Local factors mediate climate and land use effects on global fire regimes (2003-2020)

Abstract

Changes in fire activity challenge policymakers, land managers and the general public. Burned area (BA) is declining globally, but 81% of BA occurs in just 22 countries, and growth rate may be more important for public safety. We used eight fire regime components from country-level datasets to characterize fire regimes for 241 countries from 2003-2020. Fire regimes followed two axes of variation, with BA versus event duration on one axis, and season length versus event size and spread rate on the other. Annual trends in fire regime components were mixed, with no trend being most common, as expected given the short time series. Increases in fire activity were associated with increases in aridity in boreal, temperate and equatorial countries, and with land cover changes in arid countries. But these associations explained <40% of model variation, indicating that local and regional circumstances are more important than broad generalizations from global models.