By the end of this century, residents of major US cities could experience greater exposure to extreme heat than at present, a study suggests. Previous projections of future temperature extremes in the continental United States have not accounted directly for warming due to urban development or its interactions with greenhouse gas (GHG)-induced climate change. Such projections have also defined extremes using a fixed temperature threshold, but threshold temperatures at which excess mortality occurs vary regionally. Ashley Broadbent, Matei Georgescu, and colleagues assessed the simultaneous contributions of GHG-induced warming, urban development, and population growth to projected changes in population-weighted exposure to extreme heat and cold in 47 major metropolitan areas in the continental United States across the 21st century. The authors projected that under a high-emissions scenario, population-weighted exposure to locally defined extreme heat would increase by 12.7-29.5 times by the end of the 21st century, relative to the beginning of the century, substantially greater than in previous projections. Cities in the US Sunbelt, such as Austin, Miami, and Atlanta, were projected to have the largest relative increases in population heat exposure, driven primarily by simultaneous GHG-induced warming and rapid population growth. The authors also projected a marginal increase in population-weighted cold exposure. The findings could help prioritize urban climate adaptation measures and policy, according to the authors.
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Article #20-05492: "The motley drivers of heat and cold exposure in 21st century US cities," by Ashley Mark Broadbent, Eric Scott Krayenhoff, and Matei Georgescu.
MEDIA CONTACT: Matei Georgescu, Arizona State University, Tempe, AZ; tel: 732-433-7161; e-mail: Matei.Georgescu@asu.edu ; Ashley Mark Broadbent, Arizona State University, Tempe, AZ; tel: +64-022-599-1823; e-mail: ashley.broadbent@asu.edu
Proceedings of the National Academy of Sciences