Illinois, Indiana Could Be Part of ‘Extreme Heat Belt,’ Impacted by 125-Degree Heat Indices Within 30 Years: Study – NBC Chicago
Both Illinois and Indiana could potentially be part of an “extreme heat belt” that could be impacted with heat indices of 125 degrees within the next 30 years due to climate change, according to a new study released this week.
According to the national risk assessment compiled by the non-profit First Street Foundation, all of Illinois and most of Indiana would be part of that belt, which could stretch from Texas all the way through a good portion of the Midwest.
As of 2023, more than eight million Americans are expected to see heat indices of 125 degrees in a given year, a level which the National Weather Service says is “highly likely” to cause sunstroke or heatstroke for those exposed to it for an extended period of times.
By 2053, that number could grow to more than 107 million Americans, covering more than 1,000 counties across the country.
Researchers say that the “extreme heat belt” would be primarily focused on the middle of the country due to its lack of proximity to large bodies of water that could potentially mitigate the effects of the heat.
To quantify the impact of the increasing temperature estimates, researchers used a statistic called “Local Hot Days,” which are defined as an area’s projected hottest seven days’ worth of heat indices in the year 2023, and then used modeling to determine how many days will exceed that threshold within the next 30 years.
In more than a dozen counties in Illinois, including Madison and Jefferson counties, the number of “Local Hot Days” are expected to grow by more than 200% within the next 30 years. In Madison County, a “Local Hot Day” is defined as a day with a heat index of higher than 107, and in the year 2053, that number could grow from seven days to 21 days, according to researchers.
Cook County and most of northeastern Illinois, thanks to the mitigating influence of Lake Michigan, will see a smaller increase in “Local Hot Days,” but residents could still see that number grow by more than seven days in some instances.
According to the foundation’s “Risk Factor” tool, Cook County is expected to see its number of days with heat indices over 100 degrees to increase by more than 114% over the next 30 years.
First Street Foundation’s models use “high-resolution measurements of land surface temperatures,” and takes other factors into account, including canopy cover, proximity to water and other factors, according to the report.
The model then looks at the seven hottest days expected for any property this year, and compared it to what the equivalent could be in 30 years. On average, a community’s hottest seven days this year are projected to become its 18 hottest days by 2053.