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Moderation in Pursuit of Extremes

How many network "news" programs presented this fall's perfectly average hurricane season as a sign of dreaded global warming? How many times has President Clinton remarked that the "increase" in extreme weather events seems pretty obvious, after he was seen toting Ross Gelbspan's dopey reverie The Heat is On? We can't even count them all—and we don't even want to—knowing as we do that these and a lot of other statements about wacky weather are just plain wrong.

That is, if we are to believe the recent compendium Weather and Climate Extremes, edited by Thomas Karl, head of the National Climatic Data Center, and two others. This tour-de-force volume, hot off the presses, should be required reading for any climate cassandra, including Clinton or his sidekick.

A comprehensive paper by aptly named hurricanologist Chris Landsea puts it pretty bluntly. Landsea, who played on the 1984 Olympic water polo team, isn't shy about throwing cold water on the folks from "Working Group III" of the United Nations Intergovernmental Panel on Climate Change (IPCC).

Figure 1.  No trend exists in the number of Atlantic hurricanes per year since 1944, the year good records began.

Working Group III's Economic and Social Dimensions of Climate Change, whose chief author is IPCC head Robert T. Watson, stated that we could save 8,000 lives per year and $630 million in hurricane damages if only we reduced our greenhouse gas emissions. As Landsea puts it: "There is an obvious inconsistency between the projections by IPCC Working Group III....and the conclusions of Working Group I [the science guys], which stated that 'the state of the science does not allow assessment of future changes.'" Landsea goes on to say:

...the logic of the IPCC Working Group III is fundamentally flawed...the climatological record gives no indication that society can modulate hurricane impacts through energy policies. That is, as atmospheric CO2 levels have increased, "there is currently no evidence that there has been systematic change in the observed tropical cyclones in the observed tropical cyclones around the globe" (Landsea, 1998)...There is no evidence to suggest that society can intentionally modulate tropical cyclone frequencies and magnitudes through energy policies. Therefore, policy responses to hurricanes ought to focus on the reduction of society's vulnerabilities to hurricanes, rather than on the prevention of storms themselves (Pielke and Pielke, 1977).

The next paper, by British researcher Phil Jones, reiterates what WCR readers have known for years—that the longest high-quality temperature record in the world, the 225-year daily (!) Central England Temperature, "shows no significant increase in very warm days in recent years, but there is a marked decrease in the frequency of very cold days." How too, too bad. Using more recent global records, Jones demonstrates that the area of the planet exceeding its 90th percentile in temperature has increased threefold, while there has been an equal and opposite drop in the area of very cold temperatures—those below the 10th percentile. Jones neglects to remind us of the well-known fact that this is primarily because of a warming in the coldest winter temperatures in Siberia and northwestern North America, according to the same record.

Figure 2.  There is no evidence for increasing wind speeds in Atlantic hurricanes since 1944.

Following this entry is a compilation of climate extremes in Northern and Central Europe, by R. Heino and 10 co-authors.

Below, we quote some notable results listed in their "Concluding Remarks":

• a decrease in the diurnal [daily] temperature range

• a decrease in the number of frost days

• no major change in daily precipitation extremes

• no major change in the number of precipitation days [greater than] 10 mm

• no long-term intensification of strong winds

• a decrease in the occurrences of thunderstorms and hails.

In the next paper, Neil Plummer, from the Australian Bureau of Meteorology, shows the problems with "outlier" data. He reports an increase in the percentage of Australia experiencing precipitation in the 90th percentile or above; but, as the accompanying figure shows, an awful lot of this "trend" occurred because of one very wet year around 1975. There is also a decrease in the frequency of Australian rain below the 10th percentile. Not a bad outcome from global warming for the driest continent in civilization.

Figure 3.  Percentage of Australia experiencing extreme wet conditions on an annual basis.

WCR readers may recall our recent article pointing out that an AP story relating increased flooding in China to global warming had no basis in fact. The truth is, there's no change in the amount of land area there receiving heavy rain, as Panmao Zhai shows, even though there is an increase in flood frequency. Can anyone here say "deforestation"?

As for temperature trends:

The mean minimum temperature has increased significantly in China in the past 40 years, especially in the winter in northern China. Meanwhile, nationwide cold wave activity has weakened and the frequency of cold days in northern China has been reduced significantly. Mean maximum temperatures display no statistically significant trend for China as a whole. However, decreasing summer mean maximum temperatures are obvious in eastern China, where the number of hot days has been reduced.


Will someone please send copies of Weather and Climate Extremes to President Clinton, Al Gore, and Ross Gelbspan? C'mon, Tom Karl, go to the mail room—we know you're reading this!


Karl, T.R., et al., Eds., Weather and Climate Extremes: Changes, Variations and a Perspective from the Insurance Industry, Boston: Kluwer Academic Publishers, 1999.