“A good way to deal with a problem”
In the UEA statement of Nov 24, 2009, Phil Jones said:
CRU has not sought to hide the decline. Indeed, CRU has published a number of articles that both illustrate, and discuss the implications of, this recent tree-ring decline, including the article that is listed in the legend of the WMO Statement figure. It is because of this trend in these tree-ring data that we know does not represent temperature change that I only show this series up to 1960 in the WMO Statement.”
Here is the corresponding figure in the UEA statement. I’ve added a yellow line for 1960. Although Jones’ statement says that he “only showed this series up to 1960”, the series attributed to “Briffa (1999)” obviously continues past 1960 into the 1990s. Jones said that CRU did not attempt to hide the decline in the Briffa reconstruction. And it is true that earlier articles did not take advantage of “Mike’s trick”. However, although the “real” Briffa reconstruction goes down after 1960, the series in the diagram attributed to “Briffa (1999)” goes up. The decline in the Briffa reconstruction is not shown; it is hidden. Gavin Schmidt of real climate says that this is “a good way to deal with a problem”. I disagree (and recorded this disagreement in a related context in connection with IPCC AR4 as discussed elsewhere.)
WMO Original caption: Northern Hemisphere temperatures were reconstructed for the past 1000 years (up to 1999) using palaeoclimatic records (tree rings, corals, ice cores, lake sediments, etc.), along with historical and long instrumental records. The data are shown as 50-year smoothed differences from the 1961–1990 normal. Uncertainties are greater in the early part of the millennium (see page 4 for further information). For more details, readers are referred to the PAGES newsletter (Vol. 7, No. 1: March 1999, also available at http://www.pages.unibe.ch) and the National Geophysical Data Center (http://www.ngdc.noaa.gov). (Sources of data: P.D. Jones, K.R. Briffa and T.J. Osborn, University of East Anglia, UK; M.E. Mann, University of Virginia, USA; R.S. Bradley, University of Massachusetts, USA; M.K. Hughes, University of Arizona, USA; and the Hadley Centre, The Met. Office).