If you can't take the heat, maybe you should get out of the city

(Photo of time and temperature during heat wave of 2005 from Flickr and swanksalot/Seth Anderson)

Cities retain heat more than rural or even suburban areas. A combination of steel, concrete and asphalt that absorb the heat and large buildings that break up cool breezes cause what's known as "urban heat islands." That heat is retained at night, with so little vegetation or soil moisture to cool it down.

In New York City, night-time temperatures are as much as 14 degrees higher than those in outlying areas as close as 60 miles away, according to a 2009 American Meteorological Society study.

Now researchers at the Met Office in London are saying there will be an increased effect of urban warming as CO2 concentrations in the air rise.

In case you haven't noticed, a heat wave has descended over Washington, New York and much of the East Coast, with temperatures up around 100 degrees. Too bad the Congressmen who mocked global warming during the cold, snowy winter, are out of town right now. They might begin to have second thoughts. (Though, probably not.)

Increased CO2 will only make things worse, Met scientists say. Urban areas are warming faster than rural ones, according to the Met study, published in Geophysical Research Letters. The researchers forecast daytime urban temperatures will increase 5 degrees Fahrenheit when CO2 levels reach 645ppm, probably by 2050. Night temperatures will rise by the same amount, their models say.

Climate change and rapidly increasing migration to cities, especially in third-world countries, will create health hazards, the study said.

Some climate change deniers have said death from cold equals or surpasses death from heat, so health should not be a concern. However, the U.S. Global Change Research Program said winter cold snaps increase death rates by 1.6%, while heat waves drive them up by 5.7%. So heat is more deadly than cold. And the number of hot nights in most cities is expected to increase significantly.

The heat wave in Chicago in 1995, which killed some 700 people, was deadly because temperatures didn't cool at night and apartments without air conditioning got hotter and hotter as the days went on and it didn't cool down at night.

The Intergovernmental Panel on Climate Change reports in 2007 predicted with increasing global warming, there would be more heat waves with hot nights as well as hot days.

"Every degree is huge, in a city," said Stuart Gaffin, co-author of the Meteorological Society's New York study. "It's the difference between a blackout and getting through a heat wave. NYC this week was flirting with a blackout because of increased demand for air conditioning. A blackout would compound the danger and drive up the number of fatalities in a hot spell.

Which tells us we need to increase the capacity and modernize the electrical grid. And also that we need a price on carbon to slow down emissions into the air that will make all this worse and worse.

(Source: ClimateWire)