In a new study, a scientist has come up with the suggestion that global warming may be tackled with white paint.
According to a report in The Guardian, the scientist in question is Hashem Akbari from the Lawrence Berkeley National Laboratory in California, US, who suggests painting roads and the rooftops of buildings with the color white to fight global warming.
Advertisement"Turn enough of the world's black urban landscape white, and it would reflect enough sunlight to delay global warming, and grant us some precious breathing space in the global struggle to control carbon emissions," he said.
His big idea is based on principles as old as the whitewashed villages that scatter the hills of southern Europe and North Africa.
Akbari is poised to launch a campaign to paint the world white.
He wants dozens of the world's largest cities to unite in an effort to replace the dark-coloured materials used to cover roads and roofs with something a little more reflective.
It sounds simple, but the effect could be dramatic.
Study after study has shown that buildings with white roofs stay cooler during the summer. The change reduces the way heat accumulates in built-up areas (known as the urban heat island effect) and allows people who live and work inside to switch off power-hungry air conditioning units.
Dark roofs reflect about 10-20 percent of sunlight, while white surfaces tend to send back at least half.
"Roofs are going to have to be changed one by one and to make that effort at a very local level, we need to have an organisation in place to make it happen," said Akbari.
Groups in several US cities, including Houston, Chicago and Salt Lake City, are on board with his plan, and he is talking to others.
According to Akbari, his plan is more workable than other geo-engineering ideas.
The science is simple. Sunlight reflected from a surface does not contribute to the greenhouse effect, which drives global warming.
Like all geo-engineering schemes, it will need to be kept up indefinitely, and does not address the growing acidification of the oceans, caused as extra CO2 dissolves.
But, the cooling effect and energy savings in cities would be welcome though, said Akbari.
Akbari said his idea is not intended to replace efforts to cut carbon emissions, but to work alongside them.
"We can give the atmosphere time to breathe," he said. "I just don't see a downside to this idea. It benefits everybody and you don't have to have hard negotiations to make it happen," he added.