White Roofs May Successfully Cool Cities, Computer Model Demonstrates

White Roofs May Successfully Cool Cities, Computer Model Demonstrates

ScienceDaily (Feb. 2, 2010) — Painting the roofs of buildings white has the potential to significantly cool cities and mitigate some impacts of global warming, a new study indicates. The new NCAR-led research suggests there may be merit to an idea advanced by U.S. Energy Secretary Steven Chu that white roofs can be an important tool to help society adjust to climate change.

But the study team, led by scientists at the National Center for Atmospheric Research (NCAR), cautions that there are still many hurdles between the concept and actual use of white roofs to counteract rising temperatures.

"Our research demonstrates that white roofs, at least in theory, can be an effective method for reducing urban heat," says NCAR scientist Keith Oleson, the lead author of the study. "It remains to be seen if it's actually feasible for cities to paint their roofs white, but the idea certainly warrants further investigation."

The study is slated for publication later this winter in Geophysical Research Letters. It was funded by the National Science Foundation, NCAR's sponsor.

Cities are particularly vulnerable to climate change because they are warmer than outlying rural areas. Asphalt roads, tar roofs, and other artificial surfaces absorb heat from the Sun, creating an urban heat island effect that can raise temperatures on average by 2-5 degrees Fahrenheit (about 1-3 degrees Celsius) or more compared to rural areas. White roofs would reflect some of that heat back into space and cool temperatures, much as wearing a white shirt on a sunny day can be cooler than wearing a dark shirt.

http://www.sciencedaily.com/releases/2010/02/100201145445.htm

painting the roofs white in the summer, black in the winter (no need to cool the cities when it's freezing outside).

Plus the footprint of all the evaporating hyrdocarbons as the paint dries.

Well, it's a theory, anyway.

:hi:

In many cities, they're just going to be covered by snow anyway.

That's right, snow is white. Although, this year there's been very little snow around S.E. Michigan, maybe a quarter of what we had last year.

So my house roof is absorbing heat for now.

and there should be a tax incentive to do so

this action could help reign in global warming as reflective roofing replaces the reflective forests we are missing.

that the new HH Gregg and SuperWalmart which had been built across from one another here in JAX both had white roofs (you can see them from I95). I wish that trend would spill over through this entire region, including housing and schools as well.