Recent increases in regional wildfire activity have been linked to climate change. Here, we analyse trends in observed global extreme fire weather and their meteorological drivers from 1979 to 2020 using the ERA5 reanalysis. Trends in annual extreme (95th percentile) values of the fire weather index (FWI₉₅), initial spread index (ISI₉₅) and vapour pressure deficit (VPD₉₅) varied regionally, with global increases in mean values of 14, 12 and 12%, respectively. Significant increases occurred over a quarter to almost half of the global burnable land mass. Decreasing relative humidity was a driver of over three-quarters of significant increases in FWI₉₅ and ISI₉₅, while increasing temperature was a driver for 40% of significant trends. Trends in VPD₉₅ were predominantly associated with increasing temperature. These trends are likely to continue, as climate change projections suggest global decreases in relative humidity and increases in temperature that may increase future fire risk where fuels remain abundant.

最近区域野火活动的增加与气候变化有关。在这里，我们使用 ERA5 再分析分析了 1979 年至 2020 年观测到的全球极端火灾天气及其气象驱动因素的趋势。火灾天气指数 (FWI ₉₅ )、初始蔓延指数 (ISI ₉₅ ) 和水汽压差 (VPD ₉₅ ) 的年度极端（第 95 个百分位）值趋势因地区而异，全球平均值分别增加 14%、12% 和 12% ， 分别。全球可燃土地面积的四分之一至近一半显着增加。_{降低相对湿度是 FWI 95}和 ISI ₉₅显着增加四分之三以上的驱动因素，而温度升高是 40% 的重要趋势的驱动因素。VPD ₉₅的趋势主要与温度升高有关。这些趋势可能会继续下去，因为气候变化预测表明全球相对湿度下降和温度升高，这可能会增加未来燃料仍然充足的火灾风险。