New Scientist posts this article on the need for geoengineering research, which is noteworthy in that it discusses the "social tipping point" where society is coming to grips with the need to study geoengineering now.

IN A room in London late last year, a group of British politicians were grilling a selection of climate scientists on geoengineering - the notion that to save the planet from climate change, we must artificially tweak its thermostat by firing fine dust into the atmosphere to deflect the sun's rays, for instance, or perhaps even by launching clouds of mirrors into space.

Surely the scientists gave such a heretical idea short shrift. After all, messing with the climate is exactly what got us into such trouble in the first place. The politicians on the committee certainly seemed to believe so. "It is not sensible, is it? It is not a serious suggestion?"

Had the question been posed a few years ago, most climate scientists would have agreed. But the mood is changing. In the face of potentially catastrophic climate change, the politicians and scientists all agreed that since cuts to carbon emissions will likely fall short we need to be exploring "Plan B". Climatologists have hit a "social tipping point" says Tim Lenton of the University of East Anglia, UK.

The article also attempts to rank the various geoengineering techniques, but doesn't explain how the rankings are calculated. Considering that ocean iron fertilization has already had 20 years of research, it's probably much closer to readiness than any other technique. Also the cost of OIF is considerably less than other approaches.