Escalating Fire-Driven Forest Loss in Protected Tropical Forests.

Wildfires are driving substantial losses of tropical forest, with climate change expected to increase fire-driven losses throughout the century. Whether Protected Areas (PAs)-and the vital habitat they protect-are buffered from fire is a key question. Here we combine PA and stand-replacing fire data to estimate that > 4 million hectares (Mha) of protected tropical forest have been lost to stand-replacing fire since 2001, with one-third of losses (1.35 Mha) occurring in 2024 alone. The vast majority of losses (89%) were concentrated in the tropical Americas (3.6 Mha), most of which occurred in Brazil (2.7 Mha), followed by Asia-Pacific (0.31 Mha) and Africa (0.14 Mha). Increasing trends in annual losses were observed across the Americas and Africa, occurring in 30 countries across the tropics. Counterfactual analysis suggests that despite considerable heterogeneity PAs most often reduce the probability of stand-replacing fires relative to non-PAs across the tropics. In the Americas, protection reduced stand-replacing fires in 48% of protected plots, rising to 71% and 55% in Africa and Asia-Pacific, respectively. However, temporal burn trends remained tightly coupled inside and outside of PAs, suggesting PAs are equally exposed to increasing global trends in fire activity. Ensuring existing PAs are protected from anthropogenic ignition sources is a priority, but subsequent PA planning must consider future fire risk to ensure they remain an effective conservation tool in a changing climate.