Improve Livestock Grazing

Submitted by Drawdown Admin on
Sector
Nature-Based Carbon Removal
Mode
Remove Carbon
Cluster
Shift Agriculture Practices
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Peatland
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Description for Social and Search
The Improve Livestock Grazing solution is coming soon.
Methods and Supporting Data

Methods and Supporting Data

Action Word
Improve
Solution Title
Livestock Grazing
Classification
Highly Recommended
Updated Date

Deploy Agroforestry

Submitted by Drawdown Admin on
Sector
Nature-Based Carbon Removal
Mode
Remove Carbon
Cluster
Shift Agriculture Practices
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Peatland
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Description for Social and Search
The Deploy Agroforestry solution is coming soon.
Methods and Supporting Data

Methods and Supporting Data

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Action Word
Deploy
Solution Title
Agroforestry
Classification
Highly Recommended
Updated Date

Protect Seaweed Ecosystems

Submitted by Drawdown Admin on
Sector
FALO & Nature-Based Carbon Removal
Mode
Cut Emissions and Remove Carbon
Cluster
Protect & Manage Ecosystems
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Seaweed
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Summary

Seaweed ecosystem protection is the long-term protection from degradation of wild subtidal brown and red seaweed ecosystems. Seaweeds, also called macroalgae, are photosynthetic marine organisms that absorb CO₂ from the water and convert it into biomass. This can lower surface-water CO₂ concentrations, allowing additional CO₂ from the atmosphere to be dissolved in the ocean. Some of the fixed carbon can be sequestered through export to the deep sea or burial in the seafloor, while a portion may persist in forms that resist degradation even at the ocean surface. 

Protecting seaweed ecosystems can reduce a range of human impacts (wild harvesting, coastal development, overgrazing, and poor water quality) and improve resilience to other stressors (warming), which helps preserve carbon removal by the seaweed and avoid CO₂ emissions from biomass losses. 

This solution focuses on legal mechanisms of protection through the establishment of Marine Protected Areas (MPAs), which are managed with the primary goal of conserving nature. This solution does not include cultivated seaweed (see Deploy Seaweed Farming for Food).

Extreme weather events
Income & work,Food security,Equality
Nature protection,Water quality
Description for Social and Search
Protecting seaweed ecosystems is a Highly Recommended climate solution. It can likely deliver globally relevant levels of climate impact while providing additional benefits for humans and ecosystems.
Overview

Seaweeds are diverse marine photosynthetic organisms composed of three groups: brown (Phaeophyceae), green (Chlorophyta), and red algae (Rhodophyta). They can form ecosystems, such as kelp forests, and contribute to other marine ecosystems by providing habitat and food. Seaweeds are distinguished from other algae, such as phytoplankton, based on their larger size and because most are attached to substrate rather than free-floating. Seaweeds cover an estimated 600 Mha of the ocean (Duarte et al., 2022), an area that is an order of magnitude greater than the area associated with coastal wetlands (~55 Mha, see Protect Coastal Wetlands). 

This solution focuses on wild subtidal (always submerged) brown and red seaweed ecosystems, which together account for over 75% of global seaweed extent (Duarte et al., 2022) (Figure 1). We do not include green seaweeds due to their smaller extent and data limitations. We also do not include seaweeds that occur in intertidal zones, as free-floating colonies (e.g., some species of Sargassum) or are cultivated due to data limitations or coverage in other Explorer solutions (e.g., Deploy Seaweed Farming for Food).

Figure 1. Seaweed ecosystem types considered in this solution (left to right): subtidal brown (central California, USA) and subtidal red (Atlantic coast of Spain)

Two photos demonstrating seaweed ecosystem types. Left: subtidal brown. Right: subtidal red.

fdastudillo | iStock; Damocean | iStock

Seaweed ecosystems exhibit high net primary productivity (NPP) rates, comparable to those of terrestrial forests (Filbee-Dexter, 2020). Unlike many terrestrial ecosystems, however, nearly all carbon storage in seaweed ecosystems occurs as above-ground biomass, since seaweeds lack below-ground roots. A smaller amount can be buried on site in sediment (Krause-Jensen & Duarte, 2016). Most long-term carbon storage attributable to seaweeds occurs largely outside of seaweed ecosystems, through the export of carbon in dissolved and suspended forms (Figure 2). Some of this carbon reaches the deep sea, where it can persist for more than 100 years (Krause-Jensen & Duarte, 2016; Krause-Jensen et al., 2018; Ortega et al., 2019). Roughly 11.4% (25th quartile, 6.0%; 75th quartile, 13.7%) of NPP from global seaweed ecosystems is estimated to contribute to long-term carbon storage in the deep sea, equivalent to as much as 0.62 Gt CO₂‑eq/yr (173 Tg C/yr, Krause-Jensen & Duarte, 2016). While uncertain and requiring more research, recent modeling efforts support these estimates, suggesting that more than 12.5% of NPP may be removed on 100-yr timescales (Filbee-Dexter et al., 2024b).

Figure 2. Overview of a seaweed ecosystem showing carbon fluxes into and out of the ecosystem (g=gaseous, aq=aqueous) that can result in carbon removal. Some carbon is exported to the shallow sea, where it may be recycled or persist for longer periods depending on its form, some is exported to the deep sea (~1000 m), and some is buried in seafloor sediments. 

diagram illustration of seaweed ecosystem, showing carbon fluxes into and out of the ecosystem

Adapted from: Hurd, C. L., Gattuso, J.-P., & Boyd, P. W. (2024). Air-sea carbon dioxide equilibrium: Will it be possible to use seaweeds for carbon removal offsets? Journal of Phycology, 60(1), 4–14. 

Seaweed ecosystems face growing threats from a range of climate change impacts (Harley et al., 2012), such as increasing sea surface temperatures, marine heat waves, ocean acidification, and extreme storm events, as well as local drivers, such as overfishing, overgrazing, pollution, disease outbreaks, invasive species, and bottom fishing (Corrigan et al., 2025; Filbee-Dexter et al., 2024a; Hanley et al., 2024). For instance, overfishing can deplete top predators in ecosystems, leading to increases in herbivores, such as sea urchins, that overgraze seaweed (Steneck et al., 2002). 

In this solution, we calculate how legal protection of seaweed ecosystems via MPAs can reduce CO₂ emissions and preserve carbon removal through avoided ecosystem loss. In addition to preventing direct losses from impacts such as wild harvest, MPAs can help restore predator populations that keep herbivores in balance. For instance, many MPAs include no-take zones that allow predatory fish populations to recover, thereby lessening overgrazing impacts over time. MPAs can also increase the resilience of seaweed ecosystems against climate change stressors, such as marine heat waves (Kumagai et al., 2024; Ortiz-Villa et al., 2025). While some seaweed can release methane, offsetting CO₂ removal (Roth et al., 2023), we exclude this process from our analysis due to existing data limitations. We also do not consider nitrous oxide, though protection might provide additional climate benefits because enhanced nitrous oxide production has been tied to nutrient-polluted seaweed systems (Wong et al., 2021). 

We present estimates of climate impact as likely upper bounds under several key assumptions (see Appendix and Caveats), which can be improved upon as more research unfolds. We consider subtidal brown and red seaweed to be protected if they are within designated MPAs based on global datasets from UNEP-WCMC and IUCN (2024). Importantly, protection can help reduce – but will not eliminate – ecosystem loss in MPAs relative to unprotected areas (see Effectiveness). 

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Bauer, J., Beas-Luna, R., Malpica-Cruz, L., Abadía-Cardoso, A., Filz, P., Bonilla, J. C., & Lorda, J. (2025). Community-led management maintains higher predator biomass supporting kelp forests persistence in Baja California. Scientific Reports, 15(1), Article 23253. Link to source: https://doi.org/10.1038/s41598-025-86140-6

Best, R. J., Chaudoin, A. L., Bracken, M. E. S., Graham, M. H., & Stachowicz, J. J. (2014). Plant–animal diversity relationships in a rocky intertidal system depend on invertebrate body size and algal cover. Ecology, 95(5), 1308–1322. Link to source: https://doi.org/10.1890/13-1480.1

Corrigan, S., Cottier-Cook, E. J., Lim, P. E., & Brodie, J. (2025). The state of the world’s seaweeds 2025 [Data set]. Natural History Museum. Link to source: https://doi.org/10.5519/4ln9oqk7

Cotas, J., Gomes, L., Pacheco, D., & Pereira, L. (2023). Ecosystem services provided by seaweeds. Hydrobiology, 2(1), 75–96. Link to source: https://doi.org/10.3390/hydrobiology2010006

Cottier-Cook, E. J., Lim, P. E., Mallinson, S., Yahya, N., Poong, S. W., Wilbraham, J., Nagabhatla, N., & Brodie, J. (2023). Striking a balance: Wild stock protection and the future of our seaweed industries [Policy brief]. United Nations University Institute on Comparative Regional Integration Studies. Link to source: https://cris.unu.edu/sites/cris.unu.edu/files/UNU-CRIS_Policy-Brief_CottierCook_Et.al_23.06.pdf

Cuba, D., Guardia-Luzon, K., Cevallos, B., Ramos-Larico, S., Neira, E., Pons, A., & Avila-Peltroche, J. (2022). Ecosystem services provided by kelp forests of the Humboldt current system: A comprehensive review. Coasts, 2(4), 259–277. Link to source: https://doi.org/10.3390/coasts2040013

Duarte, C. M., Gattuso, J. P., Hancke, K., Gundersen, H., Filbee-Dexter, K., Pedersen, M. F., Middelburg, J. J., Burrows, M. T., Krumhansl, K. A., Wernberg, T., Moore P., Pessarrodona, A., Ørberg, S. B., Pinto, I. S., Assis, J., Queirós, A. M., Smale, D. A., Bekkby, T., Serrão, E. A., & Krause-Jensen, D. (2022). Global estimates of the extent and production of macroalgal forests. Global Ecology and Biogeography, 31(7), 1422–1439. Link to source: https://doi.org/10.1111/geb.13515

Earp, H. S., Smale, D. A., Almond, P. M., Catherall, H. J. N., Gouraguine, A., Wilding, C., & Moore, P. J. (2024). Temporal variation in the structure, abundance, and composition of Laminaria hyperborea forests and their associated understorey assemblages over an intense storm season. Marine Environmental Research, 200, Article 106652. Link to source: https://doi.org/10.1016/j.marenvres.2024.106652

Eger, A. M., Eddy, N., McHugh, T. A., Arafeh-Dalmau, N., Wernberg, T., Krumhansl, K., Verbeek, J., Branigan, S., Kuwae, T., Caselle, J. E., Ospina, A. G., & Vergés, A. (2024). State of the world’s kelp forests. One Earth, 7(11), 1927–1931. Link to source: https://doi.org/10.1016/j.oneear.2024.10.008

Eger, A. M., Marzinelli, E. M., Christie, H., Fagerli, C. W., Fujita, D., Gonzalez, A. P., Hong, S. W., Kim, J. H., Lee, L. C., McHugh, T. A., Nishihara, G. N., Tatsumi, M., Steinberg, P. D., & Vergés, A. (2022). Global kelp forest restoration: Past lessons, present status, and future directions. Biological Reviews, 97(4), 1449–1475. Link to source: https://doi.org/10.1111/brv.12850

Eger, A. M., Marzinelli, E. M., Beas-Luna, R., Blain, C. O., Blamey, L. K., Byrnes, J. E. K., Carnell, P. E., Choi, C. G., Hessing-Lewis, M., Kim, K. Y., Kumagai, N. H., Lorda, J., Moore, P., Nakamura, Y., Pérez-Matus, A., Pontier, O., Smale, D., Steinberg, P. D., & Vergés, A. (2023). The value of ecosystem services in global marine kelp forests. Nature Communications, 14(1), Article 1894. Link to source: https://doi.org/10.1038/s41467-023-37385-0

Elsmore, K., Nickols, K. J., Miller, L. P., Ford, T., Denny, M. W., & Gaylord, B. (2024). Wave damping by giant kelp, Macrocystis pyrifera. Annals of Botany, 133(1), 29–40. Link to source: https://doi.org/10.1093/aob/mcad094

Food and Agriculture Organization of the United Nations. (2024). The state of world fisheries and aquaculture 2024: Blue transformation in action [Report]. Link to source: https://doi.org/10.4060/cd0683en

Filbee-Dexter, K. (2020). Ocean forests hold unique solutions to our current environmental crisis. One Earth, 2(5), 398–401. Link to source: https://doi.org/10.1016/j.oneear.2020.05.004

Filbee-Dexter, K., & Wernberg, T. (2020). Substantial blue carbon in overlooked Australian kelp forests. Scientific Reports, 10, Article 12341. Link to source: https://doi.org/10.1038/s41598-020-69258-7

Filbee-Dexter, K., Feehan, C. J., Smale, D. A., Krumhansl, K. A., Augustine, S., de Bettignies, F., Burrows, M. T., Byrnes, J. E. K., Campbell, J., Davoult, D., Dunton, K. H., Franco, J. N., Garrido, I., Grace, S. P., Hancke, K., Johnson, L. E., Konar, B., Moore, P. J., Norderhaug, K. M., … Wernberg, T. (2022). Kelp carbon sink potential decreases with warming due to accelerating decomposition. PLOS Biology, 20(8), Article e3001702. Link to source: https://doi.org/10.1371/journal.pbio.3001702

Filbee‐Dexter, K., Starko, S., Pessarrodona, A., Wood, G., Norderhaug, K. M., Piñeiro‐Corbeira, C., & Wernberg, T. (2024a). Marine protected areas can be useful but are not a silver bullet for kelp conservation. Journal of Phycology, 60(2), 203–213. Link to source: https://doi.org/10.1111/jpy.13446

Filbee-Dexter, K., Pessarrodona, A., Pedersen, M. F., Wernberg, T., Duarte, C. M., Assis, J., Bekkby, T., Burrows, M. T., Carlson, D. F., Gattuso, J.-P., Gundersen, H., Hancke, K., Krumhansl, K. A., Kuwae, T., Middelburg, J. J., Moore, P. J., Queirós, A. M., Smale, D. A., Sousa-Pinto, I., … Krause-Jensen, D. (2024b). Carbon export from seaweed forests to deep ocean sinks. Nature Geoscience, 17(6), 552–559. Link to source: https://doi.org/10.1038/s41561-024-01449-7

Gao, G., Gao, L., Jiang, M., Jian, A., & He, L. (2022). The potential of seaweed cultivation to achieve carbon neutrality and mitigate deoxygenation and eutrophication. Environmental Research Letters, 17(1), Article 014018. Link to source: https://doi.org/10.1088/1748-9326/ac3fd9

Gibbons, E. G., & Quijón, P. A. (2023). Macroalgal features and their influence on associated biodiversity: Implications for conservation and restoration. Frontiers in Marine Science, 10, Article 1304000. Link to source: https://doi.org/10.3389/fmars.2023.1304000

González-Roca, F., Gelcich, S., Pérez-Ruzafa, Á., Vega, J. M. A., & Vásquez, J. A. (2021). Exploring the role of access regimes over an economically important intertidal kelp species. Ocean & Coastal Management, 212, Article 105811. Link to source: https://doi.org/10.1016/j.ocecoaman.2021.105811

Hanley, M. E., Firth, L. B., & Foggo, A. (2024). Victim of changes? Marine macroalgae in a changing world. Annals of Botany, 133(1), 1–16. Link to source: https://doi.org/10.1093/aob/mcad185

Harley, C. D. G., Anderson, K. M., Demes, K. W., Jorve, J. P., Kordas, R. L., Coyle, T. A., & Graham, M. H. (2012). Effects of climate change on global seaweed communities. Journal of Phycology, 48(5), 1064–1078. Link to source: https://doi.org/10.1111/j.1529-8817.2012.01224.x

Heckwolf, M. J., Peterson, A., Jänes, H., Horne, P., Künne, J., Liversage, K., Sajeva, M., Reusch, T. B. H., & Kotta, J. (2021). From ecosystems to socio-economic benefits: A systematic review of coastal ecosystem services in the Baltic Sea. Science of the Total Environment, 755, Article 142565. Link to source: https://doi.org/10.1016/j.scitotenv.2020.142565

Hurd, C. L., Gattuso, J.-P., & Boyd, P. W. (2024). Air-sea carbon dioxide equilibrium: Will it be possible to use seaweeds for carbon removal offsets? Journal of Phycology, 60(1), 4–14. Link to source: https://doi.org/10.1111/jpy.13405

Kelp Forest Alliance. (2024). State of the world’s kelp report [Report]. Link to source: https://kelpforestalliance.com/state-of-the-worlds-kelp-report/

Krause-Jensen, D., & Duarte, C. M. (2016). Substantial role of macroalgae in marine carbon sequestration. Nature Geoscience, 9(10), 737–742. Link to source: https://doi.org/10.1038/ngeo2790

Krause-Jensen, D., Lavery, P., Serrano, O., Marbà, N., Masque, P., & Duarte, C. M. (2018). Sequestration of macroalgal carbon: The elephant in the blue carbon room. Biology Letters, 14(6), Article 20180236. Link to source: https://doi.org/10.1098/rsbl.2018.0236

Krumhansl, K. A., Okamoto, D. K., Rassweiler, A., Novak, M., Bolton, J. J., Cavanaugh, K. C., Connell, S. D., Johnson, C. R., Konar, B., Ling, S. D., Micheli, F., Norderhaug, K. M., Pérez-Matus, A., Sousa-Pinto, I., Reed, D. C., Salomon, A. K., Shears, N. T., Wernberg, T., Anderson, R. J., … Byrnes, J. E. K. (2016). Global patterns of kelp forest change over the past half-century. Proceedings of the National Academy of Sciences, 113(48), 13785–13790. Link to source: https://doi.org/10.1073/pnas.1606102113

Kumagai, J. A., Goodman, M. C., Villaseñor-Derbez, J. C., Schoeman, D. S., Cavanuagh, K. C., Bell, T. W., Micheli, F., De Leo, G., & Arafeh-Dalmau, N. (2024). Marine protected areas that preserve trophic cascades promote resilience of kelp forests to marine heatwaves. Global Change Biology, 30(12), Article e17620. Link to source: https://doi.org/10.1111/gcb.17620

Lindhart, M., Daly, M. A., Walker, H., Arzeno-Soltero, I. B., Yin, J. Z., Bell, T. W., Monismith, S. G., Pawlak, G., & Leichter, J. J. (2024). Short wave attenuation by a kelp forest canopy. Limnology and Oceanography Letters, 9(4), 478–486. Link to source: https://doi.org/10.1002/lol2.10401

McCrea-Strub, A., Zeller, D., Rashid Sumaila, U., Nelson, J., Balmford, A., & Pauly, D. (2011). Understanding the cost of establishing marine protected areas. Marine Policy, 35(1), 1–9. Link to source: https://doi.org/10.1016/j.marpol.2010.07.001

Ortega, A., Geraldi, N. R., Alam, I., Kamau, A. A., Acinas, S. G., Logares, R., Gasol, J. M., Massana, R., Krause-Jensen, D., & Duarte, C. M. (2019). Important contribution of macroalgae to oceanic carbon sequestration. Nature Geoscience, 12(9), 748–754. Link to source: https://doi.org/10.1038/s41561-019-0421-8

Ortiz‐Villa, E. M., Rassweiler, A., Caselle, J. E., Cavanaugh, K. C., Arafeh‐Dalmau, N., Bell, T. W., & Cavanaugh, K. C. (2025). Marine protected areas enhance climate resilience to severe marine heatwaves for kelp forests. Journal of Applied Ecology, 62(9), 2439–2453. Link to source: https://doi.org/10.1111/1365-2664.70112

Pessarrodona, A., Franco-Santos, R. M., Wright, L. S., Vanderklift, M. A., Howard, J., Pidgeon, E., Wernberg, T., & Filbee-Dexter, K. (2023). Carbon sequestration and climate change mitigation using macroalgae: A state of knowledge review. Biological Reviews, 98(6), 1945–1971.  Link to source: https://doi.org/10.1111/brv.12990

Rodríguez-Rodríguez, D., & Martínez-Vega, J. (2022). Chapter three—Ecological effectiveness of marine protected areas across the globe in the scientific literature. In C. Sheppard (Ed.), Advances in marine biology (Vol. 92, pp. 129–153). Academic Press. Link to source: https://doi.org/10.1016/bs.amb.2022.07.002

Roth, F., Broman, E., Sun, X., Bonaglia, S., Nascimento, F., Prytherch, J., Brüchert, V., Lundevall Zara, M., Brunberg, M., Geibel, M. C., Humborg, C., & Norkko, A. (2023). Methane emissions offset atmospheric carbon dioxide uptake in coastal macroalgae, mixed vegetation and sediment ecosystems. Nature Communications, 14(1), Article 42. Link to source: https://doi.org/10.1038/s41467-022-35673-9

Steen, H., Moy, F. E., Bodvin, T., & Husa, V. (2016). Regrowth after kelp harvesting in Nord-Trøndelag, Norway. ICES Journal of Marine Science, 73(10), 2708–2720. Link to source: https://doi.org/10.1093/icesjms/fsw130

Steneck, R. S., Graham, M. H., Bourque, B. J., Corbett, D., Erlandson, J. M., Estes, J. A., & Tegner, M. J. (2002). Kelp forest ecosystems: Biodiversity, stability, resilience and future. Environmental Conservation, 29(4), 436–459. Link to source: https://doi.org/10.1017/S0376892902000322

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Thurstan, R. H., Brittain, Z., Jones, D. S., Cameron, E., Dearnaley, J., & Bellgrove, A. (2018). Aboriginal uses of seaweeds in temperate Australia: An archival assessment. Journal of Applied Phycology, 30(3), 1821–1832. Link to source: https://doi.org/10.1007/s10811-017-1384-z

United Nations Environment Programme World Conservation Monitoring Centre, & International Union for Conservation of Nature. (2024). Protected planet: The world database on protected areas (WDPA) and world database on other effective area-based conservation measures (WD-OECM) [Data set]. Retrieved April 2024, from Link to source: https://www.protectedplanet.net

United Nations Environment Programme. (2023). Into the blue: Securing a sustainable future for kelp forests [Report]. Link to source: https://wedocs.unep.org/handle/20.500.11822/42331

Waldron, A., Adams, V., Allan, J., Arnell, A., Asner, G., Atkinson, S., Baccini, A., Baillie, J. E. M., Balmford, A., Beau, J. A., Brander, L., Brondizio, E., Bruner, A., Burgess, N., Burkart, K., Butchart, S., Button, R., Carraso, R., Cheung, W., … Zhang, Y. P. (2020). Protecting 30% of the planet for nature: Costs, benefits and economic implications [Report]. Campaign for Nature. Link to source: https://www.conservation.cam.ac.uk/files/waldron_report_30_by_30_publish.pdf

Wong, W. W., Greening, C., Shelley, G., Lappan, R., Leung, P. M., Kessler, A., Winfrey, B., Poh, S. C., & Cook, P. (2021). Effects of drift algae accumulation and nitrate loading on nitrogen cycling in a eutrophic coastal sediment. Science of The Total Environment, 790, Article 147749. Link to source: https://doi.org/10.1016/j.scitotenv.2021.147749

Credits

Lead Fellow

  • Christina Richardson, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • Avery Driscoll, Ph.D.

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Avery Driscoll, Ph.D.

  • Christina Swanson, Ph.D.

  • Paul C. West, Ph.D.

Effectiveness

The globally weighted average effectiveness of seaweed ecosystem protection is 0.32 tCO₂‑eq /ha/yr. Protecting 1 ha of seaweed ecosystem avoids emissions of 0.043–0.13 tCO₂‑eq /ha/yr while also sequestering an additional 0.083–0.43 tCO₂‑eq /ha/yr, with effectiveness higher in subtidal brown than subtidal red seaweed ecosystems (100-yr GWP; Table 1; Appendix).

We estimated effectiveness as the avoided emissions and retained carbon sequestration capacity attributable to the reduction in seaweed ecosystem loss conferred by protection, as detailed in Equation 1. First, we calculated the difference between the rate of seaweed ecosystem loss outside and inside MPAs (Seaweed lossbaseline). We assumed a reduction in loss of 53% (Reduction in loss), which is based on estimates for a range of ecosystems in MPAs (Rodríguez-Rodríguez & Martínez-Vega, 2022). Importantly, this number is highly uncertain and likely to be highly variable, too. 

Next, we multiplied this product by the sum of the avoided CO₂ emissions associated with the one-time loss of all above ground biomass carbon in 1 ha of seaweed ecosystem each year over 30 years (Carbonavoided emissions) and the amount of carbon sequestered via long-term storage (on-site or off-site) in 1 ha of protected seaweed ecosystem each year over 30 years (Carbonsequestration). 

We based these rates on original analysis of a subset of studies conducted over, at least, 20 years, collated from Krumhansl et al. (2016), that show a median loss rate of 1.2% per year for kelp forests. Due to data limitations, we applied this loss rate to subtidal red seaweed ecosystems as well, but recognize that loss rates are likely to be highly variable. We did this calculation separately for red and brown seaweed ecosystems due to their distinct biomass densities and sequestration capacities, and then averaged the results with accommodations for their relative global areas.

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Equation 1.

\[ \text{Effectiveness} = \left( \text{Seaweed loss}_{\text{baseline}} \times \text{Reduction in loss} \right) \times \left( \text{Carbon}_{\text{avoided emissions}} + \text{Carbon}_{\text{sequestration}} \right) \]

Table 1. Effectiveness of seaweed ecosystem protection in avoiding emissions and sequestering carbon.

Unit: tCO₂‑eq /ha/yr, 100-year basis

Avoided emissions, estimate 0.13
Sequestration 0.43
Total effectiveness, estimate 0.56
Total effectiveness, 25th percentile 0.21
Total effectiveness, 75th percentile 0.91

Unit: tCO₂‑eq /ha/yr, 100-year basis

Avoided emissions, estimate 0.043
Sequestration 0.083
Total effectiveness, estimate 0.13
Total effectiveness, 25th percentile 0.034
Total effectiveness, 75th percentile 0.22

Unit: tCO₂‑eq /ha/yr, 100-year basis

Avoided emissions, estimate 0.080
Sequestration 0.24
Total effectiveness, estimate 0.32
Total effectiveness, 25th percentile 0.11
Total effectiveness, 75th percentile 0.52
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Cost

We estimate that seaweed ecosystem protection might save approximately US$72/tCO₂‑eq , but emphasize that these estimates are highly uncertain due to existing data limitations. This is based on protection costs of roughly US$14/ha/yr and revenue of US$43/ha/yr compared with the baseline (Table 2). The costs of seaweed ecosystem protection also include up-front one-time expenditures of US$208 (surveys, administrative setup, legal fees, etc.), estimated from McCrea-Strub et al. (2011). However, data related to the costs of seaweed ecosystem protection are limited, and these estimates are uncertain. For consistency across solutions, we did not include revenue associated with other ecosystem services. 

We estimated costs of MPA maintenance at US$14/ha/yr based on data from existing MPAs, though only 16% of MPAs surveyed reported their current funding was sufficient (Balmford et al., 2004). Maintenance is critical for seaweed ecosystems, especially those prone to overgrazing. Tourism revenues directly attributable to protection were estimated to be $43/ha/yr (Waldron et al., 2020) based on estimates for all MPAs (and PAs) and not including downstream revenues. However, estimates of tourism revenues are highly uncertain for seaweed ecosystems. In some seaweed ecosystems, such as kelp forests, tourism is likely a real revenue generator through diving or other recreational activities, but the financial contribution is generally unclear and poorly documented across all seaweed ecosystems. 

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Table 2. Cost per unit of climate impact. Negative values indicate cost savings.

Unit: 2023 US$/tCO₂‑eq , 100-yr basis

Estimate -72
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Methods and Supporting Data

Methods and Supporting Data

Learning Curve

A learning curve is defined here as falling costs with increased adoption. The costs of seaweed ecosystem 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 emergency brake, gradual, or delayed.

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

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Caveats

Additionality is an important caveat for ecosystem protection. In our analysis, we used baseline rates of seaweed ecosystem loss to calculate the effectiveness of protection, which are highly uncertain and understudied. This assumes that seaweed ecosystems would continue to be lost at these rates in the absence of protection and thus that protection provides additional carbon benefits from the ecosystems whose loss is avoided. 

Importantly, effective protection depends on adequate funding and management. Poorly managed MPAs can fail to prevent key stressors, such as urchin overgrazing, from increasing and undermine the viability of seaweed ecosystems. Similar dynamics have been documented in kelp restoration efforts, where inadequate management has led to overgrazing and project failure (Eger et al., 2022).

The permanence of ecosystem carbon benefits is another key caveat. While seaweed ecosystems are expanding or expected to expand with climate change, in some regions many will contract (Corrigan et al., 2025). Protection may increase resilience to some climate change stressors, but it will not fully prevent ecosystem loss in many regions. Additionally, because seaweed ecosystems sequester carbon both on-site and off-site, the effectiveness of protection partly depends on downstream activities. For instance, carbon at the seafloor is threatened by disturbances such as bottom fishing and mining (see Protect Seafloors). Protection of seaweed ecosystems does not prevent loss of downstream stored carbon, some of which is contributed by seaweed ecosystems (Ortega et al., 2019). Additionally, seaweed biomass extent can change dramatically from year to year, which could result in substantial variability in carbon removal rates despite protection.

Another caveat in this solution lies in our assumptions about carbon dynamics at the ocean surface. We assume that seaweed NPP results in an equivalent removal of CO₂ from the atmosphere. In reality, this influx may not be fully efficient (Hurd et al., 2024). In some regions of the ocean, water carrying a CO₂ deficit from seaweed photosynthesis might be subducted before it reaches equilibrium with the atmosphere, which would reduce the atmospheric removal attributed to seaweed productivity in our calculations.

In our analysis, avoided emissions are calculated under the assumption that destruction of a seaweed ecosystem results in the loss of all biomass carbon This likely overestimates near-term emissions, as some carbon may remain in the ocean for long periods. However, this fraction is expected to be small given that an estimated 6.0–13.7% (average: 11.4%) of NPP is thought to be stored long term (Krause-Jensen & Duarte, 2016). 

Finally, the relative fraction of NPP removed and durably stored (>100 years) is also uncertain (Pessarrodona et al., 2023). Despite this uncertainty, our use of 11.4% is supported by recent modeling of particulate carbon fluxes that suggest ~12.5% of NPP could be sequestered on a 100-year timescale (based on 44 Tg C of particulate organic carbon export to 1,000 m, where carbon is less likely to return to the atmosphere within a century, and ~353 Tg C as NPP; Filbee-Dexter et al., 2024b), but requires more research.

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Current Adoption

A total of 78.80 Mha of seaweed ecosystems are currently within MPAs (Table 3). Cumulatively, roughly 18% of seaweed ecosystems are under some form of protection, with 4% located in strictly protected MPAs, 6% in nonstrict MPAs, and 8% in other IUCN protection categories. Subtidal brown and red seaweed ecosystems have similar rates of existing protection in all protection categories (Figure 3).

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Table 3. Current (circa 2024) extent of seaweed ecosystems under legal protection. “Strict protection” includes land within IUCN categories I–II Marine Protected Areas (MPAs). “Nonstrict protection” includes land within IUCN Categories III–VI MPAs. “Other” includes land within all remaining IUCN MPA categories. Values may not sum to global totals due to rounding.

Unit: Mha protected

Strict protection 8.43
Nonstrict protection 11.4
Other 15.5
Total 35.3

Unit: Mha protected

Strict protection 9.28
Nonstrict protection 16.3
Other 18.0
Total 43.5

Unit: Mha protected

Strict protection 17.7
Nonstrict protection 27.6
Other 33.4
Total 78.8
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Adoption Trend

We calculated the rate of MPA expansion in seaweed ecosystems based on recorded year of establishment (UNEP-WCMC & IUCN, 2024). Protection expanded by a median of 0.74 Mha/yr in subtidal brown seaweed ecosystems and 0.97 Mha/yr in subtidal red seaweed ecosystems (Table 4; Figure 3a). The global average rate of expansion was roughly 2.13 Mha/yr, with a median of 1.71 Mha/yr. The adoption trend for subtidal brown and red seaweed was relatively similar, with both expanding 0.46–0.55%/yr, on average (median of 0.39–0.40%/yr) (Figure 3b).

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Table 4. 2000–2024 adoption trend. Global totals reflect independent statistics, not sums of subtidal brown and red values.

Unit: Mha/yr

25th percentile 0.40
Median (50th percentile) 0.74
Mean 1.01
75th percentile 1.31

Unit: Mha/yr

25th percentile 0.62
Median (50th percentile) 0.97
Mean 1.12
75th percentile 1.45

Unit: Mha/yr

25th percentile 1.02
Median (50th percentile) 1.71
Mean 2.13
75th percentile 2.76
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Figure 3. Trend in seaweed ecosystem protection (2000–2024) in terms of (A) total hectares protected and (B) the percent of the current adoption ceiling that is currently protected. These values reflect only the area located within Marine Protected Areas. Units: million hectares protected and percent protected relative to the adoption ceiling.

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Adoption Ceiling

We estimated that approximately 430 Mha of wild seaweed ecosystems are available for protection (Table 5). Subtidal red seaweeds compose ~240 Mha, with subtidal brown seaweeds occupying the remaining ~190 Mha. These adoption areas do not include other types of seaweed habitats/ecosystems, such as those found in the intertidal zone, rhodolith beds, Halimeda bioherms, coral reefs, and pelagic, free-floating seaweed, which could account for an additional ~150 Mha (Duarte et al., 2022). These adoption areas are highly uncertain due to data limitations and are also likely to shift with climate change.

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Table 5. Adoption ceiling: upper limit for the adoption of legal protection of seaweed ecosystems.

Unit: Mha

Estimate 189.6

Unit: Mha

Estimate 243.0

Unit: Mha

Estimate 432.6
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Achievable Adoption

We defined the lower end of the achievable range for seaweed ecosystem protection (across all IUCN categories) as 50% of the adoption ceiling and the upper end of the achievable range as 70% of the adoption ceiling (Table 6). These adoption levels are ambitious relative to existing levels of protection (~18%), but align with targets to protect 30% of ecosystems by 2030 (Eger et al., 2024) and serve as an optimistic benchmark for the 30-year time horizon considered in our analysis. Several countries already protect more than 30% of subtidal brown seaweed ecosystems, such as kelp forests (Kelp Forest Alliance, 2024). For example, the United Kingdom, Japan, China, and France protect over 41%, 68%, 68%, and 47% of their kelp beds, respectively. 
 

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Table 6: Range of achievable adoption levels for seaweed ecosystems.

Unit: Mha

Current adoption 78.8
Achievable – low 216.3
Achievable – high 302.9
Adoption ceiling 432.6
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We estimated that MPAs currently avoid emissions of 0.03 GtCO₂‑eq/yr in seaweed ecosystems, with potential impacts of 0.14 GtCO₂‑eq/yr at the adoption ceiling (Table 7). Achievable levels of seaweed ecosystem protection could safeguard 0.07 to 0.10 GtCO₂‑eq/yr by reducing emissions from biomass loss and retaining sequestration fluxes (Table 7). However, these estimates are highly uncertain and will benefit from more research (see Caveats).

Limited data exist on the potential climate impacts of seaweed ecosystem protection for comparison. However, a rough estimate of the benefits of conservation, restoration, and afforestation interventions of seaweeds suggests carbon benefits of at least 0.04 GtCO₂‑eq/yr (Pessarrodona et al., 2023). Other estimates suggest that total carbon sequestration in seaweed ecosystems could be on the order of 0.22–0.98 GtCO₂‑eq/yr (Krause-Jensen & Duarte, 2016). This is higher than our estimates because we account only for the carbon benefits of protection in seaweed ecosystems at risk of loss.

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Table 7. Climate impact at different levels of adoption. Values may not sum to global totals due to rounding.

Unit: GtCO₂‑eq/yr, 100-year basis

Current adoption 0.02
Achievable – low 0.05
Achievable – high 0.07
Adoption ceiling 0.11

Unit: GtCO₂‑eq/yr, 100-year basis

Current adoption 0.01
Achievable – low 0.02
Achievable – high 0.02
Adoption ceiling 0.03

Unit: GtCO₂‑eq/yr, 100-year basis

Current adoption 0.03
Achievable – low 0.07
Achievable – high 0.10
Adoption ceiling 0.14
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Additional Benefits

Extreme Weather Events

Seaweeds can provide coastal resilience to the impacts of storms by lowering wave heights before they reach shorelines (Corrigan et al., 2025; Cotas et al., 2023). The magnitude of this benefit can vary based on the species and location of seaweed, and some evidence suggests that severe storms can harm seaweed habitats (Earp et al., 2024). Evidence suggests that kelp forests can attenuate wave heights locally, especially in the summer at peak kelp growth, but protection varies at larger spatial scales (Elsmore et al., 2024; Lindhart et al., 2024). Emerging research has found that protected seaweed ecosystems show more resilience to marine heat waves than unprotected areas (Kumagai et al., 2024). During heat waves, protected ecosystems maintain a habitat for species such as sea urchins that consume species that might degrade kelp ecosystems (Bauer et al., 2025; Kumagai et al., 2024).

Income and Work

Seaweeds support species that are important for tourism and fishing (Cuba et al., 2022; Eger et al., 2023). Many species that are supported by seaweeds have high economic value for fishing, such as crabs, lobsters, and abalones (Corrigan et al., 2025). For example, Eger et al. (2023) estimated that 1 ha of kelp forest where about 900 kg of fish biomass is harvested could yield about US$29,900 a year. The same study estimated that the global value of kelp forests that support fisheries is about US$465–562 billion (Eger et al., 2023). Seaweed habitats can also be tourist destinations for snorkeling and diving (UNEP, 2023), providing income-earning opportunities for nearby communities.

Food Security

The contribution of seaweeds to fisheries production can play a role in global food security (Cottier-Cook et al., 2023; Eger et al., 2023). Additionally, seaweeds are an essential part of many diets, especially in East Asia (FAO, 2024). Because seaweeds are a culturally important food in many geographies, protecting seaweeds can play an important role in equitably improving global food security (FAO, 2024).

Equality

For some cultures, seaweeds and their habitats shape shared identities and livelihoods (Cotas et al., 2023). For example, seaweeds are a source of traditional foods, medicines, art, and knowledge for many coastal communities and Indigenous peoples (Thurstan et al., 2018). Protecting seaweeds can preserve the cultural identities, practices, and knowledge of Indigenous communities that are often vulnerable (Corrigan et al., 2025).

Nature Protection

Seaweeds support biodiversity by providing habitat for a variety of marine species (Best et al., 2014; Cuba et al., 2022; Gibbons & Quijón, 2023; Tano et al., 2016). Literature reviews of the ecosystem services of seaweeds find that they contribute to increases in biodiversity (Gibbons & Quijón, 2023). Seaweeds can provide habitat and refuge from large predators (Best et al., 2014; Gibbons & Quijón, 2023). Invertebrates, detritivores, and other small species found in seaweed forests are essential food sources for other marine species (Cuba et al., 2022; Tano et al., 2016). 

Water Quality

Seaweeds improve water quality by supporting nutrient cycling and reducing pollutants (Cotas et al., 2023; Heckwolf et al., 2021). Evidence suggests that seaweeds can reduce eutrophication by filtering excess nutrients from the water (Corrigan et al., 2025; Gao et al., 2022; Heckwolf et al., 2021). 

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Risks

Leakage, in which protecting one ecosystem results in the degradation of another, could offset the climate impact of seaweed ecosystem protection. For instance, restricting wild harvesting through the establishment of an MPA could shift pressure to other unprotected areas. Another key risk is weakly enforced or poorly managed MPAs. This is a real concern with existing MPAs due to a lack of funding, and can result in low protection effectiveness. Finally, climate change stressors, such as ocean warming and marine heat waves, are a major risk to permanence because they could lead to widespread mortality, even in protected areas.

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Interactions with Other Solutions

Reinforcing

Intact and healthy seaweed ecosystems can enhance fish stocks, biodiversity, and habitat quality, which benefits all connected coastal and marine ecosystems.

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Protecting seaweed ecosystems can help ensure the underlying areas of the seafloor remain intact.

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Competing

Protection of seaweed ecosystems could potentially reduce the adoption of offshore wind in some regions.

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Dashboard

Solution Basics

ha of seaweed ecosystem protected

t CO₂-eq (100-yr)/unit/yr
00.110.32estimate
units
Current 7.88×10⁷ 02.163×10⁸3.029×10⁸
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.03 0.070.1
US$ per t CO₂-eq
-72
Emergency Brake

CO₂

Trade-offs

Seaweed ecosystems can release methane, which could reduce the climate benefits of protection estimated in this solution. While data are scarce, a recent study suggests that methane emissions could offset 28–35% of the carbon sink capacity in some seaweed ecosystems (Roth et al., 2023) if they escape to the atmosphere, which may be unlikely if methane production occurs at depth in sediments (Pessarrodona et al., 2023). 

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Action Word
Protect
Solution Title
Seaweed Ecosystems
Classification
Highly Recommended
Lawmakers and Policymakers
  • Set achievable targets and pledges for seaweed protection with clear effectiveness goals; regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; incorporate statutory protections for seaweeds in existing MPAs; expand MPA designations to meet international goals.
  • Create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Seek to identify local drivers of seaweed decline, address drivers of decline through stringent legal protections, ensure strict enforcement of regulations, and allow for restoration activities.
  • When designating new MPAs, prioritize strategies such as no-take-fishing regulations and strong enforcement measures with high penalties for noncompliance; target large (>100 km2) areas that can be protected over the long term (>10 years) and are ecologically isolated by natural barriers such as deep water and/or sand.
  • Consider placing MPAs near protected or undisturbed terrestrial areas to help avoid nutrient and other land pollution.
  • Codesign seaweed protection projects with the local community; ensure the community engagement process starts early and is transparent, inclusive, and ongoing; solicit feedback from the local community – including from opposition groups – on location, design, finance, and management; ensure finalized protections address sociological, economic, and ecological considerations.
  • Coordinate seaweed protection and restoration policies horizontally (e.g., across agencies) and vertically (e.g., across subnational, national, and international efforts); seek to align social and environmental safeguards with seaweed protection policies and goals.
  • Develop regional and transboundary coordination mechanisms for seaweed protection, especially when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Ensure projects operating in or with Indigenous communities only do so under Free, Prior, and Informed Consent (FPIC); codify FPIC into legal systems.
  • Strengthen land tenure rights; grant Indigenous communities full property rights and autonomy to protect coastal areas and watersheds.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Create programs to monitor for activity and market leakage from protected sites; adjust enforcement and policies to reduce leakage, if necessary.
  • Maintain up-to-date records of seaweed harvesting and populations; monitor impacts; adjust regulations and enforcement to ensure harvesting is sustainable.
  • Remove harmful agriculture subsidies, particularly those that incentivize livestock and overuse of fertilizers that can impact seaweed habitats and MPAs.
  • Put into place locally relevant laws and regulations that help indirectly protect seaweed ecosystems, such as bans on sea otter trapping or bottom trawling.
  • Create “climate-smart” MPAs that connect seaweed ecosystems, allow for gene exchanges, and adjust boundaries to address changing oceanic conditions; target protection of taxa such as brown seaweedss that maximize climate benefits while not neglecting others such as red seaweeds; incorporate climate refugia into MPAs; create strategies for MPAs to address both climate mitigation and adaptation.
  • Invest in research on seaweed biodiversity seeking to document new species, sample from underrepresented regions, and use the most up-to-date techniques to assess taxonomies; support efforts to update key databases such as the IUCN Red List; support research to improve confidence in estimates of global seaweed ecosystem extent, biomass, composition, productivity, and loss rates; monitor related long-term trends.
  • Create educational and volunteer programs that work with schools, universities, NGOs, and the general public to inform communities how to participate in seaweed protection efforts, benefits, and opportunities; expand extension services to develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Practitioners
  • Set achievable targets and pledges for seaweed protection with clear effectiveness goals; regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long term impacts, including metrics to capture social and biodiversity impacts.
  • Establish MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; incorporate statutory protections for seaweeds in existing MPAs; expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Seek to identify local drivers of seaweed decline, address drivers of decline through stringent legal protections, ensure strict enforcement of regulations, and allow for restoration activities.
  • When designating new MPAs, prioritize strategies such as no-take-fishing regulations and strong enforcement measures with high penalties for noncompliance; target large (>100 km2) areas that can be protected over the long term (>10 years) and are ecologically isolated by natural barriers such as deep water and/or sand.
  • Create “climate-smart” MPAs that connect seaweed ecosystems, allow for gene exchanges, and adjust boundaries to address changing oceanic conditions, target protection of taxa such as brown seaweeds that maximize climate benefits while not neglecting others such as red seaweeds; incorporate climate refugia into MPAs; create specific strategies for MPAs to address both climate mitigation and adaptation.
  • Consider placing MPAs near protected or undisturbed terrestrial areas to help avoid nutrient and other land pollution.
  • Codesign seaweed protection projects with the local community; ensure the community engagement process starts early and is transparent, inclusive, and ongoing; solicit feedback from the local community – including from opposition groups – on location, design, finance, and management; ensure finalized protections address sociological, economic, and ecological considerations.
  • Develop regional and transboundary coordination mechanisms for seaweed protection - especially, when working across international borders; consider using proven methods from adjacent issue areas such as fresh-water management or combining MPA management with existing coordinating bodies.
  • Review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Maintain detailed financial records of activities related to MPA designation and management; share costs publicly and provide recommendations for best practices.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweed and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; adjust enforcement and strategies to reduce leakage, if necessary.
  • Maintain up-to-date records of seaweed harvesting and existing populations; monitor impacts; adjust regulations and enforcement to ensure harvesting is sustainable.
  • Invest in research on seaweed biodiversity seeking to document new species, sample from underrepresented regions, and use the most up-to-date techniques to assess taxonomies; support efforts to update key databases such as the IUCN Red List; support research to improve confidence in estimates of global seaweed ecosystem extent, biomass, composition, productivity, and loss rates; monitor related long-term trends.
  • Create educational and volunteer programs that work with schools, universities, NGOs, and the general public to inform communities of how to participate in seaweed protection efforts, benefits, and opportunities; expand extension services to develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Business Leaders
  • Ensure operations, development, and supply chains are not degrading seaweed communities or interfering with MPA management.
  • Develop markets for native species products and other sustainable uses of seaweed and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Consider offering company grants to suppliers or other partners to improve resource management within your supply chain.
  • Offer incubator services for those working on seaweed protection; offer pro bono business advice or general support for community protection efforts.
  • Enter into outgrower schemes to support sustainable harvesters; make long-term commitments to help stabilize projects.
  • Consider donating or contributing to local seaweed protection efforts; consider using an internal carbon fee or setting aside a percentage of revenue to fund protection projects.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support Indigenous and local communities' capacity for management, legal protection, and public relations.
  • Leverage political influence to advocate for stronger seaweed protection policies at national and international levels.
  • Offer employee professional development funds to be used for certification in seaweed protection or related fields such as curricular economies.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Nonprofit Leaders
  • Ensure operations, development, and supply chains are not degrading seaweed communities or interfering with MPA management, if relevant.
  • Assist in managing restoration projects; consider using alternative business structures such as cooperatives.
  • Develop seaweed protection tool kits specific for nations or regions; include best practices, management strategies, typical interventions, recommendations for regulations, and strategies for civil society to impact legal classifications and MPA designations.
  • Advocate for achievable targets and pledges for seaweed protection with clear effectiveness goals; help regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish or advocate for the establishment of MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; advocate for statutory protections for seaweeds in existing MPAs; help expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Seek to identify local drivers of seaweed decline, help address causes when possible, and advocate for stringent legal protections with strict enforcement.
  • Help develop or advocate for regional and transboundary coordination mechanisms for protecting seaweeds, especially when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Help review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Codesign seaweed protection projects with the local community; ensure the community engagement process starts early and is transparent, inclusive, and ongoing; solicit feedback from the local community – including from opposition groups–- on location, design, finance, and management strategies; ensure finalized protections address relevant sociological, economic, and ecological considerations.
  • Help maintain and/or audit detailed financial records of activities related to MPA designation and management; share costs publicly and provide recommendations for best practices.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; advocate to codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweed and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Help establish outgrower schemes and negotiate contracts to support sustainable harvesters to ensure they receive the most favorable terms possible.
  • Assist in maintaining up-to-date records of seaweed harvesting and existing ecosystems; monitor impacts; advocate for adjustments to regulations and enforcement to ensure harvesting is sustainable.
  • Help create educational and volunteer programs that work with schools, universities, other NGOs, and the general public to inform communities of how to participate in seaweed protection efforts, benefits, and opportunities; develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Investors
  • Create investment portfolios that support seaweed protection and sustainable use; use current data and the latest technology to guide sustainable investments.
  • Apply environmental and social standards to existing investments; divest from destructive industries and/or work with portfolio companies to improve practices.
  • Offer specific credit lines for seaweed protection projects with long-term timelines; offer low-interest loans, microfinancing, and specific financial products for small and medium-sized projects.
  • Own equity in sustainable projects that manage or support seaweed protection, especially during the early and middle phases.
  • Offer incubator services for those working on seaweed protection; offer pro bono business advice or general support for community protection projects.
  • Provide catalytic financing for businesses developing sustainable products made from native species, local ecotourism, or other sustainable uses of seaweed and MPAs.
  • Invest in blue bonds or high-integrity carbon credits for seaweed protection or supportive efforts.
  • Support seaweed protection, other investors, and NGOs by sharing data, information, and investment frameworks that successfully avoid investments that drive declines in seaweeds and damage their habitats.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Philanthropists and International Aid Agencies
  • Ensure operations, development, and supply chains are not degrading seaweed communities or interfering with MPA management, if relevant.
  • Help manage restoration projects; consider using alternative business structures such as cooperatives.
  • Offer grants or specific credit lines for seaweed protection projects with long-term timelines; offer low-interest loans, microfinancing options, and favorable financial products for small and medium-sized projects.
  • Own equity in sustainable projects that manage or support seaweed protection, especially during the early and middle phases.
  • Offer incubator services for those working on seaweed protection; offer free business advice or general support for community protection projects.
  • Provide catalytic financing for business developing sustainable products made from native species, local ecotourism, or other sustainable uses of reforested lands.
  • Develop seaweed protection tool kits specific for nations or regions; include best practices, management strategies, typical interventions, recommendations for regulations, and strategies for civil society to impact legal classifications and MPA designations.
  • Advocate for achievable targets and pledges for seaweed protection with clear effectiveness goals; help regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish or advocate for the establishment of MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting other taxa such as red seaweeds; advocate for statutory protections for seaweeds in existing MPAs; help expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Help develop or advocate for regional and transboundary coordination mechanisms for protecting seaweeds, especially when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Help review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Help maintain and/or audit detailed financial records of activities related to MPA designation and management; share costs publicly and provide recommendations for best practices.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; advocate to codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweeds and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Help establish outgrower schemes and negotiate contracts to support sustainable harvesters to ensure they receive the most favorable terms possible.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Thought Leaders
  • If possible, initiate seaweed protection projects in your area; work with local experts, share your experience, and document your progress.
  • Advocate for achievable targets and pledges for seaweed protection with clear effectiveness goals; help regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish or advocate for the establishment of MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; advocate for statutory protections for seaweeds in existing MPAs; help expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Help develop or advocate for regional and transboundary coordination mechanisms for protecting seaweeds, especially, when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Help review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; advocate to codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweeds and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Help establish outgrower schemes and negotiate contracts to support sustainable harvesters to ensure they receive the most favorable terms possible.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Technologists and Researchers
  • Help develop spatial distribution models of seaweed ecosystems combining field surveys, satellite data, and machine learning to help identify likely locations of seaweed and vulnerable ecosystems; conduct field observations to validate and/or improve models; update existing or create new databases with the information.
  • Help improve confidence in estimates of global seaweed ecosystems and monitor related long-term trends, including impacts of harvesting and adaptive capacity of seaweeds.
  • Conduct research on seaweed biodiversity seeking to document new species, sample from underrepresented regions, and use the most up-to-date techniques to assess taxonomies; help update key databases such as the IUCN Red List.
  • Help develop national seedstocks and biosecure nurseries for local and vulnerable seaweed.
  • Research the interactions of disturbances such as overfishing, eutrophication, coastal darkening, invasive species, climate change, and other related variables on seaweed ecosystems; identify loss rates and protection strategies to mitigate impacts from these events.
  • Examine and document ecosystem functions of various seaweed varieties, including their productivity and potential contributions to carbon removal; research the benefits of seaweed protection for human well-being.
  • Help classify existing MPAs according to IUCN categories; monitor ongoing efforts; use learnings to inform management.
  • Help gather accurate financial data on MPAs; assess average and global costs; provide cost projections for potential MPA sites; assess financial gains provided by MPAs, such as increased tourism and economic activity.
  • Work with Indigenous communities under FPIC to help document, examine, and apply traditional practices; help amplify relevant Indigenous knowledge.

Further information:

Communities, Households, and Individuals
  • If possible, initiate seaweed protection projects in your area; work with local experts, share your experience, and document your progress.
  • Help establish and participate in local protection efforts; consider volunteering with a local nonprofit or establishing one if none exists.
  • Conduct citizen science research to map and monitor local seaweed communities; share your findings with policymakers, local experts, and the public.
  • If seaweed communities are being damaged in your area and no action is being taken, conduct individual advocacy by speaking to local officials, handing out fliers, and other relevant methods.
  • Help identify local sources of degradation and distribute findings to policymakers and the public; help address causes when possible and advocate for stringent legal protections with strict enforcement.
  • Call on governments and administrators to use transparent, inclusive, and ongoing community engagement processes to codesign seaweed protection projects; help solicit community feedback on area designations, finance, monitoring, and distribution of benefits; help ensure finalized projects address relevant sociological, economic, and ecological considerations.
  • Reduce and/or eliminate use of chemicals on your lawn and/or property to reduce pollution runoff, especially if your property contains or is located on a coastally connected watershed; set up a sign that indicates your lawn is chemical-free.
  • Have community conversations about local seaweed habitats, MPAs, and local drivers of damage; seek to reduce harmful practices such as overuse of fertilizers and pesticides; educate friends and neighbors about local degraded seaweed habitats and potential solutions.
  • Consider donating or contributing to local protection efforts.
  • Try to purchase sustainable seaweed products that support local protection efforts.
  • When traveling, look for opportunities to support seaweed protection projects and ecotourism.
  • Advocate for strong land tenure rights; support Indigenous property rights and autonomy to protect watersheds and adjacent terrestrial systems to seaweed habitats.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPIC into legal systems.
  • Help document and develop knowledge-sharing opportunities for Indigenous and local knowledge.
  • Help create educational and volunteer programs that work with schools, universities, NGOs, and the general public to inform communities of how to participate in seaweed protection efforts, benefits, and opportunities; develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Sources
Evidence Base

Consensus of effectiveness at reducing emissions and maintaining carbon removal: Mixed

There is mixed scientific consensus that protection prevents the degradation of seaweed ecosystems, but high consensus that degradation leads to losses in biomass carbon stocks and sequestration capacity. Seaweed ecosystems can be degraded by diverse stressors that directly or indirectly affect biomass stocks. Management actions, such as establishment of MPAs, can help prevent both direct and indirect habitat loss and thereby maintain the carbon removal capacity of seaweed ecosystems with relatively high certainty against stressors such as wild harvesting, coastal development, overgrazing, and poor water quality (Pessarrodona et al., 2023). However, some stressors, such as marine heat waves and ocean warming, are less effectively addressed by protection alone (Filbee-Dexter et al., 2024a). Benefits are still expected in some systems because MPAs can enhance resilience and recovery by reducing co-occurring stressors common that contribute to seaweed ecosystem degradation (Krumhansl et al., 2016; Ortiz-Villa et al., 2025). Moreover, MPAs, even when established in areas with addressable stressors, are typically not fully effective. Here, we applied a protection effectiveness of 53%, based on aggregated estimates from MPAs beyond seaweed ecosystems (Rodríguez-Rodríguez & Martínez-Vega, 2022). If the effectiveness of protection is lower (higher), climate impacts could likewise be lower (higher).

There is high scientific consensus that degradation of seaweed ecosystems leads to losses in biomass carbon stocks and sequestration capacity. While direct estimates of CO₂ emissions from biomass are limited, degradation has been shown to remove biomass carbon and reduce sequestration. For instance, drivers of habitat loss and degradation, such as overharvesting (González-Roca et al., 2021; Steen et al., 2016), overgrazing (Akaike & Mizuta, 2024), and poor water quality (Filbee-Dexter & Wernberg, 2020), reduce standing biomass and therefore associated carbon export from seaweed ecosystems (Pessarrodona et al., 2023). 

The carbon sink capacity of seaweed ecosystems, such as kelp forests, is also expected to decline with climate change stressors such as warming, which can increase rates of decomposition by 9–42% (Filbee-Dexter et al., 2022) and drive habitat loss, both of which reduce the likelihood that carbon makes its way to the deep sea for long-term storage. Off the coast of Australia, over 140,000 ha of subtidal brown seaweed forests have already been lost to warming over two decades, representing a decline of 2–4% of regional seaweed biomass carbon stocks and sequestration capacity (Filbee-Dexter & Wernberg, 2020).

The results presented in this assessment synthesize findings from 5 global datasets. We recognize that geographic bias in the information underlying global data products creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions and on understudied aspects of these ecosystems.

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Appendix

This analysis quantifies emissions that can be avoided by protecting seaweed ecosystems via the establishment of Marine Protected Areas (MPAs). We leveraged two global seaweed distribution maps alongside a shapefile of MPAs, available data on rates of avoided ecosystem loss attributable to MPA establishment, and global data on biomass carbon stores and carbon sequestration rates to calculate climate impacts. This appendix describes the source data products and how they were integrated.

Seaweed Ecosystem Extent

We relied on the global maps of seaweed extent developed by Duarte et al. (2022), which classify subtidal brown and red seaweeds (among others). We used the “LT2 Brown Algae Benthic” raster to calculate subtidal brown seaweed extent and the “LT2 Red Algae Benthic” raster to calculate subtidal red seaweed extent. We did not consider red seaweed in subtidal brown-dominant environments, such as kelp forests, due to existing limitations with the global maps. 

Protected Seaweed Ecosystem Areas

We identified protected seaweed ecosystem areas using the World Database on Protected Areas (UNEP-WCMC & IUCN, 2024), which contains boundaries for each MPA and additional information, including the establishment year and IUCN management category (Ia to VI, not applicable, not reported, or not assigned). In this analysis, we considered all categories. While some MPA categories likely allow for wild harvest, which can be unsustainably conducted, wild seaweed harvest is currently estimated at 1.3 Mt/yr (wet weight) (FAO, 2024), which represents a relatively small portion of the global loss rate used (<0.2%/yr). We converted the MPA boundary data to a raster and used them to calculate the seaweed area within MPA boundaries for each seaweed type analyzed (subtidal brown and red) and each MPA category. To evaluate trends in adoption over time, we also aggregated protected areas by establishment year as reported in the WDPA. 

Calculation of Effectiveness

The following equations show a detailed breakdown of the stepwise set of calculations used to implement Equation 1, including estimation of avoided seaweed loss and of emissions and retained sequestration across the 30-year time horizon considered.

Avoided Seaweed Ecosystem Conversion

We compiled baseline estimates of seaweed ecosystem loss (%/yr) from existing literature and used them in conjunction with an estimate of reductions in loss associated with protection of 53% (derived from Rodríguez-Rodríguez & Martínez-Vega, 2022) to calculate the rate of avoidable macroalgae loss (Seaweed lossavoided). Seaweed ecosystem loss rates were based on the original analysis of data aggregated from Krumhansl et al. (2016) for studies over 20 years long (Seaweed lossbaseline; median loss rate of 1.2%/yr). 

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Equation A1.

\[ Seaweed\ loss_{avoided}=Seaweed\ loss_{baseline} \times Reduction\ in\ loss\]

We then used the avoidable seaweed loss rates to calculate avoided CO₂ emissions and additional carbon sequestration for each adoption unit. Specifically, we estimated the carbon benefits of avoided seaweed ecosystem loss by multiplying avoided seaweed ecosystem loss by avoided CO₂ emissions (Equation A2) and by applying carbon sequestration rates over 30 years (Equation A3) for each seaweed type. 

We estimated avoided CO₂ emissions by assuming a one-time release of all aboveground biomass carbon upon loss. We derived our estimates of retained carbon sequestration from global databases on NPP for each seaweed type from Duarte et al. (2022) and a global estimate of NPP-derived sequestration (11.4%) from NPP based on Krause-Jensen and Duarte (2016). 

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Equation A2.

\[Avoided\ emissions= Seaweed\ loss_{avoided} \times \sum_{t=1}^{30}(Emissions)\]

Equation A3.

\[Sequestration= Seaweed\ loss_{avoided} \times \sum_{t=1}^{30}(Sequestration)\]

We then estimated effectiveness (Equation A4) as the avoided CO₂ emissions and retained carbon sequestration capacity attributable to the reduction in seaweed ecosystem loss conferred by protection estimated in Equations A1–3.

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Equation A4.

\[Effectiveness = (Carbon_{avoided\ emissions}+ Carbon_{sequestration})\]
Updated Date

Restore Salt Marsh Ecosystems

Submitted by Drawdown Admin on
Sector
Nature-Based Carbon Removal
Mode
Remove Carbon
Cluster
Restore & Manage Ecosystems
Image
Salt marsh ecosystem
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Summary

Summary 

Restore Salt Marsh Ecosystems involves actively reestablishing salt marshes in areas where they were previously lost to conversion or other disturbance, allowing vegetation to regrow and carbon to accumulate in biomass and sediments. Advantages include salt marshes’ ability to durably store substantial quantities of carbon over long time periods and their numerous co-benefits for the environment and humans. Disadvantages include variable but potentially low effectiveness due to site-to-site differences in carbon removal rates and potential emissions of other GHGs, such as methane and nitrous oxide, as well as costs that might exceed US$500/t CO₂‑eq in some areas. Salt marsh restoration is not expected to have a globally meaningful climate impact (>0.1 Gt CO₂‑eq/yr ), primarily because the adoption ceiling is constrained by the limited area available for restoration, but there are no major environmental risks associated with the solution. Therefore, Restore Salt Marsh Ecosystems is “Worthwhile.”

Description for Social and Search
The Restore Coastal Wetlands solution is coming soon.
Overview

What is our assessment?

Based on our analysis, restoring salt marsh ecosystems is a “Worthwhile” carbon removal technique that is ready for large-scale deployment. While the capacity for adoption is limited, limiting climate impact, this solution has no major risks and provides widespread added benefits for people and the environment.

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

What is it?

Restore Salt Marsh Ecosystems removes carbon from the air by reestablishing salt marshes in areas where they were previously drained, filled, or otherwise degraded and lost. As plants take up CO₂ through photosynthesis and vegetation traps sediments, some of this carbon is stored long term in waterlogged soils with slow decomposition rates. Restoration typically reconnects land to tidal exchange and rebuilds marsh elevation and vegetation, which promotes plant growth and sediment accumulation. Active restoration can include breaching levees or removing barriers to restore tidal flow, regrading or adding sediment to raise elevations, planting native marsh vegetation, and controlling invasive species. In many cases, restoration can also reduce GHG emissions by replacing land uses, such as drained agriculture, that emit CO₂.

Does it work?

The fundamental idea of restoring salt marsh ecosystems is scientifically sound, and, on average globally, restored salt marshes have been shown to remove carbon over long timescales through vegetation recovery and sustained carbon burial in waterlogged soils, even after accounting for methane and nitrous oxide emissions. This solution has been in practice worldwide for many decades, and global assessments suggest it could expand to roughly 2 million hectares because ~67% of salt marshes have been destroyed since the early 1900s. Restoration success rates are high relative to those of many other marine habitats. However, its potential adoption ceiling is still low relative to other nature-based solutions (e.g., Restore Forests) because restoration is limited to suitable coastal areas, which are constrained by coastal development and other human stressors. As a result, its climate impact is likely well below 0.1 Gt CO₂‑eq /year. 

Why are we excited?

Restoration of salt marsh ecosystems is a well-established, scalable practice with many benefits for the environment. Restored salt marshes can reduce shoreline erosion and costal flooding, improve water quality by retaining nutrients and sediments, and provide habitat for fish and birds. While global impact is limited, this intervention can be an important multi-benefit tool for building climate resilience and removing carbon in some countries and coastal regions. Restoration is already widely implemented. In some restorations, such as those that reestablish tidal exchange in previously impounded ecosystems, increases in salinity can reduce methane and nitrous oxide production relative to pre-restoration conditions.

Why are we concerned?

The climate impact of salt marsh restoration is constrained by its limited adoption ceiling, variable but potentially high costs, vulnerability to future loss, and potentially low effectiveness. Adoption is limited by where marshes can actually be restored, such as on low-elevation coastal lands that are not heavily developed, and where they can be maintained into the future with climate change stressors, such as sea-level rise. If salt marshes are not restored with consideration of projected sea level rise, loss or conversion to mud flats or open water habitats in the future is possible, which would result in the loss of carbon benefits. Restored salt marshes can also emit potent GHGs such as methane and nitrous oxide as low oxygen conditions and ecosystem function are reestablished, which can offset some of the climate benefits of restoration. As a result, costs vary widely by site, and can exceed US$500/t CO₂‑eq (~US$1,000–7,000/ha), depending on site-specific effectiveness rates. Additionally, few data are available for understanding long-term, multi-decadal changes in carbon accumulation rates in restored sites, and some regions remain underrepresented globally.

Burden, A., Garbutt, A., & Evans, C. D. (2019). Effect of restoration on saltmarsh carbon accumulation in Eastern England. Biology Letters, 15(1). Link to source: https://doi.org/10.1098/rsbl.2018.0773

Convention on Wetlands. (2025). Global Wetland Outlook 2025: Valuing, conserving, restoring and financing wetlands (Scientific and Technical Review Panel report). Secretariat of the Convention on Wetlands. Link to source: https://www.ramsar.org/launch-global-wetland-outlook-2025

Danovaro, R., Aronson, J., Bianchelli, S., Boström, C., Chen, W., Cimino, R., Corinaldesi, C., Cortina-Segarra, J., D’Ambrosio, P., Gambi, C. and Garrabou, J. (2025). Assessing the success of marine ecosystem restoration using meta-analysis. Nature Communications, 16(1), 3062. Link to source: https://doi.org/10.1038/s41467-025-57254-2

Holmquist, J. R., Eagle, M., Molinari, R. L., Nick, S. K., Stachowicz, L. C., & Kroeger, K. D. (2023). Mapping methane reduction potential of tidal wetland restoration in the United States. Communications Earth & Environment, 4(1), 353. Link to source: https://doi.org/10.1038/s43247-023-00988-y

Mason, V. G., Burden, A., Epstein, G., Jupe, L. L., Wood, K. A., & Skov, M. W. (2024). Navigating research challenges to estimate blue carbon benefits from saltmarsh restoration. Global Change Biology, 30(10), 1–3. Link to source: https://doi.org/10.1111/gcb.17526

Pétillon, J., McKinley, E., Alexander, M., Adams, J.B., Angelini, C., Balke, T., Griffin, J.N., Bouma, T., Hacker, S., He, Q. and Hensel, M.J. (2023). Top ten priorities for global saltmarsh restoration, conservation and ecosystem service research. Science of the Total Environment, 898, 165544. Link to source: https://doi.org/10.1016/j.scitotenv.2023.165544

Reilly, A. V., Merrill, N. H., Mulvaney, K. K., Colarusso, P., & Burman, E. (2024). Fantastic wetlands and why to monitor them: Demonstrating the social and financial benefit potential of methane abatement through salt marsh restoration. PLOS Climate, 3(7), e0000317. Link to source: https://doi.org/10.1371/journal.pclm.0000317

Rolando, J., Hodges, M., Garcia, K., Krueger, G., Williams, N., Carr Jr, J., Robinson, J., George, A., Morris, J. and Kostka, J., (2023). Restoration and resilience to sea level rise of a salt marsh affected by dieback events. Ecosphere, 14(4), e4467. Link to source: https://doi.org/10.1002/ecs2.4467

Rowland, P. I., Wartman, M., Bursic, J., & Carnell, P. (2024). Restored and created tidal marshes recover ecosystem services over time. Environmental and Sustainability Indicators, 24, Article 100539. Link to source: https://doi.org/10.1016/j.indic.2024.100539

Taillardat, P., Thompson, B. S., Garneau, M., Trottier, K., & Friess, D. A. (2020). Climate change mitigation potential of wetlands and the cost-effectiveness of their restoration. Interface focus, 10(5). Link to source: https://doi.org/10.1098/rsfs.2019.0129

Williamson, P., Schlegel, R. W., Gattuso, J. P., Andrews, J. E., & Jickells, T. D. (2024). Climate benefits of saltmarsh restoration greatly overstated by Mason et al. (2023). Global Change Biology, 30(10). Link to source: https://doi.org/10.1111/gcb.17525

WWF UK. (2025, June 11). Vanishing saltmarshes threaten climate progress – but recovery is within reach, says new global report [Press release]. WWF UK. Link to source: https://www.wwf.org.uk/our-reports/state-worlds-saltmarshes

Credits

Lead Fellow

Christina Richardson, Ph.D.

Internal Reviewers

Christina Swanson, Ph.D.
Paul West, Ph.D.

Action Word
Restore
Solution Title
Salt Marsh Ecosystems
Classification
Worthwhile
Updated Date

Restore Peatlands

Submitted by Drawdown Admin on
Sector
Nature-Based Carbon Removal
Mode
Remove Carbon
Cluster
Restore & Manage Ecosystems
Image
Peatland
Coming Soon
On
Description for Social and Search
The Restore Peatlands solution is coming soon.
Methods and Supporting Data

Methods and Supporting Data

Dashboard
Action Word
Restore
Solution Title
Peatlands
Classification
Highly Recommended
Updated Date

Restore Grasslands & Savannas

Submitted by Drawdown Admin on
Sector
Nature-Based Carbon Removal
Mode
Remove Carbon
Cluster
Restore & Manage Ecosystems
Image
Grassland restoration area sign
Coming Soon
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Summary

Grassland and savanna restoration removes CO₂ from the atmosphere through photosynthesis as the ecosystem regrows, storing carbon in soils and vegetation. Grassland and savanna restoration faces relatively low barriers to implementation, provides substantial benefits for biodiversity, and may be deployable on large land areas. However, we currently lack sufficient information to assess whether the climate impact of grassland and savanna restoration falls above or below our threshold of globally meaningful carbon removal (>0.1 Gt CO₂‑eq/yr ), given limited data on the magnitude of its effectiveness and adoption potential. Therefore, we conclude that Restoring Grasslands and Savannas is “Worthwhile,” and will reassess the climate impact of this solution as further research is done. 

Description for Social and Search
Restore Grasslands & Savannas is a Worthwhile climate solution. It is relatively easy to implement, but data on the climate impact are limited.
Overview

What is our assessment?

Based on our analysis, grassland and savanna restoration is a promising climate solution, but there is insufficient evidence to ascertain how much carbon it could remove at the global scale. Restoring Grasslands and Savannas is therefore “Worthwhile.” 

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

What is it?

Restoring grasslands and savannas removes carbon from the atmosphere via photosynthesis and stores it in soils and vegetation. Grassland and savanna restoration includes a spectrum of practices, such as returning ecologically appropriate grazing and fire regimes, reseeding with native species, and controlling invasive and woody plants. 

Because grasslands and savannas are diverse, widespread ecosystems spanning a large climatic range, appropriate restoration and management strategies vary depending on the type of degradation and the natural history of the area. For this solution, we considered only degraded areas that were historically grassland and savanna and are not currently used as croplands or grazing lands. Other Project Drawdown solutions, including Deploy Silvopasture, Reduce Grazing Intensity, and Deploy Alternative Grazing, address increasing carbon removal in grasslands managed for grazing. Protect Grasslands & Savannas addresses protecting existing carbon stocks by reducing ongoing ecosystem degradation.

Does it work?

Grassland and savanna restoration will generally remove carbon when implemented with ecologically appropriate strategies on grasslands and savannas with depleted carbon stocks. Restoration efforts covering millions of hectares have already been initiated in some regions, though data tracking restoration progress are sparse. Although grassland and savanna restoration will remove carbon in principle, very little information is available to quantitatively assess the amount of carbon removed by restoration of degraded, ungrazed grasslands and savannas. One study in the United States found that planting diverse species on degraded grasslands increased total carbon uptake by up to 178% of that associated with natural succession over 22 years; however, the generalizability of this finding is unclear. Other studies that focused on activities outside of the scope of this solution, such as changing grazing practices, restoring croplands to grasslands, planting legumes, and adding fertilizers, found an average increase in carbon uptake rates of ~1.7 t CO₂‑eq /ha/yr with a range of 0.1–3.2 t CO₂‑eq /ha/yr. These estimates may serve as a rough benchmark of the maximum per-hectare carbon removal that grassland restoration could achieve.

Why are we excited?

Grassland and savanna restoration may be an effective, low-risk strategy for sequestering carbon on hundreds of millions of hectares while also providing substantial benefits for biodiversity and other ecosystem services. Grasslands and savannas are the largest ecosystem on Earth, covering more than 2.8 billion hectares (see Protect Grasslands & Savannas) from the tropics to the tundra. Some studies estimate that roughly half of grasslands are degraded, suggesting that the opportunity for grassland and savanna restoration is in the range of hundreds of millions of hectares even after excluding grazed areas. Grasslands and savannas also play a critical role in the global carbon cycle, containing roughly 30% of the world’s soil carbon stock. Therefore, even small relative increases in grassland and savanna carbon stocks could translate into large absolute climate benefits. Because most grassland and savanna carbon is stored in below-ground biomass and soils, these carbon stocks can be more resilient to disturbance, such as fire, than carbon stored in above-ground biomass. 

In addition to the potential climate benefits, healthy grasslands and savannas support diverse biological communities, regulate hydrology, improve water quality, reduce erosion, and provide pollination, cultural, and provisioning services to local communities. 

Why are we concerned?

While grassland and savanna restoration can consistently remove carbon, large uncertainties remain in the magnitude of the effectiveness and adoption potential of this solution. 

First, most research on the carbon removal potential of grasslands and savannas focuses on improving grazing management or conversion of croplands back to grasslands, which are outside the scope of this solution. Effectiveness at removing carbon also depends on post-restoration management because many grasslands and savannas depend on establishment of ongoing, ecologically appropriate fire and grazing regimes. Additionally, climate change is reducing grassland and savanna productivity in many regions and may prohibit successful restoration in some places. 

Second, the area of degraded, ungrazed grasslands and savannas that are restorable remains largely unknown. The definition of land degradation varies across studies, and maps of degraded lands are inconsistent with one another. While maps of grazing extent have improved, they are still uncertain. Thus, it is difficult to assess the adoption potential of this solution. Without sufficient data on effectiveness and adoption potential, we are ultimately unable to assess whether the climate impact of this solution falls above or below our threshold of 0.1 Gt CO₂‑eq/yr. We encourage additional research to alleviate data limitations related to grassland and savanna restoration.

Assis, G. B., Pilon, N. A. L., Siqueira, M. F., & Durigan, G. (2021). Effectiveness and costs of invasive species control using different techniques to restore cerrado grasslands. Restoration Ecology, 29(S1), e13219.  https://doi.org/10.1111/rec.13219

Bai, Y., & Cotrufo, M. F. (2022). Grassland soil carbon sequestration: Current understanding, challenges, and solutions. Science, 377(6606), 603–608. Link to source: https://doi.org/10.1126/science.abo2380

Bardgett, R. D., Bullock, J. M., Lavorel, S., Manning, P., Schaffner, U., Ostle, N., Chomel, M., Durigan, G., L. Fry, E., Johnson, D., Lavallee, J. M., Le Provost, G., Luo, S., Png, K., Sankaran, M., Hou, X., Zhou, H., Ma, L., Ren, W., … Shi, H. (2021). Combatting global grassland degradation. Nature Reviews Earth & Environment, 2(10), 720–735. Link to source: https://doi.org/10.1038/s43017-021-00207-2

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Veldman, J. W., Overbeck, G. E., Negreiros, D., Mahy, G., Le Stradic, S., Fernandes, G. W., Durigan, G., Buisson, E., Putz, F. E., & Bond, W. J. (2015). Where tree planting and forest expansion are bad for biodiversity and ecosystem services. BioScience, 65(10), 1011–1018. Link to source: https://doi.org/10.1093/biosci/biv118

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Credits

Lead Fellow

Avery Driscoll, Ph.D.

Internal Reviewers

Christina Swanson, Ph.D.

Paul C. West, Ph.D.

Methods and Supporting Data

Methods and Supporting Data

Action Word
Restore
Solution Title
Grasslands & Savannas
Classification
Worthwhile
Updated Date

Restore Forests

Submitted by Drawdown Admin on
Sector
Nature-Based Carbon Removal
Mode
Remove Carbon
Cluster
Restore & Manage Ecosystems
Image
person planting trees
Coming Soon
Off
Summary

Forest restoration is the process of returning previously forested land to a forested state. As forests regrow, they remove carbon from the atmosphere and sequester it in biomass.

Heat stress,Wildfires,Floods,Droughts
Income & work,Food security,Health,Equality
Nature protection,Water quality
Description for Social and Search
Restore Forests is a Highly Recommended climate solution. Diverse, healthy forests sequester carbon as biomass.
Overview

We define forest restoration as planting new trees or allowing trees to naturally regrow on previously forested land that has been cleared. Through photosynthesis, forests take carbon from the atmosphere and store it in biomass. On net, forests currently take up an estimated 11.4–14.7 Gt CO₂‑eq/yr  (Friedlingstein et al., 2023; Gibbs et al., 2025; Pan et al., 2024), equal to approximately 19–25% of total global anthropogenic GHG emissions (Dhakal et al., 2022). Restoring forests increases the size of the forest carbon sink, sequestering additional CO₂.  

As commonly defined, restoration ranges from improving management of existing ecosystems, to re-establishing cleared ecosystems, to maintaining the health of functional ecosystems. Forest restoration includes activities such as exclusion of non-native grazing animals from a regenerating site, weed management, assisted seed dispersal, controlled burning, stand thinning, direct seeding, soil amendment, tree planting, and modification of topography or hydrology and other activities (Chazdon et al., 2024; Gann et al., 2022; Kübler & Günter 2024). While acknowledging that all restoration occurs along a spectrum of intervention intensity, we report effectiveness, cost, and adoption data for “low intensity” and “high intensity” restoration separately, with “low intensity” restoration including all interventions up to, but not including, tree planting, and “high intensity” restoration referring to direct seeding or seedling planting. To account for variability in carbon sequestration rates and area available for forest restoration, this analysis also evaluates forest restoration in boreal, temperate, subtropical, and tropical regions separately where possible.

Our definition of forest restoration is more limited than that used by many other sources. First, we only include reforestation of previously forested land with an element of direct human intervention, and therefore exclude entirely passive tree regrowth on abandoned land (i.e., unassisted natural regeneration) and afforestation of native grasslands and savannas. We also exclude areas currently used for crop production. To avoid double counting, we also do not include activities covered in other Project Drawdown solutions, including increasing carbon stocks in existing forests and establishing timber plantations, agroforestry, or silvopasture (see Improve Forest Management, Deploy Biomass Crops on Degraded Land, Deploy Agroforestry, and Deploy Silvopasture, respectively). Restoration of mangroves and forests on peat soils is also excluded, as this is covered in the Restore Coastal Wetlands and Restore Peatlands solutions. Because the scope of this solution is narrower than that of many other studies, the estimated impacts are correspondingly lower as well. 

Intact and regenerating forests take up carbon, but human clearing of forests for logging, agriculture, and other activities emits carbon. Humans clear an estimated 15.5 Mha of forests annually, emitting ~7.4 Gt CO₂‑eq/yr (2001–2024; Harris et al., 2021; Gibbs et al., 2025; Sims et al., 2025). Protecting existing forests reduces emissions from deforestation (see Protect Forests) and is an essential complement to forest restoration. 

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Credits

Lead Fellow

  • Avery Driscoll, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • James Gerber, Ph.D.

  • Megan Matthews, Ph.D.

  • Paul C. West, Ph.D.

Effectiveness

We estimated that forest restoration can sequester 5.86–18.19 t CO₂‑eq /ha/yr (Table 1), depending on the climate zone and type of intervention, as growing trees take up carbon through photosynthesis and store it in above- and below-ground biomass. Sequestration rates are highly variable globally; much of this variability is driven by climate, soil properties, forest type, and the type of restoration. 

For this solution, we used modeled carbon sequestration rates from natural regeneration to represent low-intensity restoration (Robinson et al., 2025) and modeled carbon sequestration rates from plantation forests to represent high-intensity carbon restoration, which we define as initiatives that include tree planting (Bukoski et al., 2022; Busch et al., 2024). We calculated carbon sequestration rates at the climate zone level (boreal, temperate, subtropical, and tropical) across the potential extent for each reforestation type.

Generally, high-intensity restoration has higher sequestration rates (median values 12.02–18.19 t CO₂‑eq /ha/yr) than low-intensity restoration (median values 5.86–17.06 t CO₂‑eq /ha/yr). Median effectiveness is also higher in tropical areas, where forest growth often continues year-round, than it is in other climate zones. These estimates reflect average sequestration rates over the first 30 years of forest growth. Carbon sequestration rates are also influenced by non-climatic factors. For example, higher tree species diversity is often associated with higher forest carbon storage and uptake (Bialic-Murphy et al., 2024; Poorter et al., 2015; van der Sande et al., 2017).

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Table 1. Effectiveness of forest restoration at sequestering carbon.

Unit: t CO₂‑eq /ha/yr, 100-yr basis

Boreal 5.86
Temperate 11.49
Subtropical 11.53
Tropical 17.06

Unit: t CO₂‑eq /ha/yr, 100-yr basis

Boreal 14.57
Temperate 12.74
Subtropical 12.02
Tropical 18.19
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Cost

We estimated the median cost of low-intensity forest restoration at US$23/t CO₂‑eq (2023 US$) and the median cost of high-intensity forest restoration at US$83/t CO₂‑eq (Table 2). The value given in the dashboard above is the average of the low- and high-intensity cost estimates (US$53/t CO₂‑eq). 

On a per-hectare basis, the estimated cost of low-intensity restoration ranges from US$213/ha (25th percentile) to US$739/ha (75th percentile), with a median cost of US$304/ha. The estimated cost of high-intensity restoration ranges from US$811/ha (25th percentile) to US$1,914/ha (75th percentile), with a median of US$1,348/ha. We derived these estimates from compilations of global restoration project cost data by Verhoeven et al. (2024) and Busch et al. (2024), supplemented with estimates from five additional publications, representing a total of 50 unique projects.

Estimates of restoration costs remain very uncertain, as data are scarce, costs and revenues are highly variable across geographies and projects, and costs are nonlinear, tending to increase under higher adoption scenarios (Austin et al., 2020; Schimetka et al., 2024). Moreover, the success of a project at establishing new forests drives the cost per metric ton of CO₂‑eq , but such success rates are rarely reported alongside costs. Because of data limitations, we did not separate cost estimates into climate zones. 

Our estimates do not account for any new revenues associated with forest restoration, such as carbon credits or provisioning of timber and non-timber forest products (Adams et al. 2016; Ager et al., 2017; Busch et al., 2024). They also do not account for the economic value of ecosystem services, such as increased biodiversity, improved water quality, local cooling, and reduced soil erosion, which have been estimated to outweigh the costs of forest restoration (De Groot et al., 2013).

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Table 2. Cost per unit of climate impact.

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

Median 23

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

Median 83
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Methods and Supporting Data

Methods and Supporting Data

Learning Curve

We define a learning curve as falling costs with increased adoption. Reforestation has been practiced for many decades, and there is no evidence of a decrease in costs associated with increasing adoption. Therefore, 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 emergency brake, gradual, or delayed.

Restore Forests is a DELAYED climate solution. It works more slowly than gradual or emergency brake solutions. Delayed solutions can be robust climate solutions, but it’s important to recognize that they may not realize their full potential for some time.

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Caveats

Barriers to effective forest restoration include challenges around governance, financing, technical capacity (including seed and seedling supply), labor availability, and site-specific knowledge for initial restoration and long-term management (Brumberg et al., 2024; Chazdon et al., 2016; Chazdon et al., 2021; Fargione et al., 2021; Kroeger et al., 2025). Additional research and monitoring are needed to identify locally relevant restoration strategies, reduce barriers, and evaluate the success of restoration projects (Crouzeilles et al., 2019).

Forest restoration also faces challenges around permanence and additionality. Carbon stored in vegetation and soils through forest restoration can be lost to climatic and environmental stressors like wildfire, drought, heat waves, pests, or disease. Young, regenerating forests can be particularly susceptible to these types of stressors. Restored forests are also at risk of clearing (e.g., Piffer et al., 2022), so forest restoration must be coupled with long-term, effective protections against clearing. Additionality refers to the degree to which carbon uptake associated with forest restoration would have occurred in the absence of a project, policy, or incentive. Evaluating additionality is challenging in the context of natural forest regeneration, some of which simply arises from land abandonment without any intervention.

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Current Adoption

Data on current adoption of forest restoration are very limited. While there are extensive compilations of restoration pledges, estimates of the actual area being restored are noncentralized, typically rely on self-reporting without validation, do not have global coverage, use inconsistent definitions, often include establishment of plantations and agroforestry, and rarely separate estimates by ecosystem. Satellite-based data on tree cover gain are occasionally used as a proxy for restoration, but these do not differentiate among restoration, establishment of timber plantations, regeneration in the absence of human intervention, and plantation regrowth after timber harvest (Reytar et al., 2024). Moreover, they can fail to capture actual restoration areas (Begliomini & Brancalion, 2024).

Due to these limitations, we do not provide an estimate of the global area currently under forest restoration. However, we did compile current restoration estimates from three databases: The Mongabay Reforestation Catalog, The Restoration Initiative, and The Restoration Barometer. These databases are subject to the limitations discussed above. Assuming that there is no overlap in projects reported across these databases, including projects with an agroforestry component, and including projects across all ecosystems, we found 40.6 Mha currently being restored. Under more conservative assumptions, including removing projects with an agroforestry component, removing projects from countries that are reported across multiple databases, and discounting estimates to account for restoration in other ecosystems, we estimated that 9.2 Mha are currently being restored. These estimates provide context, but should not be interpreted as representative of the global area under forest restoration.

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Adoption Trend

Despite extensive data on restoration pledges, comprehensive data on the actual implementation of restoration efforts are very limited and not often temporally resolved. The available data are insufficient to calculate an adoption trend for this solution.

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Adoption Ceiling

We estimated that there are 96.8 Mha available for forest restoration, with 19.4 Mha in boreal regions, 19.0 Mha in temperate regions, 3.5 Mha in the subtropics, and 54.8 Mha in the tropics (Table 3a–e). In this solution, we only included cleared areas that were previously forests in the calculation of the adoption ceiling. To calculate the adoption ceiling, we started with a recent, conservative map of potential forest restoration areas (Fesenmeyer et al., 2025), which we masked to exclude areas classified as other ecosystems in other solutions (peatlands, grasslands and savannahs, and coastal wetlands). We then used a map of the cost-effectiveness of natural regeneration versus plantation establishment (Busch et al., 2024) to remove areas more suitable for plantation establishment from this solution, and assigned them instead to the Deploy Biomass Crops on Degraded Land solution.

Estimates of the area available for forest restoration vary widely due to differing definitions, ranging from 195 Mha (Fesenmeyer et al., 2025) to 900 Mha (Bastin et al., 2019), for example. Using base maps of forest restoration potential from Griscom et al. (2017) and Walker et al. (2022) gave an estimated global adoption ceiling of 426–434 Mha, after applying the same data processing approach to exclude other ecosystems and plantations. 

Because of the constrained scope of this solution, we find a smaller adoption ceiling relative to other studies, which often include plantation establishment, agroforestry, densification of existing forests, afforestation on grasslands, restoration of forests on peat soils, reforestation of croplands, and other activities sometimes classified as forest restoration. We leveraged the map from Fesenmeyer et al. (2025) for the estimates reported in Table 3 because its scope aligns most closely with our relatively narrow definition of forest restoration, is one of the most recent studies, includes a review of 89 other forest restoration maps, and incorporates safeguards against conflicts between restoration and biodiversity loss, water scarcity, albedo effects, and land use. However, we note that this estimate is lower than other published estimates of potential forest restoration area and that differences across studies are driven by subjective judgments on land suitability for restoration.

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Table 3. Adoption ceiling.

Unit: ha available for restoration

Estimate 19,400,000

Unit: ha available for restoration

Estimate 19,000,000

Unit: ha available for restoration

Estimate 3,500,000

Unit: ha available for restoration

Estimate 54,800,000

Unit: ha available for restoration

Estimate 96,800,000
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Achievable Adoption

We assigned an arbitrary achievable range of 50–75% of the adoption ceiling, equal to 48.4–72.6 Mha of forest restoration (Table 4a–e). Much of the adoption potential is located in the tropics, which we estimated to contain 27.4 Mha under the Achievable – Low Scenario and 41.1 Mha under the Achievable – High Scenario. We estimated similar achievable ranges of forest restoration area in boreal and temperate regions (9.7–14.6 Mha and 9.5–14.3 Mha, respectively), and an additional 1.7–2.6 Mha in subtropical regions.

Additional research is needed to determine more realistic estimates of the achievable adoption range, particularly differentiated across different restoration activities. National commitments to restoration, as with studies on the potential restoration area, include many activities that are beyond the scope of this solution, such as plantation establishment, agroforestry, and densification. Because of the inconsistency in definitions, we were unable to rely on restoration commitments to quantify the adoption achievable range. For context, the Global Restoration Commitments database (Mariappan & Zumbado, 2024) reports that, under the Rio Conventions, countries have committed to increasing forestland by 122 Mha, with an additional 154 Mha of commitments to restoring or improving forestland. Similarly, 210.1 Mha of land have been pledged for restoration across all ecosystems under the Bonn Challenge (Mariappan & Zumbado, 2024).

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Table 4. Range of achievable adoption levels.

Unit: ha

Current adoption NA
Achievable – low 9,700,000
Achievable – high 14,600,000
Adoption ceiling 19,400,000

Unit: ha

Current adoption NA
Achievable – low 9,500,000
Achievable – high 14,300,000
Adoption ceiling 19,000,000

Unit: ha

Current adoption NA
Achievable – low 1,700,000
Achievable – high 2,600,000
Adoption ceiling 3,500,000

Unit: ha

Current adoption NA
Achievable – low 27,400,000
Achievable – high 41,100,000
Adoption ceiling 54,800,000

Unit: ha

Current adoption NA
Achievable – low 48,400,000
Achievable – high 72,600,000
Adoption ceiling 96,800,000
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We estimated that forest restoration could sequester 0.718 Gt CO₂‑eq/yr at the low-achievable adoption scenario, 1.077 Gt CO₂‑eq/yr at the high-achievable adoption scenario, and 1.437 Gt CO₂‑eq/yr at the adoption ceiling (Table 5a–e). Nearly 70% of the total climate impacts under these scenarios occur in tropical regions, where much of the current investment in restoration is focused.

Our climate impact estimates are lower than existing literature estimates due to our more constrained definition of this solution. Existing estimates also vary widely. For example, Cook-Patton et al. (2020) estimated that fully implemented national forest restoration commitments as of 2020 would take up 5.9 Gt CO₂‑eq/yr, while the Intergovernmental Panel on Climate Change (IPCC) reported an economically feasible mitigation potential of 1.6 Gt CO₂‑eq/yr (Nabuurs et al., 2022), and Griscom et al. (2017) reported a technical mitigation potential of 10.1 Gt CO₂‑eq/yr. Recently, Wang et al. (2025) estimated an upper-end mitigation potential of 5.85 Gt CO₂‑eq/yr (including afforestation and plantation establishment), with current commitments across all of these activities projected to take up 1.8 Gt CO₂‑eq/yr. Discrepancies between estimates are driven by the area considered suitable for restoration, types of restoration activities considered and their associated carbon uptake rates, and inclusion of cost constraints. Each of these individual estimates is also associated with substantial uncertainty, and further work is needed to standardize definitions of forest restoration and constrain the range of impact estimates.

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Table 5. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-year basis

Current adoption NA
Achievable – low 0.099
Achievable – high 0.149
Adoption ceiling 0.198

Unit: Gt CO₂‑eq/yr, 100-year basis

Current adoption NA
Achievable – low 0.115
Achievable – high 0.173
Adoption ceiling 0.230

Unit: Gt CO₂‑eq/yr, 100-year basis

Current adoption NA
Achievable – low 0.020
Achievable – high 0.031
Adoption ceiling 0.041

Unit: Gt CO₂‑eq/yr, 100-year basis

Current adoption NA
Achievable – low 0.483
Achievable – high 0.725
Adoption ceiling 0.966

Unit: Gt CO₂‑eq/yr, 100-year basis

Current adoption NA
Achievable – low 0.718
Achievable – high 1.077
Adoption ceiling 1.437
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Additional Benefits

Heat Stress

Forests help regulate local climate by reducing temperature extremes (Lawrence et al., 2022; Walton et al., 2016). Zhang et al. (2020) found the land surfaces of restored forests were 1–2 °C cooler than grasslands.

Extreme Weather Events

Forest restoration can improve biodiversity and health of the ecosystem, leading to more ecological resilience (DeGroot et al., 2013; Hua et al., 2022). Restored forests can intercept rainfall and attenuate flood risk during extreme rainfall events (Kabeja et al., 2020; Gardon et al., 2020). In some climates, certain reforestation methods could increase ecosystem resilience to wildfires (North et al., 2019).

Floods

For a description of the flood benefits, please refer to the “Extreme Weather Events” subsection. 

Droughts

Forest restoration may increase or decrease the ecosystem’s resilience to drought, depending on changes in factors such as evapotranspiration, precipitation, and water storage in vegetation (Andres et al., 2022; Sankey et al., 2020; Teo et al., 2022). For example, Teo et al. (2022) found that reforestation of degraded lands reduced the probability of experiencing extremely dry conditions in water-insecure regions of East Asia.

Income and Work

Forest restoration creates both temporary and permanent job opportunities, especially in rural areas (DeGroot et al., 2013). A study in Brazil found that restoration can generate about 0.42 jobs per hectare of forest undergoing restoration (Brancalion et al., 2022). Restoration of forests may also improve livelihoods and income opportunities based on the ecosystem services the forest provides. While these benefits vary substantially with household and community characteristics, in general, they include income diversification and the availability of food and fiber from forests (Adams et al., 2016). For example, in Burkina Faso, smallholders who restored lands through assisted regeneration diversified their income by harvesting resources such as fodder for livestock and small wildlife (Kumar et al., 2015). 

Food Security

Forests provide income and livelihoods for subsistence households and individuals (de Souza et al., 2016; Herrera et al., 2017; Naidoo et al., 2019). Forest restoration may improve food security for some households by improving incomes and livelihoods.

Health

Reforestation may promote the health of nearby communities. 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. Biodiverse forests are linked to a reduced risk of animal-to-human infections because zoonotic hosts tend to be less abundant in less disturbed ecosystems (Keesing & Ostfeld, 2021; 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), and restoring the health and function of forests is essential for protecting indigenous cultural values and practices. Indigenous communities provide vital ecological functions for preserving landscape health, such as seed dispersal and predation (Bliege Bird & Nimmo, 2018). Indigenous peoples also have spiritual and cultural ties to their lands (Garnett et al., 2018). Restoration must be implemented using an equity-centered approach that reduces power imbalances between stakeholders, ensures people are not displaced, and involves local actors (Löfqvist et al., 2023).

Nature Protection

Forests are home to a wide range of species and habitats and are essential for safeguarding biodiversity. Reforestation of native forests increases the biodiversity of an ecosystem relative to its previous cleared state (Brancalion et al., 2025; Hua et al., 2022). While many factors, such as the restoration method, time since restoration, and biophysical conditions, can impact restoration, studies of reforestation report increases in biodiversity and more species abundance after restoration, though the biodiversity typically remains below that of intact forests (Crouzeilles et al., 2016; Hua et al., 2022).

Water Quality

The impacts of reforestation on water quality vary based on factors such as geography and time since undergoing restoration (Dib et al., 2023). In general, forests act as natural water filters, maintaining and improving water quality (Dib et al., 2023; Melo et al., 2021). Restoration of forests is associated with improved water quality in streams compared with their previously degraded state (dos Reis Oliveira et al., 2025).

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Risks

Forest restoration initiatives that are not responsive to local socioeconomic conditions risk displacing community land access and compromising local livelihoods. Effective forest restoration activities can be highly diverse, but must be targeted towards local environmental, sociopolitical, and economic conditions (Stanturf et al., 2019). 

If forest restoration encroaches on agricultural lands, it can trigger clearing of forests elsewhere to replace lost agricultural production. 

Planting trees in areas where they do not naturally occur, such as in grasslands and savannas, can alter hydrologic cycles and harm biodiversity (Veldman et al., 2015a; Veldman et al., 2015b). The estimates of potential forest restoration area that we use in this analysis are constrained to minimize these risks by including only land that was once forested and not allowing for forest restoration on croplands or in urban areas.

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Interactions with Other Solutions

Reinforcing

Forest restoration can improve the health and function of adjacent ecosystems that are being protected or restored.

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Competing

These solutions are all suitable to implement on degraded land, and thus are in competition for the available degraded land.

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Dashboard

Solution Basics

ha under restoration

t CO₂-eq (100-yr)/unit/yr
09.4410.21median
units
Current Not Determined 09.7×10⁶1.46×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current Not Determined 0.0990.149
US$ per t CO₂-eq
53
Delayed

CO₂

Solution Basics

ha under restoration

t CO₂-eq (100-yr)/unit/yr
010.1612.11median
units
Current Not Determined 09.5×10⁶1.43×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current Not Determined 0.1150.173
US$ per t CO₂-eq
53
Delayed

CO₂

Solution Basics

ha under restoration

t CO₂-eq (100-yr)/unit/yr
09.6811.78median
units
Current Not Determined 01.7×10⁶2.6×10⁶
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current Not Determined 0.0210.031
US$ per t CO₂-eq
53
Delayed

CO₂

Solution Basics

ha under restoration

t CO₂-eq (100-yr)/unit/yr
014.6717.63median
units
Current Not Determined 02.74×10⁷4.11×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current Not Determined 0.4830.725
US$ per t CO₂-eq
53
Delayed

CO₂

Trade-offs

Forest restoration can divert resources from other climate solutions, including protecting intact forests. Humans clear approximately 0.4% of forests annually (Curtis et al., 2018; Hansen et al., 2013; Sims et al., 2025), and halting further deforestation is an urgent priority with huge benefits for the climate, biodiversity, and other ecosystem services (see Protect Forests). While restoration provides carbon sequestration over a period of decades, preventing deforestation reduces emissions immediately and is typically more cost-effective. Restoration should therefore complement, rather than compete with, efforts to reduce deforestation.

Forest restoration can also decrease the albedo, or reflectivity, of Earth’s surface. This can increase temperatures as more of the sun’s energy is absorbed and reradiated as thermal energy. Albedo effects are most pronounced in boreal and dryland regions, where they reduce the net climate benefits of forest restoration (Hasler et al., 2024).

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Action Word
Restore
Solution Title
Forests
Classification
Highly Recommended
Lawmakers and Policymakers
  • Set achievable targets and pledges for forest restoration with clear effectiveness goals; regularly measure and report on restoration progress, area under restoration, challenges, and related data points.
  • Help develop definitions at the international level for forest restoration and degradation along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Ensure public procurement uses deforestation-free products and sustainable products from reforested areas.
  • Create strong regulatory frameworks with clear definitions for active and passive restoration and/or related terms such as reforestation, regeneration, improving forest functionality, and increasing forest cover; ensure the framework is gender responsive and seeks to include women throughout the restoration process.
  • Coordinate forest protection and restoration policies horizontally (e.g., across agencies) and vertically (e.g., across subnational, national, and international efforts); seek to align social and environmental safeguards with protection and reforestation policies and goals.
  • Develop regional and transboundary coordination mechanisms for protection and restoring forests, especially, when working across international borders; consider using coordination methods from adjacent issue areas such as water management and/or working closely with existing coordination bodies for relevant watersheds.
  • Prioritize forest protection first and restoring forests second; ensure areas under restoration are classified as protected lands.
  • Create financial incentives for both active and passive restoration techniques, such as direct payments, payment for ecosystem services (PES), property tax breaks, rebates, subsidies, and cash prizes for meeting tree and/or vegetative growth metrics; ensure incentives allow for long timelines; provide similar incentives to reduce fertilizer use; ensure equitable access to incentives for low- and middle-income communities.
  • Provide financial incentives for businesses that support restoration by developing sustainable products.
  • Create disincentives by taxing or fining land clearance, deforestation, poor land management, and agricultural pollution.
  • Remove harmful agriculture and logging subsidies, particularly those that incentivize livestock, biofuels, land encroachment, and overuse of fertilizers.
  • Seek to designate lands for reforestation that are adjacent to or connect with already protected areas, intact lands, and/or watersheds.
  • Delegate the authority to allocate direct payments for fiscal incentives to local governments.
  • Use tax revenues from extractive industries to pay for restoration.
  • Use taxes from beneficiaries of forest services to pay for nearby restoration (e.g., use taxes from downstream users to improve practices upstream); before instituting such a tax regime, consult with stakeholders, clearly define tax arrangements, and put into place strict enforcement measures.
  • Create an ongoing, equity-centered community engagement process; ensure local communities help shape local projects and receive benefits.
  • Strengthen land and tree tenure rights; grant Indigenous communities’ full property rights and autonomy.
  • Ensure projects operating in or with Indigenous communities only do so under free, prior, and informed consent (FPIC); codify FPIC into legal systems.
  • Ensure regulations allow and encourage a variety of legal models for reforestation efforts, such as cooperatives.
  • Prioritize reducing food loss and waste and improving diets.
  • Invest in R&D to identify best practices, where reforestation is viable, and how to improve the local enabling environment(s).
  • When possible, use social science research to determine the best interventions, incentives, and community engagement models before beginning restoration projects.
  • Create programs to monitor for activity and market leakage from reforestation sites; adjust enforcement and policies to reduce leakage, if necessary.
  • Foster national pride for the natural landscape and reforestation efforts through communication campaigns.
  • Work with public universities and other educational institutions to develop degree and certification programs in forest restoration; encourage them to offer subspecialities, such as protected lands governance, management, policy, and finance.
  • Create educational programs that work with schools, universities, NGOs, and the general public to inform communities how to participate in restoration efforts, benefits, and opportunities; expand extension services to develop local capacity in forest restoration, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify restoration activity and sustainable use of forest products.

Further information:

Practitioners
  • Set achievable targets and pledges for forest restoration with clear effectiveness goals.
  • Help develop regulatory frameworks with clear definitions for active and passive restoration and/or related terms such as reforestation, regeneration, improving forest functionality, and increasing forest cover; ensure the framework is gender responsive and seeks to include women throughout the restoration process.
  • Help develop definitions at the international level for forest restoration and degradation along with frameworks for measurement and monitoring; design indicators to capture long term impacts, including metrics to capture social and biodiversity impacts.
  • Help develop or advocate for regional and transboundary coordination mechanisms for restoring forests, especially, when working across international borders; consider using coordination methods from adjacent issue areas such as water management and/or working closely with existing coordination bodies for relevant watersheds.
  • Offer or take advantage of financial incentives such as direct payments or PES; if necessary, advocate for public incentives for both active and passive restoration, such as property tax breaks, rebates, subsidies, and cash prizes for meeting tree and/or vegetative growth metrics; help ensure incentives allow for long timelines; help ensure equitable access to incentives for low- and middle-income communities.
  • Seek to designate lands for reforestation that are adjacent to or connect with already protected areas, intact lands, and/or watersheds.
  • Create an ongoing, equity-centered community engagement process; ensure local communities help shape local projects and receive benefits.
  • Advocate for strong land and tree tenure rights; support Indigenous property rights and autonomy.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPICinto legal systems.
  • Help create high-integrity carbon markets with long durations; use dynamic baselines for more accurate additionality assessments.
  • Create programs to monitor for activity and market leakage from reforestation sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Develop markets for native species products and other sustainable uses of reforested lands.
  • Develop or support opportunities for ecotourism industries in locally restored forests.
  • Explore and use alternative legal models for reforestation, such as cooperatives.
  • Invest in R&D to identify best practices, where reforestation is viable, and how to improve the local enabling environment(s).
  • When possible, use social science research to determine the best interventions, incentives, and community engagement models before beginning restoration projects.
  • Help foster pride for natural landscape and reforestation efforts through communication campaigns.
  • Work with educational institutions to develop degree and certification programs in forest restoration; encourage them to offer subspecialities such as protected lands governance, management, policy, and finance.
  • Create educational programs that work with schools, NGOs, and the general public to inform communities how to participate in restoration efforts, benefits, and opportunities; advocate for expanded extension services to develop local capacity in forest restoration, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify restoration activity and sustainable use of forest products.

Further information:

Business Leaders
  • Create deforestation-free supply chains, using data, information, and the latest technology to inform product sourcing.
  • Develop markets and supply chains for native species products; innovate other sustainable uses for resources from reforested lands.
  • Integrate deforestation-free business and investment policies and practices into your net-zero strategies.
  • Develop or support opportunities for ecotourism in restored forests.
  • Offer company grants to suppliers or others to improve resource management and support reforestation within your supply chain.
  • Offer incubator services for those restoring forests; offer pro bono business advice or general support for community restoration projects.
  • Enter into outgrower schemes to support smallholder farmers restoring their land; make long-term commitments to help stabilize projects.
  • Contribute to local restoration efforts; use an internal carbon fee or set aside a percentage of revenue to fund reforestation.
  • Only purchase carbon credits from high-integrity, verifiable carbon markets, and do not use them as replacements for reducing emissions.
  • Help create high-integrity carbon markets with long durations; use dynamic baselines for additionality assessments.
  • Help shift the public narrative around carbon markets as integrity increases to boost education, dialogue, and awareness.
  • Develop financial instruments to invest in reforestation, focusing on supporting Indigenous communities.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Offer employee professional development funds to be used for certification in reforestation or related fields such as curricular economies.
  • Create company volunteer opportunities such as annual-tree planting days; consider partnering with a relevant local non-profit.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify restoration activity and sustainable use of forest products.

Further information:

Nonprofit Leaders
  • Use deforestation-free products and sustainable products from reforested areas.
  • Help manage restoration projects; consider using alternatives to corporate business structures such as cooperatives to facilitate management and legal structures.
  • Advocate for achievable public targets and pledges for forest restoration with clear effectiveness goals.
  • Help develop regulatory frameworks with clear definitions for active and passive restoration and/or related terms such as reforestation, regeneration, improving forest functionality, and increasing forest cover; ensure the framework is gender responsive and seeks to include women throughout the restoration process.
  • Help develop definitions at the international level for forest restoration and degradation along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including social and biodiversity impacts.
  • Help develop or advocate for regional and transboundary coordination mechanisms for restoring forests, especially, when working across international borders; consider using coordination methods from adjacent issue areas such as water management and/or working closely with existing coordination bodies for relevant watersheds.
  • Offer or take advantage of financial incentives such as direct payments or PES; if necessary, advocate for public incentives such as property tax breaks, rebates, subsidies, and cash prizes for meeting tree and/or vegetative growth metrics; help ensure incentives allow for long timelines; help ensure equitable access to incentives.
  • Seek to designate lands for reforestation that are adjacent to or connect with already protected areas, intact lands, and/or watersheds.
  • Advocate to remove harmful agriculture and logging subsidies, particularly those that incentivize livestock, biofuels, land encroachment, and overuse of fertilizers.
  • Call on governments and administrators of reforestation projects to use transparent, inclusive, and ongoing community engagement processes to co-design restoration projects; help solicit community feedback on area designations, finance, monitoring, and distribution of benefits; help ensure projects address relevant sociological, agricultural, and ecological considerations.
  • Advocate for strong land and tree tenure rights; support Indigenous property rights and autonomy.
  • Ensure projects operating in or with Indigenous communities only do so under FIPC; help codify FIPC into legal systems.
  • Help create high-integrity, long-lasting carbon markets; use dynamic baselines for more accurate additionality assessments.
  • Help monitor reforestation projects for success metrics such as vegetative growth, biodiversity, and water quality using high-resolution data and active remote sensing if possible.
  • Help translate reforestation materials into locally relevant languages.
  • Conduct cost-benefit analyses of potential local interventions to identify optimal strategies.
  • Develop markets and supply chains for native species products; innovate other sustainable uses for resources from reforested lands.
  • Develop or support opportunities for ecotourism in restored forests.
  • Facilitate investment in reforestation; create economic models to help maintain long-term financing; identify priorities for financing and help distribute incentives.
  • Help identify local sources of degradation and distribute findings to policymakers and the public; document and share best practices for reforestation.
  • Help establish outgrower schemes and negotiate favorable contracts for smallholder farmers.
  • Create programs to monitor for activity and market leakage from reforestation sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Support high-integrity carbon markets, institutions, rules, and norms to cultivate demand for high-quality carbon credits.
  • Help shift the public narrative around carbon markets as integrity increases to boost education, dialogue, and awareness.
  • 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, administration, and public relations.
  • When possible, use social science research to determine the best interventions, incentives, and community engagement models before beginning restoration projects.
  • Help foster national pride for the natural landscape and reforestation efforts through communication campaigns.
  • Work with educational institutions to develop degree and certification programs in forest restoration; encourage them to offer subspecialities such as protected lands governance, management, policy, and finance.
  • Create educational programs that work with schools, NGOs, and the general public to inform communities how to participate in restoration efforts, benefits, and opportunities; advocate for expanded extension services to develop local capacity in forest restoration, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify restoration activity and sustainable use of forest products.

Further information:

Investors
  • Create deforestation-free investment portfolios.
  • Apply environmental and social standards to existing investments; divest from destructive industries and/or work with portfolio companies to improve practices.
  • Offer specific credit lines for reforestation projects with long-term timelines; offer low-interest loans, microfinancing, and specific financial products for medium-sized projects.
  • Own equity in sustainable projects that manage or support reforestation, especially during the early and middle phases.
  • Offer incubator services for those working on forest restoration projects; offer pro bono business advice or general support for community restoration projects.
  • Offer insurance and risk mitigation products for reforestation projects, especially, to farmers transitioning their lands.
  • Provide catalytic financing for businesses developing sustainable products made from native species, ecotourism, or other sustainable uses of reforested lands.
  • Invest in green bonds or high-integrity carbon credits for reforestation.
  • Support reforestation, other investors, and NGOs by sharing data, information, and investment frameworks that successfully avoid investments that drive deforestation.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.

Further information:

Philanthropists and International Aid Agencies
  • Use deforestation-free products and sustainable products from reforested areas.
  • Offer grants or credit lines for reforestation projects with long-term timelines; offer low-interest loans, microfinancing options, and favorable financial products for medium-sized projects.
  • Own equity in sustainable projects that manage or support reforestation, especially during the early and middle phases.
  • Offer incubator services for those working on forest restoration; offer pro bono business advice or general support for community restoration projects.
  • Offer insurance and risk mitigation products for reforestation projects, especially, to farmers transitioning their lands.
  • Provide catalytic financing for businesses developing sustainable products made from native species, local ecotourism, or other sustainable uses of reforested lands.
  • Advocate for achievable public targets and pledges for forest restoration with clear effectiveness goals.
  • Help develop regulatory frameworks with clear definitions for active and passive restoration and/or related terms such as reforestation, regeneration, improving forest functionality, and increasing forest cover; ensure the framework is gender responsive and seeks to include women throughout the restoration process.
  • Help develop definitions at the international level for forest restoration and degradation along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Help develop or advocate for regional and transboundary coordination mechanisms for restoring forests, especially, when working across international borders; consider using coordination methods from adjacent issue areas such as water management and/or working closely with existing coordination bodies for relevant watersheds.
  • Offer or take advantage of financial incentives such as PES; if necessary, advocate for public incentives for both active and passive restoration techniques such as property tax breaks, rebates, subsidies, and cash prizes for meeting tree and/or vegetative growth metrics; help ensure incentives allow for long timelines; help ensure equitable access to incentives.
  • Seek to designate lands for reforestation that are adjacent to or connect with already protected areas, intact lands, and/or watersheds.
  • Advocate to remove harmful agriculture and logging subsidies, particularly those that incentivize livestock, biofuels, land encroachment, and overuse of fertilizers.
  • Call on governments and administrators to use transparent, inclusive, and ongoing community engagement to co-design restoration projects; help solicit community feedback on area designations, finance, monitoring, and distribution of benefits; help ensure projects address relevant sociological, agricultural, and ecological considerations.
  • Advocate for strong land and tree tenure rights; support Indigenous property rights and autonomy.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPIC into legal systems.
  • Help create high-integrity carbon markets with long durations; use dynamic baselines for more accurate additionality assessments.
  • Help monitor reforestation projects using high-resolution data and active remote sensing if possible.
  • Help translate reforestation materials into local relevant languages.
  • Conduct cost-benefit analysis of potential local interventions to identify optimal reforestation strategies.
  • Develop markets and supply chains for native species products; innovate other sustainable uses for resources from reforested lands.
  • Develop or support opportunities for ecotourism industries in locally restored forests.
  • Facilitate investment strategies among stakeholders; create economic models to help maintain long-term financing; identify priorities for financing and help to distribute both financial and nonfinancial incentives to stakeholders.
  • Help identify local sources of degradation and distribute findings to policymakers and the public; document and share best practices for reforestation.
  • Help establish outgrower schemes and negotiate contracts for smallholder farmers to ensure they receive the most favorable terms possible.
  • Create programs to monitor for activity and market leakage from reforestation sites; advocate for adjustments to enforcement and policies to reduce leakage if necessary.
  • 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.
  • 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, administration, and public relations.
  • When possible, use social science research to determine the best interventions, incentives, and community engagement models before beginning restoration projects.
  • Work with educational institutions to develop degree and certification programs in forest restoration; encourage them to offer subspecialities such as protected lands governance, management, policy, and finance.
  • Create educational programs that work with schools, NGOs, and the general public to inform communities of how to participate in restoration efforts, benefits, and opportunities; advocate for expanded extension services to develop local capacity in forest restoration, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify restoration activity and sustainable use of forest products.

Further information:

Thought Leaders
  • If possible, conduct restoration projects on your property; work with local experts, share your experience, and document your progress.
  • Advocate for achievable public targets and pledges for forest restoration with clear effectiveness goals.
  • Help develop regulatory frameworks with clear definitions for active and passive restoration and/or related terms such as reforestation, regeneration, improving forest functionality, and increasing forest cover; ensure the framework is gender responsive and seeks to include women throughout the restoration process.
  • Help develop definitions at the international level for forest restoration and degradation along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Help develop or advocate for regional and transboundary coordination mechanisms for restoring forests, especially, when working across international borders; consider using coordination methods from adjacent issue areas such as water management and/or working closely with existing coordination bodies for relevant watersheds.
  • Take advantage of and/or advocate for public incentives for both active and passive restoration techniques such as direct payments, PES, property tax breaks, rebates, subsidies, and cash prizes for meeting tree and/or vegetative growth metrics; help ensure incentives allow for long timelines; help ensure equitable access to incentives.
  • Seek to designate lands for reforestation that are adjacent to or connect with already protected areas, intact lands, and/or watersheds.
  • Advocate to remove harmful agriculture and logging subsidies, particularly those that incentivize livestock, biofuels, land encroachment, and overuse of fertilizers.
  • Call on governments and administrators to use transparent, inclusive, and ongoing community engagement processes to co-design restoration projects; help solicit community feedback on area designations, finance, monitoring, and distribution of benefits; help ensure projects address relevant sociological, agricultural, and ecological considerations.
  • Advocate for strong land and tree tenure rights; support Indigenous property rights and autonomy.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPIC into legal systems.
  • Help create high-integrity carbon markets with long durations; use dynamic baselines for more accurate additionality assessments.
  • Help identify local sources of degradation and distribute findings to policymakers and the public; document and share best practices for reforestation.
  • 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.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Work with educational institutions to develop degree and certification programs in forest restoration; encourage them to offer subspecialities such as protected lands governance, management, policy, and finance.
  • Create educational programs that work with schools, NGOs, and the general public to inform communities of how to participate in restoration efforts, benefits, and opportunities; advocate for expanded extension services to develop local capacity in forest restoration, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify restoration activity and sustainable use of forest products.

Further information:

Technologists and Researchers
  • Examine and compare a wide range of interventions, ideally in local sites, to inform reforestation.
  • Help document and examine local knowledge as it relates to reforestation; help integrate Indigenous and local knowledge into restoration science and technology.
  • Help develop local spatial models to identify sites suitable for restoration with low risk of being recleared.
  • Use or improve Artificial Intelligence models and satellite imagery to help develop early warning systems and predictive models for degraded forests and illegal deforestation.
  • Use AI and satellite data to monitor and evaluate restoration activities; map practices and identify locally relevant interventions.
  • Develop web-based platforms and applications to support large-scale forest restoration; include peer-reviewed studies that map risks and amounts of buffer pools available for each disturbance.
  • Research locally viable risk management strategies in restoration; study and identify social risks and related mitigation strategies.
  • Create a database to measure reforestation progress against global commitments.
  • Develop or improve techniques to monitor for activity and market leakage from reforestation sites.
  • Examine and compare a wide range of local incentive structures to identify optimal policies.
  • Conduct long-term documentation of socioeconomic and biodiversity outcomes for restoration projects; identify challenges and opportunities; distill best practices for a global audience.
  • Conduct social ground truthing for local restoration projects to gather data, test models, and develop potential interventions.
  • Conduct research on native species found in restored forests and potential uses for sustainable commercial development.
  • Evaluate the relationships among large-scale forest restoration, food security, and wood demand; develop recommendations for land and resource allocation among these activities.
  • Improve understanding of forest dynamics, including how they relate to cloud feedbacks, volatile organic compounds, aerosol effects, and black carbon.

Further information:

Communities, Households, and Individuals
  • If possible, restore forests on your property; work with local experts, share your experience, and document your progress.
  • Help establish and participate in local restoration efforts; volunteer with a local nonprofit or establish one if none exists.
  • If degraded forests are in your area and no action is being taken, speak to local officials, hand out fliers, or otherwise advocate for restoration.
  • Reduce and/or eliminate use of chemicals on your lawn and/or property; set up a sign that indicates your lawn is chemical-free.
  • Prioritizing reducing your household’s food waste and improving your diet to incorporate more plant-rich meals.
  • Have community conversations about local forests, agriculture, and lawn maintenance practices; seek to reduce harmful practices such as overuse of fertilizers and pesticides and to initiate restoration efforts; educate friends and neighbors about local degraded forests and potential solutions.
  • Contribute to local restoration efforts.
  • When traveling, look for opportunities to support reforestation projects and ecotourism.
  • Help document and develop knowledge-sharing opportunities for Indigenous and local knowledge.
  • Help identify local sources of degradation and distribute findings to policymakers and the public; document and share best practices for reforestation.
  • Try to purchase sustainable forest products that support local reforestation.
  • Take advantage of and/or advocate for public incentives for restoration techniques such as direct payments, PES, property tax breaks, rebates, subsidies, and cash prizes for meeting tree and/or vegetative growth metrics; help ensure incentives allow for long timelines; help ensure equitable access to incentives.
  • Seek to designate lands for reforestation that are adjacent to or connect with already protected areas, intact lands, and/or watersheds.
  • Advocate to remove harmful agriculture and logging subsidies, particularly those that incentivize livestock, biofuels, land encroachment, and overuse of fertilizers.
  • Call on governments and administrators to use transparent, inclusive, and ongoing community engagement processes to co-design restoration projects; help solicit community feedback on area designations, finance, monitoring, and distribution of benefits; help ensure projects address relevant sociological, agricultural, and ecological considerations.
  • Advocate for strong land and tree tenure rights; support Indigenous property rights and autonomy.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPIC into legal systems.
  • Create educational programs that work with schools, NGOs, and the general public to inform communities how to participate in restoration efforts, benefits, and opportunities; advocate for expanded extension services to develop local capacity in forest restoration, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, restoration activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify restoration activity and sustainable use of forest products.

Further information:

Sources
Evidence Base

Consensus of effectiveness in enhancing carbon removal: High

Many scientific studies have evaluated the potential for forest restoration, consistently reporting that forest restoration has potential to provide substantial carbon removal. The effectiveness of forest restoration in terms of carbon uptake per hectare is highly spatially variable, with over 100-fold variability in uptake rates globally (Cook-Patton et al., 2020). These uptake rates have been extensively modeled, though estimates vary with respect to restoration activity (e.g., natural regeneration or plantation establishment) and carbon pools included (e.g., above-ground biomass only, above- and below-ground biomass, or total biomass and soil carbon). For forests undergoing natural regeneration, estimates of effectiveness ranged from 1.0 t CO₂‑eq /ha/yr for biomass in boreal forests (Cook-Patton et al., 2020) to 18.8 t CO₂‑eq /ha/yr for biomass and soils in humid tropical forests in South America (Bernal et al., 2018).

Estimates of the potential climate impacts of forest restoration vary widely, with differences driven largely by variability in the estimates of land area available for forest restoration. The IPCC reported a global technical mitigation potential of 3.9 Gt CO₂‑eq/yr with an uncertainty range of 0.5–10.1 Gt CO₂‑eq/yr, and an economically feasible mitigation potential of 1.6 Gt CO₂‑eq/yr with an uncertainty range of 0.5–3.0 Gt CO₂‑eq/yr (Nabuurs et al., 2022). Cook-Patton et al. (2020) estimated a maximum mitigation potential of 8.91 Gt CO₂‑eq/yr and a mitigation potential of 5.87 Gt CO₂‑eq/yr under existing national commitments. Roe et al. (2021) estimated a technical mitigation potential of 8.47 Gt CO₂‑eq/yr and a cost-effective mitigation potential of 1.53 Gt CO₂‑eq/yr. Griscom et al. (2017) reported a technical mitigation potential of 10.1 Gt CO₂‑eq/yr, though the uncertainty estimates spanned 2.7–17.9 Gt CO₂‑eq/yr. Using a more conservative estimate of the area available for forest restoration than previous studies, Fesenmeyer et al. (2025) estimated that sequestration of 2.2 Gt CO₂‑eq/yr is feasible.

The quantitative results presented in this assessment synthesize findings from 16 global datasets supplemented by four national-scale studies. We recognize that geographic bias in the information underlying global data products creates bias and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Updated Date

Improve Annual Cropping

Submitted by Drawdown Admin on
Sector
FALO & Nature-Based Carbon Removal
Mode
Cut Emissions Remove Carbon
Cluster
Shift Agriculture Practices
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Coming Soon
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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. New adoption is estimated from the 2025 level as a baseline which is therefore set to zero.

Extreme weather events,Droughts
Income & work,Food security
Nature protection,Land resources,Water quality
Description for Social and Search
Improve Annual Cropping is a highly recommended climate solution. It enhances soil’s ability to store carbon and reduces emissions of nitrous oxide, a potent greenhouse gas.
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).

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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. Link to source: https://doi.org/10.1016/j.ecolecon.2018.05.005

Tiefenbacher, A., Sandén, T., Haslmayr, H.-P., Miloczki, J., Wenzel, W., & Spiegel, H. (2021). Optimizing carbon sequestration in croplands: A synthesis. Agronomy, 11(5), 882. Link to source: https://doi.org/10.3390/agronomy11050882

Toensmeier, E. (2016). The Carbon Farming Solution: A Global Toolkit of Perennial Crops and Regenerative Agriculture Practices for Climate Change Mitigation and Food Security. Green Publishing. Link to source: https://www.chelseagreen.com/product/the-carbon-farming-solution/?srsltid=AfmBOoqsMoY569HfsXOdBsRguOzsDLlRZKOnyM4nyKwZoIALvPoohZlq 

Vendig, I., Guzman, A., De La Cerda, G., Esquivel, K., Mayer, A. C., Ponisio, L., & Bowles, T. M. (2023). Quantifying direct yield benefits of soil carbon increases from cover cropping. Nature Sustainability, 6(9), 1125–1134. https://doi.org/10.1038/s41893-023-01131-7

WCCA (2021). The future of farming: Profitable and sustainable farming with conservation agriculture. 8th World Congress on Conservation Agriculture, Vern Switzerland. Link to source: https://ecaf.org/8wcca

Wooliver, R., & Jagadamma, S. (2023). Response of soil organic carbon fractions to cover cropping: A meta-analysis of agroecosystems. Agriculture, Ecosystems & Environment, 351, 108497. https://doi.org/10.1016/j.agee.2023.108497

Xing, Y., & Wang, X. (2024). Impact of agricultural activities on climate change: a review of greenhouse gas emission patterns in field crop systems. Plants, 13(16), 2285. Link to source: https://doi.org/10.3390/plants13162285

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 C. 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 is not 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, 100-yr basis

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

Unit: t CO₂‑eq/ha/yr, 100-yr basis

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

Unit: t CO₂‑eq/ha/yr, 100-yr basis

25th percentile 0.87
Median (50th percentile) 1.79
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 Damania et al. (2023) to create a weighted average profit of US$76.86/ha/yr.

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/yr. 

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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Methods and Supporting Data

Methods and Supporting Data

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 emergency brake, gradual, or delayed.

Improve Annual Cropping is a DELAYED climate solution. It works more slowly than gradual or emergency brake solutions. Delayed solutions can be robust climate solutions, but it’s important to recognize that they may not 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). Note that in Solution Basics in the dashboard we set current adoption at zero. This is a conservative assumption to avoid counting carbon sequestration from land that has already ceased to sequester net carbon due to saturation, which takes place after 20–50 years (Lal et al., 2018).

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Table 3. Current (2025) adoption level.

Unit: Mha of improved annual cropping

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, as shown in Table 4.

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

Unit: Mha adopted/yr

Mean 9.99
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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  by adding 800 Mha of remaining potential to the 267.4 Mha of current adoption (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 Achievable – High 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

Current adoption 267.4
Achievable – low 331.7
Achievable – high 700.0
Adoption ceiling 1,067

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. Much of the current adoption of improved annual cropping has been in place for decades and sequestration in some of this land has presumably already slowed down to almost zero. We apply an adoption adjustment factor of 0.5 to current adoption (see methodology) to reflect that an estimated half of current adoption is no longer sequestering significant carbon, yet there is substantial new adoption within the last 20-50 years.

For new adoption, the calculation is effectiveness * new adoption = climate impact.

For calculating impact of current adoption, the calculation is the sum of a and b where:

a:  for carbon sequestration, the calculation is effectiveness * 0.5 * current adoption = climate impact, and

b: for nitrous oxide reduction, the calculation is effectiveness * current adoption = climate impact.

Climate impacts shown in Table 6 are the sum of current and new adoption impacts. Combined effect is 0.31 Gt CO2-eq/yr for current adoption, 0.43 for Achievable – Low, 1.09 for Achievable – High, and 1.87 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 0.14
Achievable – low 0.17
Achievable – high 0.36
Adoption ceiling 0.58

(from nitrous oxide)

Unit: Gt CO₂ ‑eq/yr, 100-yr basis

Current adoption 0.17
Achievable – low 0.25
Achievable – high 0.73
Adoption ceiling 1.29

(from SOC)

Unit: Gt CO₂ ‑eq/yr, 100-yr basis

Current adoption 0.31
Achievable – low 0.43
Achievable – high 1.09
Adoption ceiling 1.87
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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, dry conditions, and other adverse weather events (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; Martínez-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 and 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. 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. 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. 

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 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, 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 crops 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

ha cropland

t CO₂-eq (100-yr)/unit/yr
00.881.8median
units
Current 2.674×10⁸ 03.317×10⁸7.0×10⁸
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.31 0.431.09
US$ per t CO₂-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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t CO2-eq/ha
0≥ 400

Thousands of years 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. Link to source: https://doi.org/10.1073/pnas.1706103114

t CO2-eq/ha
0≥ 400

Thousands of years 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. Link to source: https://doi.org/10.1073/pnas.1706103114

Maps 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., 2024; Lessmann et al., 2022). 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

Consensus of effectiveness of cover cropping for sequestering carbon: 

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). 

Consensus of effectiveness of reduced tillage for sequestering carbon: 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., 2024; Kan et al., 2022). Lessmann et al. (2022) 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

Reduce Overfishing

Submitted by Drawdown Admin on
Sector
Food, Agriculture, Land & Ocean (FALO)
Mode
Cut Emissions
Cluster
Restore & Manage Ecosystems
Image
An image of a fishing boat at sea
Coming Soon
Off
Summary

Reduce Overfishing refers to the use of management actions that decrease fishing effort and therefore cut CO₂ emissions from fishing vessel fuel use on overfished stocks. Advantages include the potential to replenish depleted fish stocks, support ecosystem health, and enhance long-term food and job security. Disadvantages include the short-term reductions in fishing effort needed to allow systems to recover, which could impact local livelihoods and economies. While these interventions are not expected to reach globally meaningful levels of emissions reductions (>0.1 Gt CO₂‑eq/yr ), we conclude that Reduce Overfishing is “Worthwhile” with important ecosystem and social benefits.

Description for Social and Search
Our analysis concludes that, despite its limited global impact for reducing emissions, Reduce Overfishing is a “Worthwhile” climate solution that has other important benefits for ecosystem health and long-term food security.
Overview

What is our assessment?

Our analysis concludes that, despite its limited global impact for reducing emissions, Reduce Overfishing is a “Worthwhile” climate solution that has other important benefits for ecosystem health and long-term food security.

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

What is it?

Reducing overfishing lowers fuel use and CO₂ emissions from wild capture fishing vessels by reducing fishing effort on overfished stocks. This is typically achieved through management actions, such as seasonal closures, gear restrictions, and catch limits. Fishing effort, whether measured as the hours spent fishing or distance traveled, is generally proportional to fuel use. In addition to immediate reductions in emissions, reducing overfishing can allow overfished stocks to recover, which can lead to reduced future emissions since fuel use is lowered when fish are easier to catch and harvested sustainably.

Does it work?

Reducing fishing effort in locations with depleted and overfished wild fish stocks is expected to reduce emissions from fishing vessels. When stocks are overfished, fishers must exert additional effort, traveling further and/or searching longer to make the same catch, which increases fuel use and CO₂ emissions. Reducing overfishing through management actions, such as harvest control rules, gear restrictions, seasonal closures, stronger enforcement of existing regulations, and establishment of marine protected areas, can help fish stocks recover. Other policy tools, such as reducing harmful fuel subsidies that currently enable many otherwise unprofitable fishing fleets, are also likely to result in lower fuel use and CO₂ emissions. Healthy fish stocks can be caught with lower fishing effort, translating to future fuel savings and reduced CO₂ emissions. Global estimates suggest that reductions in overfishing could avoid up to 0.08 Gt CO₂‑eq/yr, representing almost half of the entire capture fisheries sector's annual emissions (0.18 Gt CO₂‑eq/yr ).

Why are we excited?

Currently, overfishing affects more than 35% of global wild marine fish stocks, increasing by 1%, on average, every year. Reducing overfishing not only lowers fuel use and emissions but also allows overfished stocks to recover. Healthy fish stocks strengthen marine food webs and contribute to ecosystem resilience and biodiversity. Overfishing has widespread consequences for diverse marine ecosystems, such as kelp forests, where declines in fish have led to overgrazing of the kelp by sea urchins. Over time, management interventions will also likely improve the sustainability and long-term reliability of coastal livelihoods and food security by supporting sustainable fisheries.

Why are we concerned?

Policy and management tools for reducing overfishing and, by extension, fishing-related emissions come with some challenges. For instance, management measures or legal protections may not be fully effective if implementation or enforcement is weak. Management and enforcement can be particularly challenging on the high seas, where jurisdiction is limited or shared across many nations, and where illegal, unreported, and unregulated fishing can be widespread. Even when effective, fish stock recovery can take years to decades, and the costs and trade-offs are unlikely to be evenly distributed across fishing fleets. In the short term, efforts to reduce overfishing could create economic challenges for small-scale fishers who may have fewer resources and less capacity to adapt to management restrictions.

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Credits

Lead Fellow

  • Christina Richardson, Ph.D.

Internal Reviewer

  • Christina Swanson, Ph.D.
Action Word
Reduce
Solution Title
Overfishing
Classification
Worthwhile
Updated Date
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