Extreme Heat Is a Disease for Cities. Treat It That WayThe “urban heat island effect” creates extra-hot temperatures that kill. But cities can prescribe powerful treatments, like green spaces and reflective roofs.
Matt Simon
Apr 25, 2022 7:00 AM
 Photograph: Kevin Dietsch/Getty Images
For millennia, cities have thrived by attracting people with diverse backgrounds and talents. But as the world warms, urban areas are attracting something less desirable: heat. A city’s roads, buildings, and other infrastructure absorb the sun’s energy, raising temperatures far above those in surrounding rural areas. This “urban heat island effect” varies dramatically not only from neighborhood to neighborhood, but from block to block and even house to house. Because it’s so hyperlocal and erratic, it’s hard to factor into predictions; a person’s actual experience of heat may be out of step with their local weather forecast. And with climate change, it’s increasingly difficult to keep vulnerable ( and rapidly growing) populations safe during extreme heat events.
“I often talk about heat as the silent killer, and I say that because it doesn't get the headlines that tornadoes, flooding, and blizzards get,” says Jonathan Porter, chief meteorologist at AccuWeather, the forecasting service. “We think heat-illness deaths are woefully undercounted because people oftentimes have other medical conditions that yes, may have contributed to or caused their death, but it was aggravated by a heat situation.”
Predicting extreme heat is paramount so public health officials can prepare. But forecasts only go so far. AccuWeather, for instance, blends over 170 forecast models that are run by meteorologists with decades of experience. They can partially account for the heat island effect by incorporating land use data that shows which parts of a city have vegetation, which helps cool things off. That’s because plants “sweat” as they photosynthesize, releasing water vapor and cooling the air.
Heavily industrialized areas, on the other hand, tend to be devoid of vegetation. “You've got a lot of surfaces that are basically just reradiating heat, a lot of concrete and particularly asphalt, because it's dark,” says Carl Parker, a meteorologist and climate specialist at the Weather Group, which runs the Weather Channel. “Then on top of that, you've got these artificial sources [of heat], including air conditioning units, and then cars that are also putting excess heat into the atmosphere.”
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