Quelle: nytimes.com – Studie Compound Climate and Infrastructure Events: How Electrical Grid Failure Alters Heat Wave Risk

The author of a new study said the combination of blackouts and extreme heat “may be the deadliest climate-related event we can imagine.”

The growing risk of overlapping heat waves and power failures poses a severe threat that major American cities are not prepared for, new research suggests.

Power failures have increased by more than 60 percent since 2015, even as climate change has made heat waves worse, according to the new research published in the journal Environmental Science & Technology. Using computer models to study three large U.S. cities, the authors estimated that a combined blackout and heat wave would expose at least two-thirds of residents in those cities to heat exhaustion or heat stroke.

And although each of the cities in the study has dedicated public cooling centers for people who need relief from the heat, those centers could accommodate no more than 2 percent of a given city’s population, the authors found, leaving an overwhelming majority of residents in danger.

“A widespread blackout during an intense heat wave may be the deadliest climate-related event we can imagine,” said Brian Stone Jr., a professor at the School of City & Regional Planning at Georgia Institute of Technology and the lead author of the study. Yet such a scenario is “increasingly likely,” he said.

The findings come just months after a winter storm knocked out power for millions of people in Texas, causing more than 150 deaths and demonstrating how easily severe weather can overwhelm electrical grids and other infrastructure.

But as much as winter storms and extreme cold remain a threat, the greater risk to human health as temperatures rise is from extreme heat.

Heat is already the most dangerous type of severe-weather event, by one estimate killing some 12,000 Americans each year. And climate change is making heat waves more frequent and severe.

The changing climate also seems to be making power failures more common. From 2015 to 2020, the number of blackouts annually in the United States doubled, Dr. Stone said. And those blackouts were more likely to occur during the summer, suggesting they were being driven in part by high temperatures, which increase demand on the electrical grid as people turn up their air-conditioners.

Because both heat waves and blackouts are becoming more frequent, “the probability of a concurrent heat wave and blackout event is very likely rising as well,” Dr. Stone said.

“We find that millions are at risk,” Dr. Stone said. “Not years in the future, but this summer.”