A human-driven decline in global burned area

TLDR

Fire is an essential Earth system process that alters ecosystem and atmospheric composition. The study assessed long‑term fire trends with multiple satellite datasets and developed a conceptual model using economic and demographic variables to predict fire in human‑dominated landscapes. Global burned area declined by 24.3 ± 8.8 % over the past 18 years, a robust decrease driven mainly by agricultural expansion and intensification, largest in savannas, leading to fewer and smaller fires that reduced aerosol concentrations, altered vegetation structure, and increased the terrestrial carbon sink, while fire models failed to reproduce this pattern, suggesting they may overestimate future fire emissions.

Abstract

Fire is an essential Earth system process that alters ecosystem and atmospheric composition. Here we assessed long-term fire trends using multiple satellite data sets. We found that global burned area declined by 24.3 ± 8.8% over the past 18 years. The estimated decrease in burned area remained robust after adjusting for precipitation variability and was largest in savannas. Agricultural expansion and intensification were primary drivers of declining fire activity. Fewer and smaller fires reduced aerosol concentrations, modified vegetation structure, and increased the magnitude of the terrestrial carbon sink. Fire models were unable to reproduce the pattern and magnitude of observed declines, suggesting that they may overestimate fire emissions in future projections. Using economic and demographic variables, we developed a conceptual model for predicting fire in human-dominated landscapes.