Impact of anthropogenic climate change on wildfire across western US forests
Impact of anthropogenic climate change on wildfire across western US forests
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DOI：
10.1073/pnas.1607171113
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发表时间：
2016-10-18
影响因子：
11.1
通讯作者：
Williams, A. Park
中科院分区：
文献类型：
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作者：
Abatzoglou, John T.;Williams, A. Park
近几十年来，美国西部大陆森林火灾活动的增加可能是由多种因素造成的，包括灭火和人类住区的遗留问题、自然气候变化和人为造成的气候变化。我们使用模拟气候预测来估计人为气候变化对观察到的美国西部八个燃料干旱指标和森林火灾面积增加的贡献。过去几十年来，人为造成的温度和蒸气压不足的增加显着加剧了美国西部森林的燃料干旱，并且在 2000 年至 2015 年期间，导致 75% 的森林面积经历高（> 1 西格玛）火灾季节燃料干旱，并且每年平均增加 9 天的高火灾可能性。 1979年至2015年，美国西部森林观测到的燃料干旱增加中，有55%是由人为气候变化造成的，这凸显了人为气候变化和自然气候变化是近几十年来野火潜力增加的重要因素。我们估计，1984-2015 年期间，人为引起的气候变化导致森林火灾面积增加了 420 万公顷，几乎是没有气候变化时预期森林火灾面积的两倍。自然气候变率将继续在调节和复合人为增加燃料干旱之间交替，但人为气候变化已成为森林火灾活动增加的驱动因素，并且在燃料不受限制的情况下应该继续这样做。
Increased forest fire activity across the western continental United States (US) in recent decades has likely been enabled by a number of factors, including the legacy of fire suppression and human settlement, natural climate variability, and human-caused climate change. We use modeled climate projections to estimate the contribution of anthropogenic climate change to observed increases in eight fuel aridity metrics and forest fire area across the western United States. Anthropogenic increases in temperature and vapor pressure deficit significantly enhanced fuel aridity across western US forests over the past several decades and, during 2000-2015, contributed to 75% more forested area experiencing high (> 1 sigma) fire-season fuel aridity and an average of nine additional days per year of high fire potential. Anthropogenic climate change accounted for similar to 55% of observed increases in fuel aridity from 1979 to 2015 across western US forests, highlighting both anthropogenic climate change and natural climate variability as important contributors to increased wildfire potential in recent decades. We estimate that human-caused climate change contributed to an additional 4.2 million ha of forest fire area during 19842015, nearly doubling the forest fire area expected in its absence. Natural climate variability will continue to alternate between modulating and compounding anthropogenic increases in fuel aridity, but anthropogenic climate change has emerged as a driver of increased forest fire activity and should continue to do so while fuels are not limiting.