Sunday, October 17, 2010;
Regarding Rep. Joe Barton's Oct. 12 letter, "The right to question climate science":
I would like to correct some potential misunderstanding about the conclusions of the 2006 National Research Council report to which Mr. Barton referred. Quoting from the report's summary: "Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium."
While we did find some of the methods used in Michael E. Mann's original papers to be less cautious than some of our members might have used, we have not found any evidence that his results were incorrect or even out of line with other works published since his original papers.
Mr. Barton's reference to "Mr. Mann's global warming projections" is incorrect and quite misleading. Mr. Mann's work does not make projections about global warming. His work, and that of our committee, was concerned with the reconstruction of temperatures in the past. As stated in the report, this area of research does not attempt to make any inference about future temperatures. While knowledge of past climates fills in context, the arguments for anthropogenic global warming are mainly based upon the past 50 years of data, including temperatures, model simulations and numerous other indicators.
Gerald R. North, Bryan, Tex.
The writer was chair of the National Research Council's Committee on Reconstruction of Surface Temperatures for the Last 2000 Years, mandated by Congress. The views expressed are his own.