Global changes in floods and their drivers

Flooding is a major natural hazard that poses serious threats to lives and property safety, but changes in the multidimensional behavior of global floods (magnitude, frequency, and duration) are still not well understood. Additionally, a quantitative assessment of drivers that control multidimensional flood changes across the globe is currently unavailable. Here, we provided a global analysis of multidimensional flood changes and then developed a new attribution framework to quantify these changes to driving factors regarding heavy rainfall, antecedent wetness conditions, and snowmelt changes. The global assessment indicates that multidimensional floods tended to decrease during 1960–2014. Attribution analysis suggested that the dominant mechanism controlling flood magnitude changes was antecedent wetness, but flood frequency and duration changes were primarily driven by heavy rainfall. Notably, the increases in multidimensional flooding were mainly caused by the increasing heavy rainfall (primarily for maximum 30-day rainfall), while the decreases generally followed decreasing antecedent wetness conditions. Snowmelt mainly controlled the decrease in multidimensional floods for the stations in high-latitude regions. In addition, atmospheric circulation variation, water storage changes, catchment characteristics, and dams had considerable impacts on flood changes.