Congressman unmoved by peer review, asks to see raw data
In what observers are calling an unprecedented request, a member of the U.S. Congress has asked prominent researchers for all the raw data underpinning an influential historical study that shows that the earth’s climate has been warming dramatically since 1900.
View a PDF of the letter
In a letter dated June 23 and sent to three scientists, Rep. Joe Barton (R-TX) charges that other researchers have found methodological flaws and data errors in their study, which has become known as the hockey-stick paper. Barton also asserts that the researchers have failed to share their raw data and the computer code used in the analysis.
However, scientists familiar with the research say that the hockey-stick paper has already stood up to intense scientific scrutiny and that the raw data are already available. They say that the request is simply politics and is meant to intimidate climate scientists from further linking global warming to human activity.
The hockey-stick paper (Nature 1998, 329, 779–787) became a fundamental part of the UN Intergovernmental Panel on Climate Change (IPCC) third assessment report, Climate Change 2001. The article and report synthesize 12 data sets—such as the width of tree rings and the isotopic composition of ice cores—to generate a chart of temperature variation in the Northern Hemisphere. Temperatures remain flat before 1900 but then increase, so that the resulting graph looks like a hockey stick Although many scientists point to this analysis and numerous other studies to argue that global warming is real and is caused by human activity, a small group of self-styled skeptics continue to pick away at the science.
Barton’s requests come as a growing number of scientists charge that President Bush has been attempting to make the science on global warming appear uncertain. Rick Piltz, a government employee in the U.S. Climate Change Science Program, recently resigned because White House officials were making excessive changes to the program’s reports.
Request for information
In letters to Michael Mann, an assistant professor with the department of environmental sciences at the University of Virginia, and two of his colleagues, Barton wrote: “Provide the location of all data archives relating to each published study for which you were an author or coauthor.” Barton also asked for curricula vitae, lists of all sources of financial support for research, and the computer code used to generate the hockey-stick analysis.
The U.S. National Science Foundation (NSF) also received a letter from Barton requesting a list of “all grants and all other funding given for research in the area of climate.” The letter also asks for details of any violations concerning the sharing of information and enjoins NSF to describe “in detail how your agency has supported or disseminated the information in the Mann et al. studies.”
According to a staff spokesperson in Barton’s office, who requested anonymity, “the letter is part of an overarching goal of data quality.” When asked whether Barton’s letters might have a chilling effect on scientists, she said, “I don’t know.”
“The thrust and tone of the letters indicates that [Barton] has been advised by someone who does not understand the science,” says John Holdren, a professor of environmental science and public policy at Harvard University and president-elect of the American Association for the Advancement of Science.
“What a pain,” says Frank von Hippel, a professor of public and international affairs at Princeton University and a former assistant director in the White House Office of Science and Technology Policy. “It looks like the work of these anti-climate-change fundamentalists,” he added. “These guys are really feeling their oats.”
Barton chairs the U.S. House of Representatives’ Committee on Energy and Commerce but does not sit on the Committee on Science. When asked whether the energy committee had any scientists on staff, Barton’s spokesperson again responded, “I don’t know.” She added that Barton has a degree in engineering.
In his letter, Barton references a February news story in The Wall Street Journal that focused on work by Stephen McIntyre, a former director of several small public mineral exploration companies, who charges that Mann’s Nature article contains methodological flaws and data errors.
According to Barton’s spokesperson, the key arguments in his letter are found in a paper published by McIntyre and McKitrick this year in Energy & Environment—an obscure journal found in only 25 institutions worldwide, according to Journal Citation Reports. Energy & Environment is not included in the Journal Citation Reports list of impact factors for the top 6000 peer-reviewed journals. McIntyre and University of Guelph (Canada) environmental economist Ross McKitrick have also published their critique in Geophysical Research Letters, a peer-reviewed journal (Geophys. Res. Lett. 2005 32 L03710).
McKitrick is also a senior fellow at the Fraser Institute, a conservative Canadian think tank that received $60,000 from oil giant ExxonMobil in 2003. In Energy & Environment, McIntyre and McKitrick write that peer review by paleoclimate journals does not compare “with the level of due diligence involved in auditing financial statements or carrying out a feasibility study in mineral development.” They then say that IPCC should not have used Mann’s hockey-stick model without verifying it. In the article, they also claim that Mann will not release the computer source code used in the hockey-stick paper despite “unsuccessful appeals to Nature and the U.S. National Science Foundation.”
Responding to congressional requests
“It is my intent to comply with the committee’s request,” wrote Mann in an email to ES&T. “They have asked for a substantial amount of material, and it will take some time to compile this.” He adds, “I am confident that when members of Congress take a look at the science, they will join with the consensus of the world’s scientists that the earth is indeed warming and that human activity has played a primary role in the warming observed in recent decades.”
David Stonner, the congressional liaison at NSF, says that the agency is meeting with Barton’s staff to try to figure out exactly what they want. “They have basically asked us to send them everything we’ve ever done on climate change in the last 10 years,” he says.
Stonner adds that NSF policy is that all research results should be shared. Still, he finds Barton’s letter unique. “We sometimes get complaints [from Congress], maybe on awards, but to the best of my knowledge it’s never concerned data.”
Mann says that his data are freely available on the web. In May of this year, Caspar Amman, a paleoclimatologist at the U.S. National Center for Atmospheric Research, reanalyzed Mann’s data on his own computer and found that Mann’s finding “is robust even when numerous modifications are employed.” Amman has two papers undergoing peer review, at the journals Climatic Change and Geophysical Research Letters.
“I feel there is an attempt to intrude on the work of scientists,” says Michael Bender, a professor of geosciences at Princeton University and a member of the board on atmospheric sciences and climate at the U.S. National Academies. “The other issue is government attempting to intimidate scientists that have findings they don’t agree with.”
Gavin Schmidt, a climate scientist at NASA’s Goddard Institute for Space Studies says he does not feel that scientists will feel intimidated by Barton because Mann’s paper is becoming less crucial as more studies agree with the original findings. “This isn’t a serious attempt to understand the science,” he says. “It’s just politics.”
Holdren says that half a dozen different studies that used separate data sets, such as those from boreholes and glaciers, have confirmed the findings of Mann’s original study. “I think that once you get into the gory details, the result is going to show that Mann is right.”
Holdren adds that although research in obscure journals has little effect on scientists, it does lead to editorials and news coverage in The Wall Street Journal, which changes how other media cover global warming. “The New York Times and The Washington Post are so afraid of being accused of bias,” Holdren says.
In June of this year, the presidents of 11 national academies of science signed a statement that climate change is real. “Action taken now to reduce significantly the buildup of greenhouse gases in the atmosphere will lessen the magnitude and rate of climate change,” wrote the presidents. Signatories included scientific leaders from the U.S., U.K., China, India, and Russia.
This statement was largely ignored by major media outlets in the U.S.
