Global Warming Is Turning Cities Into Costly “Urban Heat Islands”


Katy Evans

Katy is Managing Editor at IFLScience where she oversees editorial content from News articles to Features, and even occasionally writes some.

Managing Editor

Heat from rising global temperatures and pollution trapped in big cities is going to prove expensive in the future. r.nagy/Shutterstock

If you think “urban heat islands” sound like a rather pleasant tropical cityscape destination, you would be wrong. They are highly populated metropolitan areas that are heating faster than their rural surroundings due to human activity, and according to a new assessment, this is going to cost them – both environmentally and economically – dearly.

A new study on the impact of climate change on cities suggests 25 percent of the world’s cities could be 7°C warmer by the end of the century, and they face paying twice the economic cost to fight climate change than the rest of the world. The study is published in Nature Climate Change.


Cities heat up faster than other areas because of the concentrated energy released from traffic, building insulation, and industrial output combined with heat being trapped by large cities’ dark concrete buildings, asphalt roads, and close together structures.

The international team of economists analyzed the policies of 1,692 cities in the hopes of helping to reduce the impacts and effects of climate change. The authors point out that many studies focus on the threats to cities from sea-level rise or damage to health and water resources, but that these impact estimates don’t take into consideration the “urban heat island” effect.

"Any hard-won victories over climate change on a global scale could be wiped out by the effects of uncontrolled urban heat islands,” said Professor Richard SJ Tol, professor of economics at the University of Sussex, UK, in a statement. "We show that city-level adaptation strategies to limit local warming have important economic net benefits for almost all cities around the world."

According to the study, cities cover just 1 percent of the Earth’s surface but house over half of the world’s population, consuming 78 percent of the world’s energy and producing 80 percent of the Gross World Product (GWP), so measures that could limit the impact of rising temperatures should be pretty high priority.


They modeled different solutions, including ideas as simple as installing heat-reflective pavements and roofs. They showed that changing just 20 percent of a city’s roofs and pavements could reduce temperatures by 0.8°C and save up to 12 times what they cost to install and maintain.  

The worst-case scenario they modeled saw cities such as Tokyo, New York, London, and Beijing lose 10.9 percent of their GDP due to increased spending on the rising costs of energy to keep citizens cool and the price of keeping pollution down.

While the world waits for Trump to come to a decision on the Paris climate agreement, perhaps the effects of climate change in terms of economic loss is a language he can understand and a more effective way to reach him and get the message across. 


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  • climate change,

  • global warming,

  • pollution,

  • heat