Increasing Tropical Cyclone Precipitation Exposures over the Continental U.S.

Abstract Extreme tropical cyclone precipitation (TCP) can cause massive stress to society by generating inland flooding events. Historical observations have shown global and regional trends in TCP and climate models predict there will be substantial increases in TCP under anthropogenic global warming. Changes in both physical risk and in human society together determine the exposure to extreme weather events. However, they are rarely studied together and more knowledge is needed to be understood how they interact and to determine exposure at the local level. Here high-quality in-situ precipitation observations and gridded population and Gross Domestic Product (GDP) data were used to develop a social exposure index to quantify how TCP risk changes as a function of both physical risk and socioeconomic exposure. We demonstrate that while physical TCP risk is increasing in the United States, there are regional differences in exposure due to the heterogeneity of the population and economic development. Exposure hot spots are mostly concentrated in southern states with high population density. Rapid population growth and economic development have magnified societal exposure to those extreme TCP events. This multi-scale evaluation framework identifies locations where mitigation and adaptation to climate change are important.