- More than 94% of the nation could see hottest days double
- By 2053, more than 105 million residents could be exposed to heat indexes above 125 degrees
- Central US becoming a heat belt
A new report examines how dangerously hot temperatures could increase over the next 30 years and reveals a grim outlook for much of the nation, especially a vast swath of the Central US where residents aren’t accustomed to extreme heat.
South Florida is forecast to see the biggest increases in the number of very hottest days, according to a new heat model and assessment by the First Street Foundation. But the report shows even some of the nation’s northernmost counties can’t escape the effects of the warming world.
“Extreme heat exposure is increasing across the country,” said Jeremy Porter, chief research officer for First Street, a Brooklyn-based research and technology group.
The foundation looked at average heat index temperatures – what it feels like outside based on temperature and humidity – on the seven hottest days of the year.
considering how climate change could increase the frequencyduration and intensity of dangerously hot days over 30 years, the report found more than 94% of the nation could see those days double.
Next year, more than 8.1 million residents in 50 counties could experience at least one day with a heat index above 125 degrees. By 2053, that could grow to more than 105 million residents spanning a third of the country.
The findings build on earlier heat studies, raise questions about how people will handle the heat, and offer further proof that communities already should be preparing, experts said.
Stopping climate change? We have the tools we need to fix things
The new report arrives just as the nation is experiencing a succession of heat waves and broken records.
July was the third warmest on record in the US, and the 76.4-degree average temperature was nearly 3 degrees above normal, the National Oceanographic and Atmospheric Administration said last week. Texas sweltered under its warmest July on record, while Oregon just saw its 4th warmest July.
First Street’s 2053 projections look a lot different depending on where you are.
- Today, temperatures feel like 103° or warmer on the seven hottest days of the year in Florida’s Miami-Dade County. That could rise to 34 days by 2053.
- On Martha’s Vineyard in Massachusetts, only three days a year feel like 90 degrees, but that number could quadruple to a dozen.
- High in the Rocky Mountains in northern Montana, Glacier National Park could see three days a year when the temperature feels like 90 degrees or more.
Learning the days with a heat index of 100 or more could more than quadruple in Miami didn’t much surprise Miami Beach native Steve Keats.
“Nature is after us – heat and sea level rise,” Keats said.
What’s a heat wave? Here’s what it is, how it affects your body and how to stay safe.
What is First Street’s report and where can you find it?
A peer-reviewed assessment and extreme heat model, it’s the latest in a series by First Street and its partners looking at warming-related risks in communities across the lower 48 states, including floodingsea level rise and wild fire. The foundation and its partners put together federal weather records, property records, satellite information and other data for its model, using intermediate global climate projections. It also considered tree cover, paved surfaces and proximity to water.
The public can find the tool, Heat Factor, at RiskFactor.com and look at future property projections and trends over the past 30 years.
Showing past trends should help build trust in the projections, Porter said, because people will see there are more hot days today and a higher probability of heat waves and dangerously hot days.
A heat belt emerges
By 2053, residents in 430 counties in 16 states could see the number of days with their current hottest temperatures more than triple, according to First Street’s modeling.
Outside of Florida and the Southwest, the counties and states forecast to see the biggest increases are concentrated in an arc northward from Texas and Louisiana on the Gulf of Mexico north to Missouri and Illinois, and include western Kentucky and Tennessee.
First Street has dubbed that region “an emerging heat belt,” because of its risk of exposure to extreme heat index temperatures of more than 125 degrees, Porter said. The low-lying region between the Rocky Mountains and the Appalachian Mountains is “almost a bowl where high humidity sits, and it’s interacting with the increased temperatures.”
Unlike coastal areas, the region doesn’t have sea breezes to cool down the heat.
A 2021 investigation by USA TODAY found the region has also experienced an increase in intense rainfall events from the warming Gulf of Mexico.
USA TODAY Investigation:How a summer of extreme weather reveals a stunning shift in the way rain falls in America.
The top five metropolitan areas with the most neighborhoods that could experience extremely dangerous heat days are St. Louis and Kansas City, Missouri; Memphis, Tennessee; Tulsa, Okla.; and Chicago, according to First Street’s report.
Residents in southern states, people in states like Missouri and Illinois may be less prepared, less likely to have air conditioners and unlike more likely to experience extreme heat.
Where are other hot spots?
- When looking at percent increases, two counties in the top of the Texas Panhandle — Hartley and Oldham — could see the largest increase in days above a 100 degree index, a 600% increase. Counties in North Carolina, West Virginia and Colorado also made that top 20 list.
- Colder counties show up more often when looking at the percent increase in days that feel warmer than 90 degrees. Instead of seeing one day a year with a feels-like temperature of 90 degrees, Snohomish County, Washington, just to the north of Seattle, could see five such days a year, a 400% increase.
- The country’s West Coast has the highest probability of consecutive locally hot days, but feels the greatest cooling effect from the ocean.
Want to keep cool?:12 ways you can beat the heat this summer
What do the projections mean?
The increase in potential heat waves and warmer nights is “really concerning,” said Gabriel Filippelli, executive director of Indiana University’s Environmental Resilience Institute.
People tend to handle one or two days of hot weather, Filippelli said, but when that stretches to three or four days, human body systems start to break down, especially in children, the elderly and those in lower-income communities.
when heat concentrates in urban areashe said temperatures don’t drop at night and people get little, if any, relief.
That can create significant health problems, said Ashley Ward, a climate health scientist at Duke University. “When overnight temperatures remain high, what we’re seeing is the body doesn’t have a chance to recover from any heat exposure during the day.”
Structural changes are needed now to prepare, she said.
Meanwhile, in South Florida, Keats, a shipping industry executive, has made his own adjustments to avoid heat stress.
“I don’t go out much until after 4 pm unless I’m in or on the water,” he said. “I take siestas too on the weekends … because that’s what you have to do to adapt to the heat.”
Learn about heat with this interactive:Get up close with heat domes
Dinah Voyles Pulver covers climate and environment issues for USA TODAY. She can be reached at [email protected] or at @dinahvp on Twitter.
George is Digismak’s reported cum editor with 13 years of experience in Journalism