Newly released climate data suggests a quarter of the United States' land could experience temperatures exceeding 125 degrees Fahrenheit in just 30 years.
According to a Monday press release from the First Street Foundation, an extreme heat model shows more than 1,000 counties are expected to experience the high temperatures by 2053.
These counties are currently home to 107.6 million Americans who, according to data from the U.S. Census Bureau, make up about a third of the country's population.
The foundation is also warning of what it calls an "extreme heat belt," which would stretch from the Northern Texas and Louisiana borders to Illinois, Indiana and Wisconsin.
"We need to be prepared for the inevitable, that a quarter of the country will soon fall inside the Extreme Heat Belt with temperatures exceeding 125°F and the results will be dire," Matthew Eby, founder and CEO of First Street Foundation, said in the press release.
First Street Foundation A map showing areas at risk
Next year, 50 counties in the United States are expected to experience temperatures above 125 degrees Fahrenheit, the foundation said. More than 8 million residents currently live in those areas.
That number is expected to explode over the next three decades, especially in central states "where there are no coastal influences to mitigate extreme temperatures," according to an article also published Monday by First Street Foundation.
Never miss a story — sign up for PEOPLE's free weekly newsletter to get the biggest news of the week delivered to your inbox every Friday.
Counties in Texas, California, Arizona and Florida are expected to see the largest number of dangerously hot days, per the article.
Some southern states could see more than 70 straight days of a heat index over 100 degrees, The Washington Post reported.
However, Miami-Dade County is projected to experience "the most severe shift in local temperatures" in the coming years, with an estimated 91 days of a heat index over 100 degrees by 2053, the Post noted.
Heat indixes between 103 and 124 degrees are considered dangerous, and can lead to heat cramps, heat exhaustion or heat stroke "with prolonged exposure" to the conditions, according to the National Weather Service.
Heat stroke is "highly likely" if the heat index reaches 125 degrees or above.
First Street Foundation is a nonprofit "research and technology group working to define America's growing climate risk," they say.
The foundation's website says the group is comprised of "cutting-edge scientists, technologists, and communicators."