Atmospheric geoengineering could make climate worse

Posted by Kate Taylor

One suggested method of countering man-made climate change, injecting sulfate particles into the stratosphere, could carry serious consequences, say scientists.

A team at the University of Washington says it would likely achieve only part of the desired effect, and could have serious repercussions at the poles.

The modeling study shows that significant changes would still occur, as increasing the levels of such aerosols in the atmosphere wouldn't balance changes in atmospheric and oceanic circulation brought on by higher levels of atmospheric carbon dioxide.

"There is no way to keep the climate the way it is now. Later this century, you would not be able to recreate present-day Earth just by adding sulfate aerosols to the atmosphere," says doctoral student Kelly McCusker.

Using the National Center for Atmospheric Research's Community Climate System Model version 3, and working at the Texas Advanced Computing Center, the researchers found that there would be less overall warming with a combination of increased atmospheric aerosols and increased carbon dioxide than there would be with just increased carbon dioxide.

They also found that injecting sulfate particles into the atmosphere might even suppress temperature increases in the tropics enough to prevent serious food shortages and limit negative impacts on tropical organisms in the coming decades.

But things would be very different in polar regions, they say. Increased winter surface temperatures in northern Eurasia could have serious ramifications for Arctic marine mammals not equipped to adapt quickly to climate change.

In Antarctic winters, changes in surface winds would also bring changes in ocean circulation - with potentially significant consequences for ice sheets in West Antarctica.

It's not worth the risk, they say, as it would simply create more uncertainties, on top of those about climate change.