NOAA: Warmest June Ever! Caveat: We Made It Up (Corrected)
David W. Walters claimed:
Yet the proxy data backs up recent observable data.
That claim is false in two ways:
1) Some of the proxy data — even including proxies used in the “hockey stick” graph — most definitely does NOT back up the recent observations. Some tree ring studies crucial to the hockey stick fail to replicate the late 20th century warming. In fact, the whole “hide the decline” scandal in the Climategate e-mails involved a tactic for “hiding the decline” in the proxy data — not in the observations.
When Phil Jones said he was using “Mike’s Nature trick to hide the decline”, he was referring to the fact that when Mann created his hockey stick for a Nature article, he truncated some of the tree ring data — simply stopped showing it after about 1950 — in order to hide the fact that from that point forward, the tree ring data actually went DOWN when the instrument record went up.
This phenomena is well-known in the community of people who do tree-ring studies — they call it “the divergence problem”. Mann and Jones effort to “hide this decline” is motivated by the fact that if one shows this decline on the “hockey stick“ graph, it raises one very obvious question:
“If this proxy is not responding to the warming of the second half of the 20th century, how do you know it also did not fail to respond to similar warming in the medieval warm period?”
In other words, the divergence problem raises the very real possibility that trees are lousy thermometers, probably because their growth is affected by so many things in addition to temperature, such as rainfall, atmospheric CO2 concentrations, etc.
2) There are many tree ring series that do NOT show modern warming at all — and they are simply ignored by people like Michael Mann and Phil Jones. For instance, one crucial tree ring study used by Mann was done by Graybill using the notorious strip-bark pines from Sheep Mountain. A new study done of trees from the same area shows substantially different results — instead of getting a big rise in tree ring widths in the 20th century, the tree rings in the new study show essentially no warming at all. This data is simply ignored by the Manns and Jones of the world.
See here for more:
http://climateaudit.org/2008/01/31/more-mystery-at-sheep-mountain/
See here for another example of a tree ring study that does not agree with a study used to make “hockey stick” graph and which is, accordingly simply ignored:
http://climateaudit.org/2009/10/19/re-visiting-the-yamal-substitution/
