Attribution analysis of changes in global droughts to anthropogenic influences

Drought is one of the most destructive natural disasters due to its prolonged and extensive socioeconomic impacts. It affects a massive number of people each year and inflicts significant challenges to the society and the environment. Compared to other natural hazards, the identification and characterization of drought are more challenging because of its slow onset and slow recovery, lack of a unified definition and the difficult specification of its exact area. It becomes even more complex by the interdependencies between drought characteristics and between drought and other extreme events such as heatwaves. A concurrent occurrence of drought and heatwave events can cause more severe impacts than any of the single hazards alone. The occurrence probability of such compound events is expected to rise due to climate change. Owing to these interdependencies at different spatial and temporal scales, a univariate analysis may lead to a significant underestimation of the overall drought impact. It thus calls for a multivariate analysis for a more realistic estimation of the impact to design adequate adaptation strategies, which has been overlooked. This research addresses this knowledge gap by a multivariate analysis of the contribution of anthropogenic influences to single drought events and compound drought-heatwave events at the global scale.