In metro Atlanta, days over 100 degrees to double by 2053, report says

Region to see more ‘dangerous days’ of triple-digit heat indices, climate researchers say.

Longer heat waves and a doubling of dangerously hot days will bake metro Atlanta over the next three decades, according to report that predicts much of the U.S. faces greater risks from extreme heat caused by climate change.

The number of days in metro Atlanta with a heat index of 100 degrees or more will rise, with some counties expected to experience more than six weeks of triple-digit heat by 2053, an Atlanta Journal-Constitution analysis of data from nonprofit climate research group First Street Foundation shows. Dangerous heat risk will also grow across Georgia — most acutely in the rural southern reaches of the state, the report shows.

The predictions have implications for the health and safety of residents, especially those who work outside, as well as for the economies of the region and state and overall quality of life.

“I think anybody can think about how hot it was during the hottest week of the summer — that’s going to become the hottest month in 30 years,” said Jeremy Porter, the chief research officer of First Street.

The report concludes hazardous heat will become an ever greater threat across the country. It uses methodology for projecting temperature on a hyperlocal level that was first published in the peer-reviewed journal Climate. The report published Monday also includes a risk analysis tool that forecasts heat risk for individual properties nationwide.

Credit: Sam Baskin

Credit: Sam Baskin

The most dire predictions of the study center on the U.S. West, the Sun Belt and much of the central part of the country from the Gulf Coast to Illinois. The desert Southwest, home to about 8 million people, faces days with a heat index of 125 degrees. But by 2053, areas of the country that experience such high heat could cover parts of the country stretching from Texas to the Great Lakes, affecting more than 100 million U.S. residents, the report said.

The report said Gulf and Southeastern Atlantic states, including Georgia, “will face the highest probability and longest duration of exposure to Dangerous Days,” which it terms as those with a heat index or “feels like” temperature in the triple digits.

Charlton County, in southeast Georgia, was was ranked as the state’s most vulnerable to dangerous increases in intensity and duration of heat waves. It is expected to see 56 days over 100 degrees in 2023, and 82 by 2053, an increase of 46%.

The First Street report echoes warnings from the world’s leading scientific bodies that some temperature increases are inevitable, although the worst outcomes could still be avoided by sharply cutting carbon emissions.

In Atlanta, annual average temperatures have risen about 3 degrees since 1930, and the city experiences roughly six more heat waves each year than it did in the 1960s, according to an AJC analysis of federal data. Emergency room visits for heat-related illness were up about a third in the Southeast this May and June compared to the previous three years, according to a report from the U.S. Health and Human Services Department.

With smart planning, local governments can adapt to a hotter climate, said Brian Stone, the director of the Urban Climate Lab at Georgia Tech, which is preparing to undertake a citywide heat risk assessment. He said his research has shown that cities like Atlanta are warming more rapidly than surrounding areas because of land use and development, which drives the urban heat island effect.

“What that tells us is we can change the way we are developing the city and managing the city to cool things down quite a bit,” Stone said. “There are many things we can do.”

Stone said protecting and replacing the tree canopy is “By far the most effective thing we can do.”

He also called for making the city more reflective with white roofs, reflective roofs, and reflective streets and parking lots.

Stone acknowledged that the imperative to protect green cover can sometimes conflict with efforts to increase density to make the city more walkable, bike-friendly and affordable.

“I wouldn’t pretend there’s not a tension there — there is,” Stone said. “Largely what we want to do or will be recommended is to increase density where you have density.”

That means increasing density near mass transit and existing bike and pedestrian infrastructure, he said.

Mayor Andre Dickens’ office declined to make officials available to discuss heat resilience plans. The mayor’s office, in response to previous stories in the AJC about heat risks, pointed to various initiatives, including the creation of a “green cabinet” of community and nonprofit leaders to advise city leaders. Others include the creation of tree fund paid into by developers to purchase more green space, and the development of the 2.4-billion-gallon Westside reservoir, which is said to have increased Atlanta’s reserve drinking water supply from three to 30 days.

The city recently announced it was hiring a new chief sustainability officer, about six months after the previous head left the position.

That new person “will have broad responsibility for implementing a sustainability and resilience strategy, Dickens spokesman Michael Smith wrote in an email. “In the meantime, the Office of Sustainability continues to address all aspects of sustainability, including heat resiliency, equity, clean energy and building efficiency.”

Stone said Atlanta has a long way to go.

“I would say, of the most populous cities in the U.S., which Atlanta is, at least on a metro level, we have the least ambitious sustainability and resilience goals,” Stone said.

The city is the densest core of a region known for sprawl. But the city’s suburbs also face a hotter future.

The risk analysis tool released by First Street integrates temperature data with other factors such as land development and green space, distance to water and elevation to produce hyperlocal projections on a property and county level. Different counties face slightly different risks depending on these factors, but all are expected to see a sharp increase in 100-degree-plus days.

Cobb County does not have a climate change strategy, though departments react as issues arise, county spokesman Ross Cavitt said. The growing threat of severe weather, exacerbated by climate change, is one of the driving forces behind a discussion around creating a dedicated Cobb storm water utility.

Gwinnett County created its first sustainability commission in 2021 that’s made up of residents appointed by the county commission. That board recently collected resident feedback that helped inform the county’s first sustainability plan.

DeKalb County has launched a “green team” that includes representatives of all county departments. The county has also adopted a tree preservation policy, and is working to retrofit county buildings with solar panels and create a broader heat resilience plan.

Fulton officials did not immediately respond to questions about their climate plans.


A note of disclosure

This coverage is supported by a partnership with 1Earth Fund, the Kendeda Fund and Journalism Funding Partners. You can learn more and support our climate reporting by donating at ajc.com/donate/climate/