Precipitation extremes are increasing globally due to anthropogenic climate change. However, there remains uncertainty regarding impacts upon flood occurrence and subsequent population exposure. Here, we quantify changes in population exposure to flood hazard across the contiguous United States. We combine simulations from a climate model large ensemble and a high‐resolution hydrodynamic flood model—allowing us to directly assess changes across a wide range of extreme precipitation magnitudes and accumulation timescales. We report a mean increase in the 100‐year precipitation event of ~20% (magnitude) and >200% (frequency) in a high warming scenario, yielding a ~30–127% increase in population exposure. We further find a nonlinear increase for the most intense precipitation events—suggesting accelerating societal impacts from historically rare or unprecedented precipitation events in the 21st century.

中文翻译：

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美国气候变化和人口增长导致洪水泛滥

由于人为气候变化，全球范围内的极端降水正在增加。但是，对于洪水的发生和随后的人口暴露的影响仍然不确定。在这里，我们量化了整个连续美国人口遭受洪灾危害的变化。我们将来自大型整体气候模型和高分辨率水动力洪水模型的模拟相结合，使我们能够直接评估各种极端降水量和累积时间尺度的变化。我们报告说，在高度变暖的情况下，100年降水事件的平均增加幅度为〜20％（幅度），> 200％（频率），导致人口暴露增加了〜30–127％。