Affirming what we’ve all guessed at by now, a new report ranked the hottest urban heat islands across the U.S., and unsurprisingly, Houston ranked high -- like the setting most of us crank our A.C.’s at all summer long. This confirmation comes courtesy of Climate Central, a nonprofit news organization that analyzes and reports on climate science.
The new report evaluates the intensity of urban heat islands in cities around the country. The report defines urban heat islands as “metropolitan areas that are hotter than their outlying regions, with the impacts felt most during summer months.”
About 85% of the U.S. population lives in metropolitan areas, according to the report.
Paved roads, parking lots, hospital campuses, malls, and buildings, which the concrete jungle we call home obviously has in abundance, absorb and retain heat during the day and radiate that heat back into the surrounding air. According to Climate Central, neighborhoods in a highly-developed city can experience peak temperatures that are 15°F to 20°F hotter than nearby communities with more trees and less pavement or rural areas with fewer people and buildings.
“Climate change is making extreme heat events worse and more frequent, with summer temperatures stretching into the shoulder seasons of spring and fall,” Climate Central researchers stated in the report. “Heat events adversely affect health and quality of life—and this is especially acute in urban communities. Higher cooling demand strains the electric grid and raises electric bills. And heat-related impacts fall unequally, with historically underserved populations facing greater health threats.”
The nonprofit created an index to evaluate the intensity of urban heat islands and applied it to 159 cities across the U.S. The report ranked Houston’s heat island the fourth most intense.
The index score for a city indicates the potential difference in average temperature for the city compared to its less developed surroundings. The temperatures range from less than 5°F to nearly 9°F.
New Orleans, secured the No. 1 spot, with Newark, New Jersey, at No. 2 and New York City at No. 3.
At No. 20, McAllen was the only other Texas city listed.
The index showed that Houston may be up to 7.46°F hotter than the less-developed areas outside the city limits. According to the Climate Central report, Houston scored so high because of its large percentage of heat-absorbing, impenetrable surfaces.
Extreme heat is the leading cause of deaths among weather-related fatalities over the past 30 years, according to the National Weather Service. Although Arizona, California, and Texas account for only approximately 23 percent of the U.S. population, these three states accounted for approximately one third of the country’s heat-related deaths between 2004 and 2018.
Unfortunately, our solution to the sweltering heat, air conditioners, dump even more heat into the surrounding atmosphere, contributing directly to the urban heat island effect, according to the Climate Central report.
Wondering why more extremely hot cities in the southwest didn’t appear on the list?
“Their relatively low scores are largely because their surrounding areas have temperatures similar to city temperatures, “Climate Central researchers stated in the report.
“That doesn’t mean these cities aren’t experiencing heat impacts. Rather, it emphasizes that much of the outlying area consists of desert or rock, which have lower albedo and are thus naturally hotter.”
Here are the top 20 cities with the most intense urban heat islands:
The temperature listed alongside each city indicate the potential difference in average temperature for the city compared to its less developed surroundings.
1. New Orleans (8.94°F)
2. Newark, N.J (7.71°F)
3. New York City (7.62 °F)
4. Houston (7.46°F)
5. San Francisco (7.37°F)
6. Boston (7.24°F)
7. Chicago (7.24°F)
8. Miami (7.08°F)
9. Baltimore, Md. (7.08°F)
10. Providence, R.I. (7.08°F)
11. Sacramento, Calif. (7.08°F)
12. Salinas, Calif. (7.08°F)
13. Burlington, Vt. (7.05°F)
14. Bend, Ore. (6.97°F)
15. Cleveland, Ohio (6.97°F)
16. Detroit (6.97°F)
17. Erie, Pa. (6.97°F)
18. Fresno, Calif. (6.97°F)
19. Lafayette, La. (6.97°F)
20. McAllen, Texas (6.97°F)
Read the full report here.