Warmest Global Temperatures in 4000 Years

New research headed by Shaun Marcott at Oregon State University has extended the famous "hockey stick" graph of temperature change.  Not only was a long term cooling trend reversed, the recent warming is at a much faster rate of change than the previous warming trend during the early Holocene period.

ClimateProgress.org illustrates how this temperature record compares to projected temperature by the end of the century.

Update (April 2):  The authors answer questions in response to critics.

Update (September 22):  Stefan Rahmstorf comments on the end of the Holocene.  He includes a temperature reconstruction back to the peak of the last glaciation with a moderate three degree warming projection.