Confidence in Nature-based Climate Solutions Receiving the Majority of Investment is Strong; other Solutions need more Research before their Contribution to Climate Mitigation is Understood

A new peer-reviewed study by 27 authors from 11 institutions, including the Environmental Defense Fund, The Nature Conservancy and Columbia University, finds that four nature-based climate solutions have robust scientific foundations, while others need urgent additional research before their role as a climate solution is understood. The study explicitly looked at the scientific basis of, and expert confidence in, solutions for climate benefit, not the implementation of individual projects, carbon crediting methodologies or co-benefits. 

The research finds that four pathways – tropical forest conservation; temperate forest conservation; tropical forest reforestation; and temperate forest reforestation – have the greatest certainty in carbon mitigation potential. However, it also showed that other types of stewardship actions, such as avoided seabed disturbance, have uncertainties at global scales and require further research. In some cases, market-based activities are pushing the boundaries of these uncertainties: 77 percent of the pathways with higher global uncertainties have protocols developed, and 62 percent have market activity. 

Positively, the majority of investment is in high credibility stewardship action solutions; 70 percent of nature-based credits that come from American Carbon Registry (ACR), Climate Action Reserve (CAR), Gold Standard and Verra (VCS) are for projects in the four forest-based activities. 

The study examined the existing scientific foundations underlying the climate warming mitigation potential of 43 nature-based climate solutions, then sought independent expert judgment on their certainty. 

Steven Hamburg, Chief Scientist at the Environmental Defense Fund and co-author said, “Nature-based climate solutions are critical for meeting our climate goals. This study reaffirms the strength of the science underlying four major types of nature-based solutions and emphasizes the need to engage in additional research to clarify the mitigation potential of others.” 

Peter Ellis, Global Director of Natural Climate Solutions Science at The Nature Conservancy and co-author said, “Science is about bringing intelligence to action. That is exactly what we do in this paper: review the best available information to determine which nature-based climate solutions are ready for primetime.” 

Ruth DeFries, Denning Family Professor of Sustainable Development at Columbia University and co-author said, “The urgency for climate mitigation demands approaches based on sound science that can deliver effective action. The study is a call for ensuring that nature-based climate solutions focus on those actions that can deliver true mitigation, while continuing to develop the technical and scientific foundation for other types of nature-based actions.”   

Quotes from other co-authors: 

Ann Barutska, Senior Advisor at Resources for the Future, Senior Contributing Scientist for the Environmental Defense Fund and co-author said, “There is a clear need to have robust and reliable nature-based climate solution pathways as part of our climate change strategy. This work provides a clear roadmap to supporting the best options now while also guiding research towards key emerging solutions and pathways, such that we can confidently utilize and build on those in the future.” 

M. Granger Morgan, Hammerschlag University Professor of Engineering, Carnegie Mellon University and co-author said, “Because it is urgent that we reduce atmospheric concentrations of carbon dioxide rapidly, we cannot afford to be putting resources into nature-based strategies that may not work. This paper clearly identifies strategies that do work, as well as many others that should be avoided until they are robustly validated with further research.”