Don't Hold Your Breath

GLOBAL WARMING MAY OR MAY NOT BE THE GREAT environmental crisis of the next century, but - regardless of whether it is or isn't - we won't do much about it. We will (I am sure) argue ferociously over it and may even, as a nation, make some fairly solemn-sounding commitments to avoid it. But the more dramatic and meaningful these commitments seem, the less likely they are to be observed. Little will be done. I wouldn't stake my life on that, but I don't see how it could turn out otherwise.

Democracies can't easily make present sacrifices to avoid future menaces. We require (it seems) a clear and present danger, if not a crisis, to stir us to action. This is why we won't soon mobilize against global warming. The politics simply won't compute. To do something effective would require a heavy energy tax or its equivalent. A good round figure for a tax is $100 per ton of carbon; this would raise gasoline prices an estimated 26 cents a gallon and electricity and natural-gas rates by almost 30 percent. The idea would be to dampen energy use and the emission of greenhouse gases (mostly carbon dioxide) from the burning of fossil fuels (oil, coal, gas).

To put it mildly, the odds of Congress's passing such a tax are low. The problem with global warming is that we don't know yet whether it represents a genuine national threat and, if so, how large. Congress might conceivably react to a legitimate threat, even if distant. But it won't impose pain on voters for no obvious gain to solve a hypothetical problem. And if the United States won't, neither will anyone else. We generate the most greenhouse gases, about 22 percent of the annual total. Other countries won't squeeze themselves to preserve our lifestyles.

I talked last week to global-warming believers and skeptics. Despite policy differences, they tend to agree about the modest state of current knowledge. Here's what we know. Since the dawn of the Industrial Age (say, 1800), the concentration of carbon dioxide in the atmosphere has risen about 30 percent. In the past century, average surface temperatures have increased 1 degree Fahrenheit (.5 degree Celsius). The widespread suspicion is that these trends are connected. Industrial and transportation emissions increased carbon dioxide, trapping more heat in the atmosphere and raising temperatures. The rival theory is that the small temperature rise is a natural climatic variation.

Now, here's what we don't know:

We don't know how much - or if - temperatures might rise in the next century. In 1995 the United Nations' Intergovernmental Panel on Climate Change predicted that average temperature might increase between 1(degree)C and 3.5(degree)C, with the best guess at 2(degree)C. Even this huge variation is hedged with qualifications and isn't accepted by many scientists, because it's based on admittedly crude computer simulations of climate.

We don't know - despite much scare talk - what the effects of warming might be. The computer models can't predict the exact impact on regions or precise shifts in storm patterns. Warmer weather might make some areas more attractive, and others less. Hotter weather could depress crop output in some places and raise it in others.

We don't know how to prevent warming. Once greenhouse gases reach the atmosphere, they tend to stay there. So stabilizing annual emissions isn't enough; they have to be cut sharply. But economic growth requires more energy, and fossil fuels provide 85 percent of all energy. Without a breakthrough in alternative energy - nuclear, solar, something - no one knows how to lower emissions adequately without ultimately crushing the world economy. (By 2050, emissions might have to drop 50 percent or more from expected levels.)

The idea that global warming is a certain calamity simply isn't proven. Anyone who thinks otherwise should read Richard A. Kerr's superb story in the May 16 issue of Science magazine (""Greenhouse Forecasting Still Cloudy''). In it, he illuminates the doubts that plague computer modeling of climate. By altering a few assumptions, one model cuts its forecast of global warming caused by a doubling of CO2 concentrations from 5.2_C to 1.9_C. Based on present knowledge, the best way of coping with warming - if it happens - would be to adapt to it. Change would probably occur over decades. If sea levels rose because oceans warmed, coastal areas would erect retaining walls - or people would move. Farmers would adjust crops to new weather.

I write all this as someone who actually favors an energy tax, mainly for national-security reasons (to cut dependence on insecure Mideast oil). I believe that, within limits, we could improve energy efficiency without wrenching changes in lifestyles or high economic costs. Well, we had two oil crises in the 1970s and fought a war in the 1990s over oil. None of these events spurred a major energy tax, and global warming would ultimately demand a bigger tax. (A $100-per-ton carbon tax, for example, might only cut CO2 emissions back to 1990 levels by 2010.)

What I conclude is that global warming promises to become a gushing source of national hypocrisy. President Clinton recently fulminated to the United Nations about the dangers of global warming without specifying how the United States might combat it. Late this year an international conference will try to fashion a global treaty. Already 65 senators have signed a resolution sponsored by West Virginia Sen. Robert Byrd rejecting any treaty that doesn't demand emission cuts by poor countries (China, India, etc.). But these countries have - temporarily - been exempted for good reasons. They didn't cause most greenhouse gases, and penalizing their development would perpetuate their poverty.

The difference between Clinton and Byrd is less than it seems. Clinton wants to seem engaged without doing much; Byrd et al. want to find a respectable reason (i.e., poor countries aren't participating) for being disengaged. Hardly anyone wants to admit candidly the uncertainties of global warming. It's politically incorrect to question whether this is a serious problem that serious people ought to take seriously. But it would be political suicide to do anything serious about it. So shrewd politicians are learning to dance around the dilemma.

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