Cincinnati is once again sweating from a heat advisory, expected to last until Thursday night and bringing with it a heat index of 104 degrees in some parts of the city, according to The National Weather Service. Next week isn't looking much cooler, either, as current projections keep daily temperatures above 85.
These trends aren't surprising to Shel Winkley, chief meteorologist at Climate Central, a national group of scientists and researchers focusing on climate. They say these 95-degree days are at least four times more likely to happen due to human-caused carbon pollution.
"What we're living today is not what we grew up with," Winkley said. "It seems hard to fathom, but we as humans have already altered and continue to alter the climate here
on Earth."
Since the Industrial Revolution, the burning of fossil fuels − things like coal, oil and methane − has filtered more heat-trapping particles into the atmosphere. Scientists like Winkley are able to assess how big of an impact these emissions are having on our current climate by comparing climate models with and without historical emissions.
For example, Cincinnati sees 15 more days of above average temperatures per summer than it did decades ago, Winkley said, and nighttime averages are warming almost twice as fast as daytime temperatures. Cincinnati's summers have also warmed by 2.2 degrees since 1970. While that doesn't seem like much, it can have big impacts, Winkley said.
"I think the best way to really understand this is if your body temperature were to rise 2 degrees, you'd be on the couch, you'd probably take a sick day, you'd be feeling unwell," Winkley said. "It's not quite the same summer that we experienced just a couple of decades ago − than maybe our grandparents and our parents experienced."
But the cause of these warmer days, while exacerbated by climate shifts, has a lot to do with factors here at home.
Geographic landscape traps hot air and pollutants
Located in the Ohio River Valley, Cincinnati and surrounding valley areas create the perfect opportunity for warm, moist air to get trapped, Winkley said. This creates longer lasting and more intense heat domes, which prevent hot air from moving out of the valley.
But as the planet warms, its capacity for holding moisture grows. Moisture, Winkley said, is much harder to cool than dry air. And while the heat accumulated throughout the day is supposed to radiate up into the atmosphere at night, the increased moisture from warmer temperatures instead traps that heat, leading to warmer nights and even hotter days.
This trapped, hot air also creates problems for air quality, said George Leikauf, co-director of the University of Cincinnati's Center for Collaboration on Climate & Community for Health.
When you start up your car in the morning, for example, the fuel in your engine is combined with oxygen in a combustion process, but not everything gets burned away completely. This process releases nitrogen oxides and volatile organic hydrocarbons that − when met with sunlight − trigger a chemical reaction producing ozone, Leikauf said.
Ozone, along with other particulates like those from the Canadian wildfires, also gets trapped in the valley.
Urban features have hot, local impacts
And just like any metropolitan center, Cincinnati has continued to replace green spaces and trees with impermeable surfaces like roads, parking lots and sidewalks. These surfaces act as "sponges for heat," said Howard Miller, environmental manager at the city's Office of Environment & Sustainability.
In regions with more built infrastructure and industrialization − including downtown and the Mill Creek area − temperature differences between neighborhoods during warmer months range from 5 degrees to 10 degrees due to more impermeable surfaces and less green space. Those neighborhoods also tend to be home to many of the city's most vulnerable populations, Miller said.
But Cincinnati's fight against rising temperatures continues.
City launches program to cool off heat-burdened neighborhoods
The city announced on Sept. 2 that a team of volunteers will host public misting and fountain cooling stations along walking and transit routes in the city's hottest neighborhoods through a pilot program, Stay Cool Cincy. Residents and businesses in Walnut Hills, Winton Hills, Bond Hill, Roselawn, Avondale and other regions can also volunteer to host a "cool spot" using private cooling and water sources, such as hoses.
While the program is designed to help bring relief to Cincinnati residents on extreme-heat days, other efforts to mitigate the city's heat and air quality issues in the long run are making slow but steady progress.
In line with the Green Cincinnati Plan, the Office of Environment & Sustainability, and community partners, are working to add more green space to heat-burdened communities, Miller said.
For example, the city's park staff have planted almost 300 trees in Avondale since 2022, with goals of reaching over 2,000 by 2030. And through Experience Mill Creek, community leaders are working to revitalize the Mill Creek Valley and existing connect trails.
While all of this takes time, money and experimentation, even small changes, like adding in native plants to your own yard, can have an impact, Winkley said. And talking about climate with neighbors and others in the community is another key step.
"We have to ask ourselves, the world that we live in now, do we want it to get more extreme? Is this what we want to give to future generations? Or can we work on it now so that we can slow this warming and maybe even reverse it for our future generations?"
This article originally appeared on Cincinnati Enquirer: Something's in the air: Why Cincinnati sees more hot days
