Heat wave and blackout would send half of Phoenix to ER, study says
If a multi-day blackout in Phoenix coincides with a heat wave, nearly half of the population would need emergency care for heat stroke or other heat-related illnesses, a new study suggests.
While Phoenix was the most extreme example, the study warned that other cities are also at risk. Since 2015, the number of major blackouts across the country has more than doubled. At the same time, climate change is making heat waves worse and extreme weather events are increasing around the world.
The study, published Tuesday in the journal Environmental Science and Technology, suggests that the risk to cities would increase if a hurricane, cyberattack or windstorm during a heat wave knocked out power and deprived thousands of air conditioning.
This summer, two-thirds of North America, including the Southwest, could face power grid shortages, particularly during periods of extreme heat when demand for air conditioning spikes, straining resources, according to an analysis released this month. Phoenix Mayor Kate Gallego has done just that urged the federal government to add extreme heat to the list of disasters such as floods and hurricanes that could trigger a federal disaster declaration.
The new analysis found that Phoenix, which relies heavily on air conditioning to keep residents cool in the desert heat, would experience massive loss of life and illness if a citywide power outage lasted two days during a heat wave and power was cut. would gradually be restored. the next three days.
In that scenario, an estimated 789,600 people would need emergency care for heat-related illnesses, overwhelming the city’s hospital system, which has only 3,000 emergency room beds, the study said. According to the study, an estimated 12,800 people would die in Phoenix.
“I describe this as probably the biggest climate-related hazard we can imagine: a blackout during a heat wave,” he said. Brian Stone Jr., the study’s lead author and a professor in the School of City and Regional Planning at the Georgia Institute of Technology.
To anticipate the effects of a prolonged power loss during extreme heat, researchers modeled the temperatures residents of Atlanta, Detroit and Phoenix would be exposed to each hour if the power was on during a heat wave and if it wasn’t. .
The researchers began by examining past temperatures in those three cities. In Phoenix, they analyzed temperatures from a heat wave in July 2006, when the average maximum temperature was 113 degrees.
The researchers then estimated what the temperature would be at hundreds of points in the cities, not just at the airport, where the temperature is usually measured.
They estimated indoor temperatures for various residential buildings and used annual surveys from the U.S. Department of Labor to model how much time residents were likely to spend indoors and outdoors, depending on their age, gender, occupation and income. And the authors used census data to account for the racial makeup of the three cities, said Dr. Stone.
In Atlanta, 11,600 people, or about 3 percent of the population, would need emergency care if a five-day heat wave coincides with a multi-day blackout, the team found. The city only has about 2,000 emergency room beds, and the scientists estimated that six people in Atlanta would die during the twin crises.
The team, which also included researchers from Arizona State University and the University of Michigan, found that 216 people would die during a heat wave and power outage in Detroit.
The researchers acknowledged certain limitations in their findings. For example, their model assumed that people would stay put during a heat wave and blackout. In reality, the authors noted that some people might move and emergency responders would try to evacuate residents and set up power generators in cold stores.
Kristie L. Ebia professor at the University of Washington’s Center for Health and the Global Environment, who was not involved in the study, called it “quite an impressive study,” which should encourage cities to think about ways to help vulnerable residents, including protect pregnant women. outdoor workers and people in historically defined communities, which have fewer trees and more heat-retaining pavement.
David Hondula, an author of the study and that of Phoenix first director of heat response and mitigation, said that while officials there were deeply concerned about possible illnesses and deaths during a heat wave and blackout, “this is the first time we’re seeing a number, and it’s obviously a pretty alarming number.”
There are strategies, the study said, that can help protect residents during overlapping blackouts and heat waves.
If cities planted enough trees to shade half of their streets, deaths would drop 14 percent in Atlanta, 19 percent in Detroit and 27 percent in Phoenix, the study said.
And if they installed highly reflective “cool roofs” on every building, deaths would drop 21 percent in Atlanta, 23 percent in Detroit, and 66 percent in Phoenix.
But as climate change is expected to increase frequency, length and intensity of heat wavesthe study predicted that deaths and illnesses would rise even further.
Jane W Baldwin, an assistant professor of earth system science at the University of California Irvine, said the findings should underscore the importance of investing in a stronger power grid. That would “help prevent this frightening compound risk in the present and will continue to pay dividends in the future as heat waves continue to worsen,” said Dr. Baldwin.