The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 9 No.
3 • August 2006
SPECIAL REPORT ON CLIMATE CHANGE
Climate Change Keeps . . . uh . . . Changing
Academy affirms hockey-stick graph
— Headline, news article in Nature, June 29, 2006
Well, not quite. This article reports on the conclusions of a National Academy of Sciences committee asked to evaluate the Michael Mann hockey-stick graph, which appears to show that the twentieth century is the warmest in the last 1000 years and which was relied upon in the last IPCC climate report. As noted in paragraph four of the article, “‘[W]e roughly agree with the substance of their [Michael Mann and coworkers] findings,’ says Gerald North, the committee’s chair and a climate scientist at Texas A&M University in College Station. In particular, he says, the committee has a ‘high level of confidence’ that the second half of the twentieth century was warmer than any other period in the past four centuries. But, he adds, claims for the earlier period covered by the study, from A.D. 900 to 1600, are less certain. This earlier period is particularly important because global-warming skeptics claim that the current warming trend is a rebound from a ‘little ice age’ around 1600.” The article states that the committee felt that the conclusions concerning the pre-1600 period had only a two-to-one chance of being correct. We seriously doubt that two-to-one guesstimate. New data demonstrate that the Michael Mann hockey-stick graph misses a lot, including the medieval warm period and the little ice age.
A report commissioned by the House Energy Committee on the Michael Mann hockey-stick-graph model of climate change was released on July 14, 2006. The report was prepared by three statisticians (not climatologists), Edward J. Wegman of George Mason University, David W. Scott of Rice University, and Yasmin H. Said of Johns Hopkins University, to evaluate the statistical methods used in the Mann papers. They concluded that the papers were plagued by basic statistical errors that call the conclusions into doubt. Moreover, Mr. Wegman, using a technique called social network analysis, concluded that the most frequently published climatologists form such a close-knit group that there was no likely effective independent review of Mr. Mann’s work. As Wegman said, “There is a tightly knit group of individuals who passionately believe in their thesis. However, our perception is that this group has a self-reinforcing feedback mechanism and, moreover, the work has been sufficiently politicized that they can hardly reassess their public positions without losing credibility.” This paragraph was taken from an editorial in The Wall Street Journal, July 14, 2006.
The Little Ice Age
A new paper on “Solar modulation of Little Ice Age climate in the tropical Andes” shows that the Little Ice Age was, in fact, a global event (that is, it didn’t take place only in Europe) by demonstrating that there were four glacial advances between A.D. 1250 and 1810 in the Venezuelan Andes, coincident with solar-activity minima. As the authors say, “[t]he data presented here suggest that solar activity has exerted a strong influence on century-scale tropical climate variability during the late Holocene, modulating both precipitation and temperature.” The Mann hockey-stick graph did not show a Little Ice Age.
Medieval Warm Period
Another very recent paper now reports strong evidence on the effects in North America of the Medieval Warm Period, 800 to 1000 years before the present (the Medieval Warm Period does not appear in the Mann hockey-stick graph either). This paper describes the MWP (Medieval Warm Period) as “a time of warmth and aridity throughout much of the western United States; this suggests that the [wind] circulation change indicated by [sand] dune morphology is part of a larger climate anomaly.”
Global climate models predict increase in snowfall in Antarctica due to warming: but snowfall hasn’t changed in 50 years
“Future scenarios from global climate models (GCMs) suggest that Antarctic snowfall should increase in a warming climate, mainly due to the greater moisture-holding capacity of warmer air, partially offsetting enhanced loss at the ice sheet peripheries.”
A new paper reports on a 50-year time series of snowfall accumulation over Antarctica by combining model simulations and observations primarily from ice cores. They find that “[t]here has been no statistically significant change in snowfall since the 1950s. … If anything, our 50-year perspective suggests that Antarctic snowfall has slightly decreased during the past decade, while global mean temperatures have been warmer than at any time during the modern instrumental record.” They conclude, “Our results indicate that there is not a statistically significant global warming signal of increasing precipitation over Antarctica since the IGY [International Geophysical Year, 1957–58], inferring that GSL [global sea level] rise has not been mitigated by recently increased Antarctic snowfall as expected. It may be necessary to revisit GCM [global climate models] assessments that show increased precipitation over Antarctica by the end of this century in conjunction with projected warming.” [Emphasis added] A hypothesized increase in precipitation had been put forth heretofore to “explain” why the ice sheets in most of Antarctica are thickening, while in other areas (particularly the western ice sheet), ice is thinning.
As we have noted before, global climate is very far from understood and very far from wrapped up by a scientific “consensus.” We object, not to facts developed by scientific investigation, but to an alleged foregone conclusion (to which everybody except a few “skeptics” supposedly agrees) that a disaster of human* design is in the making and that governments are capable of “fixing” it. There is no scientific consensus, nor is there even an attempt to find a “consensus” among economists that governments can regulate the use of the atmosphere so that benefits outweigh costs.
- Polissar et al. Solar modulation of Little Ice Age climate in the tropical Andes. Proc Natl Acad Sci USA 103(24):8937-42 (2006).
- Sridhar et al. Large wind shift on the Great Plains during the Medieval Warm Period. Science 313:345-7 (2006).
- Monaghan et al. Insignificant change in Antarctic snowfall since the International Geophysical Year. Science 313:827-31 (2006).