EVANSVILLE — If you live in a city and you feel like the weather's been hotter than what your rural friends have experienced ... well, you're right.
Temperatures in Indiana cities such as Evansville, Fort Wayne, Indianapolis, Lafayette and South Bend are an average of 6 degrees hotter than surrounding rural areas.
That is according to a report from according to a report from nonprofit organization Climate Central that draws attention to the way urban environments amplify heat and the health issues those changes cause.
Temperatures have dropped back to the 80-degree range after a week that saw the Tri-State under an advisory for several days as heat indices — the measure of how the actual temperature and humidity combine to create a "feels like" mark — soared past 100 degrees.
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Why is it hotter in the city?
Extreme heat waves have become more frequent in recent decades, according to the National Oceanic and Atmospheric Administration. Weather patterns called heat domes have contributed to several heat waves this summer, with large areas of hot air trapped in place over parts of the country by high-pressure atmospheric conditions.
A report from the nonprofit group Climate Central says urban areas create "heat islands" that worsen the impacts of extreme heat waves. It says Evansville is an average of 6 degrees Fahrenheit hotter than surrounding areas that are less developed.
Those heat waves are being felt even more intensely in cities, creating an "urban heat island" effect, according to the Climate Central report.
The report created an index score for major metropolitan areas in each state, showing the average temperature difference between the cities and surrounding areas. Within cities, temperatures may average even higher in some areas compared to others.
Heat island effects aren't limited to large cities. Anywhere there are malls, parking lots, building complexes, playgrounds — places where there are more hard surfaces and fewer trees — can create a heat island effect, according to the Climate Central report.
Vulnerable areas
With average temperatures increasing across Indiana, even communities that have never considered themselves at risk from climate change are finding they are vulnerable to certain climate variables, said Dana Habeeb, an assistant professor at Indiana University's School of Informatics, Computing and Engineering.
"What's considered a hot day in Indiana is going to change," she said.
An expert in environmental planning and urban climatology, Habeeb's research focuses on finding ways to help communities face climate change, including the effects of urban heat.
"Temperatures increase in cities based on how we design and build our cities, increasing roads, buildings and parking lots and displacing vegetation," she said.
Any community or neighborhood can have pavement and buildings that absorb and retain heat during the day and radiate it back into the air, Habeeb said.
Looking at the impact
This year the Indiana Office of Community and Rural Affairs and IU's Environmental Resilience Institute began Beat the Heat.
The program is a two-year study in Richmond and Clarksville, Indiana, on high heat’s effect on residents and develop local strategies to protect against the health impacts of high heat in summer.
Its eventual goal is to be able to help Indiana communities create strategies for dealing with extreme heat impacts.
Indiana's temperature has been rising. The state's average yearly temperature has increased by 1.2 degrees (Fahrenheit) and has led to earlier springs in the Hoosier state, according to a report from the Purdue Climate Change Research Center. Much of that increase has occurred since the 1960s.
Across the state, the number of extreme heat days when the temperature is 95 degrees or higher is expected to rise in coming decades, according to the Purdue report. That is especially true in Southern Indiana, where there could be 38 to 51 extremely hot days by 2050.
Such high heat can contribute to air pollution, worsen existing health conditions and increase the risk of heat stress and heat-related illness, as well as cause fatalities.
Habeeb said there are ways to reduce urban heat.
"There is a lot we can do with planning, and different zoning and building codes, putting on 'cool roofs' that increase reflectivity, increasing tree plantings in neighborhoods and along streets, require 'green ratios' for new developments," she said. "There is a lot that cities can do."
While Evansville does not have a plan to respond to extreme heat events it does have a recently developed Evansville Climate Action Plan that addresses climate change, said Noah Stubbs, communication directors for Mayor Lloyd Winnecke.
The plan aims to reduce greenhouse gas emissions 15 percent by 2030, 35 percent by 2040 and 50 percent by 2050.