A new study finds that four nature-based climate solutions—the ones that companies and other entities use most often to claim carbon credits—have robust scientific foundations. The four pathways are conservation or reforestation of tropical forests; and conservation or reforestation of temperate forests.

The majority of other such methods need additional research before their potential can be assessed, say the authors. The research was just published in the journal Nature Climate Change.

Nature-based climate solutions are conservation, restoration or management strategies whose primary purpose is to mitigate greenhouse-gas emissions or remove carbon from the atmosphere. More than 100 of the 167 signatories to the Paris Accords include them as part of their mitigation plans. Many, including Indonesia, Colombia and China are already using them to demonstrate progress on their climate commitments.

The study looked at the scientific basis of, and expert confidence in, 43 solutions. It did not examine implementation of individual projects, methods of calculating carbon credits or co-benefits of carbon-reduction projects.

Carbon-crediting protocols exist for 35 of the solutions that the researchers considered, and various entities have used 28 of the solutions to garner credits. The good news: Some 70% of nature-based credits tracked by the researchers have been for projects in the four forest-based categories that they found most credible. Other methods, such as agroforestry, conservation of mangroves and peatlands, and restoration of grasslands, need more research, said the authors.

Study co-author Ruth DeFries, chief academic officer of the Columbia Climate School, 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."

Another co-author of the study, Steven Hamburg, chief scientist at the Environmental Defense Fund, 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."

This story is republished courtesy of Earth Institute, Columbia University http://blogs.ei.columbia.edu.