A controversial idea to brake global warming, first floated by the father of the hydrogen bomb, is affordable and technically feasible, but its environmental impact remains unknown, a trio of US scientists say.
Sowing the stratosphere with particles to reflect the Sun and cool the planet is possible with current technology and would cost a fraction of the bill from climate change or reducing emissions by fossil fuels, they argue.
Back in 1997, as man-made global warming became a political issue, US nuclear physicist Edward Teller and others suggested spreading sulphate particles into the upper atmosphere.
Carried around the globe on high-speed winds, the whitish particulates, known as aerosols, would reflect the Sun, reducing solar radiation by around one percent.
It would provide a cooling similar to when volcanoes spew out clouds of dust, said Teller, who argued this option was far smarter than switching out of cheap and dependable fossil fuels.
Teller, a hawk on nuclear weapons who reputedly inspired the movie character Dr. Strangelove, was lashed for an idea that critics said was unworkable and laden with risk.
The new study, published in the British journal Environmental Research Letters, makes a cost analysis of so-called solar radiation management, or SRM, by aerosols.