If You Can’t Take the Heat, Get Off the Island

Source: Climate Central

Sweaty subway brush-ups, the smell of garbage broth brewing in gutters, and most of all the heat -- heat that radiates from everywhere and escapes to nowhere. That’s what New York typically feels like in August. It’s a time when the only people walking the streets on weekends are the tourists and the overworked; everyone else skips town or stays home.

There’s a name for this particular municipal affront: urban heat islands. Asphalt and buildings absorb and radiate heat, and the lack of greenery means less shade and evaporative cooling. At its worst, New York can register 20 degrees Fahrenheit hotter than nearby rural areas (2.7 degrees hotter on average), according to a new report by nonprofit research group Climate Central.

Climate change is making the problem worse, cranking up the heat in cities even faster than in rural areas, according to the report. Heat islands aren’t unique to New York (which incidentally is enjoying an unusually mild summer); most cities are very good at trapping heat and never letting go. The study examined temperature data for 60 cities over ten years and compared each city to three nearby rural areas. The image above shows the urban heat of Louisville, Kentucky, measured by satellite.

Nearly all of the cities studied were hotter than surrounding areas, and 75 percent of cities saw temperatures rising faster than their rural counterparts. America’s worst heat island was Las Vegas, where each year the thermometer breaks 100 degrees on 29 more days than in surrounding rural areas (79 days total).

Below are the top 10 most intense summer heat islands, with the average temperature difference from surrounding areas:

Las Vegas (7.3°F)
Albuquerque (5.9°F)
Denver (4.9°F)
Portland (4.8°F)
Louisville (4.8°F)
Washington, D.C. (4.7°F)
Kansas City (4.6°F)
Columbus (4.4°F)
Minneapolis (4.3°F)
Seattle (4.1°F)

More than half of the world’s population now lives in urban areas. By 2050, seventy percent will. By that time, the average American is likely to see between two and more than three times as many 95 degree days as we're accustomed to, according to research published earlier this year.

When the move toward cities collides with climate change, the result is a dangerous level of extremely hot days that are terrible for human health and worker productivity. Not to mention wicked smells and sweaty straphangers.

Click here for an interactive graphic showing detailed results for each city.

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