US Cities Where the Heat Is Becoming Unbearable

As summers get hotter, many American cities are finding themselves facing an existential threat — extreme heat. While sizzling summers are nothing new, the frequency and intensity of heat waves are increasing due to climate change. This is causing cities to become giant ovens, trapping heat, and making life miserable, and dangerous, for residents.

Urban Areas Are Heating Up

Around 80% of the United States population lives in cities. Urban areas are particularly vulnerable to heat waves because of the urban heat island effect. Buildings, pavements, and other infrastructure absorb and radiate heat more effectively than trees and other vegetation. This can create a temperature difference of several degrees between a city and its surrounding rural areas. Socioeconomic factors can lead to higher urban heat exposure for communities, including people of color and those living beneath the poverty line, who are more likely to live in crowded urban areas.

According to the U.S. Environmental Protection Agency, "The urban heat island effect is a measurable increase in ambient urban air temperatures resulting primarily from the replacement of vegetation with buildings, roads, and other heat-absorbing infrastructure. The heat island effect can result in significant temperature differences between rural and urban areas."

Dangers of Extreme Heat

The effects of extreme heat are far-reaching. Heatstroke is a serious risk, especially for vulnerable populations like the elderly, children, and people with chronic health conditions. Beyond that, heat waves can also exacerbate air pollution, worsen allergies, and increase strain on power grids as people crank up their air conditioners.

Cities Facing Extreme Heat

So, what cities are feeling the heat the most?

• Phoenix, Arizona
• New York, New York
• Houston, Texas
• Los Angeles, California
• Dallas, Texas
• Chicago, Illinois
• San Antonio, Texas
• Detroit, Michigan

All of these cities have more than 1 million residents and are feeling an increase in temperature of 8 degrees or higher due to the heat island effect.

Besides these examples, there are many other U.S. cities that are feeling the heat. In fact, scientists say the average number of Americans who experience three days in a row of 100-degree temperatures will grow from 46% currently to 63% over the next 30 years.

Looking Forward

The good news is that there are steps that can be taken to mitigate the urban heat island effect. Planting trees, using lighter-colored materials for roads and buildings, and creating green roofs can all help to cool cities down.

Resources: Heat and Health | Reduce Urban Heat Island Effect| Urban Heat Hot Spots | 'It's unbearable': in ever-hotter US cities, air conditioning is no longer enough | Where the most U.S. residents bake because of concrete and lack of trees