Sea spray geoengineering predicted to be very weak
Modification of cloud albedo by controlled emission of sea spray particles into the atmosphere has been suggested as a possible geoengineering option to slow global warming. Previous global studies have imposed changes in cloud drop concentration in low level clouds to explore the radiative and climatic effects. Here, we use a global aerosol
transport model to quantify how an imposed flux of sea spray particles affects the natural aerosol processes, the aerosol particle size distribution, and concentrations of cloud drops.
Using spray emission rates comparable to those implied by
previous studies we find that the predicted cloud drop concentration changes are very small (maximum 20%) in regions of persistent low-level cloudiness. In one of the four regions the number of cloud drops actually decreases. The weak or negative effect is because the added spray particles suppress the humidity (supersaturation) in the clouds and prevent existing aerosol particles from forming cloud drops.
Radical plan to combat global warming ‘may raise temperatures’ – the Independent
How accurate is this newspaper article? On the whole it’s a fair reflection of our work, although we didn’t go so far to say that geoengineering would raise temperatures. I don’t think we really know for sure how changes in cloud drops would ultimately affect temperatures.
At EGU in April 2011 another paper was presented by a Norwegian group which seems to come to similar conclusions to our own article in 2010. This paper received some attention in the BBC