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Consistent drivers of lightning-ignited wildfires across global boreal forests

Year: 2026
Type: article
Abstract: Climate change is expected to change both fire susceptibility and lightning activity in global boreal forests. The mechanics governing lightning-ignited wildfire (LIW) ignition remain, however, unclear, making predictions at global boreal scale challenging. Here we examine short-term temporal impacts of weather on ignition probability using a novel dataset on LIWs in a quasi-experimental design of ignition and non-ignition lightning pairs. Specifically, our dataset is comprised of 5251 lightning pairs coupled with temperature, precipitation, relative humidity, lightning characteristics (multiplicity, polarity, peak current, and duration) and net primary productivity. We estimate the effect of these predictor variables on ignition probability across three separate models; the full boreal, open forests and closed forests. We find a clear relationship between ignition probability and temperature, relative humidity, total precipitation, and polarity. A one standard-deviation increase in temperature (∼3.3 °C) increased ignition probability by 44%–69%, while increased precipitation and relative humidity reduced ignition probability. Both temperature and precipitation were most predictive 3–8 d before lightning and the effect lasted up to 7–11 d after lightning. Positive polarity was also associated with increased ignition likelihood. Our results suggest that LIW occurrence within the global boreal is primarily driven by short-term fire weather rather than lightning characteristics alone. A projected increase in temperatures is expected to drive ignition probability in the boreal, though this may be partly offset by an increase in total precipitation.
DOI: 10.1088/1748-9326/aeb70b
Language: English
Open Access status: gold
Estimated APC paid: $3,045
OpenAlex ID: W7223153985
FWCI:
Cites: 56
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Related to: 10