The cost of extreme heat in the U.S.? 235,000 ER visits and $1 billion in healthcare bills this summer alone.

By Rachel Koning Beals

A jump in costly emergency-room visits and longer-term health impacts could worsen as climate change makes record-busting heat waves more common

An extremely hot June has given way to an even steamier July, with this week setting the record for the steepest global average temperatures.

That means a jump in costly emergency-room visits and other longer-term health impacts that could only worsen as man-made climate change makes temperature extremes more common.

The global average temperature reached 17.18 Celsius (62.9 Fahrenheit) on Wednesday, according to the University of Maine's Climate Reanalyzer, a tool that uses satellite data and computer simulations. That matched a record set Tuesday of 17.18 Celsius (62.9 Fahrenheit) and hits just after a previous record of 17.01 Celsius (62.6 Fahrenheit) was recorded Monday.

Read:Hottest day on Earth for the third straight day

Keep in mind those are global averages. For comparison, in early June, Buffalo, N.Y., set daily temperature records on consecutive days to start off the month at 90 Fahrenheit. Fargo, in North Dakota, hit 97 , according to National Weather Service data. And an extreme heat wave broke temperature records in Puerto Rico, where cooling ocean winds weren't to be found. Puerto Rico's heat index, a measure of how temperatures feel to the human body, reached 125 Fahrenheit on parts of the island.

And this week? Typically temperate Portland, Ore., hit a sweltering 98 , according to the NWS, breaking the city's daily record high by two degrees. El Paso, Texas, broke a daily record at a whopping 107 . Those temps don't include the "real feel," which accounts for humidity along with ambient temperatures.

Scientists had already warned that 2023 could see record heat as human-caused climate change, driven largely by the burning of fossil fuels like coal, natural gas and oil , warmed the atmosphere. But there's another factor to layer on.

La Niña, the regular, natural cooling of the ocean that had acted as a counter to that warming, is turning into an El Niño, the reverse phenomenon marked by warming oceans. The north Atlantic Ocean has logged record warmth this year.

Costs add up a couple of ways

When temperatures soar as they have done early this summer, scientists, economists and policy makers stress the heat-related costs that can accumulate on individuals, households, communities and companies.

Often that cost is measured almost solely in lost productivity, meaning extreme temperatures can (and should) restrict outdoor work at a construction site, for instance.

The Adrienne Arsht-Rockefeller Foundation Resilience Center says that the current figure on U.S. economic losses tied to heat is purposefully conservative when it is limited to productivity, but that it needs to paint a broader picture. Pegged at $100 billion annually, estimated heat-linked economic losses focus solely on worker productivity. When factors like healthcare, damage to infrastructure, lost tourism and, yes, worker productivity are considered all at once, climate change's heat impact will reach $200 billion annually as soon as 2030, the group predicts.

And because high healthcare costs already burden some U.S. families more than others, recent climate-change research has drilled down on heat and health.

A new report from the public policy research group Center for American Progress estimates extreme heat will create $1 billion in healthcare-related costs in the U.S. this summer alone.

Heat exposure is high risk for human health and leads to a rise in hospitalizations for cardiovascular, kidney and respiratory diseases, including asthma, particularly among the urban poor. These residents can often lack access to air conditioning, particularly in rental housing, and may find the green spaces providing natural cooling lacking.

The Center for American Progress projects that excessive heat will prompt roughly 235,000 emergency-department visits and more than 56,000 hospital admissions for conditions related to increased body temperature across the country this summer.

Read:How to prepare for extreme heat

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"As the number of heat-event days increases, the probability that people are going to get rushed to the emergency room or get hospitalized increases," Steven Woolf, a senior fellow at the Center for American Progress, a professor of family medicine and population health at Virginia Commonwealth University School of Medicine, and a co-author of the report, told Grist, which got a first look at the data. "We were interested in trying to quantify how big a risk that is," he said.

Extreme heat on health: underreported and unfair

The researchers over four-plus years logged "heat-related illnesses" that they defined as heat cramps, heat exhaustion and heat stroke, as well as "heat-adjacent illness" -- dehydration, rapid pulse, dizziness or fainting.

In Virginia, extreme heat spurred some 400 outpatient visits for heat-related illness, 4,600 emergency-room visits for heat-related or heat-adjacent illness and 2,000 heat-related hospital admissions each summer. These are likely underestimates, the report's authors noted, since many patients with higher body weight or organ diseases such as heart disease, for example, experience complications during heat waves that could be classified as heat-adjacent illnesses but are rarely formally diagnosed as such by their physicians. And many victims of extreme heat don't seek medical care at all, which further obscures the true burden of heat-related illness.

The authors extrapolated Virginia's data to reach the conclusion that extreme heat will inflate healthcare costs across the nation by at least $1 billion every summer for the foreseeable future. The authors also found that the burden of extreme heat will be shouldered unequally by Americans. The costs will be felt most acutely in low-income and historically marginalized communities, where access to cooling resources such as air conditioning is patchy, electricity bills harder to pay and green spaces scarce.

Justin Mankin, an assistant professor in Dartmouth University's geography department who was not involved in this report and published a separate study last year, told Grist that he'd like to see research widen its timeline, namely to include the health-insurance claims tied to high heat that could pile up in the months and years following an extreme event.

Climate change and heat: heading higher?

Extreme heat historically has attracted less attention than the destruction of hurricanes, wildfires or floods, because the visual shock can be less or the dangerous effects slower to take hold. But the impact of climate change in creating longer, drier summers, which, in the case of 2023, come on top of an El Niño, is increasingly throwing up alarms.

Read:Nonsmoker lung cancer is on the rise. Blame pollution, says American Lung Association

Climate-change mapping nonprofit First Street has added extreme heat to its tool called Risk Factor, accessible free of charge, and increasingly incorporated into real-estate listings, specifically through a partnership with Realtor.com, which, like MarketWatch, is a News Corp property.

The researchers look at how the frequency, duration and intensity of extremely hot days will expand over the next 30 years from a changing climate at a given location.

Risk factors, which are searchable by property, or ZIP code or state, are meant to help homeowners, real-estate agents and eventually insurers get a better handle on how climate change is impacting home values and the cost of homeownership.

Related: A retirement safe from climate change? Ask the tough questions about real estate and property insurance

Groups working with the Adrienne Arsht-Rockefeller Foundation Resilience Center are pushing for a standard practice of naming and ranking heat waves globally -- just as tropical storms are named -- so that communities and people can communicate about the emergency, adequately prepare and evacuate as needed.

Read more: What if heat waves were named like hurricanes? New push draws mega insurers, Athens and Miami mayors, Red Cross and dozens more stakeholders

-Rachel Koning Beals

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07-08-23 1110ET

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