The urban heat island effect amplifies a heat wave’s already-oppressive temperatures: areas with a lot of asphalt, buildings and freeways tend to absorb the sun’s energy then radiate heat. Areas with green space — parks, rivers, tree-lined streets — absorb less.
Andrew Pershing, the director of climate science at Climate Central, said the results were somewhat unexpected.
“Anything with ‘urban’ in its name you’re going to be surprised if New York City and Chicago and places like that don’t rate pretty highly,” Pershing said. “But I was certainly surprised to not see places like Phoenix, Las Vegas, Reno on the list.”
Recent research has shown Black and brown neighborhoods disproportionately suffer from the effects of urban heat compared to their White counterparts.
Many in these communities work outdoor jobs where they are exposed to heat for long hours, to pay rent for apartments that don’t have proper cooling systems, Shandas said.
Officials in Oregon say at least 83 people died from heat-related illness in the state, 54 of whom were in the Portland area. Many of the victims there were older, living alone, and without functioning air conditioning, according to a preliminary report on excessive heat deaths released by the county Tuesday.
In Washington, at least 78 people died, and across the border in British Columbia, officials estimate tallied 500 more deaths than normal for that time period, which they believe are heat-related.
Pershing said the color of surfaces is critical to consider when planning new buildings or roads — white is coolest, black is hottest — but another interesting factor is population. In densely populated neighborhoods, he said, “they’re going to be running machinery and running air conditioners” that adds to heat.
“I like to think of it as the human-induced microclimate,” Pershing said.
As the climate crisis makes record-breaking heat waves more frequent, researchers say cities should do more to combat the impact of urban heat islands by thinking about heat impacts before choosing materials, planting trees and planning new green spaces.
“It’s been a real issue in the development of US cities over time — that green spaces tend to be built in the suburbs, or in the places where the rich people live,” Pershing said. “I think it’s really important that those be available to everyone.”
CNN’s Rachel Ramirez and Chris Boyette contributed to this report.