Researchers previously associated with the famous and controversial "Hockey stick" temperature diagram have determined that the last decade ending in 2006 was the warmest such period in the Northern Hemisphere for at least the last 1,300 years and possibly longer.

The research team utilized a much wider variety of sources compared to the "Hockey stick" study, which led to a congressional investigation in 2005. In addition to tree rings, the team also looked at sediments, stalactites and stalagmites, which in their opinion provides much more reliable conclusions.

"We sort of removed that asterisk," because the new study's conclusion didn't depend as much on one kind of data, said Michael Mann, director of Penn State's Earth System Science Center.

The decade ending in 2006 in the Northern Hemisphere was a bit more than .5 degree F warmer than the decade-long average dating back 1,300 to 1,700 years.

According to the Arizona Daily Star article, the paper is "one brick in the wall" of the case for saying that human-induced causes such as greenhouse-gas emissions are raising temperatures, said Malcolm Hughes, a dendrochronologist at the UA's Laboratory of Tree-Ring Research.

The study will be published on September 9th in the Proceedings of The National Academy of Sciences. It was authored by Malcolm Hughes, a dendrochronologist at the University of Arizona.

The is a short summary of the study and results on the right side of the Arizona Star article in the grey box.

----------------------------------------------------------------------------------
Update

Steve McIntyre from climate audit has a detailed critique of this study. Here is the link.