The ongoing increases in anthropogenic radiative forcing have changed the global water cycle and are expected to lead to more intense precipitation extremes and associated floods. However, given the limitations of observations and model simulations, evidence of the impact of anthropogenic climate change on past extreme river discharge is scarce. Here, a large ensemble numerical simulation revealed that 64% (14 of 22 events) of floods analyzed during 2010-2013 were affected by anthropogenic climate change. Four flood events in Asia, Europe, and South America were enhanced within the 90% likelihood range. Of eight snow-induced floods analyzed, three were enhanced and four events were suppressed, indicating that the effects of climate change are more likely to be seen in the snow-induced floods. A global-scale analysis of flood frequency revealed that anthropogenic climate change enhanced the occurrence of floods during 2010-2013 in wide area of northern Eurasia, part of northwestern India, and central Africa, while suppressing the occurrence of floods in part of northeastern Eurasia, southern Africa, central to eastern North America and South America. Since the changes in the occurrence of flooding are the results of several hydrological processes, such as snow melt and changes in seasonal and extreme precipitation, and because a climate change signal is often not detectable from limited observation records, large ensemble discharge simulation provides insights into anthropogenic effects on past fluvial floods.

人为辐射强迫的持续增加改变了全球水循环，预计会导致更强烈的极端降水和相关的洪水。然而，鉴于观测和模型模拟的局限性，人为气候变化对过去极端河流流量影响的证据很少。在这里，大型集合数值模拟显示，2010-2013 年分析的洪水中有 64%（22 次事件中的 14 次）受到人为气候变化的影响。亚洲、欧洲和南美洲的四次洪水事件在 90% 的可能性范围内增强。在分析的 8 场雪灾中，有 3 场被加强，4 场被抑制，表明气候变化的影响更可能在雪灾中看到。全球尺度的洪水频率分析表明，2010-2013 年间，人为气候变化加剧了欧亚大陆北部、印度西北部部分地区和中非地区的洪水发生，同时抑制了欧亚大陆东北部部分地区的洪水发生。非洲南部、北美洲中部至东部和南美洲。由于洪水发生的变化是多个水文过程的结果，例如融雪和季节性和极端降水的变化，并且由于气候变化信号通常无法从有限的观测记录中检测到，大型集合流量模拟提供了深入了解对过去河流洪水的人为影响。印度西北部和非洲中部的部分地区，同时抑制了欧亚大陆东北部、非洲南部、北美中东部和南美部分地区洪水的发生。由于洪水发生的变化是多个水文过程的结果，例如融雪和季节性和极端降水的变化，并且由于气候变化信号通常无法从有限的观测记录中检测到，大型集合流量模拟提供了深入了解对过去河流洪水的人为影响。印度西北部和非洲中部的部分地区，同时抑制了欧亚大陆东北部、非洲南部、北美中东部和南美部分地区洪水的发生。由于洪水发生的变化是多个水文过程的结果，例如融雪和季节性和极端降水的变化，并且由于气候变化信号通常无法从有限的观测记录中检测到，大型集合流量模拟提供了深入了解对过去河流洪水的人为影响。