New research in Communications Earth & Environment shows that ozone pollution from Amazon wildfires damages leaves on trees that survive the flames. That hidden effect reduces the rainforest's ability to absorb carbon by an amount equal to about 24% of the carbon released directly by burning. The damage gets worse during El Niño droughts, with ozone-related losses nearly doubling in the 2023-2024 dry period. Most Amazon fires are started by people to clear land for farming and cattle ranching. When they spread, they release CO2 and also produce ground-level ozone. That ozone harms surviving vegetation, so carbon uptake drops even in areas that did not burn. The study analyzed observations from 1997 to 2024 with a global vegetation model. For carbon markets and nature-based climate projects, this means fire accounting should include post-fire ozone damage. Cutting deforestation and controlling fires protects both the standing forest and its ability to pull CO2 from the atmosphere.
