Synchronized Extremes in Forest Wildfires: Amplified Recovery Delays from Coupled Intensity and Severity

Extreme forest fires are escalating globally, causing extensive forest loss and prolonged recovery time, which raises the risk of forests transitioning from carbon sinks to sources. However, most studies define extreme fires solely by burned area, neglecting interactions among fire characteristics and potentially underestimating their impacts on post-fire recovery. Here we constructed a global multidimensional forest fire dataset (2001–2021) comprising >300,000 events with burned area, intensity, duration, spread rate, and severity. After around 2010, fire characteristics intensified, especially in extratropical forests, with burned area and duration often triggering cascading amplifications of intensity, spread rate, and severity. While extreme large‑area fires frequently coincided with fast spread and long duration, they seldom reached extremes in both intensity and severity. Notably, the 244 forest fires that were extreme across all five dimensions simultaneously increased significantly, yet 75% occurred after 2011. Forests affected by these synchronized extremes required 1.2 years longer to recover than the global mean and also 0.4–1.0 years longer than fires extreme in any single dimension. We further identified that the interaction between fire intensity and severity as the primary driver of prolonged recovery across nearly all biogeographic pyromes. These results demonstrate that conventionally defined extreme large-area fires do not necessarily represent the most ecologically damaging events. Despite increasing global fire-suppression investment, current strategies may primarily remove low-intensity, small fires while failing to mitigate the catastrophic consequences of climate-amplified extreme wildfires, escalating threat poses profound challenges to global forest recovery and carbon-cycle stability.