Tree Ring Study Put the Chill on Global Warming?

17 Jul 2012 09:14 #1 by Martin Ent Inc
The tree rings "prove [the] climate was WARMER in Roman and Medieval times than it is now," the British newspaper the Daily Mail reported last week, "and [the] world has been cooling for 2,000 years."

http://news.yahoo.com/does-tree-ring-st ... 18316.html

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17 Jul 2012 09:20 #2 by ScienceChic
Nope, this study looks only at tree data from Europe (hence, regional; not global), and tree ring proxy data is not comprehensive for the history of climate, as trees only survive so many hundreds or thousands of years. That's why climatologists use other proxies like Ice cores, ocean sediments, coral analysis, etc. to go back hundreds of thousands of years. Here's what I posted in another thread when this study came up. (Interestingly, Dr. Michael Mann, the hockey stick researcher, came to a similar conclusion as this study in one of his papers).

Dendrochronology
Resources for Dendrochronologists

[youtube:3pkh1unx]
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Uploaded by ChangingClimates on Apr 16, 2010
Peter Brown from Rocky Mountain Tree Ring Research explains dendrochronology and how we can use it to understand the climate.


Tree Rings and Climate: Some Recent Developments
by Michael E. Mann, Gavin Schmidt, and Eric Steig
8 July 2012

It’s been a tough few months for tree-rings, perhaps unfairly. Back in April, we commented on a study [that one of us (Mike) was involved in] that focused on the possibility that there is a threshold on the cooling recorded by tree-ring composites that could limit their ability to capture the short-term cooling signal associated with larger volcanic eruptions. Mostly lost in the discussion, however, was the fact–emphasized in the paper—that the trees appeared to be doing a remarkably good job in capturing the long-term temperature signal—the aspect of greatest relevance in discussions of climate change.

This week there have been two additional studies published raising questions about the interpretation of tree-ring based climate reconstructions.

click on the link for a detailed description of the scientific method in the papers and what it means in the big picture of climate data.


Tree ring data, like all proxies, has its limitations, which is why multiple proxies are used and factored into reconstructions of past climate (aka paleoclimate)
Progress in reconstructing climate in recent millennia
gavin @ 3 September 2008

The Value in Multiple Proxies
Michael Mann
[url=http://www.sciencemag.org" onclick="window.open(this.href);return false;]http://www.sciencemag.org[/url] SCIENCE VOL 297 30 AUGUST 2002

"Now, more than ever, the illusions of division threaten our very existence. We all know the truth: more connects us than separates us. But in times of crisis the wise build bridges, while the foolish build barriers. We must find a way to look after one another as if we were one single tribe.” -King T'Challa, Black Panther

The truth is incontrovertible. Malice may attack it. ignorance may deride it, but in the end, there it is. ~Winston Churchill

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