Getting warmer?

BEGINNING LAST SUMMER, as a severe drought and record heat dried up fields and streams across the United States, a big story hit the headlines: the earth may be getting dangerously warmer. James E. Hansen, a scientist with the National Aeronautics and Space Administration (NASA), told a congressional hearing that the evidence is "pretty strong" that the greenhouse effect had begun to operate.

"Seldom has there been such a strong consensus among scientists on a major environmental issue," intoned Richard A. Houghton and George M. Woodwell, scientists at the Woods Hole Research Center, in Scientific American this April. Stephen Schneider of the National Center for Atmospheric Research calculates that human-caused climate change will proceed ten to forty times as fast as any previous natural climate change.

Experts speculate on what the world might look like when the greenhouse effect takes hold. They predict rising sea-levels inundating wetlands, beaches, and coastal cities; forests shifting northward; new drought belts; worsening air pollution; and more catastrophes such as fires, insect plagues, and floods.

Self-appointed guardians of the environment are urging immediate steps to reduce emissions o"greenhouse gases" -especially CO[sub.2], but also methane, nitrous oxides, and CFCs (chlorofluorocarbons), which are believed to trap heat radiating from the earth. They urge cutting back on fossil-fuel use by such measures as special taxes on carbon-dioxide emissions, increased funding for alternative energy sources, incentives for solar and nuclear power, an end to deforestation, and a doubling of the current fuelefficiency standards.

CUTTING BACK significantly on the use of fossil fuels would require great sacrifices. Is global warming a sufficiently pressing issue to justify such steps?

The case for a greenhouse effect is based on the fact that the amount of CO[sub.2] in the atmosphere is indeed increasing. Studying gas trapped in glacial ice, scientists estimate that in the 1850s, at the start of the industrial revolution, the atmosphere had less than 290 parts of CO[sub.2] per million parts of air; that has risen to over 340 ppm, an increase of about 20 per cent over some 135 years.

There is also evidence that global temperatures have been going up during the past century. Hansen and his colleagues at NASA believe that the average global temperature has increased by between 0.5 degrees and 0.7 degrees C. since 1860. And the six warmest years globally during the past century appear to havc been in the 1980s, with 1988 the warmest.

But whether there is a connection between the two factors is highly debatable. Scientists aren't even sure the warming has occurred. Andrew R. Solow, a statistician at Woods Hole, points out that measured global temperatures are "not really global at all." Monitoring stations tend to be located on land rather than on oceans, where trends may be quite different, and more are in the Northern Hemisphere than in the Southern Hemisphere. Furthermore, some regions, including the contiguous United States, have not shown any observable warming during the past century. The Northern Hemisphere actually experienced a cooling period between the 1940s and the 1970s, which led to predictions in, the 1970s that we might be headed for a new Ice Age. Some scientists are convinced that the recent warm years can be explained by a periodic weather perturbation known as El Nino.

Assuming, however, that the global warming trend is real, could CO[sub.2] be the cause? If so, says Solow, we should be seeing much warmer temperatures than we have seen so far. "For example, for the planet to warm by 2 degrees C. in the next hundred years, the average rate of warming would have to be four times greater than that in the historic record." Greenhouse warming is expected to be greatest at high latitudes and more rapid in the north than in the south, but this pattern hasn't appeared either, he says.

Hugh W. Ellsaesser of Lawrence Livermore National Laboratory questions the computer models that predict the greenhouse effect, because of "the gross differences I see between how the atmosphere works and how it is modeled to work." But if carbon dioxide and other greenhouse gases didn't cause the warming that has apparently occurred, what did? Solow and Ellsaesser both think it is natural and that it simply reflects the aftermath of a period of unusual cooling, the so-called "Little Ice Age" that ended during the nineteenth century.

But suppose that a correlation could be made between increased greenhouse gases and warming. Even that doesn't mean that the warming will simply continue. Much remains to be learned about the carbon cycle, the process by which carbon is taken up by plants and released into the atmosphere. Biological factors could enter in. For example, Trevor Platt of the Bedford Institute of Oceanography in Nova Scotia has been studying the role of phytoplankton, marine plants that consume enormous amounts of CO[sub.2]. He believes that the phytoplankton increase in number as atmospheric CO[sub.2] builds up, creating a new "steady state" that will interfere with the greenhouse effect. Scientists also point to the importance of volcanic eruptions, which are largely unpredictable. Volcanic fallout tends to cool the earth because the particles help reflect sunlight back into space.

And Reid Bryson, director of the Institute of Environmental Studies at the University of Wisconsin at Madison, believes dust and smoke are the primary culprits in climate change, rather than carbon dioxide. He and a colleague, Gerald Dittberner, contend that atmospheric dust is responsible for about 90 per cent of the Northern Hemisphere's temperature variation in this century. Kenneth E. F. Watt, professor of environmental studies at the University of California at Davis, anticipates a long-term cooling. Increased carbon dioxide will heat tropical ocean surfaces, he explains, leading to additional evaporation and to denser clouds, which will decrease the penetration of sunlight. Watt suspects that the elevated level of the Great Salt Lake is a sign of cooling, not warming.

EVEN so, most people probably believe the greenhouse effect has arrived. In January, the New York Times airily dismissed a recent report that there was no warming in the U.S. during the last century. Any sign of the trend would be "hard to spot," explained the Times, and the uncertainty should not stand in the way of immediate action. ("The Greenhouse Effect Is for Real," read the editorial's headline.) In the U.S. and other Western democracies, public perceptions are critical to political outcomes. These perceptions are strongly influenced by the media, and they frequently differ from those of experts. The process has been substantiated by Stanley Rothman and S. Robert Lichter in a study published in American Political Science Review. They found that journalists are far more opposed to nuclear power than scientists who actually study nuclear issues, and that journalists more often quote the smaller group of scientists who are opposed to nuclear power. So, as Science editor Daniel Koshland put it, the government is "tilted to overreaction."

Thus the stage is set for very strong measures to reduce emissions of greenhouse gases. These measures would give governments greater power, would force people to make large sacrifices, and would probably limit innovation. Yet such measures will be introduced as moderate, even conservative, steps-in the words of the New York Times, as "cheap insurance against risks of such magnitude."

Yet any measures to remove CO[sub. 2] and other gases from the atmosphere will divert resources-land, Labor, and capital-from other productive uses. The unintended consequences of mandatory action can be severe.

Take the Times's recommendation to force Detroit to double the fuel efficiency of its cars. Such a requirement would result in many deaths. A study by Robert W. Crandall of the Brookings Institution and John D. Graham of the Harvard School of Public Health indicates that current fuel-efficiency standards are already causing deaths because automakers have had to lighten their cars, giving less protection in crashes. Crandall and Graham estimated that the congressionally established standards for 1989 models would have caused between 2,200 and 3,900 deaths. (The executive branch softened the standards a bit, so not quite that many people are dying.)

By the same token, some years ago the City of Los Angeles encouraged owners to tear down buildings that weren't earthquake-proof. The result, according to one study, was that 17,000 low-income people were deprived of housing, and replacement housing was not built. Even the best precautions typically have high costs.

Then there was the multi-billion-dollar Synthetic Fuels Corporation that the U.S. Government set up in response to the energy crisis of the late 1970s to spur production from new energy sources such as gasified coal. With no assistance from the Corporation, the oil shortage turned into a worldwide glut; the Synfuels effort was simply wasted.

In general, government policies in the environmental arena shift with the political winds and nurture special interests. For example, after World War II the Federal Government wished to encourage nuclear power; the PriceAnderson Act was passed, limiting owners' liability for nuclear accidents, which reduced the incentives for effective safety measures. Then, in the Sixties, anti-nuclear groups became politically powerful. This led to extensive regulation of nuclear utilities; costs became prohibitive and safety regulations became so complex that some analysts contend that they actually reduce safety.

Environmental policy often becomes a political tool of regional interests. The 1977 amendments to the Clean Air Act required that all electric utilities use scrubbers to eliminate sulphur-dioxide emissions-even if they could reduce emissions more effectively by just using low-sulphur coal. As Bruce Ackerman and W. T. Hassler show in Clean Coat Dirty Air, the scrubber rcquirement saved the Appalachian coal-mine owners and unions from serious competition from low-sulphur Western coal.

If things are this bad on a national scale, what can we expect on a global scale? Negotiations over the past decade to establish a Law of the Sea Treaty illustrate the problem. Nations couldn't agree on how to develop seabed minerals; Third World governments demanded that an international authority be formed to collect fees that would be distributed to Third World nations. The U.S. opposed this demand and refused to sign the treaty. Similar conflicts are emerging with the effort to control CFCs. China has indicated it plans to increase its use of CFCs ten-fold by the year 2000.

VEN MODEST FAMILIARITY with history adds to one's Even modest Familiarity taking immediate and drastic action to combat global warming. Over the centuries, competent, highly respected people have predicted timber shortages, worldwide famines, permanent energy crises, and critical mineral depletion. None of these predictions has materialized.

In 1865, the noted British economist William Jevons argued that industrial growth could not be continued for long because the world was running out of coal. He concluded that it was "inevitable that our present happy progressive condition is a thing of limited duration."

At the turn of the century, President Teddy Roosevelt and his first chief of the Forest Service, Gifford Pinchot, thought the country was running out of timber. Indeed, a New York Times headline, "Hickory Disappearing, Supply of Wood Nears End-Much Wasted and There's No Substitute," was typical, as Sherry Olson relates in her book The Depletion Myth.

In 1968 Paul Ehrlich wrote: "In the 1970s the world will undergo famines-hundreds of millions of people are going to starve to death." Fortunately, this did not prove correct, and increasing privatization of agriculture in the Third World has significantly increased food production.

Finally, what confidence can we have in the globalwarming predictions when we note that less than 15 years ago the idea that another Ice Age was pending was popular enough for a book, The Cooling, to be written and to receive respectful scientific comment?

NEVERTHELESS, the doomsayers could be right. The good news is that we probably have time to find out. Scientists are constantly accumulating information that brings them closer to understanding climatic sensitivity to greenhouse gases. As this knowledge emerges, a true consensus may develop that something should be done about the greenhouse effect.

But, since massive government solutions tend to be counterproductive, what should we do? As we learn more about the potential for global warming (or cooling), individuals will adapt their plans to defend their property, and to take advantage of the new conditions. If they are allowed to do this each in his own way, the results will be illuminating -whereas if individuals believe instead that the government will prevent the problem, then less will be tried and less will be learned. If the governments actually try and fail, then more serious dangers are likely.

The most effective thing that we can do to cope with global warming is to allow progress to continue. This is just the opposite of what Lester Brown, president of Worldwatch Institute, would like. He and two colleagues, Christopher Flavin and Sandra Postel, recently wrote that climate change "calls the whole notion of human progress into question" and urge that we take action "before it is too late." Yet Brown is flat wrong. Human progress is exactly what enabled people to cope with catastrophes in the past and it can continue to do so.

What countries can best handle the epidemic of AIDS? Clearly, countries that have sophisticated medicine, extensive hospital facilities, and a population in generally good health will cope better than countries lacking even basic sanitation for much of their population. Similarly, political scientist Aaron Wildavsky points out that an earthquake in California in 1971 caused 62 deaths. The next year a slightly less powerful earthquake in Nicaragua killed tens of thousands. Why the difference? The wealthier country had better-built houses, better transportation and communication, better health facilities. Shouldn't we encourage such progress, rather than stop it in its tracks?

In sum, mandatory steps to avert this potential disaster are the wrong way to go-especially in the near future, while scientific knowledge about global warming is seriously incomplete. As scientific understanding of the global atmosphere improves, our ability to make well-informed policy decisions should improve, too. Let's hope that those decisions take into account the resilience that comes from freedom and material progress.