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February 23, 2007 6:30 AM
Novel science fiction on global warming.
By Patrick J. Michaels
This Sunday, Al Gore will probably win an Academy Award for his global-warming documentary An Inconvenient Truth, a riveting work of science fiction.
Inconvenient Truths 02/23
Public Disservice 07/26
The Global-Warming God 10/05
The main point of the movie is that, unless we do something very serious, very soon about carbon dioxide emissions, much of Greenland’s 630,000 cubic miles of ice is going to fall into the ocean, raising sea levels over twenty feet by the year 2100.
Where’s the scientific support for this claim? Certainly not in the recent Policymaker’s Summary from the United Nations’ much anticipated compendium on climate change. Under the U.N. Intergovernmental Panel on Climate Change’s medium-range emission scenario for greenhouse gases, a rise in sea level of between 8 and 17 inches is predicted by 2100. Gore’s film exaggerates the rise by about 2,000 percent.
Even 17 inches is likely to be high, because it assumes that the concentration of methane, an important greenhouse gas, is growing rapidly. Atmospheric methane concentration hasn’t changed appreciably for seven years, and Nobel Laureate Sherwood Rowland recently pronounced the IPCC’s methane emissions scenarios as “quite unlikely.”
Nonetheless, the top end of the U.N.’s new projection is about 30-percent lower than it was in its last report in 2001. “The projections include a contribution due to increased ice flow from Greenland and Antarctica for the rates observed since 1993,” according to the IPCC, “but these flow rates could increase or decrease in the future.”
According to satellite data published in Science in November 2005, Greenland was losing about 25 cubic miles of ice per year. Dividing that by 630,000 yields the annual percentage of ice loss, which, when multiplied by 100, shows that Greenland was shedding ice at 0.4 percent per century.
“Was” is the operative word. In early February, Science published another paper showing that the recent acceleration of Greenland’s ice loss from its huge glaciers has suddenly reversed.
Nowhere in the traditionally refereed scientific literature do we find any support for Gore’s hypothesis. Instead, there’s an unrefereed editorial by NASA climate firebrand James E. Hansen, in the journal Climate Change — edited by Steven Schneider, of Stanford University, who said in 1989 that scientists had to choose “the right balance between being effective and honest” about global warming — and a paper in the Proceedings of the National Academy of Sciences that was only reviewed by one person, chosen by the author, again Dr. Hansen.
These are the sources for the notion that we have only ten years to “do” something immediately to prevent an institutionalized tsunami. And given that Gore only conceived of his movie about two years ago, the real clock must be down to eight years!
It would be nice if my colleagues would actually level with politicians about various “solutions” for climate change. The Kyoto Protocol, if fulfilled by every signatory, would reduce global warming by 0.07 degrees Celsius per half-century. That’s too small to measure, because the earth’s temperature varies by more than that from year to year.
The Bingaman-Domenici bill in the Senate does less than Kyoto — i.e., less than nothing — for decades, before mandating larger cuts, which themselves will have only a minor effect out past somewhere around 2075. (Imagine, as a thought experiment, if the Senate of 1925 were to dictate our energy policy for today).
Mendacity on global warming is bipartisan. President Bush proposes that we replace 20 percent of our current gasoline consumption with ethanol over the next decade. But it’s well-known that even if we turned every kernel of American corn into ethanol, it would displace only 12 percent of our annual gasoline consumption. The effect on global warming, like Kyoto, would be too small to measure, though the U.S. would become the first nation in history to burn up its food supply to please a political mob.
And even if we figured out how to process cellulose into ethanol efficiently, only one-third of our greenhouse gas emissions come from transportation. Even the Pollyannish 20-percent displacement of gasoline would only reduce our total emissions by 7-percent below present levels — resulting in emissions about 20-percent higher than Kyoto allows.
And there’s other legislation out there, mandating, variously, emissions reductions of 50, 66, and 80 percent by 2050. How do we get there if we can’t even do Kyoto?
When it comes to global warming, apparently the truth is inconvenient. And it’s not just Gore’s movie that’s fiction. It’s the rhetoric of the Congress and the chief executive, too.
— Patrick J. Michaels is senior fellow in environmental studies at the Cato Institute and author of Meltdown: The Predictable Distortion of Global Warming by Scientists, Politicians, and the Media.
Al Gore Is a Greenhouse Gasbag
Penn professor Bob Giegengack has a few quibbles with the former VP on this whole global warming thing
By John Marchese
LUKEWARM: Says Gieg of Gore, "What he's doing is no less than the scare tactics used by people like Karl Rove." / Photo by Chris Crisman It’s the last day of November, which means winter begins in three weeks. Yet the temperature on the Penn campus is nearing 70 degrees, and it’s muggy. Walking to the offices of the Department of Earth and Environmental Science from a remote parking lot makes me sweaty. Global Warming.
Driving here this morning, I heard a report on WHYY from National Public Radio that the International Ski Federation was canceling races because there’s no snow in the Alps. Got to be Global Warming!
Yesterday, down the road in Washington, where the temperature was 16 degrees above normal, the Supreme Court heard arguments in a case in which 13 state governments are suing the Environmental Protection Agency to force the government to begin controlling carbon dioxide as a pollutant under the decades-old Clean Air Act. If that doesn’t happen, the states claim, the rising sea levels caused by greenhouse gases will rob them of coastline. GLOBAL WARMING!!
And this is just one ordinary day in the new normal. Even if daily weather has nothing to do with global warming, and even if the scientific debate about it is not quite done, its cultural moment has certainly begun. Insurance companies have stopped writing policies for coastline residents. A government report out of England warns that global warming may be so economically deleterious that it will make the upheaval of the Great Depression and World War II seem benign.
Michael Crichton has already dramatized the issue in a best-selling novel. Leonardo DiCaprio is working on a documentary on the subject. A recent Time magazine cover featured a polar bear in danger of drowning and the warning: “Be Worried. Be Very Worried.”
I’ve come to Penn to see the skeptic.
In Room 100 of the classic Christopher Wren-inspired Towne Building, Robert Giegengack seems much less than worried. The 67-year-old professor is preparing to give one of the semester’s final lectures to his 150-student class in environmental analysis, a popular science elective among Penn’s arts and sciences undergrads.
For decades, Giegengack was content to be a relatively obscure geologist who taught more than he published. Recently, though, he’s stepped into the swirling tempest surrounding global warming, in part because he says it’s not even one of the top 10 environmental problems we face. To make that point, he occasionally joins in a panel discussion, or gives a quote to a science writer. He’s thinking about writing something for one of the smarty-pants magazines. “I’ve always been interested in this question,” he says, “but when I first started working, no one cared — you couldn’t get an article published if you wanted to.” Now, though, “The public appetite for all this crap seems to be insatiable.”
Giegengack is a slim man of medium height, with a prominent nose and a very high forehead. “I traded my hair for eyeglasses,” he’s been known to say. In this weird late-fall weather, he’s dressed as if he might run off for a round of golf or a sail — khaki pants, striped dress shirt (short-sleeved) and boat shoes. His name is pronounced “GEEG-in-gack,” and over the nearly four decades he has taught at Penn, students have developed the habit of simply calling him “Gieg.”
Gieg is situated at a lectern in the pit of an amphitheater classroom. As the seats fill, he fiddles with his Mac laptop, where he has stored a PowerPoint presentation that covers today’s lecture. Before that, though, he runs a short clip from a Simpsons episode in which Bart and Lisa argue over whether water drains in different directions in the Southern and Northern hemispheres. Though Gieg has long been known as an entertaining lecturer, he’s not The Simpsons. The students laugh out loud at the clip, as does their professor. When the lights come back on, the professor assures them: “Bart will probably not be on the final.”
The class is a typical-seeming group, heavy on girls, some of whom wear ripped jeans and do-rags, others of whom are carefully made up and snappily dressed, pulling their notebooks from designer bags. Midway through the class, Gieg says, “Now it’s time for us to talk about the number one political/environmental issue of our time.” He reads a snippet from a New York Times editorial about the Supreme Court global-warming case.
“What I’m going to try to do the rest of today and also probably on Tuesday is bring you up to date on this. I’ll try to avoid editorializing or politicking. I’ll just tell you some stuff. Give you information. There’s lot’s of stuff, and it’s very complicated.”
Gieg gazes upward toward his young charges. “Every single one of you knows more about this than Al Gore,” he tells the undergrads. “And vastly more than anyone in this present administration.”
YOU REMEMBER AL GORE. Congressman, then senator from a political dynasty in Tennessee. Vice president for the eight years of the Clinton administration. President-elect of the United States for about 10 minutes, before being waylaid by the dangling chad. Since his bitter, disputed loss to George W. Bush, Gore has gone through some changes. He tried sporting a beard, reinvented himself as a media entrepreneur, hosted Saturday Night Live, gained a lot of weight. Then, last May, he burst back into the public eye as the star of a surprisingly successful documentary on global warming called An Inconvenient Truth. In a way that sometimes happens in America, Al Gore has come to personify an issue that until recently, most of us didn’t know we needed to know or care about. Oprah calls him “our Noah.” But if she’s going to get all ancient on us, Cassandra might be the better comparison.
Gore’s film has become the third highest grossing documentary ever, way behind Michael Moore’s Fahrenheit 9/11 but closing in on number two, the equally surprising March of the Penguins. An Inconvenient Truth is basically the video of a PowerPoint presentation that Gore had been giving for years, jazzed up with animation and film clips, but weighted by some treacly autobiographical segments that seem to have been left over from an Al Gore for President campaign film.
The new Al Gore, visibly more relaxed and likable than during his last campaign, basically says this:
Our world is habitable because some of the heat from the sun is held here by gases in the atmosphere that are descriptively labeled “greenhouse gases.” Carbon dioxide is one of the main components. Unfortunately, measurements over the past 30 years show a steep climb in carbon dioxide concentrations and happen to track closely a concurrent rise in the average temperature of the Earth. All that extra carbon dioxide, a.k.a. CO2, isn’t produced “naturally”; it’s mostly a result of mankind burning fossil fuels.
If the profligate use of fossil fuels continues and the carbon dioxide levels keep rising, the temperature of the Earth’s atmosphere and oceans will rise to calamitous heights, melting glaciers, disturbing water systems, and causing droughts, crop failures, and much stronger hurricanes and cyclones. Gore forecasts the worst-case scenario as “a nature walk through the Book of Revelation.”
But the real worst case that the once (and future?) politician presents is the breakup and melting of the two massive ice sheets that cover Greenland and Antarctica, an event that would raise global sea levels so much that many coastal areas would be under water. Using an animated seeping blue stain that’s reminiscent of how filmmakers once illustrated the progress of the Nazi regime, Gore shows large parts of San Francisco, Beijing, Shanghai and New York becoming submerged. The result, he says, will be tens of millions of “climate refugees.” It will make the upheaval caused by the flooding of New Orleans and its displaced persons seem like a walk in the park.
There’s no way to watch An Inconvenient Truth without getting worried — at least a little worried.
Not Bob Giegengack. He has described Al Gore’s documentary as “a political statement timed to present him as a presidential candidate in 2008.” And he added, “The glossy production is replete with inaccuracies and misrepresentations, and appeals to public fear as shamelessly as any other political statement that hopes to unite the public behind a particular ideology.” This from a guy who voted for Gore in 2000 and says he’d probably vote for him again.
Geologists by nature and training take a long-term view. The professor clicks a slide onto the classroom screen. It reads: “In 1958, Robert Giegengack first heard about Global Warming!”
There are a few chuckles in the classroom. Giegengack waits a beat for comic effect. “I said, ‘Big deal,’” he tells the class. “I lived in New England.”
He’d been born in Brooklyn, but spent much of his life in New Haven. After a false start studying civil engineering at Yale, Giegengack discovered geology and got hooked. He got a master’s degree in Colorado, then returned to Yale for a doctorate and focused his research on rocks and climate change. He arrived as a young assistant professor at Penn just about the time the first Earth Day in 1970 was reflecting — and driving — an interest in the environment. Giegengack got the assignment to set up the university’s environmental studies program, which he would run for more than three decades.
A few years ago, Giegengack told the Pennsylvania Gazette, the school’s alumni magazine, that the environmental analysis course he’s teaching today often attracts students who want to be environmental activists and carry picket signs outside the offices of the bad guys in the military-industrial complex. “But I want them to understand that these questions are enormously complex,” he went on.
Yes, they are. I ask Gieg for a private tutorial based on the lectures he gives his students to make them consider the scientific complications of climate change. We sit one afternoon at a conference table near his office, his laptop open and the PowerPoint ready to go. Charts appear, one after another.
Giegengack may have a personal 50-year perspective on global warming, but the time range he prefers to consult is more on the geologists’ scale. The Earth has been warming, he says, for about 20,000 years. We’ve only been collecting data on that trend for about 200 years. “For most of Earth history,” he says, “the globe has been warmer than it has been for the last 200 years. It has only rarely been cooler.” Those cooler periods have meant things like two miles of ice piled over much of what is now North America. Nothing to be nostalgic for.
The professor hits a button on his computer, and the really long-term view appears — the past 650,000 years. In that time, the Earth’s temperature has gone through regular cycles of rise and fall. The best explanation of those cycles was conceived by a Serbian amateur scientist named Milutin Milankovi´c. Very basically, Milankovi´c said this: The Earth’s orbit around the sun is more or less circular, but when other planets align in certain ways and their gravitational forces tug at the Earth, the orbit stretches into a more elliptical shape. Combined with the tilt of the Earth on its axis as it spins, that greater or lesser distance from the sun, plus the consequent difference in solar radiation that reaches our planet, is responsible for long-term climate change.
NOW TO THE CRUX OF THE Al Gore argument — the idea that rising carbon dioxide levels are causing an increase in temperature.
To determine temperatures and carbon dioxide levels in the distant past, scientists rely on what they call the “proxy record.” There weren’t thermometers. So researchers drill deep down into the Antarctic ice sheet and the ocean floor and pull up core samples, whose varying chemical elements let them gauge both the CO2 levels and the temperatures of the distant past.
Gieg clicks a button, and three charts come together. The peaks and valleys of the Milankovi´c cycles for planetary temperature align well with the ocean-floor estimates, and those match closely the records of carbon dioxide concentrations and temperature indications from ice cores. So, the professor maintains, these core samples from the polar ice and ocean floor help show that the Earth’s temperature and the levels of carbon dioxide in the atmosphere have been in lockstep for tens of thousands of years.
Of course, that was long before anybody was burning fossil fuels. So Giegengack tells his students they might want to consider that “natural” climatic temperature cycles control carbon dioxide levels, not the other way around. That’s the crux of his argument with Gore’s view of global warming — he says carbon dioxide doesn’t control global temperature, and certainly not in a direct, linear way.
Gieg has lots more slides to show. He points out that within his lifetime, there was a three-decade period of unusually low temperatures that culminated in the popular consciousness with the awful winter of 1976-77. Back then, scientists started sounding the alarm about a new ice age.
Of course, it’s long been thought that the world would end either in fire or in ice. These days, the scientists are shouting fire. And in all his years around environmental issues, Giegengack has never heard so much shouting. “I don’t think we’re going to have a rational discussion of this question in the present environment,” he says. “The scientists are mad because they think nobody in Washington is listening to them. So it’s all either apocalyptic disaster or conflict of interest. If you suggest that we’re not going to hell in a handbasket because the rate of global warming is low compared to so many other environmental issues that we’re enduring, then you’re accused of being in the employ of the oil companies and you’re labeled a Republican.”
Giegengack says things started to get this way around 1988. There was a horrifically hot summer season that year, and drought led to seemingly apocalyptic fires in Yellowstone National Park. Something in those fires was galvanizing. Al Gore, who made his first run for president in 1988, published his first environmental jeremiad, Earth in the Balance, a few years later. Around the same time, the newly formed Intergovernmental Panel on Climate Change was making noise, and governments met first in Rio de Janeiro and then in Japan to forge agreements on “targets” for carbon emission cutbacks. The resulting Kyoto Protocol has been ratified by most of the countries on Earth — none of which are doing very well at actually meeting the target cutbacks — but very notably not by the United States.
“WOW," SAYS GIEG AS Al Gore struts onto the stage of The Oprah Winfrey Show. “He looks like he’s had Botox or something.”
It’s afternoon in America, and Oprah is offering her millions of viewers a class with Dr. Gore that the producers are calling Global Warming 101. I’ve asked Gieg to watch it with me.
The show turns out to be pretty much a synopsis of An Inconvenient Truth, with Gore clicking through his hyper-produced PowerPoint program and Oprah exclaiming “Wow! Wow!” with dramatic concern. To dramatize the melting of the floating ice cap at the North Pole, Gore has inserted an animated clip of a polar bear swimming desperately to a tiny ice floe that isn’t strong enough to hold him. Global warming is drowning helpless bears. Oprah thinks it’s the coolest and saddest thing in Gore’s whole movie. Gieg starts shouting:
“We don’t know that. We don’t know that! We don’t know that polar bears haven’t drowned in every interglacial period. Nobody was watching them back then.”
It’s got to be a frustrating experience, seeing a topic you’ve spent some 50 years studying turned into an Oprah episode. “I like her,” Gieg says. “She’d beat Al Gore if she ran for president.”
Then Gore clicks again to dramatic footage of a collapsing polar ice shelf. “That’s irresponsible,” Gieg says. “What he’s doing is no less than the scare tactics used by people like Karl Rove.”
Oprah says she had no idea all these terrible things were happening until she interviewed the noted authority Leonardo DiCaprio. Gore is now into his segment on the melting of glaciers and the possibility of catastrophe if Greenland goes, or parts of Antarctica. The deadly blue water seeping over the world’s great lowland cities comes onto the screen.
“Sea level is rising,” Giegengack agrees, switching off the sound. But, he explains, it’s been rising ever since warming set in 18,000 years ago. The rate of rise has been pretty slow — only about 400 feet so far. And recently — meaning in the thousands of years — the rate has slowed even more. The Earth’s global ocean level is only going up 1.8 millimeters per year. That’s less than the thickness of one nickel. For the catastrophe of flooded cities and millions of refugees that Gore envisions, sea levels would have to rise about 20 feet.
“At the present rate of sea-level rise,” Gieg says, “it’s going to take 3,500 years to get up there. So if for some reason this warming process that melts ice is cutting loose and accelerating, sea level doesn’t know it. And sea level, we think, is the best indicator of global warming.”
By now, Al Gore is taking Oprah on an anti-global-warming shopping trip, buying compact fluorescent light bulbs and programmable thermostats.
We should all buy those things, the professor says, but he’s had just about enough of Dr. Gore. “See,” Gieg says, “the thing he doesn’t mention is that there are 2.4 billion people in India and China who have launched a campaign that will increase their energy consumption by a factor of 10. No matter what we do. If we somehow cut our CO2 emissions in half, you wouldn’t be able to measure the difference because of the role played by India and China.
“It’s over. If CO2 is the problem, we’ve already lost.”
When Gieg gets to this point in his argument, as he often does when talking about global warming, he gets a little frustrated. “I always get sidetracked because, first of all, the science isn’t good. Second, there are all these other interpretations for what we see. Third, it doesn’t make any difference, and fourth, it’s distracting us from environmental problems that really matter.” Among those, Gieg says, are the millions of people a year who die from smoking and two million people a year who die because they don’t have access to clean water.
Bob Giegengack likes to point out that there was a time when people like him were called natural philosophers, and he wouldn’t mind a return to the days when scientists spent more time asking questions and less time testifying before committees.
But that won’t happen soon. Now that Democrats run Congress again, they’re likely to ramp up the hearings to chide the Republicans for what they see as nearly a decade of stonewalling and misinformation on global warming. After all, the outgoing chairman of the Senate Committee on the Environment, Oklahoma Republican James Inhofe, ignited a wildfire in the groves of environmentalism when he called the idea of catastrophic global warming a “hoax.”
Movie stars will continue to move in on the action. And look for Al Gore to keep rolling along as the Energizer Bunny of global warming, beating his drum incessantly, powered by a carbon-neutral battery.
In the long view, a geologist like Giegengack can take some comfort in, well, the long view. “There’s all this stuff about saving the planet,” he says. “The Earth is fine. The Earth was fine before we got here, and it’ll be fine long after we’re gone.”
That will probably be on the final.
John Marchese is a contributing writer. His book The Violin Maker: Finding a Centuries-Old Tradition in a Brooklyn Workshop will be published in the spring.
Comments on this story? Please send them to us.
Originally published in Philadelphia Magazine, February 2007.
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Don't Believe the Hype
Al Gore is wrong. There's no "consensus" on global warming.
BY RICHARD S. LINDZEN
Sunday, July 2, 2006 12:01 a.m. EDT
According to Al Gore's new film "An Inconvenient Truth," we're in for "a planetary emergency": melting ice sheets, huge increases in sea levels, more and stronger hurricanes, and invasions of tropical disease, among other cataclysms--unless we change the way we live now.
Bill Clinton has become the latest evangelist for Mr. Gore's gospel, proclaiming that current weather events show that he and Mr. Gore were right about global warming, and we are all suffering the consequences of President Bush's obtuseness on the matter. And why not? Mr. Gore assures us that "the debate in the scientific community is over."
That statement, which Mr. Gore made in an interview with George Stephanopoulos on ABC, ought to have been followed by an asterisk. What exactly is this debate that Mr. Gore is referring to? Is there really a scientific community that is debating all these issues and then somehow agreeing in unison? Far from such a thing being over, it has never been clear to me what this "debate" actually is in the first place.
The media rarely help, of course. When Newsweek featured global warming in a 1988 issue, it was claimed that all scientists agreed. Periodically thereafter it was revealed that although there had been lingering doubts beforehand, now all scientists did indeed agree. Even Mr. Gore qualified his statement on ABC only a few minutes after he made it, clarifying things in an important way. When Mr. Stephanopoulos confronted Mr. Gore with the fact that the best estimates of rising sea levels are far less dire than he suggests in his movie, Mr. Gore defended his claims by noting that scientists "don't have any models that give them a high level of confidence" one way or the other and went on to claim--in his defense--that scientists "don't know. . . . They just don't know."
So, presumably, those scientists do not belong to the "consensus." Yet their research is forced, whether the evidence supports it or not, into Mr. Gore's preferred global-warming template--namely, shrill alarmism. To believe it requires that one ignore the truly inconvenient facts. To take the issue of rising sea levels, these include: that the Arctic was as warm or warmer in 1940; that icebergs have been known since time immemorial; that the evidence so far suggests that the Greenland ice sheet is actually growing on average. A likely result of all this is increased pressure pushing ice off the coastal perimeter of that country, which is depicted so ominously in Mr. Gore's movie. In the absence of factual context, these images are perhaps dire or alarming.
They are less so otherwise. Alpine glaciers have been retreating since the early 19th century, and were advancing for several centuries before that. Since about 1970, many of the glaciers have stopped retreating and some are now advancing again. And, frankly, we don't know why.
The other elements of the global-warming scare scenario are predicated on similar oversights. Malaria, claimed as a byproduct of warming, was once common in Michigan and Siberia and remains common in Siberia--mosquitoes don't require tropical warmth. Hurricanes, too, vary on multidecadal time scales; sea-surface temperature is likely to be an important factor. This temperature, itself, varies on multidecadal time scales. However, questions concerning the origin of the relevant sea-surface temperatures and the nature of trends in hurricane intensity are being hotly argued within the profession.
Even among those arguing, there is general agreement that we can't attribute any particular hurricane to global warming. To be sure, there is one exception, Greg Holland of the National Center for Atmospheric Research in Boulder, Colo., who argues that it must be global warming because he can't think of anything else. While arguments like these, based on lassitude, are becoming rather common in climate assessments, such claims, given the primitive state of weather and climate science, are hardly compelling.
A general characteristic of Mr. Gore's approach is to assiduously ignore the fact that the earth and its climate are dynamic; they are always changing even without any external forcing. To treat all change as something to fear is bad enough; to do so in order to exploit that fear is much worse. Regardless, these items are clearly not issues over which debate is ended--at least not in terms of the actual science.
A clearer claim as to what debate has ended is provided by the environmental journalist Gregg Easterbrook. He concludes that the scientific community now agrees that significant warming is occurring, and that there is clear evidence of human influences on the climate system. This is still a most peculiar claim. At some level, it has never been widely contested. Most of the climate community has agreed since 1988 that global mean temperatures have increased on the order of one degree Fahrenheit over the past century, having risen significantly from about 1919 to 1940, decreased between 1940 and the early '70s, increased again until the '90s, and remaining essentially flat since 1998.
There is also little disagreement that levels of carbon dioxide in the atmosphere have risen from about 280 parts per million by volume in the 19th century to about 387 ppmv today. Finally, there has been no question whatever that carbon dioxide is an infrared absorber (i.e., a greenhouse gas--albeit a minor one), and its increase should theoretically contribute to warming. Indeed, if all else were kept equal, the increase in carbon dioxide should have led to somewhat more warming than has been observed, assuming that the small observed increase was in fact due to increasing carbon dioxide rather than a natural fluctuation in the climate system. Although no cause for alarm rests on this issue, there has been an intense effort to claim that the theoretically expected contribution from additional carbon dioxide has actually been detected.
Given that we do not understand the natural internal variability of climate change, this task is currently impossible. Nevertheless there has been a persistent effort to suggest otherwise, and with surprising impact. Thus, although the conflicted state of the affair was accurately presented in the 1996 text of the Intergovernmental Panel on Climate Change, the infamous "summary for policy makers" reported ambiguously that "The balance of evidence suggests a discernible human influence on global climate." This sufficed as the smoking gun for Kyoto.
The next IPCC report again described the problems surrounding what has become known as the attribution issue: that is, to explain what mechanisms are responsible for observed changes in climate. Some deployed the lassitude argument--e.g., we can't think of an alternative--to support human attribution. But the "summary for policy makers" claimed in a manner largely unrelated to the actual text of the report that "In the light of new evidence and taking into account the remaining uncertainties, most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations."
In a similar vein, the National Academy of Sciences issued a brief (15-page) report responding to questions from the White House. It again enumerated the difficulties with attribution, but again the report was preceded by a front end that ambiguously claimed that "The changes observed over the last several decades are likely mostly due to human activities, but we cannot rule out that some significant part of these changes is also a reflection of natural variability." This was sufficient for CNN's Michelle Mitchell to presciently declare that the report represented a "unanimous decision that global warming is real, is getting worse and is due to man. There is no wiggle room." Well, no.
More recently, a study in the journal Science by the social scientist Nancy Oreskes claimed that a search of the ISI Web of Knowledge Database for the years 1993 to 2003 under the key words "global climate change" produced 928 articles, all of whose abstracts supported what she referred to as the consensus view. A British social scientist, Benny Peiser, checked her procedure and found that only 913 of the 928 articles had abstracts at all, and that only 13 of the remaining 913 explicitly endorsed the so-called consensus view. Several actually opposed it.
Even more recently, the Climate Change Science Program, the Bush administration's coordinating agency for global-warming research, declared it had found "clear evidence of human influences on the climate system." This, for Mr. Easterbrook, meant: "Case closed." What exactly was this evidence? The models imply that greenhouse warming should impact atmospheric temperatures more than surface temperatures, and yet satellite data showed no warming in the atmosphere since 1979. The report showed that selective corrections to the atmospheric data could lead to some warming, thus reducing the conflict between observations and models descriptions of what greenhouse warming should look like. That, to me, means the case is still very much open.
So what, then, is one to make of this alleged debate? I would suggest at least three points.
First, nonscientists generally do not want to bother with understanding the science. Claims of consensus relieve policy types, environmental advocates and politicians of any need to do so. Such claims also serve to intimidate the public and even scientists--especially those outside the area of climate dynamics. Secondly, given that the question of human attribution largely cannot be resolved, its use in promoting visions of disaster constitutes nothing so much as a bait-and-switch scam. That is an inauspicious beginning to what Mr. Gore claims is not a political issue but a "moral" crusade.
Lastly, there is a clear attempt to establish truth not by scientific methods but by perpetual repetition. An earlier attempt at this was accompanied by tragedy. Perhaps Marx was right. This time around we may have farce--if we're lucky.
Mr. Lindzen is the Alfred P. Sloan Professor of Atmospheric Science at MIT.