TCS Daily


A CEO Cries Wolf

By Sallie Baliunas - July 2, 2002 12:00 AM

In US Airways' in-flight magazine, Attaché, exiting company Chairman Stephen Wolf opines in his last column about the "troubling issues facing mankind." Among the most frightening? Global warming from human effects.

Wolf discusses a handful of limited weather events - such as the low reservoir and lake levels in the Northeastern U.S. - and suggests that meaningful global climate information can be extracted from them.

But taking a snapshot of an environmental development in a particular time or place is a sorry scientific foundation from which to make pronouncements. For example, since the winter drought, the lakes and reservoirs in the Northeast Wolf cries about have been refilling with high spring rainfall. The National Climatic Data Center reports that February through April of 2002 had well above-average rainfall in the Northeast. Furthermore, the twelve-month average from May 2001 through April 2002 was only the sixth driest since 1895 - in other words, a dry but not unusual condition. Most of the driest years were in the early part of the 20th century, once again, long before the major increase in concentration of air's carbon dioxide. Thus, the temporary Northeast drought cannot be taken as a sign of human-made global warming.

Wolf also trumpets fluctuations in short weather records over small areas. For example, he mentions a scientific paper reporting winter temperatures on nine lakes on Signy Island, a 6 by 5 kilometer isle in the South Orkney Islands deep in the Southern Hemisphere. The tiny lake's temperature record shows a recent warming trend. Wolf believes this to be an alarming tragedy because the lake temperature "increased by as much as 1.3 degrees centigrade between 1980 and 1995, causing extremely fast changes in the lakes' ecology."

But a better estimate and understanding of a temperature trend can only be had from a longer record. While lake temperature is unavailable prior to 1980, the air temperature at Signy Island has been recorded since 1947, and is plotted in the accompanying chart for Southern Hemisphere winter (July - August).



An even longer record exists for the nearby Orcadas Island, 48 km from Signy Island. There the air temperature record goes back nearly 100 years, and is also plotted in the chart. First, note the good agreement between the short Signy Island record and Orcadas Island when the two records overlap, from 1947 to 1991, indicating the two records are valid for the region.

Over the last 100 years, the trend in air temperature for Orcadas -- and presumably for nearby Signy Island -- is much smaller than 1 degree centigrade per decade. The warming trend is roughly 1 degree centigrade per century, a factor of ten smaller than the trend calculated from the selective period 1980 - 1995 for the lake temperature at Signy Island.

Over a period of several years enormous variations in temperature can be seen in the temperature records for Orcadas and Signy Islands. The winter temperature fluctuates by more than 10 degrees centigrade within a decade. That means three things: first, the large fluctuations within a decade make it difficult to determine any human-made global warming trend introduced by the air's increased carbon dioxide concentration; second, the short trend makes it impossible to attribute an observed trend to human-made climate effects; and third, the sharp warming of the 1980s broadcast by Wolf is misleading, because longer records do not show such a steep warming. In other words, the warming is likely natural.

Wolf frets about abrupt changes in the lakes' ecology, but he hasn't done his homework. "[D]o we doom ...plankton in the Northern Hemisphere," by chopping down "forests to create more arable land in subtropical Latin America?" he asks. But the same scientific paper documenting the sharp rise in the warming trend between 1980 and 1995 that Wolf quotes also contains information on trends in plankton health. The warming trend observed between 1980 and 1995 has produced a stunning growth in lake biota as the melting glaciers carry nutrients into the lake. Far from doomed, plankton in the lake are thriving.

Despite his avowed concern for the environment, Wolf (and others) would do well to gain better understanding of the facts and power of scientific reasoning. Without them, the environment and humankind are doomed to false hopes and expensive solutions that solve no problems.
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