Manipulating skies to slow global warming could create havoc in tropics

An idea by the father of the H-bomb to slow global warming by sowing the stratosphere with light-reflecting particles could wreck the weather system in the tropics, a study said.

The scheme may benefit northern Europe and parts of Asia, but around the equator rainfall patterns would be disrupted, potentially drying up tropical forests in South America and intensifying droughts in Africa and Southeast Asia.

"The risks from this kind of geo-engineering are huge," said Andrew Charlton-Perez, a meteorologist at Britain's University of Reading.

In 1997, US nuclear physicist Edward Teller and other scientists suggested spreading sulphate particles into the upper atmosphere, reflecting some sunlight back into space to attenuate the Earth-warming greenhouse effect from fossil fuels.

This sunscreen - similar to the cooling effect from ash spewed by volcanic eruptions - would be cheaper than switching out of coal, gas and oil, which cause the global warming problem, they said.

The idea is a favourite among geo-engineers, who concede that manipulating the climate system on a planetary scale should be a last-ditch option.