White roofs could slow global warming
September 15, 2008
Data released at an annual Climate Change Research Conference in California suggests that the installation of white roofs and reflective pavements in the world's major cities would have a significant cooling effect and help slow global warming.
It is well known that white roofs reflect the sun's rays and keep a building cooler, but this is the first time that scientists have claimed that the use of reflective materials could have an impact on the global climate.
It has been a requirement in the Golden State since 2005, that commercial structures with flat roofs should have white roofing. From next year, heat-reflecting roofing will have to be installed on new and retrofitted residential and commercial buildings, irrespective of whether they have flat or sloping roofs. These requirements are all part of an energy-efficient building code. As yet though, there are no requirements concerning the use of "cooler" pavement materials.
The scientists claim that, if the traditional dark shingle or coatings of a 1000 sq ft roof were to be replaced with white material, the cooling effect would be sufficient to offset 10 metric tonnes of carbon dioxide emissions. Given that, for the majority of the world's cities, roofs account for approximately 25% of the surface and pavements a further 35%, it is easy to see how the carbon savings would mount up if they were all coated with reflective material.
It is calculated that such action could offset more than 10 years of emissions increases.
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