Climate was HOTTER in Roman and medieval times

A new peer reviewed paper published in Nature: Climate Change
Nature Climate Change (2012) doi:10.1038/nclimate1589
Received 27 March 2012 Accepted 15 May 2012 Published online

Orbital forcing of tree-ring data

As reported by The Register:

Climate was HOTTER in Roman, medieval times than now: Study

IPCC has got it all wrong, say boffins
A new study measuring temperatures over the past two millennia has concluded that in fact the temperatures seen in the last decade are far from being the hottest in history.
A large team of scientists making a comprehensive study of data from tree rings say that in fact global temperatures have been on a falling trend for the past 2,000 years and they have often been noticeably higher than they are today - despite the absence of any significant amounts of human-released carbon dioxide in the atmosphere back then.
"We found that previous estimates of historical temperatures during the Roman era and the Middle Ages were too low," says Professor-Doktor Jan Esper of the Johannes Gutenberg-Universität Mainz, one of the scientists leading the study. "Such findings are also significant with regard to climate policy."

See also Late 20th Century Warming Not Unusual.