Wildfire precursors show complementary predictability in different timescales

In most of the world, conditions conducive to wildfires are becoming more prevalent. Net carbon emissions from wildfires contribute to a positive climate feedback that needs to be monitored, quantified, and predicted. Here we use a causal inference approach to evaluate the influence of top-down weather and bottom-up fuel precursors on wildfires. The top-down dominance on wildfires is more widespread than bottom-up dominance, accounting for 73.3% and 26.7% of regions, respectively. The top-down precursors dominate in the tropical rainforests, mid-latitudes, and eastern Siberian boreal forests. The bottom-up precursors dominate in North American and European boreal forests, and African and Australian savannahs. Our study identifies areas where wildfires are governed by fuel conditions and hence where fuel management practices may be more effective. Moreover, our study also highlights that top-down and bottom-up precursors show complementary wildfire predictability across timescales. Seasonal or interannual predictions are feasible in regions where bottom-up precursors dominate. This paper shows that weather and fuel precursors show complementary predictability of wildfires extending across different timescales, which may be leveraged for seasonal or interannual wildfire prediction.

Automated summary

In many parts of the world, conditions for wildfires are increasing. This study examines the impact of weather and fuel conditions on wildfires and finds that weather plays a larger role than fuel, especially in tropical rainforests, mid-latitudes, and Siberian boreal forests. Fuel conditions are more dominant in North American and European boreal forests, as well as African and Australian savannahs. The study also highlights the complementary predictability of weather and fuel conditions for wildfire forecasting, with seasonal or interannual predictions feasible in areas where fuel conditions dominate.