An 18-member panel of "scientists, former government officials and national security experts" have been assembled into the Task Force on Climate Remediation Research (contains links to press release, video of press conference, and full report). They are researching whether "extreme engineering techniques, which include scattering particles in the air to mimic the cooling effect of volcanoes or stationing orbiting mirrors in space to reflect sunlight" would be effective in reducing CO2 levels.
Members are clear - mitigation of greenhouse gases (GHG) must be the first priority. However, they acknowledge that "in case the climate system reaches a 'tipping point', swift 'remedial action' is required".
"The idea of engineering the planet is 'fundamentally shocking', David Keith, an energy expert at Harvard and the University of Calgary and a member of the panel, said. "It should be shocking."
It is controversial as well as it is rejected by many environmental groups. However, this type of research is well underway in Europe.