COLUMBUS, Ohio (WCMH) – Columbus’ unlucky number last week was 90, as in 90 degrees Fahrenheit on the heat index.

The ‘feels like’ temperature in the capital city was consistently above 90 degrees in the heat of the day last week, even topping 100 at some points. Columbus is not a stranger to these conditions, but they have been increasing in recent decades due to human-caused global warming.

Since 1979, Columbus has seen an increase of seven days a year when the heat index hits at least 90 degrees, according to an analysis published last month by climate change research group Climate Central.

Using National Weather Service data, Climate Central found Columbus has gone from about 19 days a year with a 90-degree heat index to about 26 days.

Decades ago, when “you got a week of really hot days, that was something extraordinary,” said NBC4 meteorologist Bob Nunnally, who grew up in Marion and has 23 years of experience tracking Columbus weather and climate at NBC4.

“Now, if we have a week of really hot days,” he said, “people go, ‘Oh no, another week of hot days,’ but they don’t go, ‘Wow, what’s going on?’”

Of the 239 cities in Climate Central’s analysis, 70% have seen an increase in three or more dangerously hot days since the 1970s, and Columbus was among the 46% that have seen increases of a week or more. In Ohio, nine of the 10 cities studied have seen increases, with four seeing at least another week.

Dangerous conditions for elderly, people with medical conditions

Humidity worsens heat, making air temperatures feel hotter by reducing the body’s ability to sweat and cool off. As temperatures increase in Columbus over time, “it would stand to reason,” Nunnally said, that heat index readings will too.

Heat is the nation’s leading weather-related cause of death, according to the NWS, averaging 130 deaths per year from 1990-2019. When the temperature hits 90, the agency calls for “extreme caution” as prolonged exposure can cause heat illness.

“A senior or somebody with a medical challenge,” like cancer, diabetes, or heart, lung or breathing problems, “they just can’t take the heat like maybe you and I could,” said Chuck Gehring, CEO of LifeCare Alliance.

LifeCare is a Columbus nonprofit that serves seniors and people with medical conditions with nutrition and health care. 70% of its clients live on less than $1,200 a month.

For the past 20 years, LifeCare has distributed fans to people trying to beat the summer heat, going through about 2,000-4,000 donated fans each year. Gehring said doctors have told him fans can make rooms feel up to 10 degrees cooler, which makes a difference for people who “either don’t have air conditioning” in their old homes or can’t afford the electricity bills.

“What you get with heat exhaustion, you start getting nauseous and stuff, and then heat stroke gets you into dizziness, confusion and really like ‘Oh, I’ve got to take a nap,’” Gehring said. “Well, if you take a nap and you get heatstroke, you’re probably not waking up.”

He added that the need for summer health care services, both big and small, will grow as temperatures increase and the elderly population booms when Millennials reach their sixties.

“There’s no question when I was growing up,” Gehring said, “we never had these kinds of days and stuff. It’s climate change, we all know that, and it’s what it’s going to be for the next decades.”

Hotter climate in Columbus’ future

Scientists point to climate change as the main driver of warming on Earth, the result of hundreds of years of increasing fossil fuel emissions like carbon dioxide trapping heat in the atmosphere.

“It definitely is happening,” said NBC4’s Nunnally, the Marion native. “I can tell just from my lifetime that it is definitely hotter here now than it was when I was a kid.”

A 2019 study by the Union of Concerned Scientists paints a grim picture for summer heat in Columbus if current carbon emissions trends continue. Their study projects the capital city will see 65 days per year by midcentury (2036-2065) where the heat index hits 90 degrees and 97 days per year by late century (2070-2099).

“This is not stuff that we’re used to in the Midwest,” UCS climate scientist Rachel Licker, an author of the report based in Wisconsin, told NBC4 earlier this month.

Of those 90-degree heat index days in Columbus by century’s end, 52 days would exceed 100 degrees and 33 days would exceed 105.

“We’re talking about basically Ohio spending the entire summer in conditions with the heat index above 100 degrees Fahrenheit,” Licker said.