When man-made Global Warming starts to have a big impact on the economy, a new study says cities will be hit the hardest.

Researchers looked at 1,692 cities and determined that by the year 2100 the average temperature will be 2.6 times higher due to an effect researchers call the "urban heat island".  That's around 8 C Degrees.  Five degrees are because of global warming, and the rest will be caused by huge masses of concrete and asphalt that absorb the sunlight and radiate the energy back into atmosphere.  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 economics professor Richard S.J. Tol of the University of Sussex.

The cheapest and easier plans to deal with it would be to plant more trees, installing cool roofs, and replacing pavement with new materials that absorb less heat and reflect less into the nearby environment.