Hockey Stick Climate Temperature Trend Theory Challenged
Future Pundit
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A pair of Canadian researchers, University of Guelph Canada economist Ross McKitrick and Toronto-based mineral exploration consultant Stephen McIntyre, have a paper coming out in Geophysical Research Letters that challenges the "Hockey Stick" temperature trends model which shows the 20th century as the hottest centure in the last 1000 years.
Until now, criticisms of the hockey stick have been dismissed as fringe reports from marginal global warming skeptics. Today, however, the critical work of two Canadian researchers, Ross McKitrick, an economics professor at Guelph University, and Toronto consultant Stephen McIntyre, will be published by Geophysical Research Letters, the prestigious journal that published one of the early versions of Michael Mann's 1,000-year tracking of Northern Hemisphere temperatures,
Publication in Geophysical Research sets McIntyre and McKitrick's analysis and conclusions in direct opposition to the Mann research. Their criticism can no longer be dismissed as if it were untested research posted on obscure Web sites by crank outsiders. Their work is now a full challenge to the dominant theme of the entire climate and global warming movement.
The paper will be published in February. So as of this writing it is not on the Geophysical Research Letters web site. However, a pre-publication version of the paper "“Hockey Sticks, Principal Components and Spurious Significance”" is available (PDF format).
For a graphical comparison of the original hockey stick chart and the McIntyre and McKitrick analysis see this page from McKitrick's web site. That page has a lot of other useful links. McIntyre and McKitrick also have another web site with a lot more useful links.
Dutch science journalist Marcel Crok has a two part series in the Canadian Financial Post on
Up to January, 2005, none of McIntyre and McKitrick's findings had been published by major scientific journals. Thus, in the opinion of established climate researchers, there was no reason to take them seriously. Climate researchers were quite comfortable in their consensus and repeatedly referred to this "consensus" as a basis for policy. The official expression of the consensus comes from the IPCC. This group, under the flag of the United Nations, comes out with a bulky report every five years on the state of affairs in climate research. Hundreds of climate researchers from every corner of the world contribute to it. In the third report in 2001, Mann himself was a lead author of the chapter on climate reconstructions.
McKitrick and McIntyre had a hard time getting access to the data and source used in the analysis by Mann and colleagues that led to their claim that the 20th century was the hottest in the last 1000 years. No other group had seriously tried to replicate the Mann analysis.
McIntyre sent an e-mail to Michael Mann in spring 2003, asking him for the location of the data used in his study. "Mann replied that he had forgotten the location," he said. "However, he said that he would ask his colleague Scott Rutherford to locate the data. Rutherford then said that the information did not exist in any one location, but that he would assemble it for me. I thought this was bizarre. This study had been featured in the main IPCC policy document. I assumed that they would have some type of due-diligence package for the IPCC on hand, as you would have in a major business transaction. If there was no such package, perhaps there had never been any due diligence on the data, as I understood the term. In the end, this turned out to be the case. The IPCC had never bothered to verify Mann, Bradley and Hughes' study."
Despite billions of dollars spent on climate research, academic and institutional researchers had never bothered to replicate Mann's work either. In 2003, McIntyre tackled the job and, from an unusual hobby, the task has since grown to become almost a full-time occupation. On an Internet forum for climate skeptics, he met Ross McKitrick, professor of economics at the University of Guelph, just outside of Toronto. Since meeting in person in September of 2003, the two have been working on the project together. McIntyre does most of the research and McKitrick asks questions and assists in the writing of papers.
When people tell us that we urgently need to spend hundreds of billions or trillions to fix some problem we ought to demand a higher standard of proof than the effort that went into the original Hockey Stick paper.
Read the full article. Keep in mind as you read it that published science should be transparent, verifiable, and reproducible. Science that can not be checked and reproduced has no place as a basis for public policy that could cost the world's collective economies hundreds of billions or even trillions of dollars..
A lone Canadian Gaspe peninsula cedar tree's rings were heavily weighted in Mann's model for North American temperature in the 15th century.
"More strangely," said McIntyre, "the series appears twice in Mann's data set, as an individual proxy, and in the North American network. But it is only extrapolated in the first case, where its influence is very strong." McIntyre and McKitrick went back to the source of the Gaspe series and then to the archived data at the World Data Center for Paleoclimatology."We found that although the Gaspe series begins in 1404, up until 1421, it is based on only one tree. Dendrochronologists (tree ring researchers) generally do not use data based on one or two trees. The original authors only used this series from 1600 onwards in their own temperature reconstructions. This series should never have been used in the 15th century, let alone counted twice and extrapolated."
Go and read the full articles I'm linking to. Note how McIntyre and McKitrick were able to find a Fortran program and crucial datasets on an FTP server used by Mann's group that led McIntyre and McKitrick to an understanding of how Mann and his colleagues made serious mistakes in how they did a mathematical analysis called principal component analysis (PCA) on their datasets. There is a larger lesson here: More data and source code on which scientific research papers are based ought to be available in the public domain to allow replication of mathematical analyses used in scientific research papers.
Note also that in climate research McIntyre and McKitrick are essentially self-taught amateurs. But they had the mathematical chops to use basic analytical techniques to datasets and apparently that is all that is needed do analyses on climate history data.
Finally, regarding the idea of a scientific consensus on global warming the words MIT meteorologist Richard Lindzen bear repeating:
"Do you believe in global warming? That is a religious question. So is the second part: Are you a skeptic or a believer?" said Massachusetts Institute of Technology professor Richard Lindzen, in a speech to about 100 people at the National Press Club in Washington, D.C.
"Essentially if whatever you are told is alleged to be supported by 'all scientists,' you don't have to understand [the issue] anymore. You simply go back to treating it as a matter of religious belief," Lindzen said. His speech was titled, "Climate Alarmism: The Misuse of 'Science'" and was sponsored by the free market George C. Marshall Institute. Lindzen is a professor at MIT's Department of Earth, Atmospheric, and Planetary Sciences.
...
According to Lindzen, climate "alarmists" have been trying to push the idea that there is scientific consensus on dire climate change.
"With respect to science, the assumption behind the [alarmist] consensus is science is the source of authority and that authority increases with the number of scientists [who agree.] But science is not primarily a source of authority. It is a particularly effective approach of inquiry and analysis. Skepticism is essential to science -- consensus is foreign," Lindzen said.
Alarmist predictions of more hurricanes, the catastrophic rise in sea levels, the melting of the global poles and even the plunge into another ice age are not scientifically supported, Lindzen said.
"It leads to a situation where advocates want us to be afraid, when there is no basis for alarm. In response to the fear, they want us to do what they want," Lindzen said.
If global warming eventually becomes a problem we will be able to handle it. We can switch to nuclear power. In time photovoltaic cells will become much cheaper and we may switch away from fossil fuels in 30 years because market forces cause the switch even without government regulations that force the switch. The most prudent action to take at this point would be to accelerate the rate of energy research to develop cheaper alternatives to fossil fuels and cheaper ways to capture and sequester CO2. The impositions of huge costs on economies to reduce CO2 emissions today is an excessive response to a potential problem that, if it comes, could be much more cheaply handled in the future.
By Randall Parker at 2005 January 28 03:22 PM |
