US call for world's roofs to be painted white

Professor Steven Chu, the US Energy Secretary.

All the roofs in the world should be painted white as part of the global effort to slow down irreversible climate change, according to Professor Steven Chu, the US Energy Secretary.

This would mean that residences in hot climates such as the UAE would save significantly on air-con costs as the sun’s rays would be deflected.

More white surfaces, including roads, could slow global warming by reflecting heat into space, rather than allowing it to be absorbed by darker surfaces, where it is trapped by greenhouse gases and causes temperatures to spiral ever higher.

Chu claimed that lightening roofs and roads in urban environments would help offset the impact of global warming. 

“If you look at all the buildings, and if you make the roofs white, and if you make the pavement more of a concrete type of colour rather than black, and if you do that uniformly, that would be the equivalent of reducing the carbon emissions due to all the cars in the world by 11 years,” argued Chu.

He said his calculations were based on work done at Lawrence Berkeley National Laboratory, where Chu was a former employee. Last year three researchers at the laboratory concluded that changing surface colours in the world’s 100 largest cities would offset 44 billion tonnes of carbon dioxide emissions.

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Chu was addressing an audience of 60 scientists at the Prince of Wales’ Meeting on Climate Change in London, which included 20 Nobel laureates. The symposium is anticipated to conclude with specific recommendations on combating the ‘climate crisis’.

Not all scientists are enamoured with Chu’s idea. “It’s past simplistic – it’s ridiculous,” said junkscience.com publisher Steven Milloy. “Imagine the glare on roads, in urban areas, imagine the UV radiation bouncing around. Snow blindness would be replaced by road blindness.”

However, Dr Gordon Bonan, a climate scientist at the National Centre for Atmospheric Research in Boulder, Colorado in the US, defended Chu. “That’s been a pretty standard idea for many years now. It’s related to the idea of an urban heat island, that a big city will generate a large amount of heat. In urban planning and design, the idea is that painting roofs white will absorb less solar radiation and keep the city cooler.”

The ‘urban heat island effect’ has been blamed for spiraling summer temperatures in Dubai, mainly as a result of the rapid increase in the size of the urban area due to unabated construction. For example, the temperature in Dubai, Sharjah and Abu Dhabi was above 46 degrees Celsius on 27 May, which is “way above the average for this time of year,” according to the Dubai Meteorological Office.

The Ministry of Labour has ordered that outdoor work be halted between 12:30 to 15:00 from July 1 to August 30, so as to give construction workers a respite from the relentless heat.

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