Everglades' Climate Footprint shows wetlands remain a net carbon sink

A Yale School of the Environment study published in the Proceeding of the National Academy of Sciences reports the 1.5‑million‑acre Everglades removes about 13.7 million metric tons of CO2 per year and that mangroves capture more carbon while freshwater marshes emit proportionally more methane.

The Everglades continues to act as a significant carbon sink while also releasing methane, according to a Yale School of the Environment study published in the Proceeding of the National Academy of Sciences (PNAS). The research examined greenhouse gas fluxes across mangroves and freshwater marshes within the 1.5‑million‑acre system to clarify how different wetland types store and emit gases. The team combined long‑term tower records, aircraft atmospheric sampling, and satellite vegetation data to model carbon exchange over recent decades. Authors said the analysis offers a more detailed basis for informing restoration and protection decisions. Key findings: - The Everglades removes an average of about 13.7 million metric tons of carbon dioxide from the atmosphere each year. - Between 2003 and 2020, the study found an 18% increase in carbon capture across the study area. - Saltwater mangroves showed the greatest capacity for net carbon capture; in mangroves roughly 16% of captured CO2 was offset by methane emissions. - In freshwater marshes, nearly 82% of captured CO2 was offset by net methane emissions. - Methane is noted in the article as responsible for about 30% of warming since industrialization and traps over 80 times more heat than CO2 over a 20‑year period. - The analysis drew on Coastal Everglades Ameriflux tower measurements, NASA aircraft atmospheric data from 2022–2024, and satellite vegetation records, combined into a model estimating carbon exchange from 2000–2024. Summary: The study finds the Everglades remains a major carbon sink overall while showing substantial differences between mangroves and freshwater marshes in the balance of CO2 uptake and methane release. The authors said that combining tower, flight, and satellite data into a unified model can help identify conditions under which different wetland types capture and store carbon most efficiently, allowing land managers to prioritize protection and restoration efforts. Undetermined at this time