Global warming of last 50 years “unusual” in at least the previous 1300 years

The long-awaited IPCC report said a warming of about 0.2 degrees Centigrade per decade is projected for the next two decades. Even if greenhouse-gas and aerosol concentrations had been kept constant at 2000 levels, further warming of about 0.1 degrees Centigrade per decade would be expected.

Warming is expected to be greatest over land and at high northern latitudes, the report said, and least over the Southern Ocean and parts of the North Atlantic.

Even if greenhouse-gas concentrations were stabilized, warming and sea-level rise would continue for centuries due to “the timescales associated with climatic processes and feedbacks.”