July 19, 2006

Good morning and welcome. We convene this hearing today to consider questions that begin with and surround the reliability of two particular studies of historical temperatures that gained an extraordinary level of public prominence a few years ago, and recently featured in former Vice President Al Gore's motion picture, "An Inconvenient Truth."

In 2001, the results of these studies were used to promote the view that the very recent average temperatures of the northern hemisphere were likely the warmest in 1,000 years. The temperature history results were portrayed in what is widely known as the 'hockey stick' graph, for its resemblance to the shape of a hockey stick. As a result, these studies are known as the "hockey stick" studies.

With its relatively long and even trend for 900 years and then sharp up-tick during the 20th Century, the "hockey stick" graph effectively undermined what had been the prevailing view that we had experienced periods of similar or even higher average temperatures in the past - such as when the Vikings inhabited Greenland.

The fact that the United Nation's Intergovernmental Panel on Climate Change, or IPCC, prominently relied upon the graph lent the graph its apparent authority. The IPCC is an influential international body that conducts scientific assessments for use by policymakers.

The graph offered a simple and powerful message for the public and policymakers to understand. It was also a message that some say may have been based on faulty methodology. The "hockey stick" studies formed the basis for the IPCC finding in 2001 that the 1990s were likely the warmest decade of the millennium and 1998 likely the warmest year during that time. Some of today's witnesses will describe in detail that the "hockey stick" studies were critically flawed and could not support the findings reached by these studies.

Had the 'hockey stick' studies remained in the niche of climate change journals, we would not be holding this hearing. Instead, we are here because the questions surrounding these studies relate directly to the strength of the findings in the first place. What does the "hockey stick" story say about the reliability of these studies for policymakers?

Last summer, Chairman Barton and I inquired into this matter after we learned that the lead author of these federally funded studies - Dr. Michael Mann -- to share the computer code he used to generate his results with researchers who sought to replicate the result of Mann's studies. The researchers, one of whom will testify today, reportedly could not replicate his work based on what the study said. The researchers nevertheless identified several methodological and data problems with the work.

How critical were these problems identified by these researchers? Were the problems undetected because Dr. Mann assessed his own work in an IPCC report?

These are serious questions, and the answers contain broad implications for global policy on climate change. We should ensure that science is providing us with reliable, balanced, well-considered, and unbiased answers.

Today, our witnesses will help us address these critical questions.

I want to welcome, especially, Dr. Edward Wegman, a statistician with George Mason University, who will lead off the first panel this morning. Dr. Wegman is Chairman of the National Academy of Sciences Committee on Applied and Theoretical Statistics. At the Committee request, Dr. Wegman assembled an ad-hoc committee of statisticians to examine the hockey stick studies and related articles. His committee's report, prepared for Chairman Barton and me and publicly released this past Friday, provides important findings for Congress - and the public - to consider about the soundness and openness of climate change research and assessments. The Wegman Committee not only identified fundamental flaws in the "hockey stick" studies, it also addressed the larger point that climate change studies, like any work with potentially large policy implications, must be subject to careful and broad scrutiny.

Dr. Wegman and his team performed their work completely independent of the Committee and without charge. I believe Dr. Wegman's team has done a great public service and their work should help us improve how we discuss climate change when crafting policy.

Additionally, Dr. Gerald North, of Texas A&M University, will testify on the first panel about the current state of historical temperature understanding. Dr. North chaired a recent National Research Council panel on historical temperature reconstructions, and I look forward to hearing his perspective for improving climate change assessments.

To help us understand some particulars of the IPCC process, we'll hear testimony on the second panel from Dr. Thomas Karl, who was a coordinating author of the chapter upon which Dr. Mann and his colleagues worked. Dr. Thomas Crowley, of Duke University, and Dr. Hans von Storch - who traveled from Germany to be with us this morning - both can provide their considered views concerning the questions about the "hockey stick" studies, as well as questions concerning data sharing, transparency, and the IPCC process.

Finally, I'd like to welcome Mr. Steven McIntyre. Mr. McIntyre will testify about attempting to understand just what was behind the hockey stick graphic promoted by the IPCC. His examination of the facts underlying the assessments' claims really initiated some of the important questions concerning the scrutiny provided by climate change assessments. His work is a testament to the value of open debate and scrutiny. His perseverance should be commended.

Let me add that we did invite Dr. Mann to this hearing, but his attorney explained that he was unavailable, on family vacation. Dr. Mann suggested Dr. Crowley could come in his place. We do hope to have Dr. Mann at a future hearing, however.

At the end of the day, the issues of climate change require open and objective discussion. Some of the work we'll consider today points to the value of policy decisions that are informed by sound science and objective advice.

I'll now yield to Mr. Stupak, our ranking member, for his opening statement.

Related Documents