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Is The Sky Really Falling?


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IS THE SKY REALLY FALLING?

WHAT GOES UP: THE GLOBAL ASSAULT ON OUR ATMOSPHERE

By John J. Nance

Morrow 324pp $20

James Hanson, director of NASA's Goddard Institute for Space Studies, faced a Senate hearing in June, 1988, to address a burning issue: Was the climate getting warmer as a result of the greenhouse effect? Hanson sprinkled his response with caveats and said that the summer's heat wave and drought couldn't be blamed on global warming. But he did say that "the greenhouse effect has been detected, and it is changing our climate now." Those remarks wound up in headlines proclaiming that the drought was a product of global warming. They unleashed a storm of disagreement among Hanson's peers. And the dispute over whether the planet is warming still rages.

In What Goes Up: The Global Assault on Our Atmosphere, John J. Nance helps put the controversial issues of global warming and the damage to the ozone layer in perspective. He begins by describing the 15 years of wrangling that finally led scientists, politicians, and business to agree that chlorofluorocarbons (CFCs) were destroying the earth's protective ozone layer and to the landmark Montreal Protocol, which phases out the chemicals. He also fleshes out what is and is not understood about global warming. While providing a fascinating glimpse of scientists and the scientific process at work, Nance also shows how slow the route can be from the first scientific identification of a serious problem to public policy that attempts to address the issue.

Nance explores ozone loss through the experiences of the scientists who pieced together the evidence that CFCs were the culprits. His vivid, you-are-there narrative drives home how fraught with disagreements and errors the process was.

The ozone wars, as Nance calls them, began in 1974, when two University of California at Irvine chemists, Sherwood "Sherry" Rowland and Mario Molina, published a theory to explain what happens to CFCs after they are released. It was a bombshell. CFCs, they said, wend their way slowly into the stratosphere and decompose, releasing chlorine atoms. These atoms break down ozone, and that would lead to a gradual decrease in the ozone layer that protects earth from radiation. The chemists could offer no evidence of ozone loss, however, nor of elevated levels ef chlorine in the atmosphere. The theory was promptly denounced by the chemical industry and disputed by other scientists.

Support didn't come until 1985, when Joe Farman of the British Antarctic Survey published the first data that showed a hole was appearing in the ozone layer each winter over Antarctica. What Farman documented was not the linear decline Rowland and Molina predicted, but an exponential loss of 40% during the 1984 winter, far greater than the first small decline he detected in 1981.

Farman's paper stunned the scientific community. Other groups monitoring the atmosphere in Antarctica hadn't reported any decrease. Scientists at NASA's Goddard Space Flight Center quickly reviewed their own data and made a chilling discovery: Their instruments had recorded the losses, but the computer interpreting the results had been programmed to ignore readings that deviated so far from normal.

Nance goes on to describe how scientists verified the findings, discovered losses over the Arctic, and determined the process by which chlorine destroys ozone. At every point, environmentalists and industry clashed over the validity of the findings. The chemical industry continually demanded more proof. The disagreement kept Washington paralyzed.

Nance considers the current debate over whether a global warming has begun and what effect it might have on climate to be at the same point the CFC-ozone issue was in 1975. Findings that indicate a warming may have begun are very much in dispute among scientists, industry, and government. With both issues, as Nance points out, the key question has been: When does society have enough proof to justify action? With global warming that means curbing carbon dioxide emissions.

As those in the "act now" camp see it, industry and other entrenched interests oppose corrective action because it would interfere with profits. But industry is legitimately opposed to environmental laws that require huge investments unless they are absolutely necessary. It boils down to assumptions: Should you assume that what you don't know can't hurt? Or should you act on the assumption that it can?

In Nance's view, the ozone wars dramatize the perils of failing to embrace the latter assumption. The discovery of the ozone hole proved that atmospheric change is not necessarily linear. Any climate change kicked off by global warming could be sudden, exponential, and unpredicted.

Nance is clearly impatient for action on global warming. He considers the consequences of warming risky enough to justify action now, even though scientists don't agree that a warming has begun. He blames at least some of the foot-dragging on scientists' failure to communicate the issues clearly. In addition, he thinks the media's tendency to reduce complex issues to two-sided conflicts exaggerates the disagreement among scientists, creating an obstacle to public understanding.

To those familiar with the politics of public policy, Nance's analysis of the stumbling blocks to change will come as no surprise. His major prescription--better communication--is ill-defined. But for those who wonder what the hoopla over global warming is all about, Nance's lucid explanations of this complex issue make the book worthwhile.EMILY T. SMITH


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