Some like it hot: global warming is not just a scientific prediction - it's also a hot political football.

Dr. Ben Santer's computer at the Lawrence Livermore National Laboratories in California goes cuckoo every hour, on the hour. No, it's not time for Bytes 'R Us: The computerized cuckoo clock sound is just to remind Dr. Santer to get up and stretch his legs. Otherwise he'd become so absorbed in his global warming climate models that he'd never move from his keyboard.

Welcome to the wonderful world of computerized climate projection, a window on the weather that is largely responsible for predicting that, because of our continuing addiction to the burning of fossil fuels, the planet is about to get warmer. A lot warmer. Warm enough to cause melting at the polar ice caps, to kill millions of acres of forest caught in the wrong climactic zone, and to make beachfront property a chancy proposition.

Most environmental groups accept the onset of global warming - a byproduct of the world's carbon dioxide (C[O.sub.2]) emissions - as established fact. But in the universities and laboratories where scientists hang out, it's still hotly debated. And that debate has become pointedly political, with pro-business conservatives on one side and green conservationists on the other. Often, it seems, where scientists stand on global warming depends a lot on where their own sympathies lie and who's paying their bills.

A Modern Problem

The relationship between temperature change and carbon dioxide was first discussed in the 1860s, and first taken seriously by a Swedish scientist named Svante Arrhenius in 1896. Arrhenius' culprit, then, was burning coal. An American researcher, P.C. Chamberlain, brought the problem home to the U.S. in 1899. But Chamberlain and Arrhenius were talking theoretically. The actual buildup of C[O.sub.2] in the atmosphere didn't occur until the first part of this century - it rose from 280 parts per million (ppm) in 1850 to 315 ppm in 1957. And since the 50s, when the developed world's appetite for gas guzzlers and superhighways really took off, the C[O.sub.2] trajectory - nearly all scientists agree - has gone straight up.

Are we feeling the effects? You bet. According to the British government's Meteorological Office, 1990 was the planet's hottest year since climate and temperature records began. That could be dismissed as a fluke, but 1991 was the third hottest year on record, and 1993 was the sixth hottest this century. The 80s, as a whole, were the hottest decade on record, and the 90s may be hotter. And virtually no one disputes that the average world temperature has risen one degree Fahrenheit, from 58.5 to 59.5 degrees, in the last 100 years. While that may not sound like much, consider the fact that Earth's ice ages were triggered by drops in global temperature of only a few degrees. Back when Manhattan island was covered by ice a half mile deep, world average temperatures were only six degrees Celsius colder than they are now.

Reversing global warming, then would seem to be everyone's urgent problem. But since solving this injury to the Earth's atmosphere involves closing industrial plants and reducing emissions from automobiles, both big parts of western civilization's growth ethic, politics interfere with the process.

'Figures Lie, Liars Figure'

Consider what Rush Limbaugh said in his See, I Told You So: "... [T]here is nothing resembling a consensus on [global warming] among scientists who have some expertise in this area. In fact, a majority clearly doesn't believe global warming has occurred...A fact you never hear the environmentalist wacko crowd acknowledge is that 96 percent of the so-called 'greenhouse' gases are not created by man, but by nature."

As with many political naysayers on global warming, Limbaugh's claims contain a sliver of truth - greenhouse gases are largely a natural phenomenon. But he ignores the plain scientific fact that these gases are normally in balance, and that our unnatural contribution to them has thrown that balance off. According to the Environmental Defense Fund (EDF), C[O.sub.2] levels are now more than 25 percent above what they have been for the past 10,000 years. (They were actually higher in the ancient past, about which more later.)

But what of Limbaugh's claims about the scientific consensus? Do a "majority" of scientists discount the greenhouse effect? That's certainly the contention of the Maryland-based Center for Science, Technology and Media (CSTM), which charges that "the public is receiving a skewed portrait of the scientific debate over global warming." It adds that there is "considerable debate and uncertainty about global warming theory within the scientific community."

CSTM and Limbaugh both base their conjecture on a 1991 Gallup survey, which, CSTM says, showed that 41 percent of scientists questioned believed in global warming, 31 percent don't accept it and 28 percent aren't sure. (Limbaugh quotes the same poll's figures differently; he says that only 17 percent supported global warming, 30 percent don't know, and 53 percent don't believe it.) Actually, they're both wrong, as was columnist George Will, who reported on the poll in 1992. The actual poll shows 66 percent believing that global warming is already occurring. Only 10 percent disagreed with that.

E's own decidedly unscientific poll found that Americans voice concern about global warming but are not too well-informed about it. While 16 of 24 people randomly interviewed had heard of the greenhouse effect, and 12 thought it a "serious concern," only a few could accurately say what causes it or describe its consequences.

Most scientists do believe in global warming, and the percentage has grown tremendously since the Gallup poll was done in 1991. A key to understanding the scientific consensus is the work of the Intergovernmental Panel on Climate Change (IPCC), set up as a non-partisan international scientific group in 1988. IPCC's first report, in 1990, concluded both that human activity does affect climate and that greenhouse gases are building up at a rate likely to cause unprecedented temperature increases, though the effects probably wouldn't be felt for a decade.

IPCC, which draws on the work of 2,500 climate experts, reaffirmed its initial findings at the Earth Summit in Rio de Janeiro in 1992, with some hedging. "The unequivocal detection of the enhanced greenhouse effect from observations is not likely for a decade or more," it said. But what Dr. Michael Oppenheimer, an atmospheric scientist with The Environmental Defense Fund (EDF), calls "the smoking gun" is a new IPCC report, which concludes, based on model studies, that "the observed increase over the last century is unlikely to be entirely due to natural causes and that a pattern of climatic response to human activities is identifiable in the climatological record ... There is agreement that the atmospheric [greenhouse gas concentrations] have increased globally due to human activities." The report cites "an increased tendency for both floods and droughts" and, by the year 2100, "an increase in the global mean sea-level" of from four inches to two-and-a-half feet. It predicts a loss of biodiversity, "adverse consequences for food security," serious health effects in poor areas, and worsening air quality in cities.

Ironically, scientists were finally delivering their "smoking gun" just as the anti-conservation coalition in Congress prepared to deal death blows to environmental legislation. In October, the House voted along party lines to eliminate Environmental Protection Agency (EPA) research funds for global warming. Congressional Republicans are also trying to cut funding for the government's emissions reduction program. Without that money, it's highly unlikely the U.S. will reach its goal, set in Rio in 1992, of cutting emissions to 1990 levels by the year 2000.

The congressional votes prove one thing: that environmentalists are being seriously outflanked in the media. Cautious scientific appraisals like IPCC's are attacked in sensationalistic press conferences by groups like the benign-sounding Global Climate Coalition (GCC), actually an industry front group representing more than 50 corporations and trade associations. Executive Director John Shlaes says that if global warming is taken seriously, it will cripple "the nation's economy and the ability of the U.S. to compete in international markets." Small wonder, then, that it trumpets a report by TV/radio weather-for-hire firm Accu-Weather claiming that there's little evidence that global weather is becoming more extreme. The report is ridiculous on its face, since IPCC and most scientists predict that global warming's impact is still some years in the future. And it's not difficult to find anecdotal evidence that extreme weather is increasing. (Greenpeace, for one, compiled a 165-page book of such incidences. And in 1995, according to one amused scientist, we've had so many hurricanes we were already up to "S" [Sebastien] by October.)

The right-wing disinformation doesn't surprise Donella Meadows, a Dartmouth environmental studies professor best known for her 1972 book Beyond the Limits, an international bestseller which used computer models to project serious environmental disaster ahead. "Industry is throwing in a lot of deliberate distortion," she says. "But what's important to get across here is that there's this tiny bunch of skeptics that includes Dr. Richard Lindzen and Dr. S. Fred Singer, and then there's everyone else, thousands of scientists. There's not an 50-50 balance of scientific opinion. These few people are politically conservative, and their politics are driving their science. It would be an utter shock to mainstream science if global warming didn't happen."

To prevent a global warming catastrophe, IPCC recommends switching to alternative- or electric-powered vehicles, which it predicts could reduce C[O.sub.2] emissions by 95 percent per unit (when compared to 1990 levels). It says C[O.sub.2] levels can also be reduced by increased use of such sustainable energy sources as solar, biomass, wind, geothermal and micro-hydro, which today make up only 17 percent of the world's primary energy sources. Environmentalists will like that, but they'll be less sanguine about the report's conclusion that C[O.sub.2]-free nuclear power "could replace baseload fossil fuel electricity generation," though it goes on to note problems with nuclear waste disposal, reactor safety and high capital costs.

The IPCC synthesis report, which was finalized at a Rome conference last December, had already made the rounds of the scientific community in draft form. It got considerable press coverage after being leaked onto the World Wide Web in September. "Climate change will affect all countries in one way or another," said Robert T. Watson of the White House Office of Science and Technology Policy, representing one of the IPCC Working Groups. Watson's group predicted an average temperature increase of 1.5 to 6.3 degrees Fahrenheit and a sea level rise of up to 37 inches by the year 2100. Its report was immediately attacked by the right-wing GCC as neither fair nor objective, and tainted by "political considerations."

The Best Scientific Evidence

E interviewed several of the scientists involved in producing or reviewing the IPCC synthesis report, and very few are skeptics about global warming.

Dr. Ben Santer, he of the chiming cuckoo computer at Livermore Labs, is one of the world's primary authorities on global warming. One of the authors of the IPCC report, Santer is also, according to the journal Science, the leader of a scientific group that "directly implicates greenhouse warming by finding its geographic 'fingerprint' in the climate record of the past century." Dr. Santer's innovation is to program into the climate computers a cooling effect caused by the sulfur-fed haze that covers much of the Northern Hemisphere. When that sulfate aerosol pollution is taken into account, Santer says, "We clearly see the temperature change patterns that the models predict. Until that was factored in, it was hard to find convincing statistical evidence. It looks like we were missing an important part of the puzzle."

Santer describes himself as an analyzer of climate data, rather than a modeler himself. And he admits that the "whole issue of global warming is highly politically charged. It's certainly hard to achieve scientific consensus on an issue like this."

The IPCC, Santer says, addresses the current scientific uncertainties "in the best way possible. On the basis of my own research, I would say that we have indeed made a lot of progress in attempting to identify the human effect on climate." Santer compares the complex computer models he works with to "pieces of gothic architecture; they're highly complicated and made up of many different parts, reflecting changes in the Earth's surface, albedo [a measurement of the reflection of light], water vapor and temperature."

Santer admits that scientists who warn about impending global warming run the risk of being seen as Chicken Littles. "The challenge is to present the scientific uncertainties and still give people the sense that we understand something, that all is not impenetrable darkness," Santer says. "Climate is complex, and many things act on it." But Santer is on firm ground when he says that the politically motivated naysayers "ignore the incontrovertible fact that the C[O.sub.2] level in the atmosphere has increased by an order of 25 to 30 percent since the industrial revolution."

Probably the chief global warming naysayer is Dr. Richard Lindzen of MIT. He has called global warming "a largely political issue without scientific basis." Lindzen had been of the opinion that the cooling effect of water vapor in clouds cancels out the warming effect of C[O.sub.2], but no less a personage than Vice President Albert Gore, in his book Earth in the Balance, says that Lindzen withdrew that hypothesis in 1991.

Lindzen hasn't changed his opinion about global warming, though. And he's dismissive of IPCC's work. "Five years ago, IPCC wasn't sure about human effects on climate; now they've changed their minds and think they can see an effect," he says. "Their statement now is that all the changes are due to natural variability, that some part - which is unknown - might be due to man. But that's saying nothing. The predictions of global warming are based entirely on computer modeling results, and a lot of what you're seeing is defending models. It's become pretty clear that models are incapable of handling all the positive and negative feedbacks you'd need to make accurate forecasts."

Lindzen says he believes that the amount of plus-or-minus error built into the computer models is actually greater than the global warming deviation the scientists are looking for. "Are all the alarms about global warming based on anything?" Lindzen asks. "That's part of the infinitude of open questions. It's like the connection between coffee and thyroid cancer - you can't disprove it. But as something to worry about I'd certainly put global warming very low on a one-to-10 scale."

Dr. Jerry Mahlman, an affiliate professor at Princeton and director of its Geophysical Fluid Dynamics Laboratory, is one of those computer jocks that Lindzen waves impatiently away. His workstations are connected to a $100,000 Cray C90 16-processor supercomputer, 1,000 times more powerful than an Apple Power Book.

The important thing for Mahlman is that his climate data be seen as scientifically neutral, not political. "IPCC is trying to sort through all that political junk and arrive at a position that the vast majority of scientists can accept. Conservatives think it's a liberal panel; the greens think it's too crusty and conservative. But new information goes where new information goes, and no amount of screaming changes the scientific facts. IPCC is made up of human beings, and they're very aware of scientists like Oppenheimer and Lindzen sniping at each other from either end of the spectrum. It makes a good story. But the press is creating a controversy that is not real. We're trying to figure out where we're wrong, but we're not arguing about the fundamental science of the greenhouse effect."

But Mahlman is too much the scientist to agree with Oppenheimer of EDF that the IPCC report really is a smoking gun. "Is the planet warming up?" he asks. "Over the past 100 years, it has warmed up one degree Fahrenheit. Now the fun begins. Has the planet warmed up in direct response to increases in greenhouse gases? The answer is we cannot unambiguously prove that from the data." But he likes the odds. "The chances of this not happening are one in 10," he says. "It's a sucker bet at even odds. You'd win a civil trial on the evidence, but in a criminal case you might get a hung jury because of reasonable doubt."

Why There's Doubt

At the risk of being seen as too technical, Dr. Gary Russell, staff scientist at the Goddard Institute for Space Studies in New York City, can explain just why global warming is not definitively provable. "What's unclear are the feedback factors," he says. "Through our climate models, we're pretty sure about the amount of greenhouse gases being added to the atmosphere, and we can predict what will happen to it. But the further we go out in time, the estimates get weaker and are not as reliable. We've been measuring carbon dioxide and some trace gases since 1957 or 1959. But we have to make an assessment of what those gases will be in the future, and evaluate the current trend. We can only make educated guesses about how those gases will affect temperature, because they prevent a certain amount of thermal radiation from escaping the Earth's atmosphere."

Here's where the "feedback factors" get really complicated. If the Earth warms by one degree Fahrenheit, it can hold more water vapor, which is in itself a greenhouse gas. Everyone, Russell says, agrees that water vapor is a "positive" factor, contributing to more global warming. Another positive is the planet's snow and ice, which reflects sunlight back into space. When the planet warms, there's less frozen ice and snow and less reflection.

The effects of two other large feedback factors - clouds and the oceans' circulation - are in dispute. "We think we're doing everything right," says Russell, "but clouds, for instance, are very difficult because it matters whether they're high or low, whether it's day or night. They're reflective during the day and insulating at night. There are opportunities for minor feedback factors to throw off the modeling, and that's why we can't say it's a 100 percent thing. We're trying, and we're getting better at it."

Dr. Robert Giegengack, a professor of geology at the University of Pennsylvania, points out that weather predictions are still a relatively new science. "There was no decent thermometer until the 1700s," he says. "The first weather station opened in Paris in 1762. Most reconstructions of weather trends were not considered reliable until the 1850s."

Giegengack is, if not as much of a skeptic as Lindzen, at least wary of global warming claims. And even if the Earth is getting warmer and sea levels are rising, he doesn't think we should worry about it all that much. According to Giegengack, "Sea levels 130,000 years ago were 19 feet higher than they are now. And what kind of rise are we talking about now, a millimeter and a half a year? Talk to the Dutch, to people in Bangladesh, Tokyo and Manhattan - they've been handling that kind of problem for a long time."

Giegengack wonders where all the C[O.sub.2] is going. "We produce 6.2 billion tons a year from the burning of fossil fuels and from cement production. In addition, two billion tons are released as a result of tropical deforestation. In the atmosphere, the annual measured increase is 3.5 billion tons. That's five billion tons that aren't getting into the atmosphere. Where's the rest of it going? We know that some of it is going into the oceans, and some of it is being stored in forest lands. But the increase we're worrying about is smaller than the missing components. Our understanding of the carbon cycle is just not sufficient to tell us if the atmospheric C[O.sub.2] increases we're seeing are natural, natural plus artificial, or wholly artificial. One should take the computer models with the proverbial grain of salt."

The Historical Record

Skeptics like Lindzen and Giegengack can point out - and do - that global warming is nothing new. "Bob Berner at Yale will tell you that over the last 600 million years, C[O.sub.2] concentrations for most of that time were five times what they are today," Giegengack says.

And Dr. Robert Berner of Yale's Department of Geology and Geophysics does indeed say something like that. A geochemist, Berner studies the geological record through such arcana as silicate rock weathering. Though he appears to hate being drawn into popular science, he does admit that, 500 million years ago, the atmospheric C[O.sub.2] levels were 10 to 20 times what they are now. The exact reasons for this are complicated, Berner says, affected by plant growth, volcanic disturbance, amount of sunlight, mountain uplift and by climactic change itself. "C[O.sub.2] is both a cause of climate change and an effect of climate change," he says. "High C[O.sub.2] levels will warm up the world, causing more C[O.sub.2] to be produced. There's a natural balance between production and consumption, and that balance isn't perfect."

Even if we didn't dig up fossil fuels, Berner says, they'd eventually, through erosion and underground fires, produce greenhouse gases anyway. "But we're accelerating a natural process 100 times by burning fossil fuels," he says. Like the IPCC report, Berner thinks we can and should convert to other forms of energy, though he laughs at the idea that we're likely to stop using them altogether.

What's Ahead

The big question is, if greenhouse gases are really increasing at a rate dangerous to our planet, what are we going to do about it? Oppenheimer of EDF points out that "greenhouse gases continue to grow in both the industrial and developing worlds. The U.S. is falling short of the commitments it made as part of the 1992 Rio treaty, but the big moment of truth is the year 2000. Right now, Congress is slashing the budget for programs that initiate the Rio commitments. How irresponsible can our leaders be? We need to reduce our dependence on oil, clean up the air in our cities. If we're going to lick this problem, fossil fuel use needs to be cut in half in the next 50 or 100 years. By the middle of the next century, we need to be living more on solar energy than fossil fuels."

We're woefully short of the lofty goals that Oppenheimer describes. According to UN projections, of the 14 "developed" countries that account for 40 percent of global emissions, only the Czech Republic will actually reduce from 1990 levels by the year 2000. Consider it a victory if the rate of increase is cut.

People who are not inclined to believe in global warming as an imminent phenomenon will probably not change their minds because of the new IPCC report, Oppenheimer's description of it as a "smoking gun" notwithstanding. (Though the insurance industry, which stands to lose billions in claims, is taking global warming very seriously indeed; 30 industry reps descended on Washington last summer for a crash course on "The Implications of Climate Change." Greenpeace is also working the insurance angle.)

There are too many scientific variables to make computerized climate modeling infallible, and it's too easy to raise doubts. And, of course, as the Global Climate Coalition warns, the U.S. economy hangs in the balance. But if global warming is real, we'll find out about it in a very simple way: It will get warmer.

CONTACTS: Environmental Defense Fund, 257 Park Avenue South, New York, NY 10010/[phone]; Ozone Action, 1621 Connecticut Avenue NW, Washington, DC 20009/[phone]; Global Climate Coalition, 1331 Pennsylvania Avenue NW, Suite 1500, North Tower, Washington, DC 20004-1703/[phone]; Center for Science, Technology and Media, 6900 Wisconsin Avenue, Suite 700, Chevy Chase, MD 20815/[phone].

Research assistance by Chris Hayhurst.

RELATED ARTICLE: What, Me Worry About Global Warming?

What are the likely environmental consequences if global warming proves to be real? The International Panel on Climate Change (IPCC) predicts that global average temperatures could rise as much as six degrees Fahrenheit by the year 2100, a transformation equal to the warming that ended the last Ice Age.

According to Green peace, "Changing rainfall patterns will bring more droughts to some regions but more floods to others. Many plants and animals will face extinction. Water supplies will become less reliable in some regions, particularly in those already vulnerable. There may be more hurricanes in the tropics, and more windstorms in Europe. Entire island countries in the Pacific may disappear under the sea."

Writing in Massachusetts' Valley Advocate, Michael Pearlman, author of Hiroshima Forever: The Ecology of Mourning, predicts "the continued spread of disease; large-scale crop failures; unprecedented social havoc in a nuclear context; and the death of forests and wetlands, which will be overwhelmed by the pace and violence of climatic change and unable to adapt."

And if that isn't enough, Dr. Michael Oppenheimer of the Environmental Defense Fund (EDF) adds that "nearly a third of all forests would be stuck, perhaps fatally, in the wrong climate zone. Sea level could rise three times faster than over the last 100 years, flooding coastal zones used for habitation and agriculture, and beaches used for recreation. Agricultural shifts threaten to undermine food availability and increase malnutrition in poorer countries."

Specifically, scientists say, overall sea levels could rise up to three feet because of melting glaciers and water's natural expansion as it warms. Huge areas of low-lying land, including most Atlantic beaches in the U.S., several regions of China, and such island nations as the Maldives, the Seychelles and the Marshalls, would disappear entirely. Heat-related deaths would increase, as would the incidence of infectious diseases like malaria, encephalitis and yellow fever.

Should we worry about these dramatic predictions? Not according to Thomas Gale Moore, a senior fellow at the conservative Hoover Institution in California who, in a report posted on the World Wide Web, opines, "Global warming would in general be beneficial for mankind. Simple logic indicates that most of modern man's activities would be unaffected by a warming of five to nine degrees Fahrenheit."

- J.M.

JIM MOTAVALLI is the managing editor of E.