Imagine your electricity goes out for days while in temperatures exceeding 100 degrees. That would be a problem, right? If that happened in the sweltering summer heat of Phoenix, Ariz., around half of the city’s 1.6 million people would need emergency hospital care, according to a recently released study examining how blackouts during heatwaves can lead to heat-related illness and death.
Those deadly risks, published Wednesday in the journal Environmental Science and Technology, have been exacerbated by a rapidly changing climate and come at a time when the number of major blackouts nationwide has doubled in eight years. A natural disaster or cyber-attack could make the scenario far more likely.
It’s expected that at least two-thirds of the country could experience blackouts this summer, especially in areas experiencing extreme heat, according to weather analysis from last month. The threat from extreme heat is now so severe the government has created a website that shows regions under risk as well as educational tools. There has also been talk of the federal government including heat to the list of disasters, like floods and hurricanes, that would enable the release of federal aid.
While other cities are included in the latest study, Phoenix is at the greatest risk by far followed by Atlanta and Detroit.
The study estimates that 12,800 people would die in Phoenix should the power grid fail in a heatwave. The North American Electric Reliability Corporation (NERC) has said that most of the country will be at an elevated or high risk of power failure during what’s expected to be an unusually hot summer. The mid-Atlantic and southeastern states are the only areas of the country where NERC is not warning of the potential for outages should residents encounter long and intense heat waves or destructive storms.
The widespread Texas blackouts in early 2021 were caused by winter storms but still underlined how fragile the power grid can be when faced with extreme weather. Hospitals in Phoenix would also likely be overwhelmed as hundreds of thousands sought medical attention. The city has 3,000 emergency department beds.
“I describe this as probably the greatest climate-related hazard we can imagine: a blackout during a heat wave,” said Brian Stone Jr., the study’s lead author and a professor at the School of City and Regional Planning at the Georgia Institute of Technology.
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The researchers also examined conditions in Atlanta and Detroit. They estimated that 3%, or just under 12,000 residents of Atlanta, would require emergency care if the city were hit by a five-day heatwave coinciding with a multiday blackout. Six people would die, according to the modeling.
Around 216 would die in Detroit.
However, the research assumes people would not leave during heatwaves and blackouts. More likely, some people would relocate, and emergency services would evacuate some and establish cooling centers.
Extreme heat disproportionately affects people of color, who are more likely to live in areas of cities that have fewer trees and therefore have no canopy to absorb heat.
The report offers a few solutions. If the three cities shaded half of their streets with trees, deaths would drop by 14% in Atlanta, 19% in Detroit, and 27% in Phoenix. It also recommends installing “cool roofs,” which are highly reflective. Deaths would drop by 21% in Atlanta, 23% in Detroit, and 66% in Phoenix.