OldRocks said:
And this article says something vastly differant. You have my source, what is your?
http://www.pnas.org/content/early/2008/09/02/0805721105.full.pdf html
First author on your report is Mann. Sorry, but he is the guy who already famously screwed the pooch. And my reference doesn't use Mann proxies assembled to return a specific profile.
The big picture 65 million years of temperature swings JoNova
There have been more than a dozen reports since then, most of which Mann has nothing to do with, that have supported Mann's findings.
The Hockey Stick The Most Controversial Chart in Science Explained - The Atlantic
"The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world."
It didn't change the minds of the deniers, though--and soon Mann and his colleagues were drawn into the 2009 "
Climategate" pseudo-scandal, which purported to reveal internal emails that (among other things)
seemingly undermined the hockey stick. Only, they didn't.
In the meantime, those wacky scientists kept doing what they do best--finding out what's true. As Mann relates, over the years other researchers were able to test his work using "more extensive datasets, and more sophisticated methods. And the bottom line conclusion doesn't change." Thus the single hockey stick gradually became what Mann calls a "hockey team." "If you look at all the different groups, there are literally about two dozen" hockey sticks now, he says.
Mother Jones' Jaeah Lee traced the strange evolution of the hockey stick story in this video:
Indeed, two just-published studies support the hockey stick more powerfully than ever. One, just out in
Nature Geoscience, featuring more than 80 authors, showed with extensive global data on past temperatures that the hockey stick's shaft seems to extend back reliably for at least 1,400 years.
Recently in Science, meanwhile, Shaun Marcott of Oregon State University and his colleagues extended the original hockey stick shaft back
11,000 years. "There's now at least tentative evidence that the warming is unprecedented over the entire period of the Holocene, the entire period since the last ice age," says Mann.="#author-information">
A Reconstruction of Regional and Global Temperature for the Past 11 300 Years
A Reconstruction of Regional and Global Temperature for the Past 11,300 Years
- Shaun A. Marcott1,
- Jeremy D. Shakun2,
- Peter U. Clark1,
- Alan C. Mix1
+Author Affiliations
- marcotts@science.oregonstate.edu
Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago. This cooling is largely associated with ~2°C change in the North Atlantic. Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.
