A group of researchers from Canadian universities simulated the long-term effects of C02-induced climate change after a full cessation of emissions in 2100.

The results should prompt more urgent action on adaptation and mitigation responses.

The study confirms other findings that C02-induced climate change is "largely irreversible" in human timescales, with changes to continue for centuries after emissions cease. Global mean temperatures would remain roughly constant after a full cessation of emissions in 2100, but regional changes in temperature and precipitation will continue.

The simulation shows a collapse of the West Antarctic Ice Sheet by the year 3000, leading to a global sea level rise of 3 to 4 metres.

Other findings reinforce data projecting a cooling of the Northern Hemisphere, a warming of the Southern Hemisphere, and delayed and ongoing ocean warming despite no further carbon emissions.

They conclude, grimly,

Geoengineering by stratospheric aerosol injection has been proposed as a response measure in the event of a rapid melting of the West Antarctic ice sheet. Our results indicate that if such a melting were driven by ocean warming at intermediate depths, as is thought likely, a geoengineering response would be ineffective for several centuries owing to the long delay associated with subsurface ocean warming.

Full article: (2010) Gillett, Nathan P., and Zickfeld, K. "Ongoing climate change following a complete cessation of carbon dioxide emissions" in Nature Geoscience.