Amazon scientists deliver stark warning at cop30: carbon offsets are no longer viable as forests transform from climate allies to carbon sources

A groundbreaking moment occurred at COP30 in Belém, Brazil—the first UN climate summit ever held in the Amazon rainforest. Leading climate scientists have issued an unprecedented public declaration that aligns with what Indigenous communities and environmental advocates have been saying for years: forests can no longer serve as reliable carbon offsets for continued fossil fuel emissions.

The warning comes from Brazil’s COP30 Science Council, featuring world-renowned experts including Carlos Nobre, Paulo Artaxo, Piers Forster, Thelma Krug, and Johan Rockström—scientists who specialize in climate tipping points and Earth’s natural systems. Their message is unusually direct: the world is “already facing danger,” fossil fuel emissions must begin declining immediately, and the Amazon rainforest has become too unstable to function as a dependable carbon sink that can compensate for ongoing coal, oil, and gas burning.

The scientific reasoning is stark yet clear. The Amazon, once Earth’s most powerful climate stabilizer, is experiencing unprecedented stress from drought, extreme heat, wildfires, and deforestation. These pressures are fundamentally undermining the forest’s capacity to absorb and store carbon dioxide. Alarmingly, some regions of the Amazon have already reversed their role entirely—transforming from carbon absorbers into carbon emitters.

This shift exposes a critical flaw in carbon offset logic: permanent fossil fuel emissions cannot be legitimately balanced by temporary, increasingly vulnerable forest carbon storage. As forest fires release stored carbon back into the atmosphere and weakened ecosystems lose their absorption capacity, the mathematical foundation of forest-based carbon offsets crumbles. The scientists’ declaration represents a pivotal moment where established climate science definitively challenges one of the most popular corporate climate strategies.