My new favorite correspondent, Alex Avery , advises that the online Denier Brigade  is proudly boasting about this Science journal commentary  , which Avery says offers a careful reanalysis of proxy records and "finds the late 20th century is not warmer than AD 1,000."
Avery neglected to include this riposte  from the authors of the original (peer-reviewed) Science article.
While the deniers' favorite retired mining promoter and statistician Steve McIntyre actually looks at both the comment and the rebuttal - and, surprise!, declares the criticism valid - Michael Mann of RealClimate.org read both and concluded, "The rebuttal, in my view, settles the matter. The (original) Osborn and Briffa '06 conclusions stand without modification."
These scientific tempests are the only storms that get less vigorous with climate change. The "scientific" attacks get weaker even as the evidence itself  grows ever more undeniable.
But this instance shows once again that whenever someone pops up with a definitive new study that purports to disprove the science of anthropogenic global warming, it pays to look past the claim and ask for the rest of the story.