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Human activity augments lightning ignitions to reshape fire seasonality across all biomes on Earth

Year: 2025
Type: article
Abstract: The conjunction of lightning ignitions and dry vegetation has shaped fire regimes throughout geological time. These natural fire regimes have in turn influenced the adaptation of biotas globally. Anthropogenic fire use, however, radically transformed worldwide fire regimes by extending seasons to the limits bounded by periods of high fuel moisture. Conversely, active fire suppression has typically limited the occurrence and extent of lightning ignited fires – particularly where population density is higher. Disaggregating contemporary human- and lightning-caused seasonal fire patterns globally can shed light on the magnitude of the anthropogenic change to fire regimes among biomes. Using global datasets of flammability moisture thresholds and fuel moisture we define the global distribution of fire seasons. We then use a global record of lightning strike density to disaggregate the fire season into mixed (i.e., lightning present) and anthropogenic ignitions periods, before describing the respective importance of these periods amongst biomes. We assess these the breadth of these ignitions periods against a daily satellite burned area record (2001–2023) and contextualise the occurrence of areas burned within mixed and anthropogenic ignitions periods against vegetation productivity and human population density using the established productivity-fire activity relationship. Collectively, we show that current anthropogenic influences have transformed worldwide fire regimes by substantially lengthening fire seasons, irrespective of local land use and fire suppression practices, population density, lightning occurrence, and biome type.
DOI: 10.1038/s41559-025-02862-w
Language: English
Open Access status: green
OpenAlex ID: W4414392485
FWCI: 3.721
Cites: 99
Cited by: 15
Related to: 10