Global Warming May Be Beneficial - Brief Article

USA Today (Society for the Advancement of Education), June, 2000

CLIMATOLOGY

Government officials have declared repeatedly that global climate change science is "settled" and "compelling." Yet, a report released by the Center for the Study of American Business at Washington University in St. Louis (Mo.) finds that increased global warming is likely to be minor and even beneficial.

In the report, "What Do We Know About Human Influence on Climate Change?," atmospheric physicist S. Fred Singer reviews the state of the research and makes the following findings:

* Any warming from the growth of greenhouse gases is likely to be minor and, thus, difficult to detect above the natural fluctuations of the climate.

* The impacts of global warming and higher [CO.sub.2] levels are likely to be beneficial for human activities-especially agriculture.

* The 1997 Kyoto Protocol on global climate change's ultimate goal remains undefined. Ultimately, it could be a higher or lower level of greenhouse gas emissions.

* The Kyoto Protocol, while economically harmful, would be ineffective in reducing the calculated temperature increase.

Singer notes that there must be a human influence on some features of the climate, locally, if not globally. The important question is whether the available evidence supports the results of general circulation models. Unless validated, he maintains, the predictions of future global warming based on them cannot be relied on.

Earth's climate has never been steady, either warming or cooling without any human intervention. The measured temperature variations have often been larger and more rapid than those predicted by climate models for 2100. In the last 3,000 years, temperatures in the North Atlantic have changed by as much as 3 [degrees] C within a few decades. During the most recent ice age, the variability was even greater. "Is the climate more stable during warmer periods? We cannot be sure, but the evidence points in this direction," Singer suggests.

Longer-term climate changes seem to be linked to continental drift and other tectonic events. Shorter variations, on the time scale of decades, appear to be triggered by atmosphere-ocean interactions and changes in ocean circulation. Alternatively, they could be due to external causes, such as the slight variations in the general solar irradiance (the so-called solar "constant") or in the highly variable solar activity. For reasons as yet unexplained, the rate of increase of greenhouse gases in the atmosphere has slowed considerably in the last decade or so.

Catastrophists warn that global climate change will result in increased frequency and severity of storms and a rapid rise in sea levels. However, Singer says, "The empirical evidence . shows a decline in hurricanes over the last 50 years in both frequency and intensity." In addition, sea-level rise is found to slow during periods of temperature increases, suggesting that future modest warming should slow down, not accelerate, the ongoing rise of sea levels.