Project Drawdown is thrilled to announce that leading climate scientist, author, and science communicator Kate Marvel, Ph.D., will be returning to Project Drawdown this spring. She previously served as a Senior Scientist on the team in 2023–24.
Marvel recently resigned from her role at NASA in a move that was covered by Scientific American, The New York Times, Bloomberg, and others.
In her new Senior Scientist, Climate role at Project Drawdown, Marvel will lead work focused on emergency brake climate solutions – solutions that can help “bend the curve” on future warming more quickly, by curbing emissions of methane, black carbon, and other fast-acting greenhouse gas pollutants.
“I’m unbelievably excited to return to Project Drawdown,” said Marvel. “This is a unique historical moment, in which the impacts of climate change are becoming ever more apparent, political opposition is strengthening, and yet the solutions are more clear and accessible than ever. We have a real chance to move the needle on climate action, but only if we’re able to draw upon the best available science. Science is integral to Project Drawdown’s approach, and I look forward to doing research in an environment that supports free inquiry, rigorous debate, and critical thinking.”
Marvel is an acclaimed climate scientist and author based in Brooklyn, N.Y., who focuses on modeling how our planet is changing and understanding what could happen in the future. Prior to joining Project Drawdown, she worked at the NASA Goddard Institute for Space Studies, Columbia University, Stanford University, the Carnegie Institution, and Lawrence Livermore National Laboratory. She received a Ph.D. in theoretical physics from Cambridge University. Her book Human Nature was published by Ecco/HarperCollins in 2025.
“We are thrilled that Dr. Marvel will be returning to Project Drawdown after her time at NASA. She is a world-leading climate scientist, public communicator, and author, and her talents deserve to be fully supported and unleashed – especially at this critical time,” says Project Drawdown Executive Director Jonathan Foley, Ph.D. “We are thankful to have her back and excited to have her lead work on our critical emergency brake climate solutions initiative.”
For press inquiries, please contact Todd Reubold, Director of Marketing and Communications, at todd.reubold@drawdown.org
About Project Drawdown
Project Drawdown is the world’s leading guide to science-based climate solutions. Our mission is to drive meaningful climate action around the world. A 501(c)(3) nonprofit organization, Project Drawdown is funded by individual and institutional donations.
Project Drawdown has welcomed Lauren Gifford, Ph.D., and Elena Essa to its private sector engagement team to expand efforts to mobilize billions of dollars toward proven climate solutions.
Working with Amanda Bielawski, Ph.D., Director of Global Strategic Partnerships, Gifford and Essa will create pathways for philanthropists, foundations, and mission-driven investors to accelerate investment in the most effective climate solutions identified by Drawdown Explorer. Their work will focus on developing partnerships, decision-support tools, and thought leadership that help guide large-scale capital toward high-impact science-based climate strategies.
“Mobilizing capital at scale is essential to effectively address the climate crisis,” Bielawski says. “Lauren and Elena bring deep expertise and strategic insight that will help connect funders with solutions that are scientifically proven to deliver the most effective and efficient climate progress.”
Lauren Gifford, Ph.D., Senior Advisor, Climate Philanthropy and Investing, joins Project Drawdown to guide philanthropies, investors, and institutions in aligning capital with science-based, high-integrity, and equitable climate strategies. Gifford previously served as Director of the Soil Carbon Solutions Center and Assistant Professor of Carbon Management at Colorado State University. Beyond academia, Gifford has advised governments, foundations, NGOs, and Fortune 100 companies on climate finance and policy.
Elena Essa, Program Manager for Global Strategic Partnerships, provides strategic management of the program to build ambitious partnerships across the private sector to effectively scale climate solutions. She comes to Project Drawdown from RMI, where she led technoeconomic, policy, and strategic research across the Carbon-Free Electricity Program and Climate-Aligned Industries Program.
For the latest on these and other Project Drawdown initiatives, subscribe to our biweekly newsletter here.
About Project Drawdown
Project Drawdown is the world’s leading guide to science-based climate solutions. Our mission is to drive meaningful climate action around the world. A 501(c)(3) nonprofit organization, Project Drawdown is funded by individual and institutional donations.
Restore Seagrass Ecosystems involves reestablishing seagrass meadows in ocean areas where they were lost due to disturbances or degradation. As seagrasses grow, they remove CO₂ from ocean water through photosynthesis and accumulate carbon in their biomass, which allows seawater to take up additional CO₂ from the atmosphere. Some of this biomass carbon is stored long term in sediments. Restoring seagrass ecosystems offers numerous benefits for the environment and humans. Disadvantages include its cost and low climate impact due to a limited available area for restoration. Despite its limited climate impact, Restore Seagrass Ecosystems is “Worthwhile” given its environmental benefits and documented ability to remove carbon.
Based on our analysis, restoring seagrass ecosystems can remove carbon with no major environmental risks. Despite a likely small climate impact due to the limited area available for restoration and uncertainty around costs, we consider it “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? | No |
| Risk | Is it risky or harmful? | No |
| Cost | Is it cheap? | ? |
Restore Seagrass Ecosystems removes carbon from the air by reestablishing seagrasses – subtidal marine flowering plants with roots – in areas where they were previously destroyed, degraded, or otherwise lost. Seagrasses remove CO₂ from seawater for photosynthesis, accumulating carbon in their biomass that can later break down and settle into sediments on- or off-site. The removal of CO₂ allows seawater to absorb additional CO₂ from the atmosphere. Restoration typically involves seeding or transplanting seedlings and might also require infilling with sediment to compensate for previous sediment loss and accommodate sea-level rise. Seagrass restoration likely also avoids emissions by curtailing the continued loss of sediment carbon due to degradation (e.g., coastal development).
Restoration of seagrass ecosystems is a relatively new practice in many regions of the world. While its global climate benefit is uncertain but expected to be small (<0.1 Gt CO₂‑eq/yr ), research suggests that restored seagrass ecosystems generally act as net carbon sinks. Nearly 7 Mha of seagrass have been lost worldwide since the 1970s due to a wide range of stressors, such as coastal development and water quality degradation, though it is unclear precisely how much of this loss is restorable. Areas with the greatest observed losses occur in the Tropical Atlantic, Temperate North Atlantic East, Temperate Southern Oceans, and Tropical Indo-Pacific regions.
Restoration of seagrass ecosystems provides numerous benefits for the environment and humans. Seagrass meadows can reduce coastal flooding risk while stabilizing seafloor sediment. Restored seagrass ecosystems also increase biodiversity and habitat available for other organisms, including fish and other animals that transiently use seagrass meadows for foraging or as nurseries.
Despite its widespread environmental benefits, seagrass ecosystem restoration can be expensive and is not always successful. In addition, an estimated 33% of its carbon removal benefits can be offset by emissions of methane, a greenhouse gas that microbes can produce using compounds released by seagrass plants. While costs are uncertain, studies suggest they can be high, with a median cost of US$537,140/ha and an average cost of US$979,335/ha (2023 US$), though other regional projects suggest costs can be closer to US$1,200/ha. Also, restoration of seagrasses is not always successful. On average, 55% of seagrass meadows restored succeed (≥50% survival), and future success may be affected by impacts of climate change such as sea-level rise, which is already driving losses of native seagrass meadows.
Bayraktarov, E., Saunders, M. I., Abdullah, S., Mills, M., Beher, J., Possingham, H. P., Mumby, P. J., & Lovelock, C. E. (2016). The cost and feasibility of marine coastal restoration. Ecological Applications, 26(4), 1055–1074. Link to source: https://doi.org/10.1890/15-1077
Buelow, C. A., Connolly, R. M., Turschwell, M. P., Adame, M. F., Ahmadia, G. N., Andradi-Brown, D. A., Bunting, P., Canty, S. W. J., Dunic, J. C., Friess, D. A., Lee, S. Y., Lovelock, C. E., McClure, E. C., Pearson, R. M., Sievers, M., Sousa, A. I., Worthington, T. A., & Brown, C. J. (2022). Ambitious global targets for mangrove and seagrass recovery. Current Biology, 32(7), 1641–1649.e3. Link to source: https://doi.org/10.1016/j.cub.2022.02.013
Capistrant-Fossa, K. A., & Dunton, K. H. (2024). Rapid sea level rise causes loss of seagrass meadows. Communications Earth & Environment, 5, Article 87. Link to source: https://doi.org/10.1038/s43247-024-01236-7
Danovaro, R., Aronson, J., Bianchelli, S., Boström, C., Chen, W., Cimino, R., Corinaldesi, C., Cortina-Segarra, J., D’Ambrosio, P., Gambi, C., Garrabou, J., Giorgetti, A., Grehan, A., Hannachi, A., Mangialajo, L., Morato, T., Orfanidis, S., Papadopoulou, N., Ramirez-Llodra, E., ... Fraschetti, S. (2025). Assessing the success of marine ecosystem restoration using meta-analysis. Nature Communications, 16, Article 3062. Link to source: https://doi.org/10.1038/s41467-025-57254-2
Dunic, J. C., Brown, C. J., Connolly, R. M., Turschwell, M. P., & Côté, I. M. (2021). Long-term declines and recovery of meadow area across the world’s seagrass bioregions. Global Change Biology, 27(17), 4096–4109. Link to source: https://doi.org/10.1111/gcb.15684
Eyre, B. D., Camillini, N., Glud, R. N., & Rosentreter, J. A. (2023). The climate benefit of seagrass blue carbon is reduced by methane fluxes and enhanced by nitrous oxide fluxes. Communications Earth & Environment, 4, Article 374. Link to source: https://doi.org/10.1038/s43247-023-01022-x
Forrester, J., Leonardi, N., Cooper, J. R., & Kumar, P. (2024). Seagrass as a nature-based solution for coastal protection. Ecological Engineering, 206, Article 107316. Link to source: https://doi.org/10.1016/j.ecoleng.2024.107316
Krause, J. R., Cameron, C., Arias-Ortiz, A., Cifuentes-Jara, M., Crooks, S., Dahl, M., Friess, D. A., Kennedy, H., Lim, K. E., Lovelock, C. E., Marbà, N., McGlathery, K. J., Oreska, M. P. J., Pidgeon, E., Serrano, O., Vanderklift, M. A., Wong, L.-W., Yaakub, S. M., & Fourqurean, J. W. (2025). Global seagrass carbon stock variability and emissions from seagrass loss. Nature Communications, 16, Article 3798. Link to source: https://doi.org/10.1038/s41467-025-59204-4
Oreska, M. P. J., McGlathery, K. J., Aoki, L. R., Berger, A. C., Berg, P., & Mullins, L. (2020). The greenhouse gas offset potential from seagrass restoration. Scientific Reports, 10, Article 7325. Link to source: https://doi.org/10.1038/s41598-020-64094-1
Seddon, S. (2004). Going with the flow: Facilitating seagrass rehabilitation. Ecological Management & Restoration, 5(3), 167–176. Link to source: https://doi.org/10.1111/j.1442-8903.2004.00205.x
Sievers, M., Rasmussen, J. A., Nielsen, B., Steinfurth, R. C., Flindt, M. R., Melvin, S. D., & Connolly, R. M. (2025). Restored seagrass rapidly provides high-quality habitat for mobile animals. Restoration Ecology, 33, e14343. Link to source: https://doi.org/10.1111/rec.14343
Valdez, S. R., Zhang, Y. S., van der Heide, T., Vanderklift, M. A., Tarquinio, F., Orth, R. J., & Silliman, B. R. (2020). Positive ecological interactions and the success of seagrass restoration. Frontiers in Marine Science, 7, Article 91. Link to source: https://doi.org/10.1016/j.cub.2022.02.013
Christina Richardson, Ph.D.
Tina Swanson, Ph.D.
Paul West, Ph.D.
Restore Mangrove Ecosystems removes carbon by re-establishing mangrove forests in areas where they were previously destroyed by conversion or other disturbances. This allows carbon to accumulate in above- and below-ground biomass and sediment. Advantages include mangrove forests' high effectiveness at carbon removal and storage, as well as their numerous environmental benefits and generally low cost. However, the relatively small area available for restoration (~1 Mha) likely limits its global climate impact below 0.1 Gt CO₂‑eq/yr. Despite its limited global climate impact, we consider restoring mangrove forests “Worthwhile” as it is a valuable regional multi-benefit tool for carbon removal with no major environmental risks.
Based on our analysis, restoring mangrove forests is a highly effective and relatively inexpensive tool for carbon removal, but it has a small climate impact due to the limited global area available for restoration. While the climate impact is probably low, we consider it a “Worthwhile” climate solution because it poses no major risks and provides widespread co-benefits for humans 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 |
Restore Mangrove Forests is a climate solution that removes carbon from the air by re-establishing mangrove ecosystems in areas where they were previously drained, filled, or otherwise degraded and lost. Nearly 2 Mha of mangroves have been destroyed since 1970. As mangrove plants are re-established and grow, they take up CO₂ through photosynthesis and store carbon in above- and below-ground biomass. They also trap and bury carbon-containing sediments, allowing additional carbon to accumulate in waterlogged soils where decomposition is slow. Restoration actions typically involve re-planting and restoring hydrologic conditions to allow tidal exchange with the ocean. Restoration also often replaces land uses that can be sources of large CO₂ (and other GHG) emissions.
Mangrove restoration is a well-established carbon removal approach that has been practiced for at least 40 years in many regions of the world. Research shows that restored mangrove ecosystems can act as large, durable carbon sinks, with sediment carbon likely able to persist for centuries or longer, similar to natural systems. However, because the estimated global area available for restoration is ~1 Mha, its climate impact is expected to be under 0.1 Gt CO₂‑eq/yr. Despite this limitation, restoration can still be a regionally important intervention in certain regions and countries that hold a disproportionate share of restorable mangrove area, due to its high effectiveness. Indonesia (~186,600 ha) and Mexico (~145,500 ha) contain the two largest national areas of restorable mangroves globally. In a relative sense, countries such as Belize, Honduras, Mexico, Nicaragua, Sri Lanka, the United States, and Vietnam are estimated to have at least 10% of their original mangrove area restorable.
Restoration of mangrove ecosystems is an established practice that can be low cost with widespread environmental benefits. Recent global assessments suggest that restoration and natural expansion together added about 393,000 ha of mangrove area from 2000–2020. Restoration can recover ecosystem function, support biodiversity, and reduce exposure to coastal hazards, such as coastal flooding and erosion. Costs can vary from US$3,000–9,800/ha, with the removal of an estimated 0.78 Gt CO₂ over the next 40 years estimated to cost under $20/t CO₂. Low-cost restoration potential is greatest in countries such as Indonesia, Brazil, Mexico, Myanmar, and India.
This practice, while highly effective at removing carbon, is unlikely to scale to a globally relevant climate impact level given the limited area available for restoration. Although a large area of mangroves has been lost, not all of these areas remain feasible for restoration. For example, nearly 20% of all lost mangrove areas have been converted to open water habitats that are no longer suitable for restoration. Additionally, methane emissions can occur in restored mangroves, which might offset 20% of the carbon removed. Mangrove restoration is also not always successful, and reported outcomes vary widely across projects, with an estimated average success rate of ~62%.
Alongi, D. M. (2014). Carbon cycling and storage in mangrove forests. Annual Review of Marine Science, 6, 195-219. Link to source: https://doi.org/10.1146/annurev-marine-010213-135020
Bourgeois, C. F., MacKenzie, R. A., Sharma, S., Bhomia, R. K., Johnson, N. G., Rovai, A. S., Worthington, T. A., Krauss, K. W., Analuddin, K., Bukoski, J. J., Castillo, J. A., Elwin, A., Glass, L., Jennerjahn, T. C., Mangora, M. M., Marchand, C., Osland, M. J., Ratefinjanahary, I. A., Ray, R., ... Trettin, C. C. (2024). Four decades of data indicate that planted mangroves stored up to 75% of the carbon stocks found in intact mature stands. Science Advances, 10(27), eadk5430. Link to source: https://doi.org/10.1126/sciadv.adk5430
Chen, H.-Y., Ge, Z.-M., Zhu, K.-H., Zhao, W., Chen, X.-C., Li, X.-Z., Xin, P., Zhou, Z., Chen, S., & Bellerby, R. (2025). Ecosystem carbon and nitrogen recovery in restored coastal wetlands. Communications Earth & Environment. Link to source: https://doi.org/10.1038/s43247-025-03036-z
Danovaro, R., Aronson, J., Bianchelli, S., Boström, C., Chen, W., Cimino, R., Corinaldesi, C., Cortina-Segarra, J., D’Ambrosio, P., Garrabou, J., Grehan, A., Giorgetti, A., Hannachi, A., Mangialajo, L., Morato, T., Orfanidis, S., Papadopoulou, N., Ramirez-Llodra, E., Smith, C. J., ... Fraschetti, S. (2025). Assessing the success of marine ecosystem restoration using meta-analysis. Nature Communications, 16, 3062. Link to source: https://doi.org/10.1038/s41467-025-57254-2
Food and Agriculture Organization of the United Nations. (2023, July 26). Global effort to safeguard mangroves steps up. Link to source: https://www.fao.org/newsroom/detail/global-effort-to-safeguard-mangroves-steps-up/en
Goto, G. M., Goñi, C. S., Braun, R., Cifuentes-Jara, M., Friess, D. A., Howard, J., Klinger, D. H., Teav, S., Worthington, T. A., & Busch, J. (2025). Implementation costs of restoring global mangrove forests. One Earth, 8(7), 101342. Link to source: https://doi.org/10.1016/j.oneear.2025.101342
Leal, M., & Spalding, M. D. (Eds.). (2024). The State of the World’s Mangroves 2024. Global Mangrove Alliance. Link to source: https://hdl.handle.net/10088/119867
Rosentreter, J. A., Maher, D. T., Erler, D. V., Murray, R., & Eyre, B. D. (2018). Methane emissions partially offset “blue carbon” burial in mangroves. Science Advances, 4(6), eaao4985. Link to source: https://doi.org/10.1126/sciadv.aao4985
Song, S., Ding, Y., Li, W., Meng, Y., Zhou, J., Gou, R., Zhang, C., Ye, S., Saintilan, N., Krauss, K. W., Crooks, S., Lv, S., & Lin, G. (2023). Mangrove reforestation provides greater blue carbon benefit than afforestation for mitigating global climate change. Nature Communications, 14, 756. Link to source: https://doi.org/10.1038/s41467-023-36477-1
Su, J., Friess, D. A., & Gasparatos, A. (2021). A meta-analysis of the ecological and economic outcomes of mangrove restoration. Nature Communications, 12, 5050. Link to source: https://doi.org/10.1038/s41467-021-25349-1
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), 20190129. Link to source: https://doi.org/10.1098/rsfs.2019.0129
Tiggeloven, T., van Zelst, V., Mortensen, E., van Wesenbeeck, B. K., Worthington, T. A., Spalding, M., de Moel, H., & Ward, P. J. (2026). Mangrove restoration and coastal flood adaptation: A global perspective on the potential for hybrid coastal defenses. Proceedings of the National Academy of Sciences of the United States of America, 123(4), e2510980123. Link to source: https://doi.org/10.1073/pnas.2510980123
Worthington, T., & Spalding, M. (2018). Mangrove restoration potential: A global map highlighting a critical opportunity. The Nature Conservancy and International Union for Conservation of Nature. Link to source: https://oceanwealth.org/wp-content/uploads/2019/02/MANGROVE-TNC-REPORT-FINAL.31.10.LOWSINGLES.pdf
Christina Richardson, Ph.D.
Christina Swanson, Ph.D.
Paul C. West, Ph.D.
For over a century, science has been a driving force for American progress.
Science has helped us defend democracy through two World Wars and end the scourge of diseases like polio and smallpox. Science has put people on the moon and sent probes across our solar system. It’s revolutionized everything from agriculture to computing, saving millions of lives – while building the world’s greatest economy. Today, science continues to make bold discoveries, helping us lift people up, improve the human condition, and create a better world.
Only half of the calories produced on cropland go directly to human consumption, with the bulk of the remainder used for fuel or feed.
Credit: Project DrawdownTo determine the global efficiency of the agri-food system, researchers analyzed the fate of the top 50 crops by calorie production between 2010 and 2020, amounting to nearly 98% of all calories produced. They found that, in 2020, only half of all calories produced on croplands were available for people to eat, while the other half were “lost” as livestock feed, biofuels, or other non-food uses.
Concerningly, even though total calorie production increased from 2010 to 2020 by roughly 24%, calories for human consumption increased only 17%, reflecting a decrease in how efficiently croplands are being used to directly feed people.
We don’t have a food scarcity problem – we have a cropland use problem,” says study author and Project Drawdown Senior Scientist Paul West, Ph.D. “Nearly 40% of all calories produced were used as feed for livestock, which yield far fewer calories for human consumption. Beef cattle in particular are inefficient in converting feed to human food, consuming one-third of feed calories but only providing 9% of the food calories we get from livestock. Shifting cropland now used to grow feed to produce food for people instead could dramatically reduce the harmful impacts of agriculture on climate, water resources and wildlife habitat.”
Nearly 5% of calories produced were used for biofuels. Although these are less polluting than fossil fuels, they still are responsible for significant greenhouse gas emissions, particularly when land use is taken into account.
According to the study, such inefficiencies were particularly pronounced in a small set of countries. For instance, around 23% and 29% of total calorie production in the United States and Brazil, respectively, were used to feed people. In contrast, 84% of India’s calorie production feeds people.
The percent of calories produced on cropland that are available for direct human consumption varies greatly across the globe.
Credit: Project DrawdownIn particular, the researchers found that if people in higher-income countries consumed chicken in place of beef – except for the 14 grams of beef per person per day allowed for optimal human and planetary health (roughly a hamburger per week) – the “lost calories” avoided would be enough to meet the caloric needs of 850 million people. More than half of the added benefit would come from the substitution taking place in the United States and Brazil, alone.
“Today’s global food system is staggeringly unsustainable,” says study author and Project Drawdown researcher Emily Cassidy. “Shifting to lower levels of beef consumption and reducing biofuel production could free up an immense amount of land.”
Ironically, the increasing inefficiency of cropland use not only increasingly exacerbates climate change, but it also may be exacerbated by it.
“If we don’t change what we’re growing and consuming, this could contribute to a vicious cycle,” says study author and Project Drawdown Senior Scientist James Gerber, Ph.D. “These inefficiencies could drive continued cropland expansion, leading to higher agricultural emissions and more global warming, which in turn could decrease crop yields, resulting in even more cropland expansion, and on and on.”
Ultimately, the researchers hope these findings will help guide strategic interventions that can feed the planet without destroying it.
“All of the solutions to close this efficiency gap already exist,” Cassidy says. “By targeting actions and policies for the commodities and countries that are the worst offenders, we can have an outsized impact on improving food security, health, and the environment.”
About Project Drawdown
Project Drawdown is the world’s leading guide to science-based climate solutions. Our mission is to drive meaningful climate action around the world. A 501(c)(3) nonprofit organization, Project Drawdown is funded by individual and institutional donations.
Of all human activities, few have as big an impact on the planet as agriculture. Globally, the agri-food system – everything that’s produced and consumed, from farm to fork to landfill – is the largest consumer of water, the largest user of land area, and one of the largest emitters of greenhouse gases.
To ensure food security while minimizing agriculture’s adverse impacts, it’s essential to produce enough food using as little land as possible. A new study in Environmental Research: Food Systems from Project Drawdown and the University of Minnesota shows substantial opportunity for improvement in this regard, finding that just half of the calories produced on croplands globally are directly available for human consumption.
Those of us who work in and think about climate change often act as if we’re at a crossroads.
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