A new study reveals the emergence of an “extreme heat belt” from Texas to Illinois where the heat index could reach 125°F at least one day a year by 2053. The big picture: In just 30 years, climate change will make the Lower 48 states a much hotter and more unsafe place during the summer.
The findings come from a hyperlocal analysis of current and future extreme heat events released Monday by the nonprofit First Street Foundation. The new report is unique in looking at current and future heat risks down to the property level across the country and joins similar risk analyzes First Street has completed for floods and fires. As average temperatures rise due to anthropogenic greenhouse gas emissions, mainly from burning fossil fuels for energy, extreme heat events are predicted to escalate. This report makes it clear where households will be vulnerable to what would now be considered almost unheard of heat indices, which show how the air feels from a combination of air temperature and relative humidity.
Threat level: The report, which is based on First Street’s peer-reviewed heat model, shows that the number of Americans currently exposed to “extreme heat,” defined as having a peak heat index greater than 125°F; it’s only 8 million.
However, due to the expected increase in temperature over the next three decades, this number is expected to rise to 107 million people, a 13-fold increase in 13 years. The developing “Heat Zone” forms an area of vulnerability from northern Texas to Illinois and includes the cities of St. Louis, Kansas City, Memphis, Tulsa and Chicago. By 2030, some coastal areas in the Southeast and Mid-Atlantic may also see heat index days above 125°F, according to the report.
Magnification: The report shows a country that will have to deal with the effects of increased exposure to heat almost everywhere, although there will be distinctions based on geography.
For example, the study finds that in 2053, the West will have the highest chance of long stretches of “local hot days,” which are days that exceed temperatures typically seen for a particular region. The Gulf and Southeast will see the highest chances and longest exposure on what are called “danger days,” with a heat index greater than 100°F, according to the report.
Between the lines: The states likely to see the biggest growth in dangerous days are Texas, Louisiana, Arkansas, Missouri and Florida, according to First Street’s analysis.
The counties with the largest changes in dangerous days between 2023 and 2053 are mostly in Florida, led by the populous areas of Miami-Dade, Broward and Palm Beach counties.
The report shows how the characteristics of heat waves may change in the near future. Many spots are currently seeing more than 20 consecutive days with heat indices over 100°F. However, by 2053, such streaks could reach up to 74 consecutive days, the report said. The study also sheds light on cooling demand due to increasingly hot conditions, including increases in carbon emissions from cooling, which will further exacerbate warming. And Texas, Florida, California, Ohio and Missouri make up the top 5 states with the largest increase in cooling demand in CO2 emissions between now and 2053, the report shows.
Meanwhile… The US is already seeing the clear fingerprints of human-caused global warming in extreme heat events. Last month, for example, the country’s overnight lows were the warmest on record for any month.
Abnormally high overnight temperatures during heat waves increase the public health risk of heat-related illnesses. Additionally, warm temperature records outnumbered cold temperature records by a ratio of nearly eight to one.
What’s next: Communities are innovating to reduce the effects of extreme heat and implement better heat action plans, among other climate resilience steps. Go deeper…
