Pervasive fire danger continued under a negative emission scenario

Enhanced fire-prone weather under greenhouse gas warming can significantly affect local and global carbon budgets from increased fire occurrence, influencing carbon-climate feedbacks. However, the extent to which changes in fire-prone weather and associated carbon emissions can be mitigated by negative emissions remains uncertain. Here, we analyze fire weather responses in CO₂ removal climate model experiments and estimate their potential carbon emissions based on an observational relationship between fire weather and fire-induced CO₂ emissions. The results highlight that enhanced fire danger under global warming cannot be restored instantaneously by CO₂ reduction, mainly due to atmospheric dryness maintained by climatic inertia. The exacerbated fire danger is projected to contribute to extra CO₂ emissions in 68% of global regions due to the hysteresis of climate responses to CO₂ levels. These findings highlight that even under global cooling from negative emissions, increased fire activity may reinforce the fire-carbon-climate feedback loop and result in further socio-economic damage.