White roofs may successfully cool cities

While world leaders are struggling to tackle global warming, American researchers have claimed to have found a simple way to cool cities -- by painting the roofs of buildings white.

"Our research demonstrates that white roofs can be an effective method for reducing urban heat. It has the potential to significantly cool cities and mitigate some impacts of global warming," said lead author Keith Oleson Atmospheric Research.

The team found that if every roof across the world were entirely painted white, the urban heat island effect could be reduced by 33 per cent.

This would cool the world's cities by an average of about 0.7 deg Fahrenheit, with the cooling influence particularly pronounced during the day, especially in summer, Oleson said.

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 to 5 deg F (about 1 to 3 deg Celsius) or more compared to rural areas.

In the study, the team used a newly developed computer model which provided scientists with an idealised view of different types of cities around the world, Science Daily reported.

However, the team cautioned that there are still many hurdles between the concept and actual use of white roofs to counteract rising temperatures.