From Envirowiki

Atmospheric sulfur seeding is a proposal to spray sulfate particles into the atmosphere in order to decrease the heat from the sun hitting the earth's surface, as a technological mitigation of climate change.

[edit] how it works

The proposal would work by increase the reflectivity of the atmosphere, or increase heat absorption in the upper atmosphere allowing the heat to more easily to escape back into space.

[edit] problems

There are huge problems with this suggestion, as with most geo-engineering, mostly stemming from the fact the proposal is presented as simplified linear cause and effect, completely ignoring the complexity of the system it's working in. For example, the proposal completely ignores, or sidelines the fact that sulfates are a major cause of acid rain. Researchers are also saying that sulfates may contribute to the damage to the ozone layer^[1]

[edit] references

1. ↑ Julie Steenhuysen "Plan to reverse global warming could backfire", Thu Apr 24, 2008, Reuters.com