New research tracking over half a million trees across six South American countries over 30 years shows that tropical forests can stop absorbing carbon during El Nino events. The 2015-2016 El Nino caused some forests to effectively become carbon sources, with larger trees dying at double the normal rate due to hydraulic failure. Drier forests at the edges of the Amazon were hit hardest, losing 0.5% of aboveground carbon per 0.5 degree Celsius temperature increase. The study raises serious questions about the reliability of tropical forests as natural carbon sinks under a warming climate. With El Nino events becoming more frequent and intense, and 2026 potentially being the warmest year on record, the Amazon's ability to store carbon may be compromised. This has direct implications for carbon offset projects that rely on forest conservation and for global climate models that assume continued carbon uptake by tropical forests.
