The 20th century warming counters a millennial-scale cooling trend which is consistent with long-term astronomical forcing. MBH99 According to the UMass researchers, the 1,000-year reconstruction reveals that temperatures dropped an average of 0.02 degrees Celsius per century prior to the 20th century. This trend is consistent with the “astronomical theory” of climate change, which considers […]
A CA reader has provided a link to an extremely interesting presentation by dendro Brian Luckman of U of Western Ontario (Rob Wilson’s thesis supervisor) at the 2008 Canadian Society of Petroleum Geologists. Reader Erasmus de Frigid draws attention to the inhomogeneity in the tree ring record created when the tree was scarred by a […]
In our continuing quest for a North American upper treeline chronology that exemplifies the IPCC AR4 claim that additional data since TAR shows “coherent behavior” across multiple indicators, we turn now to the upper treeline proxies of Wilson and Luckman, 2002, 2003. They collected 20 Engelmann spruce sites in British Columbia in 1998, which together […]
The next installment in our search for upper treeline proxies evidencing the AR4 SPM claim that : “Studies since the TAR draw increased confidence from additional data showing coherent behaviour across multiple indicators in different parts of the world” takes us to the Canadian Rocky Mountains, to a study mentioned in the Wilson and Luckman […]
I realize that not all CA readers are interested in multivariate methods and that dendroclimatologists want to “forget the math”, but I find it interesting to try to relate dendro and paleoclimate recipes to known statistical methodologies that you can read about in texts. I commented the other day on the form of Principal Components […]
In our continued search for evidence supporting the IPCC 4AR SPM claim that “”Studies since the TAR draw increased confidence from additional data showing coherent behaviour across multiple indicators in different parts of the world”, I am reviewing upper treeline North American site chronologies specifically mentioned in the short Wilson and Luckman 2003 survey of […]
In my continuing search for updated dendroclimatological temperature proxies, I started by looking at what had been archived at ITRDB; this has proved to be a very disappointing source of candidates. I’ve re-canvassed some literature for candidate unarchived information. In an email, Connie Woodhouse mentioned that their efforts with upper treeline sites in the U.S. […]
Wilson and Luckman 2003 observe: The first PCs from the RW and MXD PCA are naturally orthogonal (r = —0.006) over the 1900—1991 period suggesting the in’?fluence of different forcing mechanisms upon these parameters. They move on without pausing here, but this point should not be left without a commentary. The issue here is one […]
(2012 Update…) CA was the first blog to discuss the recent papers by Wilmking and his associates on “positive and negative responders” – the opposite response of trees to recent warming in which – at the same site – some trees responded positively and some negatively. This is an important observation in trying to provide […]
The 2000 conference of the IAI project on “Reconstructing Climate Variability and Change from Treelines” contained the following abstract describing a network of high-elevation “temperature-sensitive” tree ring chronologies as follows: 6. An expanded network of long treeline chronologies from the Western US Brown, P.M.; Woodhouse, C.A. & Hughes, M.K. We report on new, high elevation, […]
Climate Audit 