Extreme weather and migration in the United States
研究利用美国县级1950-2010年数据，发现极端温度和降水与净迁移率下降相关，且主要由年轻人驱动，不限于农业县。
Extreme weather has become more frequent and intense over the past few decades. Given that the United States population has been historically highly mobile, direct and indirect effects of extreme weather could catalyze people to migrate. We test this empirically by exploiting spatial and temporal variation in temperature and precipitation at the county level over 6 decades (1950–2010). A non-parametric estimation yields an inverted U-shape relationship between temperature and net-migration, where decades in which the average temperature was more extreme are associated with lower net-migration. The effects are strongest for the most extreme average temperatures. We also find that extreme precipitation is associated with lower net-migration. These responses are driven by younger adults, and are not unique to agriculturally-dependent counties. These results are important as migration could mitigate the detrimental effects of climate change in the developed world. • We study the impact of extreme weather on county-level net-migration over 6 decades. • Extreme temperatures and precipitation are associated with lower net-migration. • Migration results are driven by younger adults. • Migration results are not unique to agriculturally-dependent counties. • Migration could mitigate the detrimental effects of climate change in the US.