A global view of observed changes in fire weather extremes: uncertainties and attribution to climate change

In many parts of the world, wildfires have become more frequent and intense in recent decades, raising concerns about the extent to which climate change contributes to the nature of extreme fire weather occurrences. However, studies seeking to attribute fire weather extremes to climate change are hitherto relatively rare and show large disparities depending on the employed methodology. Here, an empirical-statistical method is implemented as part of a global probabilistic framework to attribute recent changes in the likelihood and magnitude of extreme fire weather. The results show that the likelihood of climate-related fire risk has increased by at least a factor of four in approximately 40% of the world’s fire-prone regions as a result of rising global temperature. In addition, a set of recent fire weather events, occurring during a recent 5-year period (2014-2018) and identified as exceptional due to the extent to which they exceed previous maxima, are, in most cases, associated with an increase likelihood resulting from rising global temperature. The study’s conclusions highlight important uncertainties and sensitivities associated with the selection of indices and metrics to represent extreme fire weather and their implications for the findings of attribution studies. Among the recommendations made for future efforts to attribute fire weather extremes is the consideration of multiple fire weather indicators and communication of their sensitivities.