Does economic activity relocate away from areas that are at high risk of recurring shocks? We examine this question in the context of floods, which are among the costliest and most common natural disasters. Over the past thirty years, floods worldwide killed more than 500,000 people and displaced over 650,000,000 people. This paper analyzes the effect of large scale floods, which displaced at least 100,000 people each, in over 1,800 cities in 40 countries, from 2003-2008. We conduct our analysis using spatially detailed inundation maps and night lights data spanning the globe’s urban areas, which we use to measure local economic activity. We find that low elevation areas are about 3-4 times more likely to be hit by large floods than other areas, and yet they concentrate more economic activity per square kilometer. When cities are hit by large floods, these low elevation areas also sustain damage, but like the rest of the flooded cities they recover rapidly, and economic activity does not move to safer areas. Only in more recently populated urban areas, flooded areas show a larger and more persistent decline in economic activity. Our findings have important policy implications for aid, development and urban planning in a world with rapid urbanization and rising sea levels.

中文翻译：

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水淹城市

经济活动是否转移到了反复发生冲击的高风险地区？我们在洪水的背景下研究这个问题，洪水是最昂贵和最常见的自然灾害之一。在过去的三十年里，全世界的洪水造成超过 500,000 人死亡，超过 650,000,000 人流离失所。本文分析了 2003 年至 2008 年间在 40 个国家/地区的 1,800 多个城市发生的大规模洪水的影响，每次洪水至少造成 100,000 人流离失所。我们使用空间详细的淹没地图和跨越全球城市地区的夜间灯光数据进行分析，我们用这些数据来衡量当地的经济活动。我们发现低海拔地区比其他地区遭受大洪水袭击的可能性大约是其他地区的 3-4 倍，但它们每平方公里集中的经济活动更多。当城市遭受大洪水袭击时，这些低海拔地区也会遭受破坏，但与其他被洪水淹没的城市一样，它们会迅速恢复，经济活动不会转移到更安全的地区。只有在最近人口稠密的城市地区，被洪水淹没的地区才表现出更大和更持久的经济活动下降。在快速城市化和海平面上升的世界中，我们的研究结果对援助、发展和城市规划具有重要的政策意义。