Summer Heatwaves and Blackouts Put Millions at Risk

Our Daily Planet

Extreme weather and permanent droughts are sweeping across the Western US, and with them comes an increasing demand for A/C and power. But cooling buildings through increasingly severe heatwaves takes a considerable toll on power grids, and a new study has found that a significant heatwave blackout in three major American cities could put up to two-thirds of residents at risk of heatstroke and heat exhaustion. Just as extreme cold disrupted the Texas power grid in February, experts warn that cities aren't prepared for the devastating blackouts and public health risks caused by increasingly severe heatwaves.

Why This Matters

While the public eye is often hyper-focused on hurricanes and wildfires, heat is the deadliest type of extreme weather.

Overlapping blackouts and heatwaves risk the lives of millions of Americans, not only in the future but in the next few months.

History Repeated

In 2020, California saw a record-breaking heatwave where Death Valley hit 130 degrees and millions lost power across the state as the electric grid could not keep up with demand. This heatwave and blackout cost lives and substantial financial losses to businesses and households already struggling with the burdens of the pandemic. Just a year prior, rolling blackouts in California cost the state $2b in economic losses. Facing these types of power outages each year is untenable for the world's 5th largest economy and the home of ~40 million people.

These bar graphs and maps show changes in the number of heat waves per year (frequency) and the number of days between the first and last heat wave of the year (season length). These data were analyzed from 1961 to 2018 for 50 large U.S. metropolitan areas. The graphs show averages across all 50 metropolitan areas by decade. The size/color of each circle in the maps indicates the rate of change per decade. Hatching represents cities where the trend is not statistically significant.

If You Can't Stand the Heat…

"A widespread blackout during an intense heatwave may be the deadliest climate-related event we can imagine," said Brian Stone Jr., a professor at the Georgia Institute of Technology and the lead author of the study. Stone and his team evaluated severe heatwaves in Atlanta, Detroit, and Phoenix. They used computer models to estimate how hot buildings would become internally if a blackout coincided with extreme temperatures. They found that over two-thirds of residents would be in dwellings so hot, they would risk heat stroke or heat exhaustion. In Phoenix, nearly the entire population of 1.7 million people would be at risk.

In all three cities, low-income communities were 20% more likely to lack access to air conditioning to begin with. Each city evaluated had a network of cooling centers available for residents, but researchers found that in the event of a blackout, those centers could accommodate only 2% of the total population. "Based on our findings, a concurrent heatwave and blackout event would require a far more extensive network of emergency cooling centers than is presently established in each city, with mandated backup power generation," stated the study.

The Federal Emergency Management Agency (FEMA) told the New York Times that it has a plan, created in 2017, for dealing with prolonged blackouts, but the plan does address the event of a blackout during a heatwave. Researchers say that many other American cities are also unprepared, and without any real support from the federal government, they may face even more deaths than the Texas freeze's 150. "We find that millions are at risk," said Stone. "Not years in the future, but this summer."


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