A solar shield that reflects some of the sun's radiation back into space would cool the climate within a decade and could be a quick-fix solution to climate change, researchers say.
Due to their rapid effect, they should, however, be deployed only as a last resort when "dangerous" climate change is imminent, they add, reported a private TV channel.
As part of their study, Ken Caldeira at the Carnegie Institution of Washington, in California, US, and Damon Matthews at Concordia University, Canada, used computer models to simulate the effects that a solar shield would have on the Earth's climate if greenhouse gas emissions continued to rise along a "business as usual" scenario.
The computer models simulated a gradually deployed shield that would compensate for the greenhouse effect of rising carbon dioxide concentrations.
The researchers found that a sulphur shield could act very quickly, lowering temperatures to around early 20th-century levels within a decade of being deployed.
"We have been trying to pinpoint the one really bad thing that argues against geoengineering the climate. But it is really hard to find. The trouble is, the decadal timescale works both ways," said Caldeira.
"A sulphate shield would need to be continuously replenished, and the models show that failing to do so would mean the Earth's climate would suddenly be hit with the full warming effect of the CO2 that has accumulated in the meantime.
"So if you have the shield up there and it fails - or, for example, the republicans put up a shield and then the democrats come in to power and turn it down - then you effectively compress into a decade or two the warming that would have happened while the shield was up.