LONDON - US Energy Secretary Steven Chu said Tuesday the Obama administration wanted to paint roofs an energy-reflecting white, as he took part in a climate change symposium in London.

But he warned there was no silver bullet for tackling climate change, and said a range of measures should be introduced, including painting flat roofs white.

Making roads and roofs a paler colour could have the equivalent effect of taking every car in the world off the road for 11 years, Chu said.

It was a geo-engineering scheme that was "completely benign" and would keep buildings cooler and reduce energy use from air conditioning, as well as reflecting sunlight back away from the Earth.

For people who found white hard on the eye, scientists had also developed "cool colours" which looked to the human eye like normal ones, but reflect heat like pale colours even if they are darker shades.

And painting cars in cool or light colours could deliver considerable savings on energy use for air conditioning units, he said.

Speaking at the start of a symposium on climate change hosted by the Prince of Wales and attended by more than 20 Nobel laureates, Chu said fresh thinking was required to cut the amount of carbon created by power generation.

He said: "The industrial revolution was a revolution in the use of energy. It offloaded from human and animal power into using fossil fuels.

"We have to go to a different new revolution that can severely decrease the amount of carbon emissions in the generation of energy."

California has paid owners of older automobiles something like 400-500 dollars to take their car off the road and thus end it's pollutant contribution.  However, what they do is turn around and sell the right to pollute to factories based upon the pollution the vehicle would have contributed making a net profit in the sale of pollution rights.  The question is for Secretary Chu: is the mission  to paint things white and then turn around and give or sell the right to pollute based upon the carbon reduction estimated by painting things white?  Truth Injector could not pin down an answer after talking to several Department of Energy officials.