applied nitrogen emitted as nitrous oxide, while we calculated volatilization and leaching emissions factors by multiplying the proportion of applied nitrogen lost through these pathways by the proportion of volatilized or leached nitrogen ultimately emitted as nitrous oxide. Including both direct and indirect emissions, organic and synthetic fertilizers emit 4.97 kg CO₂‑eq/kg nitrogen and 8.66 kg CO₂‑eq/kg nitrogen, respectively, in wet climates, and 2.59 kg CO₂‑eq/kg nitrogen and 2.38 kg CO₂‑eq/kg nitrogen in dry climates. We included uncertainty bounds (2.5th and 97.5th percentiles) for all emissions factors. 

We classified each pixel as “wet” or “dry” using an aridity index (AI) threshold of 0.65, calculated as the ratio of annual precipitation to potential evapotranspiration (PET) from TerraClimate data (1991–2020), based on a threshold of 0.65. For pixels in dry climates that contained irrigation, we took the weighted average of wet and dry emissions factors based on the fraction of cropland that was irrigated (Mehta et al., 2024). We excluded irrigated rice from this analysis due to large differences in nitrous oxide dynamics in flooded rice systems.

Current, target, and avoidable nitrogen inputs and emissions

Using highly disaggregated data on nitrogen inputsfrom Adalibieke et al. (2024) for 21 crop groups (Table S1), we calculated total crop-specific inputs of synthetic and organic nitrogen. We then averaged over 2016–2020 to reduce the influence of interannual variability in factors like fertilizer prices. These values are subsequently referred to as “current” nitrogen inputs. We calculated nitrous oxide emissions under current nitrogen inputs as the sum of the products of nitrogen inputs and the climatically relevant emissions factors for each fertilizer type.

Next, we calculated target nitrogen application rates in terms of kg nitrogen per ton of crop yield using data on actual and attainable yields for 17 crops from Gerber et al., 2024 (Table S1). For each crop, we first identified pixels in which the ratio of actual to attainable yields was above the 80th percentile globally. The target nitrogen application rate was then calculated as the 20th percentile of nitrogen application rates across low-yield-gap pixels. Finally, we calculated total target nitrogen inputs as the product of actual yields and target nitrogen input rates. We calculated hypothetical nitrous oxide emissions from target nitrogen inputs as the product of nitrogen inputs and the climatically relevant emissions factor for each fertilizer type.

The difference between current and target nitrogen inputs represents the amount by which nitrogen inputs could hypothetically be reduced without compromising crop productivity (i.e., “avoidable” nitrogen inputs). We calculated avoidable nitrous oxide emissions as the difference between nitrous oxide emissions with current nitrogen inputs and those with target nitrogen inputs. For crops for which no yield or attainable yield data were available, we applied the average percent reduction in nitrogen inputs under the target scenario from available crops to the nitrogen input data for missing crops to calculate the avoidable nitrogen inputs and emissions. 

This simple and empirically driven method aimed to identify realistically low but nutritionally adequate nitrogen application rates by including only pixels with low yield gaps, which are unlikely to be substantially nutrient-constrained. We did not control for other factors affecting nitrogen availability, such as historical nutrient application rates or depletion, rotation with nitrogen fixing crops, or tillage and residue retention practices.

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Table S1. Crops represented by the source data on nitrogen inputs (Adalibieke et al., 2024) and estimated and attainable yields (Gerber et al., 2024). Crop groups included consistently in both datasets are marked as “both,” and crop groups represented in the nitrogen input data but not in the yield datasets are marked as “nitrogen only.”

Crop Dataset(s)
BarleyBoth
CassavaBoth
CottonBoth
MaizeBoth
MilletBoth
Oil PalmBoth
PotatoBoth
RiceBoth
RyeBoth
RapeseedBoth
SorghumBoth
SoybeanBoth
SugarbeetBoth
SugarcaneBoth
SunflowerBoth
Sweet PotatoBoth
WheatBoth
GroundnutNitrogen only
FruitsNitrogen only
VegetablesNitrogen only
OtherNitrogen only
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Updated Date

Protect Forests

Submitted by Drawdown Admin on
Sector
Food, Agriculture, Land & Ocean
Mode
Cut Emissions
Cluster
Protect & Manage Ecosystems
Image
Fog sitting among trees of a dense forest canopy
Coming Soon
Off
Summary

We define the Protect Forests solution as the long-term protection of tree-dominated ecosystems through establishment of protected areas (PAs), managed with the primary goal of conserving nature, and land tenure for Indigenous peoples. These protections reduce forest degradation, avoiding GHG emissions and ensuring continued carbon sequestration by healthy forests. This solution addresses protection of forests on mineral soils. The Protect Peatlands and Protect Coastal Wetlands solutions address protection of forested peatlands and mangrove forests, respectively, and the Restore Forests solution addresses restoring degraded forests.

Extreme weather events
Food security,Health,Equality
Nature protection,Water quality
Overview

Forests store carbon in biomass and soils and serve as carbon sinks, taking up an estimated 12.8 Gt CO₂‑eq/yr  (including mangroves and forested peatlands; Pan et al., 2024). Carbon stored in forests is released into the atmosphere through deforestation and degradation, which refer to forest clearing or reductions in ecosystem integrity from human influence (DellaSala et al., 2025). Humans cleared an average of 0.4% (16.3 Mha) of global forest area annually 2001–2019 (excluding wildfire but including mangroves and forested peatlands; Hansen et al., 2013). This produced a gross flux of 7.4 Gt CO₂‑eq/yr (Harris et al., 2021), equivalent to ~14% of total global GHG emissions over that period (Dhakal et al., 2022). Different forest types store varying amounts of carbon and experience different rates of clearing; in this analysis, we individually evaluate forest protection in boreal, temperate, subtropical, and tropical regions. We included woodlands in our definition of forests because they are not differentiated in the satellite-based data used in this analysis.

We consider forests to be protected if they 1) are formally designated as PAs (UNEP-WCMC and IUCN, 2024), or 2) are mapped as Indigenous peoples’ lands in the global study by Garnett et al. (2018). The International Union for Conservation of Nature defines PAs as areas managed primarily for the long-term conservation of nature and ecosystem services. They are disaggregated into six levels of protection, ranging from strict wilderness preserves to sustainable-use areas that allow for some natural resource extraction, including logging. We included all levels of protection in this analysis, primarily because not all PAs have been classified into these categories. We rely on existing maps of Indigenous peoples’ lands but emphasize that much of their extent has not been fully mapped nor recognized for its conservation benefits (Garnett et al., 2018). Innovative and equity-driven strategies for forest protection that recognize the land rights, sovereignty, and stewardship of Indigenous peoples and local communities are critical for achieving just and effective forest protection globally (Dawson et al., 2024; Fa et al., 2020; FAO, 2024; Garnett et al., 2018; Tran et al., 2020; Zafra-Calvo et al., 2017).

Indigenous peoples’ lands and PAs reduce, but do not eliminate, forest clearing relative to unprotected areas (Baragwanath et al., 2020; Blackman & Viet 2018; Li et al., 2024; McNicol et al., 2023; Sze et al. 2022; Wolf et al., 2023; Wade et al., 2020). We rely on estimates of current PA effectiveness for this analysis but highlight that improving management to further reduce land use change within PAs is a critical component of forest protection (Jones et al., 2018; Meng et al., 2023; Vijay et al., 2018; Visconti et al., 2019; Watson et al., 2014).

Market-based strategies and other policies can complement legal protections by increasing the value of intact forests and reducing incentives for clearing (e.g., Garett et al., 2019; Golub et al., 2021; Heilmayr et al., 2020; Lambin et al., 2018; Levy et al., 2023; Macdonald et al., 2024; Marin et al., 2022; Villoria et al., 2022; West et al., 2023). The estimates in this report are based on legal protection alone because the effectiveness of market-based strategies is difficult to quantify, but strategies such as sustainable commodities programs, reducing or redirecting agricultural subsidies, and strategic infrastructure planning will be further discussed in an Appendix (coming soon). 

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Credits

Lead Fellow

  • Avery Driscoll, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Yusuf Jameel, Ph.D. 

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Hannah Henkin

  • Ted Otte

  • Tina Swanson, Ph.D.

  • Paul West, Ph.D.

Effectiveness

We estimated that one hectare of forest protection provides total carbon benefits of 0.299–2.204 t CO₂‑eq/yr depending on the biome (Table 1; Appendix). This effectiveness estimate includes avoided emissions and preserved sequestration capacity attributable to the reduction in forest loss conferred by protection (Equation 1). First, we calculated the difference between the rate of human-caused forest loss outside of PAs (Forest lossbaseline) and the rate inside of PAs (Forest lossprotected). We then multiplied the annual rate of avoided forest loss by the sum of the carbon stored in one hectare of forest (Carbonstock) and the amount of carbon that one hectare of intact forest takes up over a 30-yr timeframe (Carbonsequestration). 

Equation 1.

Effectiveness= (Forest lossbaseline- Forest lossprotected)* (Carbonstock + Carbonsequestration) 

Each of these factors varies across biomes. Based on our definition, for instance, the effectiveness of forest protection in boreal forests is lower than that in tropical and subtropical forests primarily because the former face lower rates of human-caused forest loss (though greater wildfire impacts). Importantly, the effectiveness of forest protection as defined here reflects only a small percentage of the carbon stored (394 t CO₂‑eq ) and absorbed (4.25 t CO₂‑eq/yr ) per hectare of forest (Harris et al., 2021). This is because humans clear ~0.4% of forest area annually, and forest protection is estimated to reduce human-caused forest loss by an average of 40.5% (Curtis et al., 2018; Wolf et al., 2023). 

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Table 1. Effectiveness at avoiding emissions and sequestering carbon (t CO₂‑eq /ha/yr, 100-yr basis), with carbon sequestration calculated over a 30-yr timeframe. Differences in values between biomes are driven by variation in forest carbon stocks and sequestration rates, baseline rates of forest loss, and effectiveness of PAs at reducing forest loss. See the Appendix for source data and calculation details. Emissions and sequestration values may not sum to total effectiveness due to rounding.

Unit: t CO₂‑eq/ha/yr

Avoided emissions 0.207
Sequestration 0.091
Total effectiveness 0.299

Unit: t CO₂‑eq/ha/yr

Avoided emissions 0.832
Sequestration 0.572
Total effectiveness 1.403

Unit: t CO₂‑eq/ha/yr

Avoided emissions 1.860
Sequestration 0.344
Total effectiveness 2.204

Unit: t CO₂‑eq/ha/yr

Avoided emissions 1.190
Sequestration 0.300
Total effectiveness 1.489
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Cost

We estimated that forest protection costs approximately US$2/t CO₂‑eq (Table 2). Data related to the costs of forest protection are limited, and these estimates are uncertain. The costs of forest protection include up-front costs of land acquisition and ongoing costs of management and enforcement. The market price of land reflects the opportunity cost of not using the land for other purposes (e.g., agriculture or logging). Protecting forests also generates revenue, notably through increased tourism. Costs and revenues vary across regions, depending on the costs of land and enforcement and potential for tourism. 

The cost of land acquisition for ecosystem protection was estimated by Dienerstein et al. (2024), who found a median cost of US$988/ha (range: US$59–6,616/ha), which we amortized over 30 years. Costs of PA maintenance were estimated at US$9–17/ha/yr (Bruner et al., 2004; Waldron et al., 2020). These estimates reflect the costs of effective enforcement and management, but many existing PAs do not have adequate funds for effective enforcement (Adams et al., 2019; Barnes et al., 2018; Burner et al., 2004). Tourism revenues directly attributable to forest protection were estimated to be US$43/ha/yr (Waldron et al., 2020), not including downstream revenues from industries that benefit from increased tourism. Inclusion of a tourism multiplier would substantially increase the estimated economic benefits of forest protection.

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Table 2. Cost per unit of climate impact.

Unit: 2023 US$/t CO₂‑eq, 100-yr basis

median 2
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Methods and Supporting Data

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Curtis, P. G., Slay, C. M., Harris, N. L., Tyukavina, A., & Hansen, M. C. (2018). Classifying drivers of global forest loss. Science, 361(6407), 1108–1111. https://doi.org/10.1126/science.aau3445

ESA CCI (2019). Copernicus Climate Change Service, Climate Data Store: Land cover classification gridded maps from 1992 to present derived from satellite observation. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). Accessed November 2024. doi: 10.24381/cds.006f2c9a

Garnett, S. T., Burgess, N. D., Fa, J. E., Fernández-Llamazares, Á., Molnár, Z., Robinson, C. J., Watson, J. E. M., Zander, K. K., Austin, B., Brondizio, E. S., Collier, N. F., Duncan, T., Ellis, E., Geyle, H., Jackson, M. V., Jonas, H., Malmer, P., McGowan, B., Sivongxay, A., & Leiper, I. (2018). A spatial overview of the global importance of Indigenous lands for conservation. Nature Sustainability, 1(7), 369–374. https://doi.org/10.1038/s41893-018-0100-6

Giri C, Ochieng E, Tieszen LL, Zhu Z, Singh A, Loveland T, Masek J, Duke N (2011). Status and distribution of mangrove forests of the world using earth observation satellite data (version 1.3, updated by UNEP-WCMC). Global Ecology and Biogeography 20: 154-159. doi: 10.1111/j.1466-8238.2010.00584.x . Data URL: http://data.unep-wcmc.org/datasets/4

Gumbricht, T. et al. An expert system model for mapping tropical wetlands and peatlands reveals South America as the largest contributor. Global Change Biology 23, 3581–3599 (2017). https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.13689 

Hansen, M. C., Potapov, P. V., Moore, R., Hancher, M., Turubanova, S. A., Tyukavina, A., Thau, D., Stehman, S. V., Goetz, S. J., Loveland, T. R., Kommareddy, A., Egorov, A., Chini, L., Justice, C. O., & Townshend, J. R. G. (2013). High-Resolution Global Maps of 21st-Century Forest Cover Change. Science, 342(6160), 850–853. https://doi.org/10.1126/science.1244693. Data available on-line from: http://earthenginepartners.appspot.com/science-2013-global-forest. Accessed through Global Forest Watch on 01/12/2024. www.globalforestwatch.org

Harris, N. L., Gibbs, D. A., Baccini, A., Birdsey, R. A., de Bruin, S., Farina, M., Fatoyinbo, L., Hansen, M. C., Herold, M., Houghton, R. A., Potapov, P. V., Suarez, D. R., Roman-Cuesta, R. M., Saatchi, S. S., Slay, C. M., Turubanova, S. A., & Tyukavina, A. (2021). Global maps of twenty-first century forest carbon fluxes. Nature Climate Change, 11(3), 234–240. https://doi.org/10.1038/s41558-020-00976-6

Hastie, A. et al. Risks to carbon storage from land-use change revealed by peat thickness maps of Peru. Nature Geoscience 15: 369-374 (2022). https://www.nature.com/articles/s41561-022-00923-4

Miettinen, J., Shi, C. & Liew, S. C. Land cover distribution in the peatlands of Peninsular Malaysia, Sumatra and Borneo in 2015 with changes since 1990. Global Ecological Conservation. 6, 67– 78 (2016). https://www.sciencedirect.com/science/article/pii/S2351989415300470

UNEP-WCMC and IUCN (2024), Protected Planet: The World Database on Protected Areas (WDPA) and World Database on Other Effective Area-based Conservation Measures (WD-OECM) [Online], Accessed November 2024, Cambridge, UK: UNEP-WCMC and IUCN. Available at: www.protectedplanet.net.

Wolf, C., Levi, T., Ripple, W. J., Zárrate-Charry, D. A., & Betts, M. G. (2021). A forest loss report card for the world’s protected areas. Nature Ecology & Evolution, 5(4), 520–529. https://doi.org/10.1038/s41559-021-01389-0

Xu et al. PEATMAP: Refining estimates of global peatland distribution based on a meta-analysis. CATENA 160: 134-140 (2018). https://www.sciencedirect.com/science/article/pii/S0341816217303004 

Learning Curve

A learning curve is defined here as falling costs with increased adoption. The costs of forest protection do not fall with increasing adoption, so there is no learning curve for this solution.

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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 gradual, emergency brake, or delayed.

Protect Forests 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

Additionality, or the degree to which emissions reductions are above and beyond a baseline, is a key caveat for emissions avoided through forest protection (e.g., Fuller et al., 2020; Ruseva et al., 2017). Emissions avoided via forest protection are only considered additional if that forest would have been cleared or degraded without protection (Delacote et al., 2022; Delacote et al., 2024; Gallemore et al., 2020). In this analysis, additionality is addressed by using baseline rates of forest loss outside of PAs in the effectiveness calculation. Additionality is particularly important when forest protection is used to generate carbon offsets. However, the likelihood of forest removal in the absence of protection is often difficult to determine at the local level.

Permanence, or the durability of stored carbon over long timescales, is another important consideration not directly addressed in this solution. Carbon stored in forests can be compromised by natural factors, like drought, heat, flooding, wildfire, pests, and diseases, which are further exacerbated by climate change (Anderegg et al., 2020; Dye et al., 2024). Forest losses via wildfire in particular can create very large pulses of emissions (e.g., Kolden et al. 2024; Phillips et al. 2022) that negate accumulated carbon benefits of forest protection. Reversal of legal protections, illegal forest clearing, biodiversity loss, edge effects from roads, and disturbance from permitted uses can also cause forest losses directly or reduce ecosystem integrity, further increasing vulnerability to other stressors (McCallister et al., 2022).

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Current Adoption

We estimated that approximately 1,673 Mha of forests are currently recognized as PAs or Indigenous peoples’ lands (Table 3; Garnett et al., 2018; UNEP-WCMC and IUCN, 2024). Using two different maps of global forests that differ in their methodologies and definitions (ESA CCI, 2019; Hansen et al., 2013), we found an upper-end estimate of 1,943 Mha protected and a lower-end estimate of 1,404 Mha protected. These two maps classify forests using different thresholds for canopy cover and vegetation height, different satellite data, and different classification algorithms (see the Appendix for additional details). 

Based on our calculations, tropical forests make up the majority of forested PAs, with approximately 936 Mha under protection, followed by boreal forests (467 Mha), temperate forests (159 Mha), and subtropical forests (112 Mha). We estimate that 49% of all forests have some legal protection, though only 7% of forests are under strict protection (IUCN class I or II), with the remaining area protected under other IUCN levels, as OECMs, or as Indigenous peoples’ lands.

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Table 3. Current (circa 2023) forest and woodland area under legal protection by biome (Mha). The low and high values are calculated using two different maps of global forest cover that differ in methodology for defining a forest (ESA CCI, 2019; Hansen et al., 2013). Biome-level values may not sum to global totals due to rounding.

Unit: Mha

low 313
mean 467
high 621

Unit: Mha

low 135
mean 159
high 183

Unit: Mha

low 85
mean 112
high 138

Unit: Mha

low 872
mean 936
high 1,000

Unit: Mha

low 1,404
mean 1,673
high 1,943
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Adoption Trend

We calculated the rate of PA expansion based on the year the PA was established. We do not have data on the expansion rate of Indigenous peoples’ lands, so the calculated adoption trend reflects only PAs. An average of 19 Mha of additional forests were protected each year between 2000 and 2020 (Table 4; Figure 1), representing a roughly 2% increase in PAs per year (excluding Indigenous peoples’ lands that are not located in PAs). There were large year-to-year differences in how much new forest area was protected over this period, ranging from only 6.4 Mha in 2020 to over 38 Mha in both 2000 and 2006. Generally, the rate at which forest protection is increasing has been decreasing, with an average increase of 27 Mha/yr between 2000–2010 declining to 11 Mha/yr between 2010–2020. Recent rates of forest protection (2010–2020) are highest in the tropics (5.6 Mha/yr), followed by temperate regions (2.4 Mha/yr) and the boreal (2.0 Mha/yr), and lowest in the subtropics (0.7 Mha/yr).

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Figure 1. Trend in forest protection by climate zone. These values reflect only the area located within PAs; Indigenous peoples’ lands, which were not included in the calculation of the adoption trend, are excluded.

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Table 4. 2000–2020 adoption trend.

Unit: Mha protected/yr

25th percentile 1.3
mean 2.8
median (50th percentile) 2.0
75th percentile 3.4

Unit: Mha protected/yr

25th percentile 1.9
mean 2.8
median (50th percentile) 2.5
75th percentile 3.1

Unit: Mha protected/yr

25th percentile 0.5
mean 1.0
median (50th percentile) 0.7
75th percentile 1.1

Unit: Mha protected/yr

25th percentile 5.4
mean 12.5
median (50th percentile) 7.7
75th percentile 17.8

Unit: Mha protected/yr

25th percentile 9
mean 19
median (50th percentile) 13
75th percentile 25
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Adoption Ceiling

We estimated an adoption ceiling of 3,370 Mha of forests globally (Table 5), defined as all existing forest areas, excluding peatlands and mangroves. Of the calculated adoption ceiling, 469 Mha of boreal forests, 282 Mha of temperate forests, 211 Mha of subtropical forests, and 734 Mha of tropical forests are currently unprotected. The high and low values represent estimates of currently forested areas from two different maps of forest cover that use different methodologies and definitions (ESA CCI, 2019; Hansen et al., 2013). While it is not socially, politically, or economically realistic that all existing forests could be protected, these values represent the technical upper limit to adoption of this solution. Additionally, some PAs allow for ongoing sustainable use of resources, enabling some demand for wood products to be met via sustainable use of trees in PAs.

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Table 5. Adoption ceiling.

Unit: Mha protected

low 686
mean 936
high 1,186

Unit: Mha protected

low 385
mean 441
high 498

Unit: Mha protected

low 260
mean 323
high 385

Unit: Mha protected

low 1,557
mean 1,669
high 1,782

Unit: Mha protected

low 2,889
mean 3,370
high 3,851
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Achievable Adoption

We defined the lower end of the achievable range for forest protection as all high integrity forests in addition to forests in existing PAs and Indigenous peoples’ lands, totaling 2,297 Mha. We estimated that there are 624 Mha of unprotected high integrity forests, based on maps of forest integrity developed by Grantham et al. (2020). High integrity forests have experienced little disturbance from human pressures (i.e., logging, agriculture, and buildings), are located further away from areas of human disturbance, and are well-connected to other forests. High integrity forests are a top priority for protection as they have particularly high value with respect to biodiversity and ecosystem service provisioning. These forests are also not currently being used to meet human demand for land or forest-derived products, and thus their protection may be more feasible. 

To estimate the upper end of the achievable range, we excluded the global areas of planted trees and tree crops from the adoption ceiling (Richter et al., 2024), comprising approximately 335 Mha globally (Table 6). Planted trees include tree stands established for crops such as oil palm, products such as timber and fiber production, and those established as windbreaks or for ecosystem services such as erosion control. These stands are often actively managed and are unlikely to be protected.

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Table 6. Range of achievable adoption levels. 

Unit: Mha protected

Current Adoption 467
Achievable – Low 847
Achievable – High 861
Adoption ceiling 936

Unit: Mha protected

Current Adoption 159
Achievable – Low 204
Achievable – High 378
Adoption ceiling 441

Unit: Mha protected

Current Adoption 112
Achievable – Low 126
Achievable – High 219
Adoption ceiling 323

Unit: Mha protected

Current Adoption 936
Achievable – Low 1,120
Achievable – High 1,577
Adoption ceiling 1,669

Unit: Mha protected

Current Adoption 1,673
Achievable – Low 2,297
Achievable – High 3,035
Adoption ceiling 3,370
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We estimated that forest protection currently avoids approximately 2.00 Gt CO₂‑eq/yr, with potential impacts of 2.49 Gt CO₂‑eq/yr at the low-achievable scenario, 3.62 Gt CO₂‑eq/yr  at the high-achievable scenario, and 4.10 Gt CO₂‑eq/yr at the adoption ceiling (Table 7). Although not directly comparable due to the inclusion of different land covers, these values are aligned with Griscom et al. (2017) estimates that forest protection could avoid 3.6 Gt CO₂‑eq/yr and the IPCC estimate that protection of all ecosystems could avoid 6.2 Gt CO₂‑eq/yr (Nabuurs et al., 2022).

Note that the four adoption scenarios vary only with respect to the area under protection. Increases in either the rate of forest loss that would have occurred if the area had not been protected or in the effectiveness of PAs at avoiding forest loss would substantially increase the climate impacts of forest protection. For instance, a hypothetical 50% increase in the rate of forest loss outside of PAs would increase the carbon impacts of the current adoption, low achievable, high achievable, and adoption ceiling scenarios to 3.0, 3.7, 5.4, and 6.1 Gt CO₂‑eq/yr, respectively. Similarly, if legal forest protection reduced forest loss twice as much as it currently does, the climate impacts of the four scenarios would increase to 3.9, 4.8, 7.0, and 7.8 Gt CO₂‑eq/yr, respectively.

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Table 7. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Boreal 0.14
Achievable – Low 0.25
Achievable – High 0.26
Adoption ceiling 0.28

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.22
Achievable – Low 0.29
Achievable – High 0.53
Adoption ceiling 0.62

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.25
Achievable – Low 0.28
Achievable – High 0.48
Adoption ceiling 0.71

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 1.39
Achievable – Low 1.67
Achievable – High 2.35
Adoption ceiling 2.49

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 2.00
Achievable – Low 2.49
Achievable – High 3.62
Adoption ceiling 4.10
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Additional Benefits

Water quality

Forests act as a natural water filter and can maintain and improve water quality (Melo et al., 2021). Forests can also retain nutrients from polluting the larger watershed (Sweeney et al., 2004). For example, forests can uptake excess nutrients like nitrogen, reducing their flow into surrounding water (Sarira et al., 2022). These excessive nutrients can cause eutrophication and algal blooms that negatively impact water quality and aquatic life. 

Biodiversity

Forests are home to a wide range of species and habitats and are essential for safeguarding biodiversity. Forests have high above- and belowground carbon density, high tree species richness, and often provide habitat to threatened and endangered species (Buotte et al., 2020). PAs can aid in avoiding extinctions by protecting rare and threatened species (Dinerstein et al. 2024). In Southeast Asia, protecting 58% of threatened forests could safeguard about half of the key biodiversity areas in the region (Sarira et al., 2022). 

Resilience to extreme weather events

Protected forests are more biodiverse and therefore more resilient and adaptable, providing higher-quality ecosystem services to surrounding communities (Gray et al., 2016). Protected forests can also buffer surrounding areas from the effects of extreme weather events. By increasing plant species richness, forest preservation can contribute to drought and fire tolerance (Buotte et al., 2020). Forests help regulate local climate by reducing temperature extremes (Lawrence et al., 2022). Studies have shown that the extent of forest coverage helps to alleviate vulnerability associated with heat effects (Walton et al., 2016). Tropical deforestation threatens human well-being by removing critical local cooling effects provided by tropical forests, exacerbating extreme heat conditions in already vulnerable regions (Seymour et al., 2022).

Food security

Protecting forests in predominantly natural areas can improve food security by supporting crop pollination of nearby agriculture. Sarira et al. (2022) found that protecting 58% of threatened forests in Southeast Asia could support the dietary needs of about 305,000–342,000 people annually. Forests also provide a key source of income and livelihoods for subsistence households and individuals (de Souza et al., 2016; Herrera et al., 2017; Naidoo et al., 2019). By maintaining this source of income through forest protection, households can earn sufficient income to ensure food security. 

Health

Protected forests can benefit the health and well-being of surrounding communities through impacts on the environment and local economies. Herrera et al. (2017) found that in rural areas of low- and middle-income countries, household members living downstream of higher tree cover had a lower probability of diarrheal disease. Proximity to PAs can benefit local tourism, which may provide more economic resources to surrounding households. Naidoo et al. (2019) found that households near PAs in low- and middle-income countries were more likely to have higher levels of wealth and were less likely to have children who were stunted. Reducing deforestation can improve health by lowering vector-borne diseases, mitigating extreme weather impacts, and improving air quality (Reddington et al., 2015). 

Equality

Indigenous peoples have a long history of caring for and shaping landscapes that are rich with biodiversity (Fletcher et al., 2021). Indigenous communities provide vital ecological functions for preserving biodiversity, like seed dispersal and predation (Bliege Bird & Nimmo, 2018). Indigenous peoples also have spiritual and cultural ties to their lands (Garnett et al., 2018). Establishing protected areas must prioritize the return of landscapes to Indigenous peoples so traditional owners can feel the benefits of biodiversity. However, the burden of conservation should not be placed on Indigenous communities without legal recognition or support (Fa et al., 2020). In fact, land grabs and encroachments on Indigenous lands have led to greater deforestation pressure (Sze et al., 2022). Efforts to protect these lands must include legal recognition of Indigenous ownership to support a just and sustainable conservation process (Fletcher et al., 2021).

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Risks

Ecosystem protection initiatives that are not led by or undertaken in close collaboration with local communities can compromise community sovereignty and create injustice and inequity (Baragwanath et al., 2020; Blackman & Viet 2018; Dawson et al., 2024; Fa et al., 2020; FAO, 2024; Garnett et al. 2018; Sze et al. 2022; Tauli-Corpuz et al., 2020). Forest protection has the potential to be a win-win for climate and communities, but only if PAs are established with respect to livelihoods and other socio-ecological impacts, ensuring equity in procedures, recognition, and the distribution of benefits (Zafra-Calvo et al., 2017).

Leakage is a key risk of relying on forest protection as a climate solution. Leakage occurs when deforestation-related activities move outside of PA boundaries, resulting in the relocation of, rather than a reduction in, emissions from forest loss. If forest protection efforts are not coupled with policies to reduce incentives for forest clearing, leakage will likely offset some of the emissions avoided through forest protection. Additional research is needed to comprehensively quantify the magnitude of leakage effects, though two regional-scale studies found only small negative effects (Fuller et al., 2020; Herrera et al., 2019).

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Interactions with Other Solutions

Reinforcing

Other intact and degraded ecosystems often occur within areas of forest protection. Therefore, forest protection can facilitate natural restoration of these other degraded ecosystems, and increase the health of adjacent ecosystems.

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Reducing the demand for agricultural land will reduce barriers to forest protection.

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Competing

Forest protection will decrease the availability and increase the prices of wood feedstocks for other applications.

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Dashboard

Solution Basics

1 hectare of forest protected

tCO2-eq/unit/yr
0.3
units
Current 4.67×10⁸8.47×10⁸8.61×10⁸
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 0.14 0.250.26
US$ per tCO2-eq
2
Emergency Brake

CO₂

Solution Basics

1 hectare of forest protected

tCO2-eq/unit/yr
1.4
units
Current 1.59×10⁸2.04×10⁸3.77×10⁸
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 0.22 0.290.53
US$ per tCO2-eq
2
Emergency Brake

CO₂

Solution Basics

1 hectare of forest protected

tCO2-eq/unit/yr
2.2
units
Current 1.12×10⁸1.26×10⁸2.19×10⁸
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 0.25 0.280.48
US$ per tCO2-eq
2
Emergency Brake

CO₂

Solution Basics

1 hectare of forest protected

tCO2-eq/unit/yr
1.49
units
Current 9.36×10⁸1.12×10⁹1.58×10⁹
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 1.39 1.672.35
US$ per tCO2-eq
2
Emergency Brake

CO₂

% tree cover
0100

Tree cover, 2000 (excluding mangroves and peatlands)

We exclude mangroves and peatlands because they are addressed in other solutions.

Global Forest Watch (2023). Global peatlands [Data set]. Retrieved December 6, 2024 from https://data.globalforestwatch.org/datasets/gfw::global-peatlands/about

Hansen, M.C., Potapov, P.V., Moore, R., Hancher, M., Turubanova, S.A., Tyukavina, A., Thau, D., Stehman, S.V., Goetz, S.J., Loveland, T.R., Kommareddy, A., Egorov, A., Chini, L., Justice, C.O., and Townshend, J.R.G. (2013). High-resolution global maps of 21st-century forest cover change [Data set]. Science 342 (15 November): 850-53. https://glad.earthengine.app/view/global-forest-change

UNEP-WCMC (2025). Ocean+ habitats (version 1.3) [Data set]. Retrieved November 2024 from habitats.oceanplus.org

% tree cover
0100

Tree cover, 2000 (excluding mangroves and peatlands)

We exclude mangroves and peatlands because they are addressed in other solutions.

Global Forest Watch (2023). Global peatlands [Data set]. Retrieved December 6, 2024 from https://data.globalforestwatch.org/datasets/gfw::global-peatlands/about

Hansen, M.C., Potapov, P.V., Moore, R., Hancher, M., Turubanova, S.A., Tyukavina, A., Thau, D., Stehman, S.V., Goetz, S.J., Loveland, T.R., Kommareddy, A., Egorov, A., Chini, L., Justice, C.O., and Townshend, J.R.G. (2013). High-resolution global maps of 21st-century forest cover change [Data set]. Science 342 (15 November): 850-53. https://glad.earthengine.app/view/global-forest-change

UNEP-WCMC (2025). Ocean+ habitats (version 1.3) [Data set]. Retrieved November 2024 from habitats.oceanplus.org

Geographic Guidance Introduction

The adoption, potential adoption, and effectiveness of forest protection are highly geographically variable. While forest protection can help avoid emissions anywhere that forests occur, areas with high rates of forest loss from human drivers and particularly carbon-rich forests have the greatest potential for avoiding emissions via forest protection. The tropics and subtropics are high-priority areas for forest protection as they contain 55% of currently unprotected forest area, forest loss due to agricultural expansion is particularly concentrated in these regions (Curtis et al., 2018; West et al., 2014; Gibbs et al., 2010), and tend to have larger biomass carbon stocks than boreal forests (Harris et al., 2021). 

Developed countries also have significant potential to protect remaining old and long unlogged forests and foster recovery in secondary natural forests. The top 10 forested countries include Canada, the USA, Russia and even Australia, with the latter moving towards ending commodity production in its natural forests and increasing formal protection. Restoration of degraded forests is addressed in the “Forest Restoration” solution, but including regenerating forests in well designed protected areas is well within the capacity of every developed country.

Buffering and reconnecting existing high integrity forests is a low risk climate solution that increases current and future forest ecosystem resilience and adaptive capacity (Brennan et al., 2022; Brink et al., 2017; Grantham et al., 2020; Rogers et al., 2022). Forests with high ecological integrity provide outsized benefits for carbon storage and biodiversity and have greater resilience, making them top priorities for protection (Grantham et al., 2020; Rogers et al., 2022). Within a given forest, large-diameter trees similarly provide outsized carbon storage and biodiversity benefits, comprising only 1% of trees globally but storing 50% of the above ground forest carbon (Lutz et al., 2018). Additionally, forests that improve protected area connectivity (Brennan et al., 2022; Brink et al., 2017), areas at high risk of loss (particularly to expansion of commodity agriculture; Curtis et al., 2018; Hansen et al., 2013), and areas with particularly large or specialized benefits for biodiversity, ecosystem services, and human well-being (Dinerstein et al., 2024; Sarira et al., 2022; Soto-Navarro et al., 2020) may be key targets for forest protection.

Action Word
Protect
Solution Title
Forests
Classification
Highly Recommended
Lawmakers and Policymakers
  • Set achievable targets and pledges for PA designation and set clear effectiveness goals for PAs, emphasizing the effectiveness of current PAs before seeking to expand designations.
  • Use a variety of indicators to measure effectiveness, such as estimated avoided deforestation.
  • Ensure public procurement utilizes deforestation-free products and supply chains.
  • Grant Indigenous communities full property rights and autonomy and support them in monitoring, managing, and enforcing PAs.
  • Ensure PAs don’t displace, violate rights, or reduce access to vital resources for local and Indigenous communities.
  • Invest in PA infrastructure, monitoring, management, and enforcement mechanisms.
  • Utilize real-time monitoring and satellite data such as the “Real-Time System for Detection of Deforestation” (DETER).
  • Join, support, or create certification schemes like the Forest Stewardship Council for sustainable logging practices.
  • Conduct proactive land-use planning to avoid roads and other development projects that may interfere with PAs or incentivize deforestation.
  • Create processes for legal grievances, dispute resolution, and restitution.
  • Remove harmful agricultural and logging subsidies.
  • Prioritize reducing food loss and waste.
  • Create education programs that educate the public on PA regulations, the benefits of the regulations, and how to use forest resources sustainably.

Further information:

Practitioners
  • Set achievable targets and pledges for PA designation and set clear effectiveness goals for PAs, emphasizing the effectiveness of current PAs before seeking to expand designations
  • Use a variety of indicators to measure effectiveness, such as estimated avoided deforestation.
  • Ensure PAs don’t displace, violate rights, or reduce access to vital resources for local and Indigenous communities.
  • Utilize real-time monitoring and satellite data such as the “Real-Time System for Detection of Deforestation” (DETER).
  • Create sustainable use regulations for PA areas that provide resources to the local community.
  • Conduct proactive land-use planning to avoid infrastructure or development projects that may interfere with PAs or incentivize deforestation.
  • Grant Indigenous communities full property rights and autonomy and support them in monitoring, managing, and enforcing PAs.
  • Join, support, or create certification schemes like the Forest Stewardship Council for sustainable logging practices.
  • Create processes for legal grievances, dispute resolution, and restitution.
  • Create education programs that educate the public on PA regulations, the benefits of the regulations, and how to use forest resources sustainably.

Further information:

Business Leaders
  • Create deforestation-free supply chains, utilizing data, information, and the latest technology to inform product sourcing.
  • Integrate deforestation-free business and investment policies and practices in Net-Zero strategies.
  • Only purchase carbon credits from high-integrity, verifiable carbon markets and do not use them as replacements for reducing emissions.
  • Help shift the public narrative around carbon markets as integrity increases to boost education, dialogue, and awareness.
  • Develop financial instruments to invest in PA jurisdictions, focusing on supporting Indigenous communities.
  • Join or create public-private partnerships, alliances, or coalitions of stakeholders and rightsholders to support PAs and advance deforestation-free markets.
  • Join, support, or create certification schemes like the Forest Stewardship Council for sustainable logging practices.
  • Conduct proactive land-use planning to avoid infrastructure or development projects that may interfere with PAs or incentivize deforestation.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support Indigenous and local communities' capacity for public relations and communications.
  • Support education programs that educate the public on PA regulations, the benefits of the regulations, and how to use forest resources sustainably.
  • Leverage political influence to advocate for stronger PA policies at national and international levels, especially policies that reduce deforestation pressure. 

Further information:

Nonprofit Leaders
  • Ensure operations utilize deforestation-free products and supply chains.
  • Advocate for PAs and for public investments and evaluation indicators to strengthen the effectiveness of PAs.
  • Assist in managing and monitoring PAs, utilizing real-time monitoring and satellite data such as the “Real-Time System for Detection of Deforestation” (DETER).
  • Provide financial support for PAs management, monitoring, and enforcement.
  • Assist in conducting proactive land-use planning to avoid infrastructure or development projects that may interfere with PAs or incentivize deforestation.
  • Advocate for creating legal grievance processes, dispute resolution mechanisms, and restitution procedures for violations or disagreements over PAs.
  • Support high-integrity carbon markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Help shift the public narrative around carbon markets as integrity increases to boost education, dialogue, and awareness.
  • Support PAs, businesses, and investors by sharing data, information, and investment frameworks that successfully avoid deforestation.
  • Help shift public narratives to mobilize public action and build political will for PAs by creating educational campaigns and strengthening networks of stakeholders and rightsholders.
  • Join, support, or create certification schemes like the Forest Stewardship Council for sustainable logging practices.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support Indigenous and local communities' capacity for legal protection and public relations.
  • Advocate for non-timber forest products to support local and Indigenous communities.
  • Advocate to remove harmful agricultural subsidies and prioritize reducing food loss and waste.

Further information:

Investors
  • Create deforestation-free investment portfolios, utilizing data, information, and the latest technology to inform investments.
  • Invest in PA infrastructure, monitoring, management, and enforcement mechanisms.
  • Invest in green bonds or high-integrity carbon credits for forest conservation efforts.
  • Develop financial instruments to invest in PA jurisdictions, focusing on supporting Indigenous communities.
  • Support PAs, other investors, and NGOs by sharing data, information, and investment frameworks that successfully avoid investments that drive deforestation.
  • Join, support, or create science-based certification schemes like the Forest Stewardship Council for sustainable logging practices.
  • Help shift public narratives to mobilize public action and build political will for PAs by creating educational campaigns and strengthening networks of stakeholders and rightsholders.
  • Require portfolio companies to eliminate deforestation from their supply chains and ask that they demonstrate strong PA practices.
  • Consider opportunities to invest in forest monitoring technologies or bioeconomy products derived from standing forests (e.g., nuts, berries, or other derivatives)

Further information:

Philanthropists and International Aid Agencies
  • Ensure operations utilize deforestation-free products and supply chains.
  • Provide financial support for PAs management, monitoring, and enforcement.
  • Assist in monitoring PAs, utilizing real-time monitoring and satellite data such as the “Real-Time System for Detection of Deforestation” (DETER).
  • Assist in conducting proactive land-use planning to avoid infrastructure or development projects that may interfere with PAs or incentivize deforestation.
  • Support and finance high-integrity carbon markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Help shift the public narrative around carbon markets as integrity increases to boost education, dialogue, and awareness.
  • Support PAs, businesses, and investors by sharing data, information, and investment frameworks that successfully avoid deforestation.
  • Help shift public narratives to mobilize public action and build political will for PAs by creating educational campaigns and strengthening networks of stakeholders and rightsholders.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support Indigenous and local communities' capacity for public relations and communications.
  • Financially support Indigenous land tenure.
  • Join, support, or create certification schemes like the Forest Stewardship Council for sustainable logging practices.
  • Advocate for PAs and for public investments and evaluation indicators to strengthen the effectiveness of PAs.
  • Advocate for legal grievances, dispute resolution, and restitution processes.

Further information:

Thought Leaders
  • Advocate for PAs and for public investments and evaluation indicators to strengthen the effectiveness of PAs.
  • Assist in monitoring PAs, utilizing real-time monitoring and satellite data such as the “Real-Time System for Detection of Deforestation” (DETER).
  • Assist in conducting proactive land-use planning to avoid infrastructure or development projects that may interfere with PAs or incentivize deforestation.
  • Advocate for legal grievances, dispute resolution, and restitution processes.
  • Support high-integrity carbon markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Help shift the public narrative around carbon markets as integrity increases to boost education, dialogue, and awareness.
  • Support PAs, businesses, and investors by sharing data, information, and investment frameworks that successfully avoid deforestation.
  • Help shift public narratives to mobilize public action and build political will for PAs by creating educational campaigns and strengthening networks of stakeholders and rightsholders.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Support Indigenous and local communities' capacity for public relations and communications.

Further information:

Technologists and Researchers
  • Improving PA monitoring methods and data collection, utilizing satellite imagery and GIS tools.
  • Develop land-use planning tools that help avoid infrastructure or development projects that may interfere with PAs or incentivize deforestation.
  • Create tools for local communities to monitor PAs, such as mobile apps, e-learning platforms, and mapping tools.
  • Conduct evaluations of the species richness of potential PAs and recommend areas of high biodiversity to be designated as PAs.
  • Develop verifiable carbon credits using technology such as blockchain to improve the integrity of carbon markets.
  • Develop supply chain tracking software for investors and businesses seeking to create deforestation-free portfolios and products.

Further information:

Communities, Households, and Individuals
  • Ensure purchases and investments utilize deforestation-free products and supply chains.
  • Advocate for PAs and for public investments and evaluation indicators to strengthen the effectiveness of PAs.
  • Assist in monitoring PAs, utilizing real-time monitoring and satellite data such as the “Real-Time System for Detection of Deforestation” (DETER).
  • Assist in conducting proactive land-use planning to avoid infrastructure or development projects that may interfere with PAs or incentivize deforestation.
  • Advocate for legal grievances, dispute resolution, and restitution processes.
  • Support Indigenous and local communities' capacity for public relations and communications.
  • Assist with evaluations of the species richness of potential PAs and advocate for PAs in areas of high biodiversity that are threatened.
  • Help shift public narratives to mobilize public action and build political will for PAs by creating educational campaigns and strengthening networks of stakeholders and rightsholders.
  • Undertake forest protection and expansion initiatives locally by working to preserve existing forests and restore degraded forest areas.
  • Engage in citizen science initiatives by partnering with researchers or conservation groups to monitor PAs and document threats. 

Further information:

Sources
Evidence Base

There is high scientific consensus that forest protection is a key strategy for reducing forest loss and addressing climate change. Rates of forest loss are lower inside of PAs and Indigenous peoples’ lands than outside of them. Globally, Wolf et al. (2021) found that rates of forest loss inside PAs are 40.5% lower on average than in unprotected areas, and Li et al. (2024) estimated that overall forest loss is 14% lower in PAs relative to unprotected areas. Regional studies find similar average effects of PAs on deforestation rates. For instance, McNichol et al. (2023) reported 39% lower deforestation rates in African woodlands in PAs relative to unprotected areas, and Graham et al. (2021) reported 69% lower deforestation rates in PAs relative to unprotected areas in Southeast Asia. In the tropics, Sze et al. (2022) found that rates of forest loss were similar between Indigenous lands and PAs, with forest loss rates reduced 17–29% relative to unprotected areas. Baragwanath & Bayi (2020) reported a 75% decline in deforestation in the Brazilian Amazon when Indigenous peoples are granted full property rights.

Reductions in forest loss lead to proportionate reductions in CO₂ emissions. The Intergovernmental Panel on Climate Change (IPCC) estimated that ecosystem protection, including forests, peatlands, grasslands, and coastal wetlands, has a technical mitigation potential of 6.2 Gt CO₂‑eq/yr, 4.0 Gt of which are available at a carbon price less than US$100 tCO₂‑eq/yr  (Nabuurs et al., 2022). Similarly, Griscom et al. (2017) found that avoiding human-caused forest loss is among the most effective natural climate solutions, with a potential impact of 3.6 Gt CO₂‑eq/yr (including forests on peatlands), nearly 2 Gt CO₂‑eq/yr of which is achievable at a cost below US$10/t CO₂‑eq/yr.

The results presented in this document were produced through analysis of 12 global datasets. We recognize that geographic biases can influence the development of global datasets and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Appendix

In this analysis, we integrated global land cover data, maps of forest loss rates, shapefiles of PAs and Indigenous people’s lands, country-scale data on reductions in forest loss inside of PAs, and biome-scale data on forest carbon stocks and sequestration rates to calculate currently protected forest area, total global forest area, and avoided emissions from forest protection. Forested peatlands and mangroves are excluded from this analysis and addressed in the Protect Peatlands and Protect Coastal Wetlands solutions, respectively.

Land cover data

We used two land cover data products to estimate forest extent inside and outside of PAs and Indigenous people’s lands, including: 1) the Global Forest Watch (GFW) tree cover dataset (Hansen et al., 2013), resampled to 30 second resolution, and 2) the 2022 European Space Agency Climate Change Initiative (ESA CCI) land cover dataset at native resolution (300 m). For the ESA CCI dataset, all non-flooded tree cover classes (50, 60, 70, 80, 90) and the “mosaic tree and shrub (>50%)/herbaceous cover (<50%)” class (100) and associated subclasses were included as forests. Both products are associated with uncertainty, which we did not address directly in our calculations. We include estimates from both products in order to provide readers with a sense of the variability in values that can stem from different land cover classification methods, which are discussed in more detail below.

These two datasets have methodological differences that result in substantially different classifications of forest extent, including their thresholds for defining forests, their underlying satellite data, and the algorithms used to classify forests based on the satellite information. For example, the ESA CCI product classifies 300-meter pixels with >15% tree cover as forests (based on our included classes), attempts to differentiate tree crops, relies on a 2003–2012 baseline land cover map coupled with a change-detection algorithm, and primarily uses imagery from MERIS, PROBA-V, and Sentinel missions (ESA CCI 2019). In contrast, the Global Forest Watch product generally requires >30% tree cover at 30-meter resolution, does not exclude tree crops, relies on a regression tree model for development of a baseline tree cover map circa 2010, and primarily uses Landsat ETM+ satellite imagery (Hansen et al., 2013). We recommend that interested readers refer to the respective user guides for each data product for a comprehensive discussion of the complex methods used for their development.

We used the Forest Landscape Integrity Index map developed by Grantham et al. (2020), which classifies forests with integrity indices ≥9.6 as high integrity. These forests are characterized by minimal human disturbance and high connectivity. Mangroves and peatlands were excluded from this analysis. We used a map of mangroves from Giri et al. (2011) and a map of peatlands compiled by Global Forest Watch to define mangrove and peatland extent (accessed at https://data.globalforestwatch.org/datasets/gfw::global-peatlands/about). The peatlands map is a composite of maps from five publications: Crezee et al. (2022), Gumbricht et al. (2017), Hastie et al. (2022), Miettinen et al. (2016), and Xu et al. (2018). For each compiled dataset, the data were resampled to 30-second resolution by calculating the area of each grid cell occupied by mangroves or peatlands. For each grid cell containing forests, the “eligible” forest area was calculated by subtracting the mangrove and peatland area from the total forest area for each forest cover dataset (GFW, ESA CCI, and high-integrity forests).

Protected forest areas

We identified protected forest areas using the World Database on Protected Areas (WDPA, 2024), which contains boundaries for each PA and additional information, including their establishment year and IUCN management category (Ia to VI, not applicable, not reported, and not assigned). For each PA polygon, we extracted the forest area from the GFW, ESA CCI, and high-integrity dataset (after removing the peatland and mangrove areas).

Each protected area was classified into a climate zone based on the midpoint between its minimum and maximum latitude. Zones included tropical (23.4°N–23.4°S), subtropical (23.4°–35° latitude), temperate (35°–50° latitude), and boreal (>50° latitude) in order to retain some spatial variability in emissions factors. We aggregated protected forest cover areas (from each of the two forest cover datasets and the high-integrity forest data) by IUCN class and climate zone. To evaluate trends in adoption over time, we also aggregated protected areas by establishment year. We used the same method to calculate the forest area that could be protected, extracting the total area of each land cover type by climate zone (inside and outside of existing PAs). 

We used maps from Garnett et al. (2018) to identify Indigenous people’s lands that were not inside established PAs. We calculated the total forest area within Indigenous people’s lands (excluding PAs, mangroves, and peatlands) using the same three forest area data sources. 

Forest loss and emissions factors

Forest loss rates were calculated for unprotected areas using the GFW forest loss dataset for 2001–2022, resampled to 1 km resolution. Forest losses were reclassified according to their dominant drivers based on the maps originally developed by Curtis et al. (2018), with updates accessible through GFW. Dominant drivers of forest loss include commodity agriculture, shifting agriculture, urbanization, forestry, and wildfire. We classified all drivers except wildfire as human-caused forest loss for this analysis. We calculated the area of forest loss attributable to each driver within each climate zone, which represented the “baseline” rate of forest loss outside of PAs. 

To calculate the difference in forest loss rates attributable to protection, we used country-level data from Wolf et al. (2021) on the ratio of forest loss in unprotected areas versus PAs, controlling for a suite of socio-environmental characteristics. We classified countries into climate zones based on their median latitude and averaged the ratios within climate zones. We defined the avoided forest loss attributable to protection as the product of the baseline forest loss rate and the ratio of forest loss outside versus inside of PAs.

We calculated the carbon benefits of avoided forest loss by multiplying avoided forest loss by average forest carbon stocks and sequestration rates. Harris et al. (2021) reported carbon stocks and sequestration rates by climate zone (boreal, temperate, subtropical, and tropical), and forest type. Carbon stocks and sequestration rates for primary and old secondary (>20 years old) forests were averaged for this analysis. We calculated carbon sequestration over a 20-yr period to provide values commensurate with the one-time loss of biomass carbon stocks.

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Updated Date

Enhance Public Transit

Submitted by Drawdown Admin on
Sector
Transportation
Mode
Cut Emissions
Cluster
Shift to Alternatives
Image
Train with city in the distance
Coming Soon
Off
Summary

We define the Enhance Public Transit solution as increasing the use of any form of passenger transportation that uses publicly available vehicles (e.g., buses, streetcars, subways, commuter trains, and ferries) operating along fixed routes. It does not include increasing the use of publicly available forms of transportation without fixed routes, such as taxis, except when these transport options supplement a larger public transit system (for example, to help passengers with disabilities). It also does not include increasing the use of vehicles traveling over long distances, such as intercity trains, intercity buses, or aircraft. The cost per climate unit is the cost to the transit provider, not the passenger.

Income & work,Health,Equality
Nature protection,Air quality
Overview

Public transit vehicles are far more fuel-efficient – and thus less GHG-intensive – on a per-pkm basis than fossil fuel–powered cars. Diesel-powered buses emit fewer GHGs/pkm than cars because of their much higher occupancy. Electric buses further reduce GHG emissions (Bloomberg New Energy Finance, 2018), as do forms of public transit that already run on electricity. Finally, a fleet of large, centralized public transit vehicles operating along fixed routes is usually easier to electrify than a fleet of fossil fuel–powered cars. 

Enhancing public transit to reduce emissions from transportation relies on two processes. First is increasing the modal share of existing public transit networks by encouraging people to travel by public transit rather than car. This requires building new public transit capacity while also overcoming political, sociocultural, economic, and technical hurdles. Second is improving the emissions performance of public transit networks through electrification and efficiency improvements. We accommodate the latter in this solution by assuming that all shifted trips to buses are electric buses.

These two processes are linked in complex ways. For example, construction of the new public transit networks needed to accommodate additional demand creates an opportunity to install low-carbon vehicles and infrastructures, and bringing additional passengers onto an underused public transit network generates close to zero additional GHG emissions. However, since these complexities are difficult to calculate, we assume that all increases in public transit ridership are supported by a linear increase in capacity.

Buses, trains, streetcars, subways, and other public-transit vehicles predate cars. During the 19th century, most cities developed complex and efficient networks of streetcars and rail that carried large numbers of passengers (Norton, 2011; Schrag, 2000). As a result, it’s clear that a good public transit network can provide for the basic mobility needs of most people, and can therefore substitute for most – if not all – transportation that fossil fuel–powered cars currently provide. Today, public transit networks worldwide already collectively deliver trillions of pkm, not only in big cities but also in small towns and rural areas. 

We identified several different types of public transit:

Buses

Low-capacity vehicles running on rubber tires on roads. Buses in the baseline are a mix of diesel and electric. For the purposes of this solution, we assume that all buses serving shifted trips are electric.

Trams or streetcars

Mid-capacity vehicles running on steel rails that for at least part of their routes run on roads with traffic, rather than in a dedicated rail corridor or tunnel.

Metros, subways, or light rail

High-capacity urban train systems using their own dedicated right-of-way that may or may not be underground.

Commuter rail

Large trains running mostly on the surface designed to bring large numbers of commuters from the suburbs into the core of a city that often overlap with regional or intercity rail.

Other modes

Ferries, cable cars, funiculars, and other forms of public transit that generally play a marginal role.

We assessed all modes together rather than individually because public transit relies on the interactions among different vehicles to maximize the reach, speed, and efficiency of the system. Public transit reduces emissions of CO₂,  methane, and nitrous oxide to the atmosphere by replacing fuel-powered cars, which emit these gases from their tailpipes. Some diesel-powered buses in regions that have low quality diesel emit black carbon. The black carbon global annual total emissions from transportation is negligible compared with carbon emissions and is therefore not quantified in our study. 

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Credits

Lead Fellow

  • Cameron Roberts

Contributors

  • Ruthie Burrows

  • James Gerber

  • Yusuf Jameel 

  • Daniel Jasper

  • Heather Jones

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Ted Otte

  • Amanda Smith

  • Tina Swanson

Effectiveness

Our calculations suggest that an efficiently designed public transit system using the best available vehicle technologies (especially battery-electric buses) would save 58.26 t CO₂‑eq /million pkm (0.000058 t CO₂‑eq /pkm) on a 100-yr basis compared with fossil fuel–powered cars, in line with the estimates by other large transportation focused organizations (International Transport Forum, 2020; US Department of Transportation, 2010). This number is highly sensitive to public transit vehicle occupancy, which we estimated using the most recent available data (American Public Transit Association, 2021). Increasing the number of trips taken via public transit would likely increase occupancy, although ideally not to the point of passenger discomfort. This elevated ridership would significantly reduce public transit’s pkm emissions.

To arrive at this figure, we first estimated the emissions of fossil fuel–powered cars as 115 t CO₂‑eq /million pkm (0.000115 t/pkm, 100-yr basis). We then separately calculated the emissions of commuter rail, metros and subways, trams and light rail systems, and electric buses. We used data on the modal share of different vehicles within public transit systems around the world (although much of the available data are biased towards systems in the United States and Europe) to determine what each transit system’s emissions would be per million pkm given our per-million-pkm values for different transit vehicles (UITP, 2024). The median of these city-level values is 58 t CO₂‑eq /pkm (0.000058 t/pkm, 100-yr basis). Subtracting this value from the per-pkm emissions for cars gives us the public transit GHG savings figure cited above. Note that none of these values includes embodied emissions (such as emissions from producing cars, buses, trains, roads, etc.), or upstream emissions (such as those from oil refineries).

Pessimistic assumptions regarding the emissions and occupancy of public transit vehicles, and optimistic assumptions about emissions from cars, can suggest a much more marginal climate benefit from public transit (see the 25th percentile row in Table 1). In most cases, however, well-managed public transit is likely to produce a meaningful climate benefit. Such an outcome will depend on increasing the average occupancy of vehicles, which faces a challenge because transit has seen declining occupancies since the COVID-19 pandemic (Qi et al., 2023). For this reason, encouraging additional use of public transit networks without expanding these networks can have an outsized impact because it will allow the substitution of fossil fuel–powered car trips by trips on public transit vehicles for which emissions would not change meaningfully as a result of adding passengers.

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq/million pkm, 100-yr basis

25th percentile 0.127
mean 61.76
median (50th percentile) 58.27
75th percentile 106.7

The extremely large range of values between the 25th and 75th percentile is the result of 1) the large diversity of public transit systems in the world and 2) multiplying multiple layers of uncertainty (e.g., varying estimates for occupancy, energy consumption per vehicle kilometer (vkm), percent of pkm reliant on buses vs. trains).

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Cost

Under present-day public transit costs and revenues, it costs the transit provider US$0.23 to transport a single passenger one kilometer. In comparison, travel by car costs the consumer US$0.42/pkm. On a per passenger basis, for the transit provider, public transit is almost 50% cheaper than car transportation, costing US$0.20/pkm less. Combined with the emissions reductions from using public transit, this means that the emissions reductions from shifting people out of cars onto public transit has a net negative cost, saving US$3,300/t CO₂‑eq mitigated (Table 2). 

This figure includes all relevant direct costs for travel by public transit and by car, including the costs of infrastructure, operations, vehicle purchase, and fuel. It does not include external costs, such as medical costs resulting from car crashes. Capital costs (i.e., the large fixed costs of building public transit infrastructure) are accounted for via the annualized capital costs listed in public transit agencies’ financial reports. 

A very large proportion of the total costs of providing public transit is labor (e.g., wages for bus drivers and station attendants). This cost is unlikely to come down as a result of technological innovations (Bloomberg New Energy Finance, 2018).

For an individual passenger, however, the marginal costs of public transit (i.e., the fares they pay) can sometimes be higher than the marginal costs of driving. This is in large part due to many external costs of driving which are borne by society at large (Litman, 2024). However, increasing the public transit availability would likely increase occupancy, which would in turn drive costs down.

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Table 2. Cost per unit of climate impact.

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

median -3300

Transit provider cost, not passenger cost.

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Learning Curve

Public transit is a largely mature technology with limited opportunities for radical cost-saving innovation. While our research did not find any papers reporting a learning curve in public transit as a whole, battery-electric buses are in fact subject to many of the same experience effects of other battery-electric vehicles. Although there are no studies assessing declines in the cost of electric buses as a whole, there are studies assessing learning curves for their batteries, which is the most costly component. The cost of batteries used in battery-electric buses has declined 19.25% with each doubling of installed capacity (Table 3).

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Table 3. Learning rate: drop in cost per doubling of the installed solution base.

Unit: %

25th percentile 18.63
mean 19.25
median (50th percentile) 19.25
75th percentile 19.88

This applies only to the cost of batteries in electric buses, not to public transportation as a whole.

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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 gradual, emergency brake, or delayed.

Enhance Public Transit 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

Public transit competes for passengers not just with cars, but also with other transportation modes – some of which have lower emissions on average. If an increase in public transit’s modal share comes at the expense of nonmotorized transportation (i.e., pedestrian travel or cycling), or electric bicycles, this will result in a net increase in emissions. Similarly, public transit could generate additional trips that would not have occurred if the public transit network those trips were taken on did not exist. Under this scenario, a net increase in emissions would occur; however, these new trips might bring additional social benefits that would outweigh these new emissions.

Low occupancy could also diminish the climate benefit of enhancing public transit. While it is certainly possible to build effective and efficient public transit networks in suburban and rural areas, there is a risk that such networks could have high per-pkm GHG emissions if they have low average occupancy (Mees, 2010). It is therefore important to efficiently plan public transit networks, ensure vehicles are right-sized and have efficient powertrains, and promote high levels of ridership even in rural areas to maximize the climate benefit of these kinds of networks.

Upscaling public transit networks – and, crucially, convincing more motorists to use them – is an enduring challenge that faces cultural resistance in some countries, issues with cost, and sometimes a lack of political will. Successfully enhancing public transit will require that these hurdles are overcome.

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Current Adoption

In cities around the world surveyed over the last 15 years, public transit has an average modal share of approximately 26.2% of trips. In comparison, fossil fuel–powered cars account for 51.4% of all trips, while nonmotorized transportation accounts for 22.4% (Prieto-Curiel & Ospina, 2024). The 26.2% of trips taken via public transit corresponds to approximately 16.7 trillion pkm traveled on public transit in cities every year (Table 4).

These numbers are calculated from modal share data (i.e., the percentage of trips in a given city that are taken via various modes of transportation). We estimated total pkm traveled by assuming a global average daily distance traveled, using travel surveys from the United States as well as several European countries (Christensen & Vázquez, 2013; Department for Transport, 2024; Ecke, 2023; Federal Highway Administration, 2022; Statistics Netherlands, 2024). We used Prieto-Curiel and Ospina’s (2024) global population-weighted mean modal share as our global adoption value. The other statistical measures in Table 4 reflect the distribution of estimates drawn from the literature, most of which do not account for population, and therefore give too much weight to small cities, skewing the results. 

We assumed that Prieto-Curiel and Ospina’s data refers only to urban modal share. While the database does include some small towns and rural areas, most of the modal share data we found comes from cities. Public transit can be useful in rural areas (Börjesson et al, 2020), but we did not attempt to estimate rural public transit adoption in this assessment .

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Table 4. Current (2024) adoption level.

Unit: million pkm/yr 

25th percentile 512,900
Population-weighted mean 16,720,000
median (50th percentile) 5,106,000
75th percentile 15,080,000

We used the population-weighted mean calculated by Prieto-Curiel and Ospina (2024) as our authoritative estimate to carry forward to other calculations.

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Adoption Trend

Based on data from Prieto-Curiel and Ospina (2024) and the UITP (2024) for 1,097 cities worldwide, the rate of adoption of public transit has not changed since 2010, with the median annual growth rate equal to 0 (Table 5). This was calculated using all of the cities in Prieto-Curiel and Ospina’s (2024) database for which modal share data exist.

Despite the lack of a global trend in public transit use, some cities, including Amsterdam, Edinburgh, and Leeds, report double-digit growth rates in the use of public transit.

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Table 5. 2023–2024 adoption trend.

Unit: million pkm/yr

25th percentile -697,100
mean 71,490
median (50th percentile) 0.00
75th percentile 1,791,000
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Adoption Ceiling

Public transit could theoretically replace all trips currently undertaken by fossil fuel–powered cars. This would amount to 75 trillion pkm on public transit annually, worldwide (Table 6). This would not be feasible to achieve in practice, as it would require construction of new public transit vehicles and infrastructure on an unfeasibly large scale, and massive changes to living patterns for many people. It would also be much more expensive than we calculated above, because such a change would require extending public transit coverage into areas where it would be highly uneconomic. Public transit is capable of providing a good transportation option in rural areas, but there is a limit to its benefits when population densities are low even by rural standards. Even in cities, this scenario would require a radical redesign of some neighborhoods to prioritize public transit. Such large public transit coverage would also inevitably shift other modes of transportation, such as pedestrian travel and cycling, leading to an even higher pkm total than that suggested by current adoption of fossil fuel–powered cars.

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Table 6. Adoption ceiling.

Unit: million pkm/yr

median (50th percentile) 75,000,000
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Achievable Adoption

The achievable range of public transit adoption is 22.2–41.9 trillion pkm traveled by public transit in cities globally.

To estimate the upper bound of achievable adoption, we assumed that urban trips taken by fossil fuel–powered car (currently 51.4% of trips globally) can be shifted to public transit until public transit increases to 76.6% of trips (the current highest modal share of public transit in any city with a population of more than 1 million) or until car travel decreases to 12.0% of trips (the current lowest modal share of fossil fuel–powered cars in any city with a population of more than 1 million). This equals a shift of 25.2 trillion pkm from fossil fuel–powered car travel to public transit, which, added to present-day public transit trips (16.7 trillion trips/yr), equals 41.9 trillion pkm/yr (Table 7).

To set the lower bound, we performed the same calculation as above, but on a regional basis, adding up all the resultant modal shifts to get a global figure. For example, every northern European city might reach the public transit modal share of London (44.5% of trips), while every South Asian city might reach that of Mumbai (52.0% of trips). Having done that, we then added together the public transit adoption rates from all world regions, apart from three (Polynesia, Micronesia, and Melanesia) for which we did not find any modal share data. This corresponds to a shift of 5.5 trillion pkm/yr from cars to public transit, and a total achievable public transit adoption rate of 22.2 trillion pkm/yr.

Achieving both of these levels of adoption would require not only major investments in expanding public transit networks, but also major changes in how cities are planned so as to allow more areas to be effectively served by transit. These levels of adoption would also require overcoming cultural and political resistance to abandoning cars in favor of public modes. However, unlike the scenario discussed under Adoption Ceiling, these scenarios are feasible, since they are based on real achievements by cities around the world.

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Table 7. Range of achievable adoption levels.

Unit: million pkm/yr

Current Adoption 16,720,000
Achievable – Low 21,980,000
Achievable – High 41,910,000
Adoption Ceiling 75,000,000
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If all public transit trips were taken by fossil fuel–powered cars instead of by public transit, they would result in an additional 0.97 Gt CO₂‑eq/yr of emissions (Table 8).

The global potential climate impact of enhancing public transit, if all car trips were shifted onto public transit systems, is 4.37 Gt. As discussed under Adoption Ceiling, this is an unrealistic scenario.

In a more realistic scenario, if every city in the world shifted car traffic onto public transit until it reached the public transit modal share of Hong Kong (i.e., the high estimate of achievable adoption), it would save 2.44 Gt CO₂‑eq/yr globally. Meanwhile, if every city shifts car trips to public transit until it reaches the car modal share of the region’s least car-dependent city (i.e., the low estimate of achievable adoption), it would save 1.28 Gt CO₂‑eq/yr.

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Table 8. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.97
Achievable – Low 1.28
Achievable – High 2.44
Adoption Ceiling 4.37
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Additional Benefits

Air Quality

GHG emissions from transportation are often emitted with other harmful air pollutants. Consequently, reducing fuel consumption by replacing transport by fossil fuel–powered cars with public transit can lead to cleaner air. The scale of this benefit varies by location and is influenced by differences in emission levels between private and public transit travels and the relative demand substitutability between modes (Beaudoin et al., 2015). For U.S. cities, significant investment in public transit could cut pollution around 1.7% on average (Borck, 2019). The benefits are more significant in low- and middle-income countries, where fossil fuel–powered cars are more polluting due to lenient air quality regulations (Goel & Gupta, 2017; Guo & Chen, 2019).

Health Benefits

Improved air quality due to enhanced public transit has direct health benefits, such as lowering cardiovascular disease risk, and secondary health benefits, such as increased physical activity (Xiao et al., 2019), fewer traffic-related injuries, lower rates of cancer, and enhanced access to health-care facilities and nutritious food (Gouldson et al., 2018; Health Affairs, 2021).

Equality

Limited access to transportation restricts labor participation, particularly for women. Expanding public transit can foster gender equity by improving women’s access to employment opportunities. For example, in Peru expansion of public transit has led to improvements in women’s employment and earnings (Martinez et al., 2020). Similarly, in India, the extension of the light rail system in Delhi has increased women’s willingness to commute for work (Tayal & Mehta, 2021).

Public transit enhances community connectivity by providing accessible transportation options. Expanded mobility allows individuals to reach employment, health-care, education, and recreational sites with greater ease, heightening social inclusion. The social equity benefits of public transit are especially significant for low-income people in terms of time and cost savings and safety and health benefits (Serulle & Cirillo, 2016; Venter et al., 2017). 

Income and work

Investment in enhancing public transit can also generate substantial economic returns. The APTA estimated that each US$1 billion invested in transit can create 49,700 jobs and yield a five-to-one economic return (APTA, 2020). According to another study, shifting 50% of highway funds to mass transit systems in 20 U.S. metropolises could generate more than 1 million new transit jobs within five years (Swanstrom et al., 2010). 

Nature protection

An indirect benefit of enhanced public transit is its contribution to reducing resource consumption, such as the minerals used in manufacturing personal vehicles. Enhanced public transit can also improve land-use efficiency by curbing urban sprawl, which helps reduce pollution and limit biodiversity loss (Ortiz, 2002). 

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Risks

If expanded service on high-quality public transit systems replaced journeys from nonmotorized transportation or electric bicycles rather than from cars – or if expanded service on high-quality public transit systems generated journeys that would not have otherwise happened – this will have a net-negative climate impact, since public transit has higher per-pkm GHG emissions than electric bicycles or not traveling (International Transport Forum, 2020). 

There may be cases where public transit networks cannot be implemented efficiently enough to provide a meaningful benefit compared to fossil fuel–powered cars in terms of GHG emissions. This would occur in places where there are so few potential riders that most trips would have a very low occupancy. The result would be a much higher rate of emissions per pkm. However, effective public transit networks can be built in suburban and even rural areas (Börjesson et al., 2020; Mees, 2010).

Finally, expanding public transit networks has proven very difficult in recent years. Entrenched preferences for car travel, reluctance on the part of governments to invest heavily in new transit infrastructure, and local political challenges over land use, noise, gentrification, and similar issues are all obstacles to increased public transit use. Public transit expansion has faced stronger headwinds in recent years in particular, due to both the impact of the COVID-19 pandemic and competition from new (and mostly less sustainable) mobility services, such as app-based ride-hailing (Shaller, 2017).

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Interactions with Other Solutions

Reinforcing

For people living without cars, public transit provides a crucial service that is hard to replace for certain kinds of trips, such as trips over long distances, with small children, or carrying large objects. As a result, public transit plays a large role in making it more viable for people to live without owning a car (Brown, 2017). Research suggests that the key to a low-carbon mobility system is to reduce the need for people to own cars altogether (Van Acker & Witlox, 2010).

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Public transit requires a lot less space than cars. Some of this space could be reallocated to ecosystem conservation through revegetation and other land-based methods of GHG sequestration (Rodriguez Mendez et al., 2024).

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Competing 

Electric cars and public transit compete for pkm. Consequently, increased use of public transit could reduce kilometers traveled using electric cars. 

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Dashboard

Solution Basics

million passenger kilometers (million pkm)

tCO2-eq/unit/yr
58.27
units/yr
Current 1.67×10⁷2.2×10⁷4.19×10⁷
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 0.97 1.282.44
US$ per tCO2-eq
-3,300
Gradual

CO₂, CH₄, N₂O

Trade-offs

Public transit vehicles are sometimes unsafe, particularly for vulnerable groups such as women (Loukaitou-Sideris, 2014). In some circumstances – although this remains controversial – new public transit routes can also lead to gentrification of neighborhoods, forcing people to move far away from city centers and use cars for travel (Padeiro et al., 2019). 

Expansion of public transit networks could also have negative consequences in areas directly adjacent to transit infrastructure. Diesel buses create air pollution (Lovasi et al., 2022), and public transit networks of all types can create noise pollution (Hemmat et al., 2023).

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Population (millions)
1
10
30
Active Mobility
Public Transport
Private Cars

Primary mode of transport

Mapping the primary mode of transportation reveals mobility patterns and opportunities to shift travel toward lower-emitting modes.

Prieto-Curiel, R. and Ospina, Juan P. (2024). The ABC of mobility [Data set]. Environmental International, https://doi.org/10.1016/j.envint.2024.108541. Retrieved May 9, 2025 from https://github.com/rafaelprietocuriel/ModalShare/tree/main

Population (millions)
1
10
30
Active Mobility
Public Transport
Private Cars

Primary mode of transport

Mapping the primary mode of transportation reveals mobility patterns and opportunities to shift travel toward lower-emitting modes.

Prieto-Curiel, R. and Ospina, Juan P. (2024). The ABC of mobility [Data set]. Environmental International, https://doi.org/10.1016/j.envint.2024.108541. Retrieved May 9, 2025 from https://github.com/rafaelprietocuriel/ModalShare/tree/main

Geographic Guidance Introduction

Public transit is most effective in urban areas with high population density, where buses, subways, trams, and commuter rail can efficiently carry large numbers of passengers. Electrified or low-emission transit modes achieve the greatest climate impact, especially in regions with clean electricity grids (Bloomberg New Energy Finance, 2018). However, even diesel-based public transit systems can outperform fossil fuel-powered cars on a per-pkm basis if they have high ridership and operate efficiently.

Socioeconomic and political factors, including investment capacity, institutional coordination, and public perceptions of reliability, safety, and comfort, highly influence the adoption and effectiveness of public transit. Regions with well-funded public infrastructure, integrated fare systems, and strong governance tend to have the highest adoption and climate benefits. Conversely, underinvestment, informal transit dominance, or poorly maintained systems can undermine public transit’s potential (Börjesson et al., 2020; Mees, 2010).

High public transit adoption is seen in Western and Northern Europe, Post-Soviet countries, East Asia (including Japan, South Korea, and China), and some Latin American cities, like Bogotá and Santiago. In contrast, many developing regions face barriers to public transit expansion, such as inadequate funding, urban sprawl, or a reliance on informal minibus systems. However, these same areas offer some of the highest potential for impact. Rapid urbanization, growing demand for mobility, and severe air quality challenges create strong incentives to expand and modernize transit networks.

Action Word
Enhance
Solution Title
Public Transit
Classification
Highly Recommended
Lawmakers and Policymakers
  • Use public transit and create incentive programs for government employees to use public transit.
  • Improve and invest in local public transit infrastructure, increasing routes and frequency while improving onboard safety, especially for women.
  • Electrify public buses, vans, and other vehicles used in the public transit system.
  • Implement the recommendations of transit-oriented development, such as increasing residential and commercial density, placing development near stations, and ensuring stations are easily accessible.
  • Provide online information, ticketing, and payment services.
  • Implement regional or nationwide public transit ticketing systems.
  • Consider a wide range of policy options that include demand-side options, such as free fare or fare reductions, and that are informed by citizen-centered approaches.
  • Create dedicated coordinating bodies across government agencies, businesses, and the public to develop public transit.
  • Disincentivize car trips in areas serviced by public transit through reduced access, increases in parking fares, congestion charges, taxes, or other means.
  • Incorporate social signaling in public transit information and signage, such as smiley faces and “sustainable transport” labels.
  • Develop public transit awareness campaigns – starting from early childhood – focusing on internally motivating factors such as money saved, health benefits, reduced pollution, free time while traveling, and lifestyle sustainability.

Further information:

Practitioners
  • Use public transit and create incentive programs for government employees to utilize public transit.
  • Increase routes and frequency while also improving onboard safety, especially for women.
  • Electrify public buses, vans, and other vehicles used in the public transit system.
  • Incorporate social signaling in public transit information and signage, such as smiley faces and “sustainable transport” labels.
  • Provide online information, ticketing, and payment services
  • Implement regional or nationwide public transit ticketing systems.
  • Consider a wide range of policy options that include demand-side options, such as free fare or fare reductions, and that are informed through citizen-centered approaches.
  • Create dedicated coordinating bodies across government agencies, businesses, and the public to develop public transit.
  • Develop public transit awareness campaigns – starting from early childhood – focusing on internally motivating factors such as money saved, health benefits, reduced pollution, free time while traveling, and a sustainable lifestyle.

Further information:

Business Leaders
  • Use public transit and encourage employees to do so when feasible.
  • Encourage public transit use for company purposes.
  • Offer employees who agree to forego a free parking space the annualized cash value or cost of that parking space as a salary increase.
  • Incorporate company policies on public transit use into company sustainability and emission reduction initiatives and communicate how they support broader company goals.
  • Ensure your business is accessible via public transit and offer information on nearest access points both online and in person.
  • Offer employees pre-tax commuter benefits to include reimbursement for public transit expenses.
  • Create and distribute educational materials for employees on commuting best practices.
  • Partner with, support, and/or donate to infrastructure investments and public transit awareness campaigns.
  • Advocate for better public transit systems with city officials.

Further information:

Nonprofit Leaders
  • Use public transit and encourage staff to do so when feasible.
  • Offer staff pre-tax commuter benefits to include reimbursement for public transit expenses.
  • Offer employees who agree to forego a free parking space the annualized cash value or cost of that parking space as a salary increase.
  • Expand access to underserved communities by providing fare assistance through microgrants and/or public-private partnerships.
  • Create, support, or partner with existing public transit awareness campaigns that – starting from early childhood – focus on internally motivating factors such as money saved, health benefits, reduced pollution, free time while traveling, and a sustainable lifestyle.
  • Ensure your office is accessible via public transit and offer information – online and in person – on the nearest access points.
  • Advocate to policymakers for improved infrastructure and incentives for riders.
  • Advocate for infrastructure improvements and note specific locations where improvements can be made.
  • Encourage local businesses to create employee incentives.
  • Host or support community participation in local public transit infrastructure design.
  • Join public-private partnerships to encourage, improve, or operate public transit.

Further information:

Investors
  • Use public transit and encourage staff to do so when feasible.
  • Encourage public transit use for company purposes.
  • Invest in electric battery and component suppliers for public buses and vehicle fleets.
  • Deploy capital to efforts that improve public transit comfort, convenience, access, and safety.
  • Seek investment opportunities that reduce material and maintenance costs for public transit.

Further information:

Philanthropists and International Aid Agencies
  • Use public transit and encourage staff to do so when feasible.
  • Award grants to local organizations advocating for improved public transit and services.
  • Expand access to underserved communities by providing fare assistance through microgrants and/or public-private partnerships.
  • Improve and finance local infrastructure and public transit capacity.
  • Build local capacity for infrastructure design, maintenance, and construction.
  • Assist with local policy design or provide means for assessments, data collection, citizen participation, and other steps in the policymaking process.
  • Create, support, or partner with existing public transit awareness campaigns that – starting from early childhood – focus on internally motivating factors such as money saved, health benefits, reduced pollution, free time while traveling, and a sustainable lifestyle.

Further information:

Thought Leaders
  • Lead by example and use public transit regularly.
  • Create, support, or partner with existing public transit awareness campaigns that – starting from early childhood – focus on internally motivating factors such as money saved, health benefits, reduced pollution, free time while traveling, and a sustainable lifestyle.
  • Share detailed information on local public transit routes.
  • Assist with local policy design or provide means for assessments, data collection, citizen participation, and other steps in the policymaking process.
  • Advocate to policymakers for improved infrastructure, noting specific locations that need improvements and incentives for riders.

Further information:

Technologists and Researchers
  • Use public transit and encourage your colleagues to use public transit when feasible.
  • Improve electric batteries and electrification infrastructure for public buses and vehicles.
  • Develop models for policymakers to demonstrate the impact of public transit policies on pollutant emissions, health, and other socioeconomic variables.
  • Conduct randomized control trials and collect longitudinal data on the impacts of interventions to increase public transit usage.
  • Innovate better, faster, and cheaper public transit networks – focusing on infrastructure, operations, and public transit vehicles.

Further information:

Communities, Households, and Individuals
  • Use public transit and encourage your household and neighbors to use public transit when feasible.
  • Share your experiences with public transit, as well as tips and reasons for choosing this mode of transportation.
  • Advocate to local officials for infrastructure improvements and note specific locations where improvements can be made.
  • Advocate to employers and local businesses to provide incentives and start local initiatives.

Further information:

Sources
Evidence Base

Consensus of effectiveness in reducing transportation emissions: High

Experts agree that public transit usually produces fewer GHG/pkm than fossil fuel–powered cars (Bloomberg New Energy Finance, 2018; Brunner et al., 2018; Ilie et al., 2014; International Transport Forum, 2020; Kennedy, 2002; Kuminek, 2013; Lim et al., 2021; Mahmoud et al., 2016; Rodrigues & Seixas, 2022; Sertsoz et al., 2013). There is also consensus on two points: First, shifting people from cars to public transit even under status-quo emissions levels will reduce transport emissions overall; second, opportunities exist to decarbonize the highest-emitting parts of public transit systems through electrification, especially buses (Bloomberg New Energy Finance, 2018).

According to the Intergovernmental Panel on Climate Change (IPCC, 2023), public transit can help decrease vehicle travel and lower GHG emissions by reducing both the number and length of trips made in fossil fuel–powered cars (medium confidence). Adjustments to public transportation operations – such as increasing bus stop density, reducing the distance between stops and households, improving trip duration and frequency, and lowering fares – can encourage a shift from fossil fuel–powered car use to public transit.

Bloomberg New Energy Finance (2018) provides a good overview of the state of electric buses – a technology crucial to reduce the public transit fleet’s fossil fuel consumption, and help transition these fleets entirely to electric power. It determined that electric buses have significantly lower operating costs and can be more cost-effective than conventional buses when considering total ownership costs.

Litman (2024) found that “High quality (relatively fast, convenient, comfortable, and integrated) transit can attract discretionary passengers who would otherwise drive, which reduces traffic problems including congestion, parking costs, accidents, and pollution emissions. This provides direct user benefits, since they would not change mode if they did not consider themselves better off overall.”

The results presented in this document summarize findings from 28 reviews and meta-analyses and 23 original studies reflecting current evidence from 32 countries, primarily the American Public Transit Association (APTA, 2020), Bloomberg New Energy Finance (2018), International Transport Forum (2020), and UITP (2024). 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 Nonmotorized Transportation

Submitted by Drawdown Admin on
Sector
Transportation
Mode
Cut Emissions
Cluster
Shift to Alternatives
Image
Many people in a crosswalk viewed from above
Coming Soon
Off
Summary

We define Improve Nonmotorized Transportation as increasing any form of travel that does not use a motor or engine. In theory, this includes a huge range of transportation modes, including horses, cross-country skis, sailboats, hand-operated rickshaws, and animal-drawn carriages. In practice, pedestrian travel and cycling account for most nonmotorized utilitarian passenger travel.

Income & work,Health
Nature protection,Air quality
Overview

Travel shifted from motorized to nonmotorized transportation saves GHG emissions – mostly CO₂, but also small amounts of nitrous oxide and methane (Center for Sustainable Systems, 2023) – that a fossil fuel-powered car would otherwise emit. Nonmotorized transportation uses human muscle power to move people from place to place. 

We divided nonmotorized transportation into three subcategories: 1) pedestrian travel, including walking and the use of mobility aids such as wheelchairs; 2) private bicycles owned by the user, meaning that they are typically used for both the outgoing and return legs of a trip; and 3) shared bicycles, which are sometimes used for only one leg of a trip and so have to be repositioned by other means.

Pedestrian travel

Pedestrian travel (including both walking and travel using mobility aids such as wheelchairs) has the advantage of being something that most people can do and often does not require special equipment or dedicated infrastructure (although some infrastructure, such as sidewalks, can be helpful). Pedestrian travel is 81.7% of global urban nonmotorized pkm. 

Private bicycles

Private bicycles cost money and require maintenance but enable travel at much faster speeds and therefore longer distances. Private bicycles are 13% of global urban nonmotorized pkm.

Shared bicycles 

Shared bicycles eliminate the financial overhead of bicycle ownership, but usually only permit travel within specific urban areas and sometimes between established docking stations. Shared bicycles are 5.1% of global urban nonmotorized pkm. 

Note that we did not include electric bicycles in this analysis. Electric bicycles are analyzed as a separate solution.

While improving nonmotorized transportation can be a valuable climate solution virtually anywhere, we limit our analysis to cities due to the high number of relatively short-distance trips and the abundance of available data compared with rural locations.

The fuel for cycling and pedestrian travel is the food the traveler eats. When the traveler metabolizes the food, they produce CO₂. Some studies factor the GHG emissions produced by the additional metabolism required by nonmotorized transportation into its climate impact because of the emissions that come from the food system (Mizdrak et al., 2020). This is controversial, however, because it is unclear whether pedestrians and cyclists have a higher calorie intake than people who travel in other ways (Noussan et al., 2022). Furthermore, additional food eaten to fuel physical labor is not typically counted in life-cycle analyses. This analysis, therefore, does not consider the upstream climate impacts of food calories that fuel cycling, pedestrian travel, driving, or any other activity.

References

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Adamos, G., Nathanail, E., Theodoridou, P., & Tsolaki, T. (2020). Investigating the effects of active travel in health and quality of life. Transport and Telecommunication Journal, 21(3), 221–230. https://doi.org/10.2478/ttj-2020-0018

Autocosts.org. (2024). World statistics of car costs. Autocosts.Info. https://autocosts.info/worldstats

Blondiau, T., van Zeebroeck, B., & Haubold, H. (2016). Economic benefits of increased cycling. Transportation Research Procedia, 14, 2306–2313. https://doi.org/10.1016/j.trpro.2016.05.247

Bonilla-Alicea, R. J., Watson, B. C., Shen, Z., Tamayo, L., & Telenko, C. (2020). Life cycle assessment to quantify the impact of technology improvements in bike-sharing systems. Journal of Industrial Ecology, 24(1), 138–148. https://doi.org/10.1111/jiec.12860

Bopp, M., Sims, D., & Piatkowski, D. (2018). Benefits and risks of bicycling. 21–44. https://doi.org/10.1016/B978-0-12-812642-4.00002-7

Brand, C., Dons, E., Anaya-Boig, E., Avila-Palencia, I., Clark, A., de Nazelle, A., Gascon, M., Gaupp-Berghausen, M., Gerike, R., Götschi, T., Iacorossi, F., Kahlmeier, S., Laeremans, M., Nieuwenhuijsen, M. J., Pablo Orjuela, J., Racioppi, F., Raser, E., Rojas-Rueda, D., Standaert, A., … Int Panis, L. (2021). The climate change mitigation effects of daily active travel in cities. Transportation Research Part D: Transport and Environment, 93, 102764. https://doi.org/10.1016/j.trd.2021.102764

Burnham, A., Gohlke, D., Rush, L., Stephens, T., Zhou, Y., Delucci, M. A., Birky, A., Hunter, C., Lin, Z., Ou, S., Xie, F., Proctor, C., Wiryadinata, S., Liu, N., & Boloor, M. (2021). Comprehensive total cost of ownership quantifications for vehicles with different size classes and powertrains (ANL/ESD-21/4). Argonne National Laoratory. https://publications.anl.gov/anlpubs/2021/05/167399.pdf

Center for Sustainable Systems. (2023). Personal transportation factsheet (CSS01-07). University of Michigan. https://css.umich.edu/publications/factsheets/mobility/personal-transportation-factsheet

Christensen, L., & Vázquez, N. S. (2013). Post-harmonised european national travel surveys. Proceedings from the Annual Transport Conference at Aalborg University, 20(1), Article 1. https://doi.org/10.5278/ojs.td.v1i1.5701

CityTransit Data. (2025). A global analysis of transit data. CityTransit Data. https://citytransit.uitp.org/ 

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Litman, T. (2024). Evaluating active transport benefits and costs: Guide to valuing walking and cycling improvements and encouragement programs. Victoria Transport Policy Institute. https://www.vtpi.org/nmt-tdm.pdf

Mailloux, N. A., Henegan, C. P., Lsoto, D., Patterson, K. P., West, P. C., Foley, J. A., & Patz, J. A. (2021). Climate solutions double as health interventions. International Journal of Environmental Research and Public Health, 18(24), Article 24. https://doi.org/10.3390/ijerph182413339

Mizdrak, A., Cobiac, L. J., Cleghorn, C. L., Woodward, A., & Blakely, T. (2020). Fuelling walking and cycling: Human powered locomotion is associated with non-negligible greenhouse gas emissions. Scientific Reports, 10(1), Article 1. https://doi.org/10.1038/s41598-020-66170-y

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Credits

Lead Fellows

  • Heather Jones, Ph.D.

  • Cameron Roberts, Ph.D.

Contributors

  • James Gerber, Ph.D.

  • Yusuf Jameel , Ph.D.

  • Daniel Jasper

  • Heather McDiarmid, Ph.D.

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Yusuf Jameel, Ph.D. 

  • Heather McDiarmid, Ph.D.

  • Ted Otte

  • Amanda Smith, Ph.D.
Effectiveness

Nonmotorized transportation can save 115.6 t CO₂‑eq /million pkm, compared with fossil fuel–powered cars (Table 1). This makes it a highly effective climate solution. Every trip shifted from a fossil fuel–powered car to cycling or pedestrian travel avoids most, if not all, of the GHG emissions associated with car travel. Nonmotorized transportation effectiveness is calculated by taking the share of each mode and multiplying it by its effectiveness, and adding this value from all three modes. 

Cars produce 116 t CO₂‑eq /million pkm (International Transport Forum, 2020; IPCC, 2023; Montoya-Torres et al., 2023; TNMT, 2021; Verma et al., 2022). Note that this value does not correspond directly to the estimates arrived at in most of these references because it is common practice to include embodied and upstream emissions in life-cycle calculations. Because we do not include embodied and upstream emissions (which are accounted for in other solutions), our estimate for the current emissions from the global vehicle fleet comes from an original calculation using values from these sources and arrives at a lower figure than they do.

Pedestrian travel and private bicycles have negligible direct emissions (Bonilla-Alicea et al., 2020; Brand et al., 2021; International Transport Forum, 2020; Noussan et al., 2022; TNMT, 2021). This means people avoid all direct GHG emissions from driving fossil fuel–powered cars when they use nonmotorized transportation instead. Thus, shifting from cars to nonmotorized transportation saves 116 t CO₂‑eq /million pkm, not including indirect emissions, such as those from manufacturing the equipment and infrastructure necessary for those forms of mobility. Life-cycle emissions from cycling are approximately 12 t CO₂‑eq /million pkm, most of which come from manufacturing bicycles (Bonilla-Alicea et al., 2019; Brand et al., 2021; ITF, 2020; Montoya-Torres et al., 2023; Noussan et al., 2020; TNMT, 2021), while emissions from pedestrian travel are negligible (TNMT, 2021). These life-cycle emissions are not quantified for this analysis, but may be addressed by other solutions in the industrial sector.

Shared bicycles provide fewer emissions savings than privately owned bicycles do. Shared bicycle schemes have direct GHG emissions of 7.49 t CO₂‑eq /million pkm, about 109 fewer than the average fossil fuel-powered car. Because people sometimes use shared bicycles for one-way trips, the bike-sharing system can become unbalanced, with fewer bicycles in places where people start their journeys and more bicycles in places where people end them. This is fixed by driving the shared bicycles from places with surplus to places with shortage, which increases emissions. The total increase in emissions caused by this can be mitigated through measures such as using electric vehicles to reposition the bikes or incentivizing riders to reposition the bicycles themselves without the use of a vehicle. 

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq /million pkm, 100-yr basis

Nonmotorized Transportation
25th percentile 99.33
mean 118.8
median (50th percentile) 115.6
75th percentile 136.9
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Cost

Driving a fossil fuel–powered car has private costs (i.e., those that accrue to the motorist themselves) of US$0.25/pkm and public costs (for roads, lights, traffic enforcement, etc.) of US$0.11/pkm. It generates public revenues of US$0.03/pkm from taxes, fees, fines, etc. (AAA, 2024; Autocosts.org, 2024; Burnham et al., 2021; Gössling et al., 2019). This means that its net cost to the passenger is US$0.32/pkm. Cars also have externality costs, such as the cost of health care due to road injuries or air pollution (Litman, 2024). We do not factor these externalities into our cost analysis.

Nonmotorized transportation (costs weighted by mode share) has private costs of US$0.08/pkm and public costs US$0.04/pkm. It produces no revenues to the user. It has a net cost of US$0.12/pkm and saves US$0.21/pkm compared with car travel. This equals a savings of US$1,771/t CO₂‑eq (Table 2).

Pedestrian travel has private costs of US$0.09/pkm (mostly for shoes) and public costs of US$0.1/pkm (for sidewalks, staircases, bridges, etc.). It produces no new revenues. It has a net cost of US$0.10/pkm and saves US$0.23/pkm compared to car travel (Gössling et al., 2019; Litman, 2024). 

Private bicycles have private costs of US$0.06/pkm (for the cost of the bicycle itself, as well as repairs, clothing, etc.) and public costs of US$0.002/pkm (for bike lanes and other infrastructure). They produce no new revenues. They have net costs of US$0.07/pkm and save US$0.26/pkm compared to car travel (Gössling et al., 2019; Litman, 2024). These costs are cheaper than those of pedestrian travel on a per-pkm basis because, while a bicycle costs more than a pair of shoes, it can also travel much farther.

Shared bicycle systems have different cost structures. They can be very expensive (US$9.00/km in London), free (Buenos Aires) and very inexpensive (less than US$0.00 in Tehran) based on what operators charge users. Rides are usually priced by time rather than distance (DeMaio, 2009). Calculations were made as to distance covered by time to arrive at a price per km (CityTransit Data, 2025; Fishman & Schepers, 2016; Pro Cycling Coaching, 2025). Assuming that this roughly covered operating costs, it means that these systems cost US$0.22/pkm more than car travel.

An important consideration for each of these is that we must divide the cost of a bicycle, car, pair of shoes, or piece of infrastructure (road, bike lane, sidewalk) by the pkm of travel it supports over its lifespan. This means that nonmotorized transportation, which is cheaper but slower than cars, can have less of a cost advantage per pkm than might seem intuitive, and is part of the reason why cycling is cheaper per pkm than pedestrian travel. In addition, all of these estimates are based on very limited data and research and should be treated as approximate. Lastly, per-pkm infrastructural costs of cycling and pedestrian travel will decrease as cyclists and pedestrians use the infrastructure more intensively.

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Table 2. Cost per unit of climate impact.

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

Nonmotorized Transportation
median -1,771
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Learning Curve

Walking and cycling are mature technologies, so the concept of a learning rate is not applicable.

There is also limited opportunity for cost reductions in cycling or pedestrian infrastructure built using construction techniques very similar to those used in the road industry. However, while learning effects might not do much to reduce the costs of nonmotorized transportation infrastructure, they could do a great deal to improve its effectiveness. Safe cycling infrastructure, in particular, has improved considerably over the past few decades. This could continue into the future as best practices are further improved.

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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 gradual, emergency brake, or delayed.

Improve Nonmotorized Transportation 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

Increases to the modal share of nonmotorized transportation only have the benefits discussed here if they replace travel by car. Replacing public transit travel with travel using nonmotorized transportation will have a much smaller climate benefit. The climate benefit of nonmotorized mobility will also diminish if the average emissions of the global car fleet shrink, for example, due to the wider adoption of electric vehicles. 

There are also uncertainties around trip length. A small number of long trips taken by car will not be replaceable by nonmotorized transportation. Replacing the average trip by car with cycling or pedestrian travel will, in many cases, require that trip to be shortened (for example, by placing businesses closer to people’s homes). If this is not possible, increased adoption of nonmotorized transportation will apply to only some trips, reducing the impact on both emissions and costs.

Weather and climate pose significant challenges and risks for nonmotorized transportation. Extreme heat or cold, wind, rain, or storms can make people reluctant to travel without the protection of a vehicle and, in some cases, can make doing so unsafe (Gössling et al., 2023). This will reduce the adoption of nonmotorized transportation in some places, although it can be mitigated through measures such as providing information and subsidies for proper clothing, removing or grooming snow on bicycle paths, and providing indoor/covered paths that allow pedestrians to travel through a city without exposure to the elements.

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Current Adoption

Analysts most frequently report adoption of nonmotorized transportation as a percentage modal share of all trips taken in a city. Cities around the world have radically different modal shares of bicycle and pedestrian trips. Cities in LMICs often have a high nonmotorized modal share because many people cannot afford cars. Cities in high-income countries are often difficult to navigate without a car, resulting in low modal shares for nonmotorized transportation (Prieto-Curiel & Ospina, 2024). 

Prieto-Curiel and Ospina (2024) estimated that northern North America (the United States and Canada) had the lowest modal share of nonmotorized transportation, at 3.5%. Western Europe reached 29% modal share, while Western and Eastern Africa reached 42.9% and 46%, respectively.

Converting these numbers into vehicle-kilometers traveled on a national level for various countries requires assumptions. A population-weighted average of data available from the United States and several Western European countries finds that people take approximately three 13.2 km trips per day, totaling 39.7 km of daily travel with considerable variation between countries (Christensen & Vázquez, 2013; Department for Transport, 2024; Federal Highway Administration, 2022; Statistics Netherlands, 2024). For example, English people in 2022 traveled an average of 25.5 km/day, while Americans in 2020 traveled 53.5 km/day. The value we use in our analysis comes from a population-weighted average that excludes data from 2020 and 2021 to exclude data skewed by the COVID-19 pandemic. Because the United States has by far the highest population of the countries for which we found data, it skews the average much higher than many of the European countries. World data (ITF, 2021) reports that nonmotorized transportation is 14.4% of all urban pkm.

We assumed that in urban environments, each trip taken by nonmotorized transportation corresponds to one fewer car trip of this average length. This implies that nonmotorized transportation currently shifts approximately 12.9 trillion pkm from cars (Table 3). However, it should be noted that this figure includes low-income countries, where some residents have less access to private vehicles.

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Table 3. Current (2024) adoption level.

Unit: million pkm/yr*

25th percentile 1,913,000
mean 12,860,000
median (50th percentile) 8,617,000
75th percentile 22,340,000

*These data are extrapolated from a range of individual city estimates from 2010 to 2020 and are limited by the fact that not all cities have accurate data on passenger travel modal share. We used the mean value from Prieto-Curiel and Ospina (2024) as the authoritative estimate of current adoption here and for calculations in future sections.

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Adoption Trend

In all cities for which appropriate data exist, nonmotorized transportation showed a growth rate of 0.45% of all passenger trips per year (Prieto-Curiel & Ospina, 2024). This amounts to 114 billion pkm (Table 4) according to our estimation procedure outlined above. In some cities, adoption has grown much more quickly. For example, Hanover, Germany, achieved an average growth of 7.8%/yr in 2011–2017, which amounts to approximately 593 million additional pkm traveled by bicycle every year during that time. However, the rate of adoption is extremely variable. The 25th percentile of estimates shows a global decline in nonmotorized transportation to the tune of 312 billion fewer pkm shifted to nonmotorized modes every year.

Adoption rates of nonmotorized transportation vary widely within a country and between different years within the same city (Prieto-Curiel & Ospina, 2024).

Many people, particularly in LMICs, walk or cycle because they have limited access to a vehicle. When countries become wealthier, travel often shifts from nonmotorized transportation to cars (Seum et al., 2020). If transportation policy in these countries prioritizes car-free mobility, high levels of nonmotorized transportation adoption could potentially be preserved even as living standards increase.

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Table 4. 2023–2024 adoption trend.

Unit: million pkm/yr

25th percentile -311,800
mean 68,450
median (50th percentile) 114,400
75th percentile 687,200
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Adoption Ceiling

We estimated that 20.2% of all trips in cities worldwide, or approximately 12.9 trillion pkm/yr, are traveled by nonmotorized transportation, while 66.2%, or approximately 42.2 trillion pkm/yr, are traveled by fossil fuel–powered car. This suggests that switching all urban trips currently taken by car to nonmotorized transportation would lead to a nonmotorized modal share of 86.4% in cities globally, or 55 trillion pkm/yr (Table 5).

This calculation uses the same assumptions discussed under Current Adoption above. In this case, however, our assumption that every nonmotorized trip is shifted from a car trip of the same length requires further justification. We are not assuming that very long car trips, trips on highways, etc., are replaced directly by bicycle or pedestrian trips. Instead, we assume that shorter nonmotorized trips can substitute for longer car trips with appropriate investment in better urban planning and infrastructure. So, for example, a 10 km drive to a large grocery store could be replaced by a 1 km walk to a neighborhood grocery store. 

This would require replanning many cities so they better accommodate shorter trips. It would also require improving options for people with disabilities or those carrying heavy loads. And it would face climatic and topographic constraints. Furthermore, it is unlikely that all car traffic would ever be substituted by any single alternative mode. Other sustainable modes, particularly public transit, are likely to play a role.

It is also possible for rural trips to be undertaken by nonmotorized transportation. Indeed, this is already very common in low-and middle-income countries. However, rural data are sparse, and discerning how many trips could be shifted to nonmotorized travel in these areas is highly speculative. Therefore, we omit rural areas from our analysis.

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Table 5. Adoption ceiling.

Unit: million pkm/yr

median (50th percentile) 55,090,000
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Achievable Adoption

To estimate the upper bound of feasible adoption, we assumed that urban trips taken by fossil fuel–powered cars can be shifted to nonmotorized transportation until the latter accounts for 65% of trips (the current highest modal share of nonmotorized transportation in any city with a population of more than one million) or until car travel decreases to 7% of trips (the current lowest modal share of fossil fuel–powered cars in any city with a population of more than one million). 

The global modal share of car travel is 51.4% of trips, or 37.6 trillion pkm/yr, and the global modal share of nonmotorized transportation in cities is 22.4% of trips, or 12.9 trillion pkm/yr. If we shift modal share from cars to nonmotorized transportation until it reaches 65% of travel in cities, that leaves the modal share of cars in cities at 8.8%, still higher than the 7% modal share mentioned above. This amounts to a total modal share shift of 42.6% in all global cities. Multiplying this by the global urban population of 4.4 billion and factoring in the average annual travel distance per capita of 16,590 pkm/yr results in a total of 31.2 million pkm/yr shifted from car travel to nonmotorized transportation in cities around the world, for a total of 41.5 trillion pkm/yr (Table 6).

To set the lower bound, we do the same calculation as above, but for each individual region, adding up all the resultant modal shifts to get a global figure. So, for example, every East Asian city might reach the nonmotorized transportation modal share of Singapore (23% of trips), while every northern European city might reach that of Copenhagen, Denmark (41% of trips). This corresponds to a total achievable nonmotorized transportation modal share of 28.6 trillion pkm/yr.

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Table 6. Range of achievable adoption levels.

Unit: million pkm/yr

Current Adoption 12,860,000
Achievable – Low 28,630,000
Achievable – High 41,490,000
Adoption Ceiling 55,090,000
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If all cycling and pedestrian trips undertaken today would otherwise have happened by car, they are currently displacing approximately 1.5 Gt CO₂‑eq/yr emissions (Table 7). This is an overestimate, however, since this figure includes data from places where most people have low access to cars.

Walking and private bicycles have a different effectiveness than shared bicycles. To calculate the climate impacts of different levels of adoption, we applied the effectiveness in the share of each mode of nonmotorized transportation. Walking and private bicycling are 94.4% of nonmotorized pkm and shared bicycling is 5.3%. This gives nonmotorized transportation effectiveness at reducing emissions 115.6 t CO₂‑eq /million pkm.

On the lower end, if every city achieved a pedestrian and cycling modal share equivalent to the least-motorized city in its region, it would save 3.3 Gt CO₂‑eq/yr. On the higher end, if every city shifted enough passenger car traffic to achieve a car modal share as low as Hong Kong, China, it would save 4.8 Gt CO₂‑eq/yr. If all trips taken by car were shifted onto nonmotorized transportation (an unrealistic scenario), it would save 6.4 Gt CO₂‑eq/yr.

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Table 7. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 1.487
Achievable – Low 3.310
Achievable – High 4.797
Adoption Ceiling 6.370
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Additional Benefits

Air pollution and health

Air pollution kills approximately 7 million people yearly (Roser, 2024). By reducing vehicle emissions, nonmotorized transportation can alleviate related air pollution (Mailloux et al., 2021) and thereby reduce premature deaths. For example, cutting U.S. transportation emissions by 75% by 2030 could prevent 14,000 premature deaths annually due to decreased exposure to PM2.5 and ozone (Shindell et al., 2016). 

Nonmotorized transportation has other health and safety benefits (Blondiau et al., 2016; European Commission, 2019; Glazener & Khreis, 2019; Gössling et al., 2023; Mueller et al., 2015; State of Colorado, 2016; Xia et al., 2013). Switching from driving to walking or cycling boosts health by promoting physical activity and decreasing risks of cardiovascular issues, diabetes, and mental disorders (Mailloux et al., 2021).

Noise pollution from motorized vehicles has significant impacts on cardiovascular health, mental health, and sleep disturbances, contributing to 1.6 million lost healthy life years in 2004 and up to 1,100 deaths attributable to hypertension in Europe in 2024 (Staatsen et al., 2004; Munzel et al., 2024). Enhancing nonmotorized transportation can reduce the health impacts of traffic noise (de Nazelle et al., 2011).

Finally, nonmotorized transportation improves quality of life. It increases opportunities for human connection, integrates physical activity and fun into daily commutes, and increases the autonomy of less mobile groups such as children and elders. Cities with high modal shares for nonmotorized transportation generally have high quality of life (Adamos et al., 2020; Günther & Krems, 2022; Glazener and Khreis, 2019).

The use of nonmotorized transportation can reduce car crashes, which kill around 1.2 million people annually (WHO, 2023).

Income and work

Nonmotorized transportation infrastructure tends to be good for local businesses. Cyclists and pedestrians are more likely to stop at businesses they pass and therefore spend more money locally, creating more jobs (Volker & Handy, 2021). 

Nature protection

In 2011, roads and associated infrastructure accounted for 10–30% of land in residential areas and 50–70% of land in commercial areas (Litman, 2011). Transforming these lands into green spaces could provide additional habitats and reduce biodiversity loss while increasing the protection of land, soil, and water resources (European Commission, 2019).

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Risks

Some literature suggested that nonmotorized transportation can lead to gentrification because bike lanes and pleasant walkable streets can increase property values, driving people who used to live in a neighborhood into other places that might still be car-dependent (Flanagan et al., 2016). This risk can be addressed by ensuring that nonmotorized transportation infrastructure is built in an equitable way, connecting different neighborhoods regardless of their social and economic status. Increasing the number of neighborhoods accessible without a car will mean that people do not have to pay a premium to live in those neighborhoods. This will avoid making accessibility without a car a privilege that only the wealthy can afford.

Cycling in a city with lots of traffic and poor cycling infrastructure puts cyclists at risk of injury from collisions with cars. This risk, however, comes mainly from the presence of cars on roads. Reducing the number of cars on the road by shifting trips to other modes can improve safety for cyclists and pedestrians (Bopp et al., 2018).

The positive impacts that nonmotorized transportation have on traffic congestion could be self-defeating if not managed well. This is because less congestion will make driving more appealing, which can, in turn, lead to additional induced demand, increasing car use and congestion (Hymel et al., 2010).

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Interactions with Other Solutions

Reinforcing

Nonmotorized transportation can help passengers access public transit systems, train stations, and carpool pickup points. This is important because research suggests that the key to a low-carbon mobility system is to reduce the need for people to own cars (Van Acker & Witlox, 2010).

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Electric bicycles use the same infrastructure as nonmotorized transportation – especially conventional bicycles. Building bike lanes, bike paths, mixed-use paths, and similar infrastructure for cyclists and pedestrians can also help with the uptake of electric bicycles. This is even more true for shared electric bicycles, which can and often do use the same sharing systems as shared conventional bicycles.

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One way to encourage the adoption of electric cars is through electric car–sharing services, in which people can access a communal electric car when they need it. This has the additional benefit of reducing the need for car ownership, which is closely correlated with car use (Van Acker and Witlox, 2010). Good nonmotorized transportation infrastructure can make it easier for users of these services to access shared vehicles parked at central locations.

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Nonmotorized transportation requires a lot less space than cars. Some of this space could be reallocated to ecosystem conservation and other land-based methods of GHG sequestration. In 2011, roads and parking accounted for 10–30% of land in residential areas and 50–70% of land in commercial areas (Litman, 2011). Transforming 35% of the land area of European cities alone into green spaces could sequester an additional 26 Mt CO₂‑eq/yr. Globally, this kind of effort could sequester 0.1–0.3 Gt CO₂‑eq/yr (Rodriguez Mendez et al., 2024).

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Competing

Electric cars, hybrid cars, and nonmotorized transportation compete for the same pool of total pkm. Increased use of nonmotorized transportation could reduce kilometers traveled using electric cars. 

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Consensus

Consensus of effectiveness in decarbonizing the transport sector: High

The large reductions in emissions that come from shifting passenger transportation from fossil fuel-powered cars to nonmotorized modes are not controversial. There is some disagreement, however, over how many pkm traveled by car can be realistically shifted to nonmotorized transportation.

Brand et al. (2021) compared the GHG emissions of active transportation with those of cars. They concluded that “locking in, investing in and promoting active travel should be a cornerstone of sustainability strategies, policies and planning.”

The Intergovernmental Panel on Climate Change (IPCC, 2023) sixth assessment report mentioned nonmotorized transportation as a solution in its transportation chapter. The authors expressed high confidence in the potential of these transportation modes to reduce emissions and recommended policy and infrastructural measures to support them.

Litman’s (2024) study of the costs and benefits of active transportation summarized the direct financial costs as well as externalities associated with pedestrian and bicycle travel compared with travel by fossil fuel–powered car. Litman noted that “active transport can provide relatively large energy savings if it substitutes for short urban trips that have high emission rates per mile due to cold starts (engines are inefficient during the first few minutes of operation) and congestion. As a result, each 1% shift from automobile to active travel typically reduces fuel consumption 2–4%.”

This research is, unfortunately, heavily biased toward richer countries, especially in Europe and North America, even though nonmotorized transportation plays a very important role in low- and middle-income countries (LMICs). The research on this topic is also biased toward cities, even though nonmotorized transportation can be a valuable means of mobility in rural areas. 

The results presented in this document summarize findings from 19 reviews and meta-analyses and 14 original studies reflecting current evidence from 84 countries, primarily the United States, the United Kingdom, and the European Union. 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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Dashboard

Solution Basics

one million passenger-kilometers (pkm)

tCO2-eq/unit
115.6
units/yr
Current 1.29×10⁷2.86×10⁷4.15×10⁷
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 1.49 3.314.8
US$ per tCO2-eq
-1,771
Gradual

CO₂, CH₄, N₂O

Trade-offs

Production of equipment (such as bicycles) and infrastructure (such as sidewalks) creates some emissions, but these are small when divided by the total distance traveled by pedestrians and cyclists. On a per-pkm basis, this makes little difference in the emissions saved by nonmotorized transportation. 

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% population
0–20
20–40
40–60
60–80
> 80

Percentage of city population living near protected bikeways, 2023

Proximity to related infrastructure, such as protected bikeways, facilitates the safe and convenient use of nonmotorized modes of transportation.

Reich, D. T. & Braga, K. (2024). Atlas of Sustainable City Transport [Data set]. Institute for Transportation and Development Policy. Retrieved June 2, 2025 from atlas.itdp.org

% population
0–20
20–40
40–60
60–80
> 80

Percentage of city population living near protected bikeways, 2023

Proximity to related infrastructure, such as protected bikeways, facilitates the safe and convenient use of nonmotorized modes of transportation.

Reich, D. T. & Braga, K. (2024). Atlas of Sustainable City Transport [Data set]. Institute for Transportation and Development Policy. Retrieved June 2, 2025 from atlas.itdp.org

Geographic Guidance Introduction

Nonmotorized transportation effectiveness is high across all geographic regions, though the built environment, safety, and socio-cultural norms heavily shape its adoption and impact. Key determinants of effectiveness include the extent of safe and connected infrastructure (e.g., sidewalks, bike lanes, protected intersections), land-use patterns supporting short trips, and public policies prioritizing nonmotorized transportation.

Overall, effectiveness depends on adoption. In many cities across Europe and Asia, walking and cycling remain integral to daily travel. Cities like Amsterdam, Copenhagen, and Tokyo have successfully integrated nonmotorized modes into their broader transport systems through dedicated infrastructure and supportive urban design. In contrast, cities in North America, Sub-Saharan Africa, and parts of Latin America often lack safe, accessible infrastructure, which limits adoption.

Socioeconomic factors, including income levels, urban design, and perceptions of status, also influence the adoption of nonmotorized transport. In wealthier regions, cycling may be viewed as a lifestyle choice or an environmental statement, whereas in lower-income settings, it may be perceived as a necessity or even a sign of economic disadvantage, influencing user behavior and policy support (Seum et al., 2020).

Although shared bicycles have a lower effectiveness than walking or private bicycles, they are much more effective than cars. Increasing the number of shared bicycle systems in any geographic area can increase adoption and, therefore, make them more effective. This is particularly effective in lower-income areas where owning a private bicycle might be cost-prohibitive (Litman, 2024). Increasing shared systems in less urban and more suburban areas can be more effective, as they often replace trips made by car (Brand et al., 2021).

Nonmotorized modes are generally resilient and functional in a wide range of climates. Extreme weather conditions, including high heat, heavy rainfall, or snow, can reduce walking and cycling, although these can be mitigated through appropriate infrastructure (e.g., shaded or covered walkways, snow clearing, bike shelters).

Action Word
Improve
Solution Title
Nonmotorized Transportation
Classification
Highly Recommended
Lawmakers and Policymakers
  • Use nonmotorized transportation.
  • Reduce the associated time, distance, risk, and risk perception of nonmotorized transportation.
  • Improve infrastructure such as sidewalks, footpaths, and bike lanes.
  • Implement traffic-calming methods such as speed bumps.
  • Increase residential and commercial density.
  • Use a citizen-centered approach when designing infrastructure.
  • Enact infrastructure standards for nonmotorized transportation, such as curb ramp designs, and train contractors to implement them.
  • Establish public bike-sharing programs.
  • Create dedicated coordinating bodies across government agencies, businesses, and the public to develop nonmotorized infrastructure.
  • Disincentivize car ownership through reduced access, increases in parking fares, taxes, or other means. 

Further information:

Practitioners
  • Use nonmotorized transportation.
  • Share your experiences, tips, and reasons for choosing your modes of transportation.
  • Participate in local bike groups, public events, and volunteer opportunities.
  • Advocate to local officials for infrastructure improvements and note specific locations for improvements.
  • Encourage local businesses to create employee incentives.
  • Create “bike buses” or “walking buses” for the community and local schools.

Further information:

Business Leaders
  • Use nonmotorized transportation.
  • Ensure your business is accessible via nonmotorized transportation.
  • Advocate for better infrastructure for nonmotorized transportation.
  • Educate customers about the local infrastructure.
  • Partner with other businesses to encourage employees to cycle or walk.
  • Encourage employees to walk or cycle to and from work as their circumstances allow.
  • Create educational materials for employees on commuting best practices.
  • Offer employees pre-tax commuter benefits to include reimbursement for nonmotorized travel expenses.
  • Organize staff bike rides to increase familiarity and comfort with bicycling.
  • Install adequate bike storage, such as locking posts.
  • Emphasize walking and biking as part of company-wide sustainability initiatives and communicate how walking and biking support broader GHG emission reduction efforts.

Further information:

Nonprofit Leaders
  • Use nonmotorized transportation.
  • Ensure your office is accessible to nonmotorized transportation.
  • Advocate for infrastructure improvements and note specific locations where improvements can be made.
  • Encourage local businesses to create employee incentives.
  • Create “bike buses” or “walking buses” for the community and/or local schools.
  • Offer free classes on subjects such as bike maintenance, local bike routes, or what to know before purchasing a bike.
  • Host or support community participation in local infrastructure design.
  • Join public-private partnerships to encourage biking and walking, emphasizing the health and savings benefits.

Further information:

Investors
  • Use nonmotorized transportation.
  • Deploy capital to efforts that improve bicycle and walking comfort, convenience, access, and safety.
  • Invest in public or private bike-sharing systems.
  • Invest in local supply chains for bicycles and other forms of nonmotorized transportation.
  • Seek investment opportunities that reduce material and maintenance costs for bicycles.
  • Finance bicycle purchases via low-interest loans.
  • Consider investments in nonmotorized transportation start-ups.

Further information:

Philanthropists and International Aid Agencies
  • Use nonmotorized transportation.
  • Award grants to local organizations advocating for improved walking and bicycle infrastructure.
  • Build capacity for walking and bicycle infrastructure design and construction.
  • Support organizations that distribute, refurbish, and/or donate bikes in your community.
  • Facilitate access to bicycle maintenance and supplies.
  • Host or support community education or participation efforts.
  • Donate fixtures such as street lights, guardrails, and road signs.
  • Educate the public and policymakers on the benefits and best practices of nonmotorized transportation.

Further information:

Thought Leaders
  • Use nonmotorized transportation.
  • Focus messages on key decision factors for nonmotorized commuters, such as the associated health benefits and importance of fitness, climate and environmental benefits, weather forecasts, and traffic information.
  • Highlight principles of safe urban design and point out dangerous areas.
  • Share information on local bike and walking routes, general bike maintenance tips, items to consider when purchasing a bike, and related educational information.
  • Collaborate with schools on bicycle instruction, including safe riding habits and maintenance.

Further information:

Technologists and Researchers
  • Use nonmotorized transportation.
  • Examine and improve elements of infrastructure design.
  • Improve circularity, repairability, and ease of disassembly for bikes.
  • Increase the physical carrying capacities (storage) for walkers and bicyclists to facilitate shopping and transporting children, pets, and materials.
  • Identify and encourage the deployment of messaging that enhances nonmotorized transportation use.

Further information:

Communities, Households, and Individuals
  • Use nonmotorized transportation.
  • Share your experiences, tips, and reasons for choosing nonmotorized transportation.
  • Participate in local bike groups, public events, and volunteer opportunities.
  • Advocate to local officials for infrastructure improvements and note specific locations where improvements can be made.
  • Encourage local businesses to create employee incentives for using nonmotorized transportation.
  • Create “bike buses” or “walking buses” for the community and local schools.

Further information:

Sources
Updated Date

Deploy Clean Cooking

Submitted by Drawdown Admin on
Sector
Buildings
Mode
Cut Emissions
Cluster
Shift Energy Sources
Image
Family cooking on a clean stove indoors
Coming Soon
Off
Summary

We define the Deploy Clean Cooking solution as the use of cleaner cooking fuels (liquid petroleum gas, natural gas, electricity, biogas, and ethanol) in place of polluting fuels such as wood, charcoal, dung, kerosene, and coal, and/or the use of efficient cookstove technologies (together called cleaner cooking solutions). Replacing unclean fuel and cookstoves with cleaner approaches can drastically reduce GHG emissions while offering health and biodiversity benefits.

Income & work,Health,Equality
Nature protection,Air quality
Overview

Worldwide, cooking is responsible for an estimated 1.7 Gt CO₂‑eq/yr (100-yr basis), (World Health Organization [WHO], 2023), or almost 3% of annual global emissions. Most of these emissions come from burning nonrenewable biomass fuels. Only the CO₂‑eq on a 100-yr basis is reported here due to lack of data on the relative contributions of GHGs. The International Energy Agency (IEA, 2023a) states that 2.3 billion people in 128 countries currently cook with coal, charcoal, kerosene, firewood, agricultural waste, or dung over open fires or inefficient cookstoves because they do not have the ability to regularly cook using cleaner cooking solutions. Even when sustainably harvested, biomass fuel is not climate neutral because it emits methane and black carbon (Smith, 2002).

Clean cooking reduces GHG emissions through three pathways: 

Improving efficiency

Traditional biomass or charcoal cookstoves are less than 15% efficient (Khavari et al., 2023), meaning most generated heat is lost to the environment rather than heating the cooking vessel and food. Cleaner fuels and technologies can be many times more efficient, using less energy to prepare meals than traditional fuels and cookstoves (Kashyap et al., 2024). 

Reducing carbon intensity

Cleaner fuels have lower carbon intensity, producing significantly fewer GHG emissions per unit of heat generated than conventional fuels. Carbon intensity includes CO₂, methane, and nitrous oxides as well as black carbon. For instance, charcoal cookstoves emit approximately 572 kg CO₂‑eq /GJ of heat delivered for cooking (Cashman et al., 2016). In contrast, liquefied petroleum gas (LPG) and biogas emit about 292 and 11 kg CO₂‑eq /GJ, respectively (Cashman et al., 2016) and, excluding the embodied carbon, stoves that heat with electricity generated from renewable energy sources such as solar, wind, or hydroelectric have zero emissions.

Reducing deforestation

Cleaner cooking also helps mitigate climate change by reducing deforestation (Clean Cooking Alliance [CCA], 2023) and associated GHG emissions. 

Figure 1. Classification of household cooking fuels as clean (green) and polluting (orange). Adapted from Stoner et al. 2021.

Source: Stoner, O., Lewis, J., Martínez, I. L., Gumy, S., Economou, T., & Adair-Rohani, H. (2021). Household cooking fuel estimates at global and country level for 1990 to 2030. Nature communications, 12(1), 5793.https://www.nature.com/articles/s41467-021-26036-x

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Afrane, G., & Ntiamoah, A. (2012). Analysis of the life-cycle costs and environmental impacts of cooking fuels used in Ghana. Applied energy, 98, 301-306. https://www.sciencedirect.com/science/article/abs/pii/S0306261912002590

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Down to Earth (2022). Ujjwala: Over 9 million beneficiaries did not refill cylinder last year, Centre admits. Retrieved 20 June 2024, from https://www.downtoearth.org.in/energy/ujjwala-over-9-million-beneficiaries-did-not-refill-cylinder-last-year-centre-admits-84130

Garland, C., Delapena, S., Prasad, R., L'Orange, C., Alexander, D., & Johnson, M. (2017). Black carbon cookstove emissions: A field assessment of 19 stove/fuel combinations. Atmospheric Environment, 169, 140-149. https://doi.org/10.1016/j.atmosenv.2017.08.040

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International Energy Agency (2023a). A vision for clean cooking access for all. https://iea.blob.core.windows.net/assets/f63eebbc-a3df-4542-b2fb-364dd66a2199/AVisionforCleanCookingAccessforAll.pdf 

International Energy Agency (2023b). Electricity market report. https://www.iea.org/reports/electricity-market-report-update-2023

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Jewitt, S., Atagher, P., & Clifford, M. (2020). “We cannot stop cooking”: Stove stacking, seasonality and the risky practices of household cookstove transitions in Nigeria. Energy Research & Social Science, 61, 101340. https://www.sciencedirect.com/science/article/pii/S2214629619304700?via%3Dihub

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Stoner, O., Lewis, J., Martínez, I. L., Gumy, S., Economou, T., & Adair-Rohani, H. (2021). Household cooking fuel estimates at global and country level for 1990 to 2030. Nature communications, 12(1), 5793.https://www.nature.com/articles/s41467-021-26036-x

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World Health Organization (2024b). Household air pollution. Retrieved 17 June 2024, https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health

Credits

Lead Fellow

  • Yusuf Jameel, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Yusuf Jameel, Ph.D.

  • Daniel Jasper

  • Heather McDiarmid, Ph.D.

  • Amanda Smith, Ph.D.

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Megan Matthews, Ph.D.

  • Ted Otte

  • Amanda Smith, Ph.D.

  • Tina Swanson, Ph.D.

Effectiveness

The climate impact of cleaner cooking depends on which fuel and technology is being replaced and what is replacing it. The WHO (2024) categorizes cooking fuels as clean, transitional, or polluting based primarily on health impacts. Clean fuels include solar, electric, biogas, LPG, and alcohols, while kerosene and unprocessed coal are polluting fuels. Biomass cooking technologies may be classified as clean, transitional, or polluting depending on the levels of fine particulate matter and carbon monoxide produced. Switching from traditional cookstoves (polluting) to improved cookstoves (transitional) can reduce emissions 20–40%, while switching to an LPG or electric cookstove can reduce emissions more than 60% (Johnson, 2009). Not including the embodied carbon, switching completely to solar-powered electric cookstoves can reduce emissions 100%.

We estimated the effectiveness of cleaner cooking by calculating the reduction in GHG emissions per household switching to cleaner cooking solutions per year (Table 1). Our analysis of national, regional, and global studies suggested that switching to cleaner fuels and technologies can reduce emissions by 0.83–3.4 t CO₂‑eq /household/yr (100-yr basis), including CO₂, methane, black carbon, and sometimes other GHGs. The large range is due to varying assumptions. For example, the IEA arrived at 3.2 t CO₂‑eq /household/yr (100-yr basis) by assuming that >50% of the households switched to electricity or LPG. In comparison, Bailis et al. (2015) assumed a switch from unclean cookstoves to improved biomass cookstoves, resulting in an emissions reduction of only 0.98 t CO₂‑eq /household/yr (100-yr basis).

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Table 1. Effectiveness at reducing GHG emissions of switching from unclean cooking fuels and technologies to cleaner versions.

Unit: t CO₂-eq/household switching to cleaner cooking solutions/yr, 100-yr basis

25th percentile 1.5
mean 2.2
median (50th percentile) 2.3
75th percentile 3.1
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While we estimated a median reduction of 2.3 t CO₂‑eq /household switching to cleaner cooking solutions/yr (100-yr basis), the actual reduction per household might be lower because households often stack cleaner cooking fuel with unclean fuel. This could result from multiple socioeconomic factors. For instance, a household may primarily rely on LPG as its main cooking fuel but occasionally turn to firewood or kerosene for specific dishes, price fluctuation, or fuel shortages (Khavari et al., 2023). In rural areas, cleaner fuels and traditional biomass (e.g., wood or dung) are used together to cut costs or due to personal preferences.

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Cost

People can obtain traditional unclean fuels and traditional woodstoves for little or no cost (Bensch et al., 2021; Kapsalyamova, 2021). Our analysis estimated the cost of woodstoves at US$1.50/household and the monetary cost of biomass fuel at US$0.00/household/yr. Over the two-yr lifespan of a woodstove, the net annualized cost is US$0.75/household/yr. While collecting this fuel might be free, it contributes to poverty because households can spend one to three hours daily collecting fuelwood. This can contribute to children, especially girls, missing school (Jameel et al., 2023). 

We estimated the median upfront cost of transitioning from primarily unclean cooking fuels and technology to cleaner cooking to be approximately US$54/household, with stoves lasting 3–10 years. However, the range of annual costs is large because several cleaner cooking technologies have significant variations in price, and cleaner fuel cost is even more variable. Our analysis showed a median annual fuel cost of US$56/household/yr with costs ranging from savings of US$9/household/yr when buying less biomass for more efficient biomass stoves to costs of US$187/household/yr for LPG. Over a five-yr lifespan, cleaner cooking solutions have a net cost of US$64/household/yr (Table 2). 

Our analysis may overestimate operational costs due to a lack of data on biomass and charcoal costs. The IEA (2023a) estimates that an annual investment of US$8 billion is needed to supply cleaner cookstoves, equipment, and infrastructure to support a transition to cleaner cooking. This translates to US$17/household/yr. 

The IEA (2023) assumes improved biomass and charcoal cookstoves are predominantly adopted in rural areas while LPG and electric stoves are adopted in urban regions because, in LMICs, economic and infrastructure challenges can limit access to LPG and electricity in rural areas. If every household were to switch exclusively to modern cooking (e.g., LPG and electricity), the cost would be much higher. The World Bank estimates the cost of implementing these solutions to be US$1.5 trillion between 2020 and 2030 or ~US$150 billion/yr over the next 10 years. This translates into an average cost of US$214/household/yr (World Bank, 2020). 

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Table 2. Cost of cleaner cooking solutions.

Unit: 2023 US$/household switching to cleaner cooking solution

Median cookstove cost 1.50
Median annual fuel cost 0.00
Net annual cost 0.74

Unit: 2023 US$/household switching to cleaner cooking solution

Median cookstove cost 54
Median annual fuel cost 56
Net annual cost 64
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The median cost per unit of climate impact was US$27/t CO₂‑eq (100-yr basis, Table 3), obtained by taking the difference between median cost of cooking with polluting sources and the cost of adopting cleaner fuel, then dividing by the median reduction per household (Table 1). Beyond climate benefits, cleaner cooking offers significant other benefits (discussed under Additional Benefits below). While the median cost presented here is a reasonable first-order estimate, the actual cost of GHG reduction will depend upon several factors, including the type of stove adopted, stove usage, fuel consumption, and scale of adoption. 

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Table 3. Cost per unit climate impact.

Unit: 2023 US$/t CO₂‑eq, 100-yr basis

median (50th percentile) 27
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Learning Curve

Deploying cleaner cooking is a mature technology, and prices are unlikely to decrease in high-income countries where cleaner cooking fuels and technologies have been completely adopted. Nonetheless, the high cost of cleaner cooking technologies and the fluctuating prices of cleaner cooking fuel have been among the main impediments in the transition of households experiencing poverty away from unclean fuels and technologies. For example, recent price surges in Africa rendered LPG unaffordable for 30 million people (IEA, 2022). Electricity prices have also fluctuated regionally. In Europe and India, prices were higher in 2023 than in 2019 (IEA, 2023b). In contrast, U.S. electricity prices have remained stable over the past five years, while China experienced an 8% decrease.

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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 gradual, emergency brake, or delayed.

Deploy Clean Cooking 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

Households may continue using unclean cooking fuel and technologies alongside cleaner fuels and technologies (referred to as stacking). The data on cleaner cooking are typically measured as the number of households primarily relying on cleaner cooking fuel. This fails to capture the secondary fuel source used in the household. A review from LMICs revealed that stacking can range from low (28%) to as high as 100%, which would mean that every household is simultaneously using cleaner and unclean fuel (Shankar et al., 2020). This can happen due to factors like an increase in the cost of cleaner cooking fuel, cooking preference, unavailability of cleaner fuel, and unfamiliarity with cleaner cooking technologies. Stacking is challenging to avoid, and there is a growing realization from cleaner cooking practitioners of the need for cleaner approaches, even when multiple stoves are used. For example, electric stoves can be supplemented with LPG or ethanol stoves.

Permanence

There are significant permanence challenges associated with cleaner cooking. Households switch back from cleaner cooking fuels and technologies to unclean fuels and technologies (Jewitt et al., 2020). 

Finance

Finance is vital to supercharge adoption of cleaner cooking. Investment in the cleaner cooking sector remains significantly below the scale of the global challenge, with current funding at approximately US$130 million. This is many times lower than the amount needed each year to expand adoption of cleaner cooking solutions for the 2.4 billion people who still rely on polluting fuels and technologies (CCA 2023). At the current business-as-usual adoption rate, limited by severe underfunding, more than 80% of the population in sub-Saharan Africa will continue to rely on unclean fuels and technologies in 2030 (Stoner et al., 2021)

Climate funding, developmental finance, and subsidies have made some progress in increasing adoption of cleaner cooking. For instance, the World Bank invested more than US$562 million between 2015 and 2020, enabling 43 million people across 30 countries to adopt cleaner cooking solutions (World Bank, 2023; ESMAP, 2023). However, the emissions reductions these programs achieve can be overestimated. A recent analysis (Gill-Wiehl et al., 2024) found that 7.8 million clean cooking offset credits in reality only amounted to about 1.1 million credits. This discrepancy underscores the urgent need for updated methodologies and standards to accurately estimate emissions reductions and the cost of reduction per t CO₂‑eq (100-yr basis). 

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Current Adoption

The WHO (2025) estimated that 74% of the global population in 2022 used cleaner cooking fuels and technologies. This translates to 1.2 billion households using cleaner cooking (Table 4) and 420 million households that have yet to switch to clean cooking solutions (Table 4). The adoption of cleaner cooking is not evenly spread across the world. On the higher end of the spectrum are the Americas and Europe, where, on average, more than 93% of people primarily rely on cleaner cooking fuels and technologies (WHO, 2025). On the lower end of the spectrum are sub-Saharan countries such as Madagascar, Mali and Uganda, where primary reliance on cleaner cooking fuel and technologies is <5%. 

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Table 4. Current adoption level (2022).

Unit: households using cleaner cooking solutions

mean 1,200,000,000
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Adoption Trend

Global adoption of cleaner cooking fuel and technologies as the primary source of cooking increased from 61% of the population in 2013 to 74% in 2023 (WHO, 2025). This translates to roughly 21 million households adopting cleaner cooking technologies/yr (Table 5). This uptake, however, is not evenly distributed (see Maps section above).

Large-scale adoption across China, India, and Indonesia has driven the recent increase. Between 2011 and 2021, use of cleaner fuels and technologies as the primary means of cooking rose from 61% to 83% of the population in China. In India, adoption expanded from 38% to 71%, and in Indonesia, it increased from 47% to 87% (WHO, 2024a). In contrast, primary reliance on cleaner cooking in sub-Saharan Africa only increased from 12% in 2010 to 16% in 2020 (Stoner et al., 2021). 

Based on the existing policies, population growth, and investments, more than 75% of the sub-Saharan African population will use unclean cooking fuels and technologies in 2030 (Stoner et al., 2021). In Central and Southern Asia, about 25% of the population will use unclean cooking fuels and technologies by 2030 (Stoner et al., 2021).

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Table 5. Adoption trend (2013–2023).

Unit: households switching to cleaner cooking solutions/yr

mean 21,000,000
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Adoption Ceiling

The World Bank (2020) estimated that universal adoption of modern energy cooking services by 2030 is possible with an annual investment of US$148–156 billion, with 26% of the investment coming from governments and development partners, 7% from private investment, and 67% from households. Universal adoption and use of cleaner fuels and technologies is possible with an investment of US$8–10 billion/yr (IEA, 2023a; World Bank, 2020). We therefore set the adoption ceiling at 100% of households adopting and using cleaner cooking solutions, which entails 420 million households switching from unclean solutions (Table 6).

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Table 6.Cleaner cooking adoption ceiling: upper limit for new adoption of cleaner cooking solutions.

Unit: households switching to cleaner cooking solutions

mean 420,000,000
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Achievable Adoption

Universal adoption and use of cleaner cooking solutions is achievable before 2050 (Table 7). This is because if the current adoption trend continues, all households that currently use unclean cooking fuels and technologies will have switched to using cleaner versions by 2043. 

China, India, and Indonesia have shown that it is possible to rapidly expand adoption with the right set of policies and investments. In Indonesia, for example, use of cleaner cooking solutions increased from 9% of the population to 89% between 2002 and 2012 (WHO, 2025). 

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Table 7. Range of achievable adoption levels.

Unit: households switching to cleaner cooking solutions

Current Adoption 0
Achievable – Low 420,000,000
Achievable – High 420,000,000
Adoption Ceiling 420,000,000
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Cooking from all fuel types is responsible for approximately 1.7 Gt CO₂‑eq (100-yr basis) emissions every year (WHO 2023), on par with global emissions from the aviation industry (Bergero et al., 2023). Unclean cooking fuels and technologies are also the largest source of black carbon (Climate & Clean Air Coalition, 2024), a short-lived climate pollutant with a GWP several hundred times higher than CO₂ that contributes to millions of premature deaths yearly (Garland et al., 2017). 

The actual reduction in climate impact will depend upon the mix of cleaner fuel and technologies that replace unclean fuel. The IEA (2023a) estimates that if the cleanest cooking fuels and technologies (e.g., electric and LPG) are adopted, emissions could be reduced by 1.5 Gt CO₂‑eq/yr (100-yr basis) by 2030. In contrast, a greater reliance on improved cookstoves as cleaner cooking solutions will result in lower emissions reductions. The WHO (2023) estimates that much of the shift by 2030 will involve using improved biomass and charcoal cookstoves, especially in rural areas, reducing emissions 0.6 Gt CO₂‑eq/yr (100-yr basis) by 2030 and ~1.6 CO₂‑eq/yr (100-yr basis) by 2050, closely matching the IEA estimate.

According to our analysis, deploying cleaner cooking can reduce emissions by 0.98 Gt CO₂‑eq/yr (100-yr basis) between now and 2050 (Table 8). Our emissions reduction estimates are lower than those of the IEA because we do not assume that the shift to cleaner cooking will be dominated by LPG and renewables.

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Table 8. Climate impact at different levels of adoption.

Unit: Gt CO₂-eq/yr, 100-yr basis

Current Adoption 0.00
Achievable – Low 0.98
Achievable – High 0.98
Adoption Ceiling 0.98
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Additional Benefits

Air Quality and Health

Unclean cooking fuels and technologies produce household air pollution (HAP), with smoke and fine particulates sometimes reaching levels up to 100 times acceptable limits, particularly in poorly ventilated spaces (WHO, 2024b). HAP is linked to numerous health issues, such as stroke, ischemic heart disease, chronic obstructive pulmonary disease, lung cancer, and poor birth outcomes (Jameel et al., 2022). It accounts for more than 3.2 million early deaths annually (WHO 2024b). In 2019, it accounted for over 4% of all the deaths globally (Bennitt et al., 2021). The World Bank (2020) estimated that the negative health impact of unclean cooking fuels and technologies is valued at US$1.4 trillion/yr. Globally, switching to cleaner fuels and technologies could prevent 21 million premature deaths 2000–2100 (Lacey et al., 2017). A recent study offered empirical evidence of potential cardiovascular benefits stemming from household cleaner energy policies (Lee et al., 2024).

Equality

Unclean cooking disproportionately impacts women and children who are traditionally responsible for collecting fuelwood or biomass. Typically, they spend an hour every day collecting solid fuel; however, in some countries (e.g., Senegal, Niger, and Cameroon), daily average collection time can exceed three hours (Jameel et al., 2022). Time-saving cooking fuels are associated with more education in women and children (Biswas & Das, 2022; Choudhuri & Desai, 2021) and can additionally promote gender equity through economic empowerment by allowing women to pursue additional employment opportunities (CCA, 2023). In conflict zones, adoption of cleaner fuels and technologies has been shown to reduce gender-based violence (Jameel et al., 2022). Finally, cleaner cooking fuels can improve health equity as women are disproportionately exposed to indoor air pollution generated from cooking (Fullerton et al., 2008; Po et al., 2011). 

Nature protection

The unsustainable harvest of wood for cooking fuel has led to deforestation and biodiversity loss in regions such as South Asia and sub-Saharan Africa (CCA, 2022). East African nations, including Eritrea, Ethiopia, Kenya, and Uganda, are particularly affected by the rapid depletion of sustainable wood fuel resources. In the Democratic Republic of the Congo, 84% of harvested wood is charcoal or firewood (World Bank, 2018). Switching to cleaner cooking fuels and technologies can reduce deforestation and protect biodiversity (Anenberg et al., 2013; Dagnachew et al., 2018; CCA, 2022).

Income and Work

Simkovich et al. (2019) found that time gained by switching to cleaner fuel can increase daily income 3.8–4.7%. Their analysis excludes the expenses related to fuel, as well as the costs associated with delivery or transportation for refilling cleaner fuel. Mazorra et al. (2020) reported that if 50% of the time saved from not gathering firewood were redirected to income-generating activities, it could lead to an estimated annual income increase of approximately US$125 (2023 dollars) in the Gambia, US$113 in Guinea-Bissau, and US$200 in Senegal. 

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Risks

The expensive nature of cleaner cooking presents a significant barrier to adoption. Households that have recently transitioned to cleaner cooking face a high risk of defaulting back to unclean fuels and technologies. For example, among the households that received free LPG connection as a part of the Pradhan Mantri Ujjwala Yojana in India, low-income households reverted to unclean fuels and technologies during extensive periods of refill gaps (Cabiyo et al., 2020). In total, 9 million recipients could not refill their LPG cylinders even once in 2021–22 due to high LPG costs and other factors (Down to Earth 2022).

Beyond the cost, there is an adjustment period  for the households adopting the cleaner cooking solution, which includes familiarizing themselves with the technology and fostering cultural and behavioral changes, including overcoming biases and adopting new habits.

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Interactions with Other Solutions

Reinforcing

Shifting to cleaner cooking reduces the need to burn biomass and so contributes positively to protecting and restoring forests, grasslands, and savannas. 

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Dashboard

Solution Basics

1 household switching to cleaner cooking

tCO2-eq/unit/yr
2.3
units
Current 04.2×10⁸4.2×10⁸
Achievable (Low to High)

Climate Impact

GtCO2-eq/yr
Current 0 0.980.98
US$ per tCO2-eq
27
Emergency Brake

CO₂, CH₄, BC

Trade-offs

Switching to electric cooking will meaningfully reduce GHG emissions only if the grid is powered by clean energy. A life-cycle assessment of cooking fuels in India and China (Cashman et al., 2016) showed that unclean cooking fuels such as crop residue and cow dung had a lower carbon footprint than electricity because in these countries >80% of the electricity was produced by coal and natural gas. 

LPG has been the leading cleaner fuel source replacing unclean cooking fuel globally (IEA, 2023a). The IEA (2023a) estimated that 33% of households transitioning to cleaner cooking fuels and technologies will do so using LPG to transition. Because LPG is a fossil fuel, increased reliance can hinder or slow the transition from fossil fuels. 

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% population
0–15
15–30
30–45
45–60
60–75
75–100
No data

Percentage of country population relying primarily on clean cooking technologies, 2023

Access to clean cooking technology – and the benefits it confers – varies widely around the world.

World Health Organization (2025). Proportion of population with primary reliance on clean fuels and technologies for cooking (%) [Data set]. The Global Health Observatory Indicators. Retrieved May 8, 2025 from https://www.who.int/data/gho/data/indicators/indicator-details/GHO/gho-phe-primary-reliance-on-clean-fuels-and-technologies-proportion

% population
0–15
15–30
30–45
45–60
60–75
75–100
No data

Percentage of country population relying primarily on clean cooking technologies, 2023

Access to clean cooking technology – and the benefits it confers – varies widely around the world.

World Health Organization (2025). Proportion of population with primary reliance on clean fuels and technologies for cooking (%) [Data set]. The Global Health Observatory Indicators. Retrieved May 8, 2025 from https://www.who.int/data/gho/data/indicators/indicator-details/GHO/gho-phe-primary-reliance-on-clean-fuels-and-technologies-proportion

Geographic Guidance Introduction

The Deploy Clean Cooking solution applies to geographies where low-cost, inefficient, and polluting cooking methods are common. Sub-Saharan Africa is the overwhelming target, with only 23% of the population relying on clean cooking technologies (WHO, 2025). 

There are significant correlations between the lack of clean cooking solutions and levels of extreme poverty (World Bank, 2024), and the financial cost of clean fuel and cookstoves is a significant barrier to adoption (WHO, 2023).  

Some of the key benefits of deploying clean cooking will vary based on geography and landscape. For instance, freeing up time spent collecting firewood will be more notable in areas with less dense forests, since people in such locations would have to travel further to harvest the wood (Khavari et al., 2023).

Barriers to the adoption of clean cooking can also vary with geography. Examples noted by Khavari et al. (2023) include robustness of supply chains, which can be influenced by population density and road networks.

Action Word
Deploy
Solution Title
Clean Cooking
Classification
Highly Recommended
Lawmakers and Policymakers
  • Prioritize the issue at the national level to coordinate policy, coordinate resources, and ensure a robust effort.
  • Create a dedicated coordinating body across relevant ministries, agencies, and sectors.
  • Create subsidies and fuel price caps, and ban unclean cooking fuels and technologies.
  • Remove taxes and levies on clean-cooking stoves.
  • Create dedicated teams to deliver cleaner cooking equipment.
  • Run public education campaigns appropriate for the context. 

Further information:

Practitioners
  • Serve as a clean cooking ambassador to raise awareness within your industry and community.
  • Participate in training programs.
  • Develop feedback channels with manufacturers to enhance design and overcome local challenges.
  • Restaurant owners and cooks can adopt clean cooking in their kitchens to reduce emissions, lower costs, and improve worker health and safety. 

Further information:

Business Leaders

Further information:

Nonprofit Leaders
  • Ensure operations use clean cooking methods.
  • Educate the public on the benefits of clean cooking, available options, and applicable incentive programs.
  • Advocate to policymakers on issues such as targeted subsidies and providing government support.
  • Educate investors and the business community on local needs and market trends. 

Further information:

Investors

Further information:

Philanthropists and International Aid Agencies
  • Distribute cleaner cooking equipment and fuel.
  • Work with local policymakers to ensure that recipient communities can maintain fuel costs over the long term (possibly through fuel subsidies).
  • Provide grants to businesses in this sector.
  • Fund education campaigns appropriate for the context.
  • Advance political action through public-private partnerships such as the CCA. 

Further information:

Thought Leaders
  • Educate the public on the health, gender, climate, and environmental impacts of unclean cooking and the benefits of cleaner cooking.
  • Hone your message to fit the context and share through appropriate messengers and platforms.
  • Use mechanisms to promote trust, such as working with local health-care workers or other respected professionals. 

Further information:

Technologists and Researchers
  • Develop regional-specific technology that uses local sources of energy, such as biogas or high-efficiency charcoal.
  • Create technology that works with the local environment and economy and has reliable supply chains.

Further information:

Communities, Households, and Individuals
  • Learn about the benefits and harms associated with unclean fuels and technologies.
  • Identify the right technology to purchase by considering the availability and affordability of fuels; practicality of the equipment in producing the quantity, quality, and type of preferred food, and ease of use. 

Further information:

Sources

Clean cooking: An “emergency brake” climate solution. Alexander et al. (2023)

Cooking industry catalyst. CCA (n.d.)

Clean cooking industry snapshot – third edition. CCA (2022)

Why investment in clean cooking is falling short. Coldrey et al. (2023)

Modern energy cooking: review of the funding landscape. Energy 4 Impact (2022)

The clean cooking planning tool: a new resource to explore the costs and benefits of transitioning to clean cooking. Energy Sector Management Assistance Program (2022)

A vision for clean cooking access for all – analysis. IEA (2023)

Tracking SDG7: the energy progress report 2023. International Renewable Energy Agency. (2023)

Behavior change approaches for clean cooking. U.S. Agency for International Development (2015)

Evidence Base

There is a strong consensus on the effectiveness of cleaner cooking as a climate solution. Research over the past two decades (e.g., Anenberg et al., 2013; Mazorra et al., 2020; Rosenthal et al., 2017) has supported the contention that replacing solid fuel cooking with cleaner fuel reduces GHG emissions. 

There is high agreement and robust evidence that switching cooking from unclean fuels and technologies to cleaner alternatives such as burning LPG or electric stoves offers health, air quality, and climate change benefits (Intergovernmental Panel on Climate Change [IPCC], 2022).

The IPCC (2022) identified unclean fuels such as biomass as a major source of short-lived climate pollutants (e.g., black carbon, organic carbon, carbon monoxide, and methane) and switching to cleaner fuels and technologies can reduce the emission of short-lived climate pollutants.

Regional and country-level analyses provide additional evidence of the efficacy of cleaner cooking solutions. Khavari et al. (2023) reported that in sub-Saharan Africa, replacing unclean solid fuels with cleaner cooking could reduce GHG emissions by 0.5 Gt CO₂‑eq/yr (100-yr basis). Life cycle assessments comparing different cooking fuels and technologies (Afrane et al., 2011; Afrane et al., 2012; Lansche et al., 2017; Singh et al., 2014) also have shown that cleaner cooking fuels and technologies emit less GHG per unit of energy delivered than unclean fuels.

The IEA estimated that switching completely to clean cooking fuels and technologies by 2030 would result in a net reduction of 1.5 Gt CO₂‑eq/yr (100-yr basis) by 2030 (IEA, 2023a). 

The results presented in this document summarize findings from five reviews and meta-analyses and 23 original studies and reports reflecting current evidence from 13 countries, primarily in sub-Saharan Africa. 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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