A new study found if stricter laws aren’t passed to regulate greenhouse gas emissions, extreme heat-related cardiovascular deaths will double by midcentury, putting already susceptible Black and older Americans at the greatest risk.

Key Facts

The researchers looked at extreme heat deaths under two circumstances: implementation of currently proposed emission reduction laws—so there’s a lower increase in greenhouse gas emissions—and no significant reduction efforts, causing greenhouse gas emissions to increase at the same rate they have for over two decades.

If proposed legislation is implemented, extreme heat-related cardiovascular deaths in the continental U.S. are estimated to increase by 162% between 2036 and 2065 due to a projected rise in extreme heat days, according to a study published Monday in Circulation.

If it’s not implemented, excess cardiovascular deaths due to extreme heat will increase by 233%.

The Federal Emergency Management Agency defines extreme heat days as a period of two to three days of high humidity and temperatures above 90 degrees, and blamed the “climate crisis” for an increase in heat waves.

Elderly adults 65 years and older are estimated to have between a 2.9% and 3.5% higher increase in death than non-elderly adults, and Black adults are projected to have between a 3.8% and 4.6% higher increase than their white counterparts, putting these two groups most at risk.

Extreme heat and dehydration force the heart to work harder to keep the body cool, resulting in more heart-related health complications, so to decrease the number of people affected by adverse health effects of extreme heat, researchers recommended more assertive legislation to tackle greenhouse emissions.

Crucial Quote

“Even under the more optimistic moderate scenario of this study, greenhouse gas emissions will increase for some time before tapering down,” Robert Brook, coauthor of the study and executive director of cardiovascular prevention at Wayne State University School of Medicine, said in a statement.

Big Number

1,651. That’s how many extreme heat-related cardiovascular deaths occurred every year in the U.S. between 2008 and 2019, according to the study. This number is expected to rise to 4,320 between 2036 and 2065 if current climate change legislation is passed, and 5,491 if it isn’t.

Key Background

Black people are at a higher risk of heat-related cardiovascular death due to an increased risk of cardiovascular disease and socioeconomic and environmental barriers. The most common conditions that increase the risk of heart disease and stroke are high blood pressure, obesity and diabetes. Black Americans were 30% more likely to die from heart disease than white Americans and 30% more likely to have high blood pressure in 2019, the U.S. Office of Minority Health reports. Black Americans were 1.3 times more likely than white Americans to be obese in 2018, and Black women had the highest rates of obesity or being overweight (around 80%) than any other group of people. Black adults were 60% more likely to be diagnosed with diabetes in 2019 compared to white adults, and they were twice as likely to die from diabetes in 2018, according to the Centers for Disease Control and Prevention. Factors in the neighborhoods and communities Black Americans live in play “a role in the disparities seen in cardiovascular outcomes,” according to a 2019 study published in the American Journal of Kidney Disease. Economic factors like the lack of readily available fresh produce, causing people to eat high volumes of prepackaged or fast food with high salt concentrations, are also reasons why heart disease is so prominent in the Black community, according to the University of Texas Southwestern Medical Center.


Trees lower temperatures by providing communities with shade. Urban forests are some 2.9 degrees cooler on average than urban areas without trees, according to the U.S. Environmental Protection Agency. It’s previously been proven Black Americans have “less access to air conditioning [and] less tree cover,” Sameed Khatana, M.D., first author of the Circulation study and assistant professor of medicine at the University of Pennsylvania, said in a statement. Urban communities, where Black Americans and other minorities make up the majority, have less trees and shade than other communities, making them hotter. Urban communities lose about 175,000 acres of tree coverage per year, the U.S. Department of Agriculture reports. Hotter temperatures are associated with more cardiovascular deaths, the Circulation study points out.

Surprising Fact

Of the over 3 million reported deaths in the U.S. in 2022, heart disease was the leading cause, resulting in 699,659 deaths, the CDC reports. Cancer, unintentional injuries and Covid were the next leading causes of deaths.