When oil pan 4 brought this up, I wanted to wait until I checked my sources before replying.
I've now done that, and here are a few things from the historical record:
1) The 'hockey stick' temperature graph, as presented in 'An Inconvenient Truth' is in fact correct.
2) This graph was called into question by Anthony Watts, Steve McIntyre, and Richard A. Muller, physicist, U.C. Berkeley National Laboratory.
3) All skepticism by the three were welcomed by the original authors of the hockey stick.
4) James Hansen, of NASA, welcomed the skepticism.
--------------------------------------------------------------------------------------
5) Richard Muller and several colleagues formed the Berkeley Earth Surface Temperature ( BEST ) Project.
6) After re-examining the data, Muller testified before the U.S. House of Representatives' Committee on Science, Space and Technology, on March 31, 2011, telling the committee members that BEST confirmed the hockey stick data, as presented by the mainstream climate scientists.
-------------------------------------------------------------------------------------
7) A sticking point with the three had been, the possibility for reporting stations to have experienced the 'heat-island' effect, which could corrupt the data.
8) The original scientists had considered this possibility, and had already adjusted the data for this contingency where applicable.
-------------------------------------------------------------------------------------
9) While scientists agree that Gore 'exaggerated', they believe that he was deeply concerned about the implications of global warming, and he accomplished real good in alerting the public.
--------------------------------------------------------------------------------------
As of 2011, Muller's testimony could be found at: ScientificAmerican.com/jun2011/muller-hearing
Also Richard Muller at:
http://muller.lbl.gov