The year 2005 has been the hottest year on record for the planet, hotter than 1998, 2002, 2004, and 2003. More importantly, perhaps, this has been the autumn when the planet has shown more clearly than before just what that extra heat means. Consider just a few of the findings published in the major scientific journals during the last three months:

—Arctic sea ice is melting fast. There was 20 percent less of it than normal this summer, and as Dr. Mark Serreze, one of the researchers from Colorado’s National Snow and Ice Data Center, told reporters, “the feeling is we are reaching a tipping point or threshold beyond which sea ice will not recover.” That is particularly bad news because it creates a potent feedback effect: instead of blinding white ice that bounces sunlight back into space, there is now open blue water that soaks up the sun’s heat, amplifying the melting process.

—In the tundra of Siberia, other researchers report that permafrost has begun to melt rapidly, and, as it does, formerly frozen methane—which, like the more prevalent carbon dioxide, acts as a heat-trapping “greenhouse gas”—is escaping into the atmosphere. In some places last winter, the methane bubbled up so steadily that puddles of standing water couldn’t freeze even in the depths of the Russian winter.

—British researchers, examining almost six thousand soil borings across the UK, found another feedback effect. Warmer temperatures (growing seasons now last eleven days longer at that latitude) meant that microbial activity had increased dramatically in the soil. This, in turn, meant that much of the carbon long stored in the soil was now being released into the atmosphere. The quantities were large enough to negate all the work that Britain had done to switch away from coal to reduce carbon in the atmosphere. “All the consequences of global warming will occur more rapidly,” said Guy Kirk, chief scientist on the study. “That’s the scary thing. The amount of time we have got to do something about it is smaller than we thought.”

Such findings—and there are more like them in virtually every issue of Science and Nature—came against the backdrop of Hurricanes Katrina and Rita, and the now record-breaking Atlantic storm season that has brought us back around the alphabet and as far as Hurricane Epsilon. Because hurricanes draw their power from the warm water in the upper layers of the sea’s surface, this bout of storminess served as a kind of exclamation point to a mid-August paper by the MIT researcher Kerry Emmanuel demonstrating that such storms have become more powerful and long-lasting, and would likely continue to increase in destructiveness in the future.

But the hurricanes also demonstrated another fact about global warming, this one having nothing to do with chemistry or physics but instead with politics, journalism, and the rituals of science. Climate change somehow seems unable to emerge on the world stage for what it really is: the single biggest challenge facing the planet, the equal in every way to the nuclear threat that transfixed us during the past half-century and a threat we haven’t even begun to deal with. The coverage of Katrina’s aftermath, for instance, was scathing in depicting the Bush administration’s incompetence and cronyism; but the President—and his predecessors—were spared criticism for their far bigger sin of omission, the failure to do anything at all to stanch the flood of carbon that America, above all other nations, pours into the atmosphere and that is the prime cause of the great heating now underway. Though Bush has been egregious in his ignorance about climate change, the failure to do anything about it has been bipartisan; Bill Clinton and Al Gore were grandly rhetorical about the issue, but nonetheless presided over a 13 percent increase in America’s carbon emissions.

That lack of preparation and precaution dwarfs even the failure to prepare for the September 11 attacks, and its effects will be with us far longer. It’s not, of course, that America could in two decades have prevented global warming. But we could have begun taking the steps to keep it from spinning entirely out of control, steps that grow ever more difficult to take with each passing season. The books under review, though neither deals directly with the politics of global warming, help us understand some of the reasons why we’ve so far done so little.

The best of the two—indeed, one of the best books yet published on climate change—is Mark Bowen’s Thin Ice, which describes the science of global warming through the experience of the Ohio State University scientist Lonnie Thompson, the preeminent explorer of tropical and semitropical glaciers today, and the principal decoder of the secrets trapped in their ice. A minor defect is that the book was clearly designed to sell to readers of Jon Krakauer’s classic Everest account, Into Thin Air—the title and the cover are bizarrely similar. And because of that decision, too much space is devoted to Thompson’s adventures in the “death zone” above 18,000 feet on various Andean and Himalayan peaks, and too many tales are told about the Sherpas who make the expeditions possible and the hot-air balloons designed to float ice cores back to the base of the mountain before they could melt. These stories make the book needlessly long and distractingly repetitive, and detract a little from its emphasis on glaciers and what is happening to them.


But only a little. Bowen is one of the few people who could have written this book. Himself an expert climber who has written for popular magazines like Climbing, he also has a Ph.D. in physics from MIT. He has been able to climb mountains along with Thompson to examine the glaciers and explain both the scientific and political consequences of their melting.

For many years, scientists trying to reconstruct past climate history have studied glaciers. Since each year’s snowfall lies in a distinct layer, a core sample from such an ice field can be read much like a tree ring to distinguish long-term trends in weather. Moreover, small bubbles of air trapped in the ice can be sampled to provide a record of atmospheric conditions from any time in the past. One can tell from them how much carbon dioxide was in the atmosphere and what the weather was like—a Siberian core extracted in the 1980s demonstrated a perfect correlation between fluctuations in temperature and carbon dioxide levels and helped to embolden a few researchers to make the first global warming forecasts with real confidence.

For many years, researchers concentrated on taking core samples from alpine and polar ice—they were relatively easy to get to, and no one thought that high mountain ice in the equatorial zones would yield much interesting information because the tropics were seen as unvarying from year to year and hence climatologically dull. But beginning in the 1970s Thompson and his team began perfecting the techniques of drilling long, thin cores from the high and wild glaciers of Peru, Ecuador, Nepal, and Tibet, and then examining them in their laboratory in Columbus. They also began to translate the information latent in the cores.

The aim of their research was to figure out what had driven changes in the earth’s climate in the past—how and why ice ages emerged and retreated, why there have been smaller but abrupt swings back and forth in climate even during the current interglacial period. Thompson has done much to demonstrate that changes in tropical regions—which account, after all, for half the world’s surface—drive the process. Many of his findings conflicted with other research that seemed to show that events in the north Atlantic—particularly the waxing and waning of warm deep ocean currents—were the chief cause of rapid climate change in times past.

An immense amount of scientific effort (and, as Bowen makes amusingly clear, scientific vitriol) has been spent on this topic, with much debate about whether the principal causes of climate change have been in the Gulf Stream or the Indonesian Warm Pool or somewhere else altogether. But what eventually becomes clear, as Bowen tells this long story, is essentially how irrelevant it is to the current climate problem. By burning coal and gas and oil in such enormous amounts, we have raised the carbon dioxide level in the atmosphere far above what it has ever been during even the very long period one can study with ice cores. As such, a brand-new experiment is taking place, one that is out of control.

The second half of Bowen’s book, interspersed throughout his tale of adventure at high altitudes but only loosely related to Thompson and his fieldwork, is a history of the realization that a vast change was taking place. It is the best compact history of the science of global warming I have read. Bowen begins, appropriately, with nineteenth-century scientists like John Tyndall and Svante Arrhenius, Europeans who began to understand how carbon dioxide acted as a heat-trapping gas in the atmosphere and who began to worry about the amounts of it that a newly industrialized society was spewing out of its stacks.

The story takes on more urgency in the 1950s, when oceanographers like Roger Revelle and Hans Suess undertook more concentrated speculation and when the environmental scientist Charles Keeling investigated the effects of CO2, taking actual measurements with a CO2 detector on the slopes of Mauna Loa in Hawaii.1 He was soon able to show that the gas was indeed accumulating in the atmosphere, and doing so rapidly. (Pre–industrial revolution concentrations of CO2 were about 275 parts per million; by the late 1950s the number was 315, and today it is nearly 380.)


The story of greenhouse science continued in the 1970s and 1980s, as scientists began developing global climate models that attempted to forecast what the new chemicals would mean for the planet. And it reached a high point in the early summer of 1988 when one of the most important of those climate modelers, a NASA scientist named James Hansen, appeared before a hearing of the Senate Committee on Energy and Natural Resources. The United States was enduring one of the great heat waves in its history:

Barges were stranded by the thousands in the Mississippi River. Civil War vessels last seen when Confederate troops scuttled them on their retreat from Vicksburg rose above the surface of the Big Muddy, a Mississippi tributary. The West experiences the worst forest fires in recorded history.

Against that backdrop, Hansen was given fifteen minutes to testify. He made three points: that he was “99 percent confident” that the earth was warming; that the warming could be traced with “a high degree of confidence” to the greenhouse effect; and that in his model the greenhouse effect was already strong enough to increase the odds of extreme summer heat and drought in the US. He was careful not to say that the heat wave of 1988 was the result of global warming (a claim that would never be possible for any particular hot spell or drought or hurricane); but he said something very important to a group of reporters as he left the hearing: “It’s time to stop waffling so much and say that the greenhouse effect is here and is affecting our climate now.”

That was the moment at which the greenhouse era really began. As a NASA employee, Hansen had shown great courage in speaking straightforwardly, which earned him endless trouble from his bosses in the federal government (the next year they tried to rewrite his congressional testimony until then-Senator Al Gore stopped them). But it also earned him contempt from his fellow scientists. In Bowen’s words,

They all objected to his simplification, his lack of caution, his disregard for the formal, highly qualified—one could even say codified—manner in which scientific conclusions are stated in the peer-reviewed journals.

If Hansen had succeeded temporarily in putting the issue before the public in 1988, “other forces had quickly swept it away.” Some of those forces came from industry—as Ross Gelbspan chronicled in his excellent 1997 book The Heat Is On, the coal and oil industry took up the work of disinformation in earnest, finding a few scientists and scientific hangers-on to write Op-Ed pieces and appear on talk shows to provide a “balanced” view. Journalism proved unequal to the task of separating scientific consensus from minor or trivial dissent; almost every story about global warming was accompanied by an obligatory statement of denial.

Science, on the other hand, both rose to the occasion and failed badly. The world’s climatologists organized themselves into the Intergovernmental Panel on Climate Change, or IPCC, in those heady months of 1988. With large government funding that was partly made available because of Hansen’s warnings, the panels of experts soon had a vast collection of studies and computer models to pore over. And though the IPCC’s procedures were byzantine—they relied, Bowen writes, on “a peer review process…incalculably more cumbersome than anything ever applied to a scientific issue before”—the group eventually managed to reach a potent conclusion. By 1995, the IPCC was ready to conclude that “the balance of evidence suggests that there is a discernible human influence on global climate.” This result was remarkable: more than a thousand scientists, working through a process that allowed much political input from governments concerned to deny global warming, nonetheless found the evidence so overwhelming that they were able to state that one species, ours, was now changing pretty much everything on the face of the planet.

But at the same time, the conclusions were watered down and over-hedged, playing at least as much into the hands of the few remaining skeptics, who seized on every possible opportunity to dampen public concern. The scientific method, pursued in this fashion, seemed unequal to the gravity of the task at hand. Bowen writes, “I believe it is fair to say that serious scientific debate about the existence and potential danger of human-induced global warming died with that statement.” That is true—but it’s also true that it contributed remarkably little to the larger public debate, especially in the US. And that’s a failure for which scientists bear some of the blame.

Bowen quotes Hansen:

The scientific method does require that you continually question the conclusions that you draw and put caveats on the conclusion—but that can be misleading to the public. It seems to me that when we talk to the public we have to try to give a summary. And it’s not easy for most scientists to do—and not easy for me.

Clearly, for the mild-mannered Hansen, who has no taste for public controversy, it was not easy. But he did it. And for that, as well as for his original scientific work, he deserves not only enormous credit but also, I would suggest, the Nobel Prize, perhaps the first joint Chemistry-Peace award.

By contrast, when Bowen first interviewed Thompson in 1997 on the slopes of the highest mountain in Bolivia, he found him reticent to a fault:

He hid behind [the] details. He would not come out with a grand pronouncement about global warming…. He may have been holding back out of fear that I would distort his words, but I think he was also looking over his shoulder at his academic peers, aiming to duck the potshots that inevitably flew in those days when anyone walked out on a scientific limb and said in public what nearly all of them knew inside.

It would be, he writes, “almost a year and a half before Lonnie would carefully open up.”

But through his talks with Bowen, and also more and more with policymakers and other journalists, Thompson has performed a very valuable public service—more valuable, in some ways, than his research into paleoclimatology, interesting as that is. Thompson’s most important scientific contribution is his simplest: by going back year after year to tropical glaciers in order to take core samples for his “real” work, he has been able to document the astonishing speed with which those glaciers are disappearing. His photographs documenting this trend have been valuable in persuading people to take global warming seriously. There is something alarming and undeniable about change occurring across the globe that can be measured from one year to the next, for instance, the Qori Kalis glacier on Quelccaya, which Thompson has been visiting for thirty years:

They always camp in the moraine by the large boulder that Qori Kalis was pushing downhill when Lonnie first saw it…in 1974. An eighteen-acre lake now lies between the boulder and receding glacial margin, a lake that did not exist as recently as 1987.

And the loss was accelerating. One set of photos taken in 1992

demonstrated that the tongue [of the glacier] had retreated three times faster over the previous eight years than it had in the twenty years before that. Volume loss, which takes thinning into account, had grown by a factor of seven. More images taken in 1998 showed that the retreat had increased by another factor of three in the intervening five years.

Thompson estimates that the entire Quelccaya ice cap, which thirty years ago covered twenty-seven square miles and was five hundred feet deep at its 18,000-foot summit, will die before he does.

Perhaps Thompson’s most dramatic contribution to the public debate over global warming came in February 2001 when he told a session at the annual meeting of the American Association for the Advancement of Science that the snows on the top of Mt. Kilimanjaro would disappear within twenty years and that “little can be done to save them.” That image stuck in people’s minds—it was at least as important as the near-simultaneous release of the IPCC’s next assessment, which was more forthright than ever in its declaration that “most of the warming observed over the last 50 years is attributable to human activities” and in its prediction that the planet’s average temperature might increase as much as ten degrees Fahrenheit before the century was out.

But by that point George Bush had been elected president of the United States, and the issue of climate change had disappeared almost entirely—and with it the chance of altering the early trajectory of development in India and particularly China, which are now starting to rival American contributions to the earth’s carbon overload. With his eventual willingness to speak unambiguously, Thompson joined the list of courageous scientists, men like Hansen, or Harvard’s James McCarthy, who several years ago reported the shock of seeing open water at the North Pole. But it’s clear to him, as to most of his colleagues, that our understanding has come very late. “I think we’d better start getting used to the idea of living in a hotter world,” he tells Bowen in a barroom conversation one day in Kenya.

Scientists are by training and nature conservative and…have probably underestimated our impact. Fifty years from now—I hope I’m wrong—I think you may be living in a world where you don’t go outside between one and four in the afternoon.

At this stage, our best hope is simply to keep the warming process from accelerating to such an extent that it gets entirely out of control.

If the dry language of science has sometimes been an impediment to action, the language of emotion has its own dangers, as can be seen from Alanna Mitchell’s Dancing at the Dead Sea, a book thick with sentiment. Mitchell, formerly a reporter with Toronto’s Globe and Mail, was in 2000 “named the best environmental reporter in the world” by the Reuters Foundation. Something has apparently happened in the years since, because her book is filled with clichés (stupid natives in Madagascar, wise natives in the Arctic) and with unlikely events (a lone man sneaking out of a protected forest carrying “a massive old growth tree balanced on his shoulder”). About her own fear of being attacked by tropical fishes, she writes:

It’s clear to me that unless I swim with the piranhas, I will be not only consumed by fear but also untouched by the hope I seek. I will be unable to believe that humans, who I know have given up even such ingrained practices as slavery and cannibalism, will also give up the fable that they can keep harming the earth.

Still, she raises an important question. Every time she corners a scientist—the veteran Oxford environmental researcher Norman Meyers, the great diver and marine biologist Sylvia Earle, the eminent conservationist Russell Mittermeier—she asks, “Are humans a suicidal species?” They mostly dismiss her question with some reassuring words to the effect that we can still make up our minds to do better. But in fact it’s a question that in some way or another needs to be near the center of our public debates. It rose for the first time in the wake of Hiroshima and Nagasaki; for a while, many people seemed to expect an Armageddon-like nuclear exchange, and then they seemed to discount the possibility. The attacks on New York and Washington at the beginning of this millennium have raised the question of our being a suicidal species again.

It is also the question raised by our environmental predicament, and Mitchell deserves credit for risking the scorn of reviewers by bringing it into the open. She quotes President Bush, a few weeks after taking office, explaining why he’s opting out of the Kyoto protocols, the only official international attempt to deal with global warming:

I will explain as clearly as I can, today and every other chance I get, that we will not do anything that harms our economy…. That’s my priority. I’m worried about the economy.

It’s not as if Bush is alone in this thought. And it does seem to epitomize the danger that the satisfactions of consumer life and business success have become almost sacred while the physical world now turning to chaos before our eyes is taken for granted, and not seen as the reality that must be faced.2

It’s to this question of reality that Gretel Ehrlich turns her formidable talent in The Future of Ice, recently published in paperback.3 Like Thompson, she is fascinated by ice—her “journey into the cold” takes her from Greenland to Argentina—and she provides what may be a kind of obituary for the planet’s ice regions, and their special forms of life, written while they still exist. It is, she says, a “cry for help—not for me, but for the tern, the ice cap, the polar bear, and the lenga forest; for the river of weather and the ways it chooses to be born.”4

It is hard not to approach this year’s oncoming winter in an elegiac mood, with the testimony of Thompson’s ice cores and the Arctic sea ice data and Ehrlich’s account making the season’s natural and lovely darkness seem suddenly somber. We are forced to face the fact that a century’s carelessness is now melting away the world’s storehouses of ice, a melting whose momentum may be nearing the irreversible. It’s as if we were stripping the spectrum of a color, or eradicating one note from every octave. There are almost no words for such a change: it’s no wonder that scientists have to struggle to get across the enormity of what is happening.

This Issue

January 12, 2006