Hockey Stick Critics Speak on Hill
Stephen McIntyre and Ross McKitrick, authors of the paper that raises questions about the quality of the data underlying the IPCCs hockey stick graph of temperatures in the last 1000 years, briefed congressional staff on the issue at a meeting organized by the George C. Marshall Institute and the Cooler Heads Coalition on November 18.
McIntyre gave a compelling account of how he became interested in the hockey-stick controversy and then suspicious of the claim that the last decade was the hottest in the third millennium A. D. His experience in the mineral explorations business taught him that all data must be checked, so that is what he and McKitrick did in their paper.
The authors gave a chronological account of the charges made by the inventor of the hockey stick, Michael Mann, since their critique was published in Energy and Environment in late October. Mann first claimed that they had analyzed the wrong data sets, which had mistakenly been sent to McIntyre by one of Manns collaborators. Instead they should have used the data sets that had long been publicly available on an ftp site.
According to McIntyre and McKitrick, this criticism was irrelevant since they had rebuilt Manns 112 data sets from original sources. They then discovered that the data sets that they had been sent were the same as those on the ftp site. Mann has since deleted the data sets from his ftp site.
Mann then explained that McIntyre and McKitricks results showed a warm period in the fifteenth century because they had failed to include three key principal components. McIntyre and McKitrick replied that they omitted one because it double counted readings included in another component and updated another with newer data from the original source. This updated data changed the components effect considerably. McIntyre pointed out that the hockey-stick graph, at least for the 1400s, appears to be driven by only three of 112 principal components, which is a slender database upon which to base any conclusion.
McIntyre and McKitrick stressed throughout the presentation that they were not saying that they had proved the 1400s were warmer than today. What their statistical re-analysis had demonstrated was that it was not possible to conclude from the data Mann used that temperatures in the 20th century were unusual. Access to all the documents in the ongoing controversy can be found online at www.uoguelph.ca/~rmckitri/research/trc.html.
Modellers at the Remote Sensing Systems firm continue to raise objections to the University of Alabama at Huntsville satellite temperature readings of Roy Spencer and John Christy. In a new article in the Journal of Climate (published by the American Meteorological Association), they claim that a re-analysis of the dataset show[s] a global trend of 0.097 0.020 K decade−1, generally agreeing with the work of Prabhakara et al. but in disagreement with the MSU analysis of Christy and Spencer, which shows significantly less (0.09 K decade−1) warming.”
The article re-asserts the claim already made by RSS that their imputations from climate models are more reliable than the actual data from weather balloon radiosonde readings, which corroborate the findings of Christy and Spencer.
Although the finding was widely reported as confirming human influence on global warming, Christy told the New York Times (Nov. 18) that the evidence was pointing more firmly toward a modest impact from rising greenhouse gases, “We’ve had enough years of this human-induced forcing to get some boundaries on it, and it’s just not going in the dramatic and catastrophic direction.”
This view was confirmed in Newsweeks coverage of the same story (Nov. 23). In a remarkably candid paragraph, the magazine said, Recently scientists predictions [of future temperature increases] have begun to converge on a narrower range, and the forecasts have gotten more modest. James Hansen of the NASA Goddard Institute for Space Studies in New York has pointed out that in recent years the actual rise of greenhouse gases hasnt accelerated as fast as the IPCC predicted. Carbon-dioxide emissions increased 4.7 percent a year from 1945 to 1973, but since then, the average increase has been only 1.4 percent a year. The rate for methane, another powerful greenhouse gas produced in landfills and rice farming, is barely increasing at all. Hansen thinks that even if nothing is done, the planet would warm only 1.5 degrees by 2050.
It is a shame, then, that Newsweek followed this anti-alarmist finding with the distinctly alarmist suggestion that, If [developing nations] succeed in making the air cleaner, temperatures may soar-perhaps by as much as seven to 10 degrees Celsius.
Methane Emissions Leveling Off
Australian scientists have determined that atmospheric concentrations of methane have leveled off. Over the past four years there has been no growth in atmospheric methane concentrations compared to a fifteen percent rise over the preceding twenty years and a 150 percent rise since pre-industrial times, said Paul Fraser, a chief research scientist at the atmospheric research section of Australias Commonwealth Scientific and Industrial Research Organisation (The Australian, Nov. 25).
The findings come from CSIRO and the Australian Bureau of Meteorologys gas monitoring station at Cape Grim in Tasmania. Methane (the principal ingredient of natural gas) is a potent greenhouse gas, but persists in the atmosphere for a far shorter time than does carbon dioxide.
According to the Australian, Dr. Fraser thinks that methane levels “would start to fall if this global decline in methane emissions continued. He speculated that emissions are declining due to better management of the exploration and use of fossil fuels (coal, oil and gas) and the increasing recovery of landfill methane.
Announcements
Cato Conference on Global Warming
The Cato Institute is holding a daylong conference on Global Warming: the State of the Debate, on December 12 at the institutes Hayek Auditorium, 1000 Massachusetts Ave., N. W., Washington, D. C.
Speakers include: Patrick Michaels (University of Virginia and a Cato Senior Fellow), Robert Balling (Arizona State University), John Christy (University of Alabama at Huntsville), Michael Schlesinger (University of Illinois), Robert Mendelsohn (Yale University), and Indur Goklany (Department of Interior).
The complete program and registration information may be found on the internet at http://www.cato.org/events/gw031212.html.