BOOK REVIEW : Warming: Century's Hottest Topic

Graber is a research biologist with the National Park Service.

Global Warming: Are We Entering the Greenhouse Century? by Stephen H. Schneider (Sierra Club Books: $18.95; 336 pages; illustrated).

If you are in the natural sciences, "global climate change" is just about the most exciting jingle--and perhaps the hottest meal ticket--to hit the catch-phrase circuit since "survival of the fittest."

And well it should be. For once, a distinct majority of climatologists are in agreement about the weather prediction: It is--as you well know unless you have been off the planet the last couple of years--a warming trend. A rather quick one, with no end in sight. And with consequences for humanity and the remainder of the Earth's fellow travelers that threaten to be rather interesting.

If I were forced to select but one chronicler for this new adventure we are undertaking, it would be Stephen Schneider. For a scientist he is too glib; for a journalist he is too technical. He has a leg firmly insinuated into each camp--and that's no pedestrian accomplishment.

Schneider is head of "Interdisciplinary Climate Systems" at the National Center for Atmospheric Research in Boulder, Colo., a National Science Foundation-sponsored institution that has consistently been at the cutting edge of research and policy.

A few years back, Schneider co-authored a book--also published by the Sierra Club--entitled "The Co-Evolution of Climate and Life" that offered a thrilling reconstruction of the Earth's past climates and the newly emerging science of global future climate modeling for those sufficiently brave to tackle a little chemistry and some complex graphs. Schneider wasn't afraid to say to his non-scientific readers, "Come on, work a little and I'll make it worth your while." And he was right. For serious fans of weather who have graduated from cumulus and occluded front, it's the best thing in print.

The modest-appearing predicted increases of 3 to 5 degrees (Celsius) over the next century would be unprecedented in human history. The average increases obscure the way we will perceive climatic change: more heat waves, more droughts, more floods, more extreme weather.

Today, scientific, public and--belatedly--governmental concern about the nature and consequences of "the greenhouse effect" is beginning to drive myriad research programs: If you are a climatologist, you are examining polar ice cores for evidence of past climates and the gas concentrations that accompanied them. You are using supercomputers to run increasingly complex models of ocean and atmospheric circulation and evaporation/condensation cycles that attempt to factor in changes in the Earth's potential for retaining the sun's heat. And you are looking at other anthropogenic greenhouse gases--CFCs, ozone, oxides of nitrogen--to try to figure how these may contribute to the equation in the future.

If you are an agricultural scientist, you may well be using the first uncertain maps predicting temperature zones and precipitation to estimate changes in the kinds of crops and their production that will take place in each region. Meanwhile, foresters are conducting parallel exercises for timber.

If you are an ecologist, you are predicting the distribution of future natural plant communities, perhaps borrowing data that paleontologists are extracting from fossil pollen in lake bottoms on the kinds of vegetation that accompanied past climates, and how fast it could migrate with climatic change.

Plant physiologists are attempting to calculate what stimulating effect increasing atmospheric carbon dioxide may have on plant growth, and the degree to which increased growth could then transfer carbon from the atmosphere to plant tissue reservoirs--a negative-feedback or homeostatic loop.

Conservation biologists, meanwhile, remind their colleagues that the biggest such carbon pool lies in the tropical rain forests, which are rapidly being converted back to CO2 (carbon dioxide) themselves, and wonder what the extinction price of global warming may be as thousands or millions of species discover their habitats are becoming less habitable and there is no place left to move.

Oceanographers ponder what dimensions the oceans will assume as they expand with increasing temperature, and what additional volume may be added by melting polar ice caps. On the other hand, the enormous mass of the world's oceans may well absorb some of the greenhouse gases, and may act as a thermal ballast to slow atmospheric warming.

Regional planners in some places are contemplating the redistribution of available water through changes in precipitation patterns, while those in places like San Francisco, New York, Calcutta, Holland or Indonesia nervously study the oceanographers' estimates of sea-level rise.

The economists, of course, are beginning to add all of the potential costs and benefits together for each regional and national economy. And they are likewise starting to weigh the costs of reducing carbon dioxide emissions, which come mostly from the burning of coal, oil and wood, against the burden of global climate change. Sociologists wonder what these changes portend for people's lives, and the political scientists ponder future conflicts arising from economic or social dislocations.

That's a taste of "Global Warming." Schneider is not certain of the greenhouse effect, but he's sufficiently convinced--he provides the evidence that convinces him--that he argues forcefully for investing in more research and better planning. And he is less than kindly toward bureaucrats and politicians who resisted such efforts during much of the past Administration.

There are plenty of puzzles he leaves unresolved. For example, there is an excellent correlation in climatic record between past temperatures and levels of methane and carbon dioxide, but there are also mechanisms by which these gases could have been the product, rather than the cause, of higher temperatures. We are almost certainly in between periods of glacial advance and retreat. There is a link between global activity, but Schneider does not fully explain this as he summarizes the most popular theories of "intrinsic" (Earth-bound) and "extrinsic" (solar or orbital fluctuations) forcing of climatic change.

Granted, this is an exceedingly complex-albeit fasinating-topic. The hottest years of the century have occurred in the 1980s. Are they the beginnings of the greenhouse or some other climatic process?

Schneider tantalizes, but remembers his scientific credentials. He does observe that the best available analyses of global records dating back many decades do show a regular rise in temperature, but at only half the rate predicted by levels of the greenhouse gases. Does this invalidate the model?

There is more. A little backpatting history of research and politics provides levening. A modest chapter suggests how we may mitigate and cope with the greenhouse century-chiefly by becoming more energy-efficient.

And there are good footnotes and a good index. This is a complex book, but because Schneider clearly has the gift of gab and a touch of the prophet, it works and works well.

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