Geophys. Res. Lett. 38, L24706 (2011)

Credit: © ISTOCKPHOTO.COM/THINKSTOCK

The injection of fine particles called aerosols into the atmosphere is one approach to geoengineering the climate in an attempt to offset global warming.

Understanding the effects of aerosol injection on the temperature structure of the upper atmosphere (stratosphere) is an important step in developing predictive models of the impact of various geoengineering options on the climate.

Angus Ferraro and colleagues from the University of Reading in the UK, investigated the pattern of stratospheric temperature change induced by injecting different aerosol compounds and size distributions into the atmosphere using atmospheric model simulations.

They found that aerosol injection consistently heated the lower stratosphere in the tropics, but that the response of the stratosphere at the poles was more variable, encompassing heating, cooling or neutral effects depending on the aerosol type and size used, and the season. These differences lead to different pole–Equator temperature gradients in the stratosphere and are therefore potentially important in determining atmospheric circulation patterns resulting from geoengineering.