Changes

'''YAD06''' is a tree growing in the Yamal Peninsula of Siberia. A core sample from this tree, YADO61, provided data used to support Michael Mann's [[hockey stick]] interpretation of global climate history. Mann's graph was first published in 1998. It shows global temperatures as stable for 900 years until the 20th century, when carbon dioxide emissions supposedly caused a rapid increase in global temperature. Mann created the graph to address reconstructions made by earlier climatologists that show a [[Medieval Warm Period]] between 950 and 1150. These reconstructions suggest that the climate was somewhat warmer at that time than it is at present. Although Mann claimed to have used a dozen proxies, analysis showed that only the data from YAD06 had the hockey stick pattern that Mann reported as his result. Compared to other samples taken Yamal, the YAD061 core was an outliner by a factor of 8 sigma.<ref>Watts, Anthony,"[http://wattsupwiththat.com/2009/10/01/response-from-briffa-on-the-yamal-tree-ring-affair-plus-rebuttal/ Response from Briffa on the Yamal tree ring affair – plus rebuttal]," October 1, 2009.</ref>

'''YAD06''' is a tree growing in the Yamal Peninsula of Siberia. A core sample from this tree, YADO61, provided data used to support Michael Mann's [[hockey stick]] interpretation of global climate history. Mann's graph was first published in 1998. It shows global temperatures as stable for 900 years until the 20th century, when carbon dioxide emissions supposedly caused a rapid increase in global temperature. Mann created the graph to address reconstructions made by earlier climatologists that show a [[Medieval Warm Period]] between 950 and 1150. These reconstructions suggest that the climate was somewhat warmer at that time than it is at present. Although Mann claimed to have used a dozen proxies, analysis showed that only the data from YAD06 had the hockey stick pattern that Mann reported as his result.

 

Compared to other samples taken Yamal, the YAD061 core was an outliner by a factor of 8 sigma.<ref>Watts, Anthony,"[http://wattsupwiththat.com/2009/10/01/response-from-briffa-on-the-yamal-tree-ring-affair-plus-rebuttal/ Response from Briffa on the Yamal tree ring affair – plus rebuttal]," October 1, 2009.</ref> YAD06 may have grown more slowly than other trees when it was in the shade. When these other trees died, YAD06 would have received more sunlight, allowing its growth rate to accelerate. Many factors can influence a tree's rate of growth, so the validity of tree ring data as a proxy for temperature is suspect.<ref>[http://borepatch.blogspot.tw/2009/10/yad061.html YAD061], ''Borepatch'',  October 3, 2009.</ref>

The Yamal samples were collected by two Russian scientists, Hantemirov and Shiyatov. However, their findings did not show anything resembling a hockey stick pattern. The Yamal data was rejiggered by Steven Briffa to fit a hockey stick pattern and published in 2000. Briffa's paper was seized upon by Mann and other researchers who found the MWP to be an inconvenience.

The Yamal samples were collected by two Russian scientists, Hantemirov and Shiyatov. However, their findings did not show anything resembling a hockey stick pattern. The Yamal data was rejiggered by Steven Briffa to fit a hockey stick pattern and published in 2000. Briffa's paper was seized upon by Mann and other researchers who found the MWP to be an inconvenience.

Mann's graph appeared prominently in the report of the UN's Intergovernmental Panel on Climate Change, used a basis for international policy on climate change. YAD06 has been dubbed, "the most influential tree in the world." Even the cherry-picked YAD06 data did not correspond closely enough to a hockey stick pattern to serve Mann's purpose. It shows a temperature decline since 1960, which is unrepresentative of the pattern of global temperature as a whole. This inconvenient trend was disguised with further manipulation. For the post-1960 period, "Mike [Mann]'s Nature trick of adding in the real temps" was used to "hide the decline," according to the [[Climategate]] emails.<ref>Booker, Christopher, "[http://www.telegraph.co.uk/comment/columnists/christopherbooker/6738111/Climategate-reveals-the-most-influential-tree-in-the-world.html Climategate reveals 'the most influential tree in the world']", ''The Telegraph'', Dec. 5, 2009.</ref>

Mann's graph appeared prominently in the report of the UN's Intergovernmental Panel on Climate Change, used a basis for international policy on climate change. YAD06 has been dubbed, "the most influential tree in the world." Even the cherry-picked YAD06 data did not correspond closely enough to a hockey stick pattern to serve Mann's purpose. It shows a temperature decline since 1960, which is unrepresentative of the pattern of global temperature as a whole. This inconvenient trend was disguised with further manipulation. For the post-1960 period, "Mike [Mann]'s Nature trick of adding in the real temps" was used to "hide the decline," according to the [[Climategate]] emails.<ref>Booker, Christopher, "[http://www.telegraph.co.uk/comment/columnists/christopherbooker/6738111/Climategate-reveals-the-most-influential-tree-in-the-world.html Climategate reveals 'the most influential tree in the world']", ''The Telegraph'', Dec. 5, 2009.</ref>

In 2013, the Climate Research Unit of the University of East Anglia quietly revised its Yamal data set.<ref name=McIntyre>McIntyre, Steve, "[http://climateaudit.org/2013/06/28/cru-abandons-yamal-superstick/ CRU Abandons Yamal Superstick]", June 28, 2013.</ref> The current reconstruction, based on ring data gathered from dozens of trees, shows that temperature in Yamal has been relatively stable for centuries, with no outstanding increase or decrease in the 20th century.<ref name=McIntyre/>

In 2013, the Climate Research Unit of the University of East Anglia quietly revised its Yamal data set.<ref name=McIntyre>McIntyre, Steve, "[http://climateaudit.org/2013/06/28/cru-abandons-yamal-superstick/ CRU Abandons Yamal Superstick]", June 28, 2013.</ref> The current reconstruction, based on ring data gathered from dozens of trees, shows that the growth rate for trees in Yamal has been relatively stable for centuries, with no outstanding acceleration or deacceleration in the 20th century.<ref name=McIntyre/>

==References==

==References==

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