A quarter of the US land area, home to more than 100mn people, will be subjected to temperatures of more than 125F (52C) in three decades, including states with rapid population growth such as Texas, a report forecasts.
The “extreme heat belt”, in which heat indices exceed such temperatures, will expand from 50 counties in 2023 to more than 1,000 by 2053, according to a new report from First Street Foundation, a New York-based non-profit climate risk research group.
The findings point to an increasingly severe impact on US population centres and property markets as the planet is warmed by greenhouse gas emissions. Temperatures have risen 1.1C globally since preindustrial times.
Heatwaves have baked much of the US this summer, with record temperatures in Texas and near-record figures from the Pacific Northwest to the north-east last month, according to the National Oceanic and Atmospheric Administration.
“Extreme danger” is the term used by the National Weather Service for a heat index — a combination of temperature and humidity — of 125F or greater, which elevates the risk of heatstroke, cardiovascular problems and death. The number of people in the US exposed to such temperatures is expected to grow from 8mn in 2023 to 107mn in 2053, First Street said.
The report said that the increase in extreme heat above 125F would be concentrated in the central US, stretching from northern Texas to states such as Indiana, Illinois and Iowa that are far from the cooling coasts.
The top five cities vulnerable to extreme heat days were St Louis and Kansas City, Missouri; Memphis, Tennessee; Tulsa, Oklahoma and Chicago, Illinois, the report said, incorporating government data and academic research.
The report also examined locations by the number of days the heat index would exceed 100F (38C). While five counties — four in Texas and one in California — presently have more than 100 such days each year, every county in the top 20 would by 2053, according to the research.
The areas adding the most days above 100F will overlap in large part with the Sunbelt, which extends from Florida to southern California.
The Sunbelt also contains six of the 10 fastest-growing states by population, according to Census Bureau data. The south, followed by the west, has had the biggest increase in single-family home and apartment sales volumes since the start of the coronavirus pandemic, according to data from the National Association of Realtors.
“The Sunbelt continues to experience the fastest growth among major US markets,” said Abby Corbett, a senior economist at CoStar, a commercial real estate research company. “Households and businesses alike continue to flock to markets throughout states like Texas, Florida, Arizona, Georgia and the Carolinas, despite the nation’s ever-increasing climate risks and challenges.”
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