The Amazon rainforest, near Manaus, Brazil. Neil Palmer / CIAT

Last year, the acreage burned in the Brazilian Amazon reached its lowest level in at least four decades.

A new analysis from the monitoring group MapBiomas finds that 7.7 million acres burned last year, down from a record high of 39 million acres the previous year. The sharp drop in acres burned came as a warming El Niño gave way to a cooling La Niña.

In 2024, El Niño helped fuel the worst drought to hit the Amazon in decades. Fires proliferated on farmland that had recently been cleared and quickly spread to surrounding rainforest. Even as Brazil cracked down on the deliberate destruction of forest, deepening drought gave rise to thousands of fires across the region.…