Freshwater ecosystems like rivers, floodplains, and wetlands offer a powerful yet overlooked way to support global carbon removal by storing carbon in vegetation and soils. In this study, we mapped these important areas around the world—called High-Value Freshwater Ecosystems (HVFEs)—using high-resolution data. We then estimated how much carbon could be removed from the atmosphere if forests were restored in these degraded areas, especially those currently used for farming or covered by short vegetation.

We found that restoring forests in these freshwater-adjacent lands could remove between 1.07 and 3.41 billion tons of CO₂ each year, depending on how floodplains are counted. About half of this potential lies in 49 countries already committed to the Freshwater Challenge, a global restoration effort. We also identified regions where restoration would have the biggest impact per hectare and compared results by countries’ climate pledges.

This work offers a practical, science-based tool to help decision-makers target restoration efforts that benefit both the climate and freshwater ecosystems.