2023-06-12 カリフォルニア大学校アーバイン校(UCI)
◆降水量の減少や高温、乾燥した燃料の蓄積などが主な要因です。今後も焼失地域は増加し、気候変動への対策が必要です。
＜関連情報＞
- https://news.uci.edu/2023/06/12/human-caused-climate-change-to-blame-for-increase-in-californias-wildfires/
- https://www.pnas.org/doi/10.1073/pnas.2213815120
人為的な気候変動の影響により、カリフォルニア州の夏の森林火災が悪化している。 Anthropogenic climate change impacts exacerbate summer forest fires in California
Marco Turco, John T. Abatzoglou, Sixto Herrera, Yizhou Zhuang, Sonia Jerez, Donald D. Lucas, Amir AghaKouchak , and Ivana Cvijanovic
Proceedings of the National Academy of Sciences Published:June 12, 2023
DOI:https://doi.org/10.1073/pnas.2213815120
Significance
The ongoing intensification in forest fire activity in California has had a dramatic impact on human activities and ecosystems alike. While an increase in temperatures and dryness has been identified to be one of the major drivers of increased summer forest burned area (BA), the extent to which such changes are due to natural variability or anthropogenic climate change remains unresolved. Using the latest simulations for climate change attribution and detection studies and accounting for the uncertainties arising from the data-driven climate-fire model and climate models, we quantify the influence of anthropogenic climate change on recent changes in BA. We show that nearly all of the observed increase in BA over the past half-century is attributable to anthropogenic climate change.
Abstract
Record-breaking summer forest fires have become a regular occurrence in California. Observations indicate a fivefold increase in summer burned area (BA) in forests in northern and central California during 1996 to 2021 relative to 1971 to 1995. While the higher temperature and increased dryness have been suggested to be the leading causes of increased BA, the extent to which BA changes are due to natural variability or anthropogenic climate change remains unresolved. Here, we develop a climate-driven model of summer BA evolution in California and combine it with natural-only and historical climate simulations to assess the importance of anthropogenic climate change on increased BA. Our results indicate that nearly all the observed increase in BA is due to anthropogenic climate change as historical model simulations accounting for anthropogenic forcing yield 172% (range 84 to 310%) more area burned than simulations with natural forcing only. We detect the signal of combined historical forcing on the observed BA emerging in 2001 with no detectable influence of the natural forcing alone. In addition, even when considering fuel limitations from fire-fuel feedbacks, a 3 to 52% increase in BA relative to the last decades is expected in the next decades (2031 to 2050), highlighting the need for proactive adaptations.
