Attributing human mortality from fire PM2.5 to climate change

Abstract

Climate change intensifies fire smoke, emitting hazardous air pollutants that impact human health. However, the global influence of climate change on fire-induced health impacts remains unquantified. Here we used three well-tested fire–vegetation models in combination with a chemical transport model and health risk assessment framework to attribute global human mortality from fire fine particulate matter (PM2.5) emissions to climate change. Of the 46,401 (1960s) to 98,748 (2010s) annual fire PM2.5 mortalities, 669 (1.2%, 1960s) to 12,566 (12.8%, 2010s) were attributed to climate change. The most substantial influence of climate change on fire mortality occurred in South America, Australia and Europe, coinciding with decreased relative humidity and in boreal forests with increased air temperature. Increasing relative humidity lowered fire mortality in other regions, such as South Asia. Our study highlights the role of climate change in fire mortality, aiding public health authorities in spatial targeting adaptation measures for sensitive fire-prone areas. The authors combine fire–vegetation models, a chemical transport model and a health risk model to link human mortality from fire emissions to climate change. They estimate that 12.8% of mortalities in 2010 were linked to climate change, with South America, Australia, Europe and boreal forests most impacted.