Unlocking Nature’s Potential to Mitigate Climate Change

Global studies have shown that natural climate solutions (NCS) could deliver over one-third of the climate mitigation needed by 2030 to keep warming below 2°C—while also advancing biodiversity conservation and multiple Sustainable Development Goals (SDGs).

What are natural climate solutions? They are practices that carefully manage and restore natural ecosystems as a means of combating climate change. These solutions reduce greenhouse gas emissions from ecosystems and/or enhance their capacity to absorb and store carbon. Examples include reforestation (planting trees in previously forested areas), agroforestry (combining trees with crop production), and wetland conservation. Truly effective NCS also prioritize social equity, respect cultural values, and safeguard biodiversity and food production to ensure comprehensive sustainability (for more information, see “Natural climate solutions” and “The principles of natural climate solutions”). 

But despite this great potential and growing global commitments, real-world uptake remains slow. Why?

From working across the U.S. and Latin America, I’ve seen many projects that are technically feasible but face significant on-the-ground challenges: short-term funding, weak policy enforcement, insecure land tenure, or important tradeoffs with agriculture. These recurring issues raised questions: do countries all over the world face these issues? How can we address them and close the gap between promise and practice?

I was fortunate to work with colleagues at The Nature Conservancy and the University of Colorado Boulder to explore these questions. In our new paper, “Global Analysis of Constraints to Natural Climate Solution Implementation,” published this week in PNAS Nexus, we present the first global, country-level analysis of NCS implementation barriers.

What we did

• We systematically reviewed the literature and compiled 2,480 observations of 39 unique constraints in 135 countries.
• We analyzed constraints by geography, ecosystem, and intervention type.
• We identified real-world strategies used to overcome these constraints.

What we found

• The most common constraint globally was high implementation costs/lack of funding, observed in studies from 65 countries. This aligned with my experience: even with strong local support, projects struggle without long-term financial backing.
• Knowledge gaps, weak or inconsistent policy, and stakeholder skepticism were also frequently reported constraints.
• Equity concerns, especially around reforestation, showed up in 61 countries. Many stem from top-down approaches that overlook local needs, disrupt livelihoods, or perpetuate historical injustices.
• Every geography and type of NCS faced multiple overlapping barriers, typically cutting across many different kinds of constraints.
• These findings show that single-issue solutions aren’t enough. Effective implementation will require integrated, cross-sector strategies that account for systemic and place-based challenges.

 We also found examples of real-world solutions

• In Kenya, equity in payment for ecosystem services helped overcome funding gaps, insecure tenure, and unequal participation.
• In Sweden, mechanized planting and natural regeneration reduced labor shortages and high manual planting costs.
• In Chile, simplifying technical forest plans helped reduce stakeholder skepticism and improve engagement.
• In Vietnam, reforms to land laws extended leases, enabling longer-term investment in agroforestry.

These examples show that successful NCS efforts are those that are systemic, adaptive, and grounded in local realities.

Implications for science, policy, and practice

1. Design integrated interventions. Because each geography faces a suite of constraints, solutions that combine many elements—such as finance, policy reform, technical capacity, and stakeholder engagement—are more likely to succeed than those that tackle issues in isolation. These solutions will likely require collaborations across sectors and disciplines.
2. Allocate resources with precision. Our results and open-access dataset highlight the most common constraints by country. This can help funders and policymakers target resources where they’ll have the greatest impact—whether supporting long-term project maintenance, legal reform, or technical training.
3. Diagnose early, adapt continuously. Constraints can emerge at any stage—before, during, or after implementation. Embedding a constraint-assessment step into planning can flag issues early. The adaptive management cycle could be a useful framework, and we provide sample guiding questions that help practitioners anticipate and address context-specific challenges.
4. Integrate feasibility into mitigation estimates. Models projecting climate mitigation from NCS should incorporate implementation constraints—not just biophysical potential. This will lead to more realistic targets and help avoid overreliance on NCS in climate planning.

A path forward

Natural climate solutions are promising tools for addressing climate change while supporting biodiversity and human well-being. By identifying where and why implementation lags, we offer a foundation for more strategic, collaborative action. I hope our results, planning framework, and open-source dataset will serve as practical tools for researchers, practitioners, and policymakers working to close the implementation gap—and help translate nature’s climate potential into equitable, lasting outcomes on the ground.

The database we generated for this project has now been integrated into the public Naturebase platform. It's a web app aiming to inform NCS project implementation based on scientific evidence — led by many e-NGOs and other partners. Users can click on a country and then "Governance" to get a list of the feasibility constraints we found for that country.

Brumberg is a Ph.D. student in the Emmett Interdisciplinary Program in Environment and Resources (E-IPER) in the Stanford Doerr School of Sustainability and at the Stanford-based Natural Capital Project.

Additional authors on the paper are from the University of Colorado Boulder: Margaret Hegwood, Waverly Eichhorst, and Anna LoPresti;  from The Nature Conservancy and Dartmouth College: James T. Erbaugh; and The Nature Conservancy: Timm Kroeger. 

This work was supported in part by a Bezos Earth Fund grant to The Nature Conservancy. This work is supported by the Food and Agricultural Sciences National Needs Graduate and Postgraduate Fellowship Grants Program (NNF), project award no. 2020-38420-30727, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Hilary Brumberg acknowledges the support of the National Science Foundation Graduate Research Fellowship (Grant number: DGE-2146755).  

Media contact: Elana Kimbrell (elanak@stanford.edu).