The risks of injecting aerosols into the stratosphere to combat global warming have been underestimated, say Klaus Keller and his team at Pennsylvania State University in University Park.

Some have proposed that adding fine particles and liquid droplets, which reflect heat, to the atmosphere could postpone the need for deep cuts to carbon emissions. But by modelling the economic effects of substituting aerosol injections for carbon cuts, the researchers show that potentially damaging side-effects of the aerosols — such as depletion of polar ozone and changes in precipitation patterns — could easily wipe out any benefit. And because aerosols disappear quickly whereas greenhouse gases linger, Earth could face even more abrupt and costly climatic change if any aerosol injections were interrupted by, for example, war or the breakdown of international pacts, the researchers say.

Clim. Change doi:10.1007/s10584-010-9961-z (2011)