Enhancement of river flooding due to global warming

Abstract

Human-induced climate change has increased the frequency and intensity of heavy precipitation¹. Due to the complexity of runoff generation and the streamflow process, the historical impact of human-induced climate change on river flooding remains uncertain. Here, we address the question of whether anthropogenic climate change has altered the probability of the extreme river flood events for the period 1951-2010 based on simulated river discharge derived from large ensemble climate experiments with and without human-induced climate change. The results indicate that human-induced climate change altered the probabilities of 20 of the 52 analyzed flood events. Fourteen of these 20 flood events, which occurred mainly in Asia and South America, were very likely to have been enhanced by human-induced climate change due to an increase in heavy precipitation. Conversely, two flood events in North/South America and two flood events in Asia and two flood events in Europe were suppressed by human-induced climate change, perhaps as a result of lower snowfall. Human-induced climate change has enhanced flooding more prominently in recent years, providing important insights into potential adaptation strategies for river flooding.

Figure 1

Global distribution of flood events included in this study. This figure was created using Python (3.9.7) and the Basemap library (1.2.2).

Figure 2

(a) Scatterplots of fraction of attribution risk (FAR, absolute values) and flood year and (b) bar chart of enhancement or suppression of flooding events during 1961–2010. Detailed information on these flood events is provided in Supplementary Table S1.