"A group of academics on Friday considered the ultimate engineering challenge: building machines to stabilize the earth's climate.

The Massachusetts Institute of Technology convened a symposium here to discuss the potential benefits and pitfalls of geoengineering, also called climate engineering. Everything from shooting light-blocking particles into the atmosphere to "artificial trees" is being seriously studied, despite trepidation among researchers and opposition from others."

http://news.cnet.com/8301-11128_3-10387137-54.html