Ideas range from simple to fantastical, but policymakers seem willing to consider the concept as a possible strategy for dealing with carbon emissions-based global climate change.
The long-term impacts (and maybe irreversible effects) are causing some hesitation.
"But, as with nearly every geo-engineering plan, there are substantial drawbacks to the gas-the-planet strategy. Opponents say it might produce acid rain and decimate plant and fish life. Perhaps more disturbing, it's likely to trigger radical shifts in the climate that would hit the globe unevenly. "Plausibly, 6 billion people would benefit and 1 billion would be hurt," says Martin Bunzl, a Rutgers climate-change policy expert. The billion negatively affected would include many in Africa, who would, perversely, live in a climate even hotter and drier than before. In India, rainfall levels might severely decline; the monsoons rely on temperature differences between the Asian landmass and the ocean, and sulfur aerosols could diminish those differences substantially."
And New Scientist recently reported that the American Meteorological Society is planning to endorse research into geoengineering. The Society is now the first major scientific group to get behind the idea.