ScienceDaily (Jan. 25, 2012) — As the reality and the impact of climate warming have become clearer in the last decade, researchers have looked for possible engineering solutions -- such as removing carbon dioxide from the atmosphere or directing the sun's heat away from Earth -- to help offset rising temperatures. New University of Washington research demonstrates that one suggested method, injecting sulfate particles into the stratosphere, would likely achieve only part of the desired effect, and could carry serious, if unintended, consequences.
http://www.sciencedaily.com/releases/2012/01/120125142212.htm