Inventory of geo-engineering proposals

Geo-engineering proposals seeking to combat global warming should be assessed according to efficacy, cost, risk, timeframe and the rate at which they can mitigate climate change, says Philip W. Boyd of New Zealand's NIWA in an article published in Nature Geoscience. 

We need more thought on whether proposals like carbon burial, geochemical carbon capture, atmospheric carbon capture, ocean fertilization, cloud manipulation, space sunshades, or strategically-placed pollution can be effective on a time-scale relevant to humankind, economical, or even safe. 

Meanwhile, AP reports that John Shepherd will head a working group at Britain's Royal Society to study geo-engineering proposals, with a report expected to be published in mid-2009.