A standing committee of the U.S. House of Representatives has formally written to the United Nations Intergovernmental Panel on Climate Change (IPCC) questioning the integrity of the Third Assessment Report and asking nine specific questions.
The letter from Committee Chairman, begins:
Questions have been raised, according to a February 14, 2005 article in The Wall Street Journal, about the significance of methodological flaws and data errors in studies by Dr. Michael Mann and co-authors of the historical record of temperatures and climate change. We understand that these studies of temperature proxies (tree rings, ice cores, corals, etc.) formed the basis for a new finding in the 2001 United Nation’s Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR). This finding – that the increase in 20th century northern hemisphere temperatures is “likely to have been the largest of any century during the past 1,000 years” and that the “1990s was the warmest decade and 1998 the warmest year” – has since been referenced widely and has become a prominent feature of the public debate surrounding climate change policy.
However, in recent peer-reviewed articles in Science, Geophysical Research Letters, Energy & Environment, among others, researchers question the results of this work. As these researchers find, based on the available information, the conclusions concerning temperature histories – and hence whether warming in the 20th century is actually unprecedented – cannot be supported by the Mann et. al. studies. In addition, we understand from the February 14 Journal and these other reports that researchers have failed to replicate the findings of these studies, in part because of problems with the underlying data and the calculations used to reach the conclusions. Questions have also been raised concerning the sharing and dissemination of the data and methods used to perform the studies. For example, according to the January 2005 Energy & Environment, the information necessary to replicate the analyses in the studies has not been made fully available to researchers upon request.
The concerns surrounding these studies reflect upon the quality and transparency of federally funded research and of the IPCC review process – two matters of particular interest to the Committee. For example, one concern relates to whether IPCC review has been sufficiently robust and independent. We understand that Dr. Michael Mann, the lead author of the studies in question, was also a lead author of the IPCC chapter that assessed and reported this very same work, and that two co-authors of the studies were also contributing authors to the same chapter. Given the prominence these studies were accorded in the IPCC TAR, we seek to learn more about the facts and circumstances that led to acceptance and prominent use of this work in the IPCC TAR and to understand what this controversy indicates about the data quality of key IPCC studies.
For complete letter and questions click here: