Extreme Weather Disasters, Economic Losses via Migration, and Widening Spatial Inequality in the U.S.

2017年，美国因160亿美元的极端天气灾害造成的经济损失创下了3130亿美元的新纪录。极端天气灾害造成的经济损失在空间上集中在佛罗里达州等州，并且随着时间的推移非常稳定。虽然人们留在易发灾害地区的原因有很多，但也有人选择迁移或被迫离开，有些是暂时的，有些是永久的。作为经济行为者，移民带来了无数的经济活动，这些经济活动构成了以前的研究没有研究过的经济损失。该项目将是第一个记录极端天气事件后美国受影响地区移民造成的经济损失规模的项目。由于移民必然将各地联系在一起，该项目还将记录移民带来的经济损失是否以及在多大程度上改变了美国整体的空间不平等。项目结果将为如何减轻美国极端天气灾害的经济成本的政策提供参考，从而为灾后恢复和经济繁荣做出贡献。该项目使用来自美国国税局（IRS）收入统计项目和纽约联邦储备银行消费者信贷小组（CCP）的县级数据，记录和分析过去20年美国极端天气灾害后受影响地区移民造成的经济损失。移民造成的总经济损失分别在IRS和CCP数据中使用调整后总收入和债务融资消费活动的信息来衡量。在总结了极端天气灾害后受灾地区人口迁移造成的经济损失规模之后，该项目将使用人口分解程序来区分经济成分（平均或人均人口迁移造成的经济损失）和人口成分（迁移倾向以及受灾地区的人口规模）的相对贡献。为了进一步认识到移民的内在空间特征，本项目还利用衡量移民网络流动的空间集中程度的两种基尼指数，记录了极端天气灾害后受影响地区移民造成的经济损失是否以及在多大程度上加剧了美国空间不平等的变化。鉴于极端天气灾害与移民之间的关系存在异质性，本项目采用个案比较方法，重点研究了三种极端天气灾害类型，包括热带气旋、龙卷风和野火。根据美国空间灾害事件和损失数据库（SHELDUS）的数据，这些县在过去20年里遭受了大量经济损失。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In 2017, the U.S. set a new record of $313 billion in economic losses from sixteen billion-dollar extreme weather disasters. Economic losses from extreme weather disasters are spatially concentrated in states like Florida and are remarkably stable over time. While there are many reasons that people stay in disaster-prone areas, others choose to migrate or are forced to leave, some temporarily and others permanently. As economic actors, migrants take with them myriad economic activities that constitute economic losses that have not been studied in previous research. This project will be the first to document the size of economic losses via migration from affected areas in the U.S. after extreme weather events. Because migration necessarily connects places to one another, the project will also document whether and to what extent such economic losses via migration contribute to changing spatial inequality in the U.S. as a whole. Project results will provide input into policies concerning how to mitigate the economic costs of extreme weather disasters in the U.S., thus contributing to disaster recovery and economic prosperity. This project uses county-level data from the Statistics of Income program at the Internal Revenue Service (IRS) and the Federal Reserve Bank of New York Consumer Credit Panel (CCP) to document and analyze economic losses via migration from affected areas after extreme weather disasters in the U.S. over the past two decades. Total economic losses via migration are measured in the IRS and CCP data using information on aggregate adjusted gross income and debt-financed consumption activities, respectively. After summarizing the size of economic losses via migration from affected areas after extreme weather disasters, the project will use demographic decomposition procedures to distinguish the relative contributions of economic components (average, or per capita, economic losses via migration) and demographic components (the propensity to migrate, as well as population size in the affected area). Further acknowledging the inherently spatial character of migration, this project also documents whether and to what extent economic losses via migration from affected areas after extreme weather disasters contribute to changing spatial inequality in the U.S. using two variants of the Gini Index that measure spatial focusing among flows in migration networks. Given heterogeneity in the relationship between extreme weather disasters and migration, this project takes a case-specific and comparative approach, focusing on three types of extreme weather disasters, including tropical cyclones, tornadoes, and wildfires, in counties that have experienced the bulk of economic losses over the last twenty years according to the Spatial Hazards Events and Losses Database for the United States (SHELDUS).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.