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.
Forthcoming, American Economic Journal: Applied Economics
If the economic costs of flooding are high, and cities at lower elevations tend to flood more frequently, why do communities continue to rebuild on the same, flood-prone lands? This blog explores the economic impact of flooding and suggests that aid for reconstruction could be used to encourage economic activity to shift away from flood prone areas.