Global warming is expected to have a big impact on the economy, and a new study says cities will be hit the hardest.
The study published Monday in the Nature Climate Change journal found that the total economic costs of climate change for cities could be 2.6 times higher due to an effect researchers call the "urban heat island."
Researchers looked at 1,692 cities and found that by 2100, they could be as much as 8 degrees C warmer. Nearly 5 degrees would be due to global warming, but the rest is from the heat island effect, which happens when parks and lakes are replaced by heat-trapping concrete and asphalt.
By 2050, cities could see temperatures rise by two degrees from heat islands. That could mean more air pollution, worse water quality, and poorer health.
Any hard-won victories over climate change on a global scale could be wiped out by the effects of uncontrolled urban heat islands," said Richard S.J. Tol of the University of Sussex in a release.
The study found the median city would lose between 1.4 per cent and 1.7 per cent of its GDP by 2050, and between 2.3 and 5.6 per cent by 2100, depending on how much the planet warms during that period of time. The worst-off city could have losses as high as nearly 11 per cent of its GDP.
Researchers looked at different policies that could mitigate the economic impact of warming, like planting more trees.
They found that the cheapest measure would be installing cool roofs and pavements that absorb less heat and reflect less into the nearby environment. The study found that changing 20 per cent of a city's roofs and half of its pavements could save 12 times the cost of installation and maintenance, and reduce air temperatures by 0.8 degrees.
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