"Rising carbon dioxide levels in the Earth’s atmosphere will cause unstoppable changes to the climate for at least the next 1,000 years, a new study suggests..." (read more).
A very interesting study which asks the question, "What if we ceased putting any more carbon dioxide from fossil fuels into the atmosphere, what would be the consequences a millenium into the future?" This is the sort of thing that one can do with models, explore areas of parameter space that we are unlikely to experience, or to sample in any reasonable timeframe. The results of this particular exercise are not encouraging. There is some recovery from the effects of warming in the Northern Hemisphere, but general catastrophe in the Southern Hemisphere as the Antarctic ice sheet collapses. Definitely not encouraging, since the scenario is run under unrealistically optimistic conditions.