To what extent were the summer 2022 wildfires in Southwest France attributable to anthropogenic climate change?

Summer 2022 was exceptionally hot and dry in Europe and especially in Southwest France where the most important wildfires since 1949 had serious environmental and socio-economic impacts. An impact-oriented climate change attribution study was conducted and published recently by Marine Lanet (Laboratoire de météorologie dynamique, Sorbonne Université, CNRS) and her colleagues from IPSL (Institut Pierre Simon Laplace, Sorbonne Université, CNRS). The authors firstly investigated an ensemble of climate indices in order to find the most correlated one with the burnt area of the Landes Forest. Actually, the index combining soil moisture integrated over 6 months and temperature and vapour pressure deficit integrated over 3 months is the best-correlated one to wildfires. It can then be used to estimate the extent of summer 2022 wildfires that can be attributed to anthropogenic climate change. The results show that climate conditions propitious for the summer 2022 wildfire development have a return period of 13 years in the current climate. This return period would be 30 years without anthropogenic climate change. The fraction of attributable risk associated with the ongoing anthropogenic climate change is estimated at 50%. This study raises the question of the sustainability of the Landes Forest and stresses the urgent need to mitigate greenhouse gas emissions and to adapt to climate change.