Which U.S. cities have the worst heat island effects?

ATHENS, Ga., Sept. 18 (UPI) -- Researchers at the University of Georgia recently published a study ranking urban heat island effects in the United States.

Cities that find themselves at or near the top of the list shouldn't be proud. A heat island effect isn't good. If you live in a city with a high heat island effect, it likely means there's too much concrete and not enough green space.

Miami, Louisville and Salt Lake City were found to have the top three highest urban heat island effects.

But the new study, published in the journal Computers, Environment and Urban Systems, wasn't meant to be an exercise in shaming. Researchers are trying to find out which kinds of urban development are best suited for minimizing the heat island effect.

"The overall goal of our study was to clarify which urban form -- sprawl or more-dense development -- is most appropriate for UHI mitigation," lead study author Neil Debbage, a doctoral student in Georgia's department of geography, said in a press release.

Researchers measured UHI using a model that incorporates a variety of climate data points to tease out the relationship between surface temperatures and air temperatures. Next, scientists used spatial modeling to look for correlations between urban morphology and UHI.

But researchers found no evidence that one size fits all when it comes to UHI mitigation. Both sprawl and high-density urban development can bolster UHI if heat-deflecting materials and green space aren't properly employed.

"Not just whether cities have high-density development, but how the built infrastructure is connected -- and disconnected by green spaces -- has a great impact on heat island intensity," said study co-author Marshall Shepherd, a professor of geography and atmospheric sciences at Georgia.

"We found that more contiguous sprawling and dense urban development both enhanced UHI intensities," Debbage added. "In other words, it does not appear to be a simplistic either-or situation regarding sprawl or density."

As more and more people live in cities, and as the climate continues to warm, finding a way to deflect heat in urban environs will be key to sustainability.