Summers in the U.S. have been warming since the 1970s due to climate change, though it might not seem like it if you’re riding out this unusually cool August in the northeast and midwest.
If you're in a city, though, your perception of the heat might be all messed up. Cities get it the worst because of something additional known as the urban heat island effect. Due to all of the dark, paved surfaces in cities that are good at absorbing sunlight, urban areas tend to be hotter than their surrounding rural areas, where vegetation reflects more sunlight. That’s why green roofs have such environmental benefits; they help cool cities down.
A new report from Climate Central, a research and journalism organization based in Princeton, New Jersey, looks at the strength of the urban heat island effect across 60 major cities over the last decade—and how the combined trends of urbanization and climate change are causing cities to get hotter much faster than their surrounding regions.
It also provides a handy interactive tool, which is embedded below, so you can look up your own city and explore how strong the effect is.
On average, Climate Central found that urban summer temperatures were 2.4 degrees Fahrenheit hotter than surrounding rural temperatures, and the worst temperature difference in a single day occurred when one city was 27 degrees Fahrenheit warmer than its rural environs. Since 2004, 12 cities reached temperatures above 90 degrees at least 20 days more often than surrounding rural areas. It also found that in 41 out of the 60 cities analyzed, urbanization and climate change combined contributed to rising summer heat faster than climate change alone is raising regional temperatures.
Hotter summer days have more serious repercussions than simple discomfort. Heat is the number one weather-related killer in the U.S., Climate Central notes. What’s more, in the summer, steamy days contribute to air pollution and it’s associated health problems, like asthma. See how hot it’s going to get in your city, and then start planting.