From Common Dreams: http://www.commondreams.org/headline/2014/01/08-4
Risky plan to mitigate climate change could dry out the tropics: study
Andrea Germanos
Published on Wednesday, January 8, 2014 by Common Dreams
New research shows how a controversial plan to rein in global warming caused by runaway greenhouse gases could bring a “new unintended side-effect over a large part of the planet” that could be as bad as the effects of rising CO2.
The study by researchers at the University of Reading published Wednesday in Environmental Research Letters used climate model simulations to show potential effects of one method of “geoengineering.”
The Guardian reports that
The controversial idea of geoengineering – deliberately changing the Earth’s climate – is being seriously discussed as a last-ditch way of avoiding dangerous global warming if efforts to slash greenhouse gas emissions fail.
But the new work shows that a leading contender – pumping sulphate particles into the stratosphere to block sunlight – could have side-effects just as serious as the effects of warming itself. Furthermore, the impacts would be different around the world, raising the prospect of conflicts between nations that might benefit and those suffering more damage.
“We have shown that one of the leading candidates for geoengineering could cause a new unintended side-effect over a large part of the planet,” BBC News quotes study co-author Dr. Andrew Charlton-Perez as saying.
Specifically, the BBC continues, putting these sulphate particles into the stratosphere—”stratospheric aerosol geoengineering”—means that
Rainfall around the tropics could be cut by 30% with significant impacts on rainforests in South America and Asia and increasing drought in Africa.
The changes would happen so quickly there would be little time to adapt, say the researchers.
“When stratospheric aerosol geoengineering is represented more realistically using a sulfate aerosol layer there is additional atmospheric heating from the aerosol layer which weakens the tropical circulation, suppressing convection and further reducing precipitation,” the researchers write in their study.
“Consequently, though stratospheric aerosol geoengineering could be used compensate for the surface warming produced by CO2 globally, or even regionally, there is a tropical precipitation change of the opposite sign to and greater in magnitude than the long-term response to CO2,” the study finds.
Continue reading at: http://www.commondreams.org/headline/2014/01/08-4