In January 1998 an international team or scientists was gathered at the coldest place on earth: a lonely Russian research station known as Vostok, on the vast ice sheet atop eastern Antarctica. They finished boring a hole 11,775 feet deep and brought to the surface the last segment of an ice core, containing the oldest sample of the earth's atmosphere ever collected. About a yard long and four inches in diameter, this cylinder of ice was labeled, slipped into a cardboard tube and, with about 3,600 other sections of the core, stored in a pit with a temperature of -67 degrees Fahrenheit.
A month later, the scientists shipped samples of the ice to their laboratories in France, Russia and the United States for study. What they found, and later wrote about in Science and Nature, two of the most reputable scientific journals, has changed the debate on the pre-eminent environmental issue of our time. The air bubbles in the ice yielded compelling evidence that since the Industrial Revolution, heat-trapping gases in our atmosphere have increased in amounts unprecedented in almost half a million years. "Man's activity has changed the atmosphere drastically," said the leader of the Vostok study, Jean Robert Petit, research director at the Laboratoire de Glaciologie et Géophysique de l'Environnement in Grenoble, France. "The atmosphere has never been in such a state."
The analysis of the Vostok ice core showed that the atmospheric concentrations of carbon dioxide, the most common heat-trapping gas in the air, naturally fluctuated from 180 to 290 parts per million for almost half a million years. Then, about 150 years ago, man began burning vast amounts of coal to drive factories and steel mills and trains. Later, millions of gasoline engines added further billions of tons of carbon dioxide to the mixture. The concentration of this gas in the atmosphere quickly broke out of its natural range and rose to 364 parts per million, its present level. The ascent is continuing apace.
Scientists believe that carbon dioxide accounts for about half of the human contribution to rising air temperatures, which vary wildly from year to year but also appear to have broken out of their natural range. In March, climatologists from the University of Massachusetts at Amherst and the University of Arizona published the results of the first-ever attempt to reconstruct the average temperature of the earth's entire Northern Hemisphere for each year of this millennium. Since this study looks back to the days before the early 18th century, when the mercury thermometer was invented, it had to draw on temperature information contained in tree rings, the annual growth bands in sea coral and the chemicals in ice cores.
The scientists found that the 1990s have been the hottest decade in ten centuries. 1998 was the hottest year in at least a thousand years, and 1997 came in second. "It's the only curve I know that's steeper than the rise of the stock market during the past two decades," says Michael Mann, who led the climate study. The average temperature in 1998, a year when El Niño exacerbated the warming, was about 1.5 degrees warmer than the average for the 20th century, Mann says.
Data for 1999 are still being collected. "It looks like global temperatures will be staying well up in the average level of the 1990s," Mann says. These and other findings have spurred scientists to renew warnings that a failure to cut emissions of heat-trapping gases will cause the warming to accelerate the so-called greenhouse effect. Some of these scientists project that wind patterns will make temperatures in the United States ascend more steeply than over the rest of the globe. "The enormity of this issue has forced the scientists to come down out of their ivory tower and take what they're doing to the public," says Lonnie Thompson, a specialist in alpine glaciers at Ohio State University's Byrd Polar Research Center. "The consequences of change are much greater now, because people live in higher concentrations in places where the infrastructure is susceptible."
Some effects of the warming are already apparent. The International Committee of the Red Cross reported on June 24th that 1998, the hottest year on record, was also a banner year for natural disasters, claiming about 21,000 lives. Sea levels have risen around the world. Tundra and glaciers are melting all over Alaska. This year in western Antarctica, a pair of centuries-old ice shelves, 1,100 square miles in size, shattered like glass into thousands of crystalline icebergs. Hemingway's snows of Kilimanjaro, like almost all the alpine glaciers on the planet, are disappearing. The ice cap floating on the Arctic Ocean appears to be shrinking. A scorching heat wave in the U.S. killed at least 56 people in ten days in July.
If scientific projections pan out, in 15 years or so, higher temperatures are likely to open the fabled Northwest Passage through the frozen channels of Arctic Canada year-round for the first time in millennia. (This waterway would be a shorter, potentially cheaper route to Europe for Asia's cars and stereos than the Panama Canal. Canadian army, police and customs officials have already begun discussing how to manage the new waterway, such as restricting it to double-hulled vessels to avoid oil spills, says Rob Huebert, a specialist in arctic and ocean politics at the University of Calgary.) Higher temperatures are also expected to raise sea levels higher and faster than they have in this century. They are likely to reduce food production and supplies of fresh water for drinking and irrigation, which could destabilize the governments of many poor countries. There could be an increase in the number and intensity of storms, forest fires, floods, droughts and other catastrophic events, including huge weather patterns like El Niño, whose 1997-98 edition ravaged the Americas, Indonesia and Africa. If these projections prove accurate, future generations may see the pollution and warming of the air as the most devastating legacy of the 20th century, more significant than the world wars and the genocides, more significant than the harnessing of the atom, space exploration and all the Fords, Einsteins and Microsofts.
Despite the scientists' calls for action and changing attitudes in industry, international negotiators have yet to work out a mechanism for reducing air pollution. Developing countries like China and India are waiting to see what the United States and Europe will do, but the warming question barely registers as a political issue in the rich countries. In the United States, by far the world's biggest polluter, most members of the Republican-dominated Congress won't hear of it. Wary of a fight during the presidential-campaign season, the Clinton administration has called for a hold on negotiations for pollution reduction until after the election in 2000.
Environmentalists are already crying foul, and scientists say critical time is being squandered. The pollution of the air is worsening. The heating process is gathering momentum. And even if the polluters clean up today, scientists say, it would take years for the ascending temperature curve to level out.
Scientists generally agree that during the last 100 years, the average temperature of the earth has warmed by about 1.1 degrees Fahrenheit to about 60 degrees and that in just over a century, the temperature in some regions of the Arctic has climbed by a hefty 5.4 degrees. What has been lacking is conclusive proof that human behavior has been the cause of the increase in temperature.
There is no denying that man has discharged billions of tons of these gases into the air from driving cars, burning coal, raising cattle on massive farms, burning rain forests and engaging in other endeavors the benefits of which people in rich countries would rather not give up and people in poor countries long to enjoy. Between 1950 and 1995, the United States alone produced more than 180 billion metric tons of carbon dioxide; Russia was second, with 67 billion tons. The statistics are also striking for methane, the gas from garbage dumps and rice paddies. The Vostok study found that atmospheric concentrations of methane stayed within a natural range of 320 to 780 parts per billion until the Industrial Revolution. Now the level is about 1,700 parts per billion, and it is rising.
And yet climate change is still a divisive issue: A minority of scientists — some of them clearly spokesmen for coal, oil and power companies that have the ear of conservative members of Congress — assail the idea that pollution is heating up the atmosphere. The higher air temperatures, they say, may have resulted from, among other things, a drop in the frequency of volcanic eruptions, a natural shift in the earth's orbit or tilt, or a subtle increase in the amount of light emitted by the sun. They say climatologists have as miserable a record of predicting climate change as TV weathermen have of predicting rain. Twenty-five years ago, after all, climatologists, including CIA analysts, rang alarm bells after spotting "ominous signs" that the planet was about to plunge into an ice age. Somebody even proposed collecting heat from sunlight by sprinkling soot atop the Arctic ice sheet. The topic still brings blushes, along with assertions that, of course, nobody back then really knew what they were talking about.
Though they are careful to couch their language, scientists like Ted Scambos, a glaciologist at the National Snow and Ice Data Center at the University of Colorado at Boulder, insist that this time around, they do know what they're talking about. "We're drawing close to proving the case, and people are coming around," Scambos says. Their confidence stems from the fact that climate science has come a long way since the botched ice-age call of the Seventies. To their once-meager arsenal of instruments, climatologists have added lasers, automatic weather stations, ice-penetrating radar, satellite-aided imaging and navigation, and techniques to analyze the chemical content of air bubbles trapped in glacial ice.
The Massachusetts and Arizona temperature study was one of at least seven historical reconstructions of air temperatures to be completed in the last two years. Each of the studies applied different methods of analysis. Each drew upon separate arrays of data. But the findings dovetailed. Jonathan Overpeck, a specialist in climates of the past at the U.S. National Oceanic and Atmospheric Administration in Boulder, led one of these efforts, a reconstruction of the temperatures in the Arctic during the last 400 years. He, too, found that the warming during the 20th century has been unique. "Looking as far back as we can on an annual basis, the globe, the Northern Hemisphere and the Arctic are all warmer now than they have ever been," he says.
"If you go back many thousands or millions of years, then, of course, you'll find higher temperatures on earth," Overpeck adds. "But in each of the cases where we have had a warmer period, we understand why. Six thousand years ago, for example, the Northern Hemisphere was as warm as or warmer than it is today. That's because the earth's orbit has changed. Six thousand years ago, the earth was closer to the sun during the Northern Hemisphere's summer. Now, in Northern Hemisphere summer, we are pointed away from the sun."
Mann, Overpeck and other scientists have concluded that increased radiation from the sun might have accounted for some of the warming measured between 1900 and 1950 but that it could not have caused most of the steep global-temperature rise since 1970. "If we left Mother Nature to do what she wanted to do, we would be going back into another ice age in the next 10,000 years," Overpeck says. "Now, because of what humans are doing, it's unlikely that we'll be going back into another ice age. Instead, glaciers around the world are receding. The earth is warming up. And it will likely continue to warm up."
To find patterns in the chaos of winds, ocean currents and the heat wrapped up in the air and water, climatologists use complex software packages, or models, that can sometimes be squeezed into the silicon chips inside a laptop. Numerical codes in the software represent natural laws governing motion, heat and fluids like air and water. These computer models lie at the heart of the controversy over pollution and climate change, because the models are far from perfect and the accuracy of their forecasts won't be known for years.
In early June, Drew Shindell and other NASA climatologists working in New York released a study that used a computer model to determine whether greater amounts of heat-trapping gases in the air affect the stratosphere, the layer of thin air that envelopes the earth six to fifteen miles above the ground. It has cooled in the 20th century, just as climatologists predicted it would if air pollutants trapped more heat in the muggier, more turbulent air closer to the ground. Until Shindell's team came along, however, most climatologists tended to ignore the stratosphere's ability to stir the warmer air beneath it.
Climatologists have been squabbling for years about the fact that some regions, like Alaska and northwestern Canada and Russia, were warming while others, like northern Quebec and eastern Antarctica, were getting cooler. These regional differences seemed to defy the theory of pollution-driven warming. NASA's model, however, appears to have resolved the problem. It found that the warming pattern is probably determined by winds blowing along the bottom of the stratosphere. These winds have speeded up as the difference in temperature between the lowest layer of air and the stratosphere has widened, Shindell says. The accelerating winds, in turn, strengthened a swirl of air that naturally forms over the Arctic pole each winter, and this swirl has sucked into parts of the Arctic region unusual amounts of relatively warm ocean air from the Pacific and Atlantic. "Alaska really feels the brunt of this," Shindell says. "So do northwestern Canada and western Russia." Shindell's study also foresees warming in southeastern Greenland, and Greenland is one of the wild cards that could dramatically affect sea level.
The earth's oceans have risen four to ten inches in this century. Hotter air has warmed ocean water and caused it to expand, scientists say, and water from melting glaciers in the Rockies, Andes, Alps, Urals and other mountain ranges has flowed into the oceans and added to the rise. In coming decades, the runoff from thawing glaciers is expected to lift sea levels even higher. For this reason, scientific papers about the decay of alpine glaciers, and prospects for a thaw of the Greenland and Antarctic ice sheets, don't escape the attention of politicians in countries like Holland, half of which lies below sea level, or risk analysts at insurance companies that write policies for beach houses, dockyards and seaside financial districts. "Low-lying countries with long coastlines and island states in the Pacific will see big problems," says Thomas Loster of the geoscience research group at Munich Re, a company that insures insurance companies against losses from natural catastrophes.
Desolate Greenland is the world's largest island. On it sits a slab of ice that is two miles thick at its center and spreads out over 708,000 square miles, an area larger than Texas, California, New York, Pennsylvania, Georgia, Florida and Illinois combined. Out the window of an airplane cruising low over central Greenland, the ice blinds the eyes with its brightness, disappearing into a horizon that merges with the sky. The ice sheet looks like a white ocean with waves caught forever in stop action. The ice, however, is always moving, pushed downward and outward by its own weight, billions of tons of it. Along Greenland's northern coast, the ice has forced its way into one valley like vanilla ice cream oozing through a crack in a sugar cone. In the northwest and southeast, photogenic chunks of ice, some the size of steel mills, break off and inch their way through steep fiords before floating out to sea.
If warm air defrosted Greenland's ice sheet, the runoff would lift the level of the oceans by about 25 feet. If the air melted the ice sheet sitting on Antarctica, the Atlantic Ocean would be caressing the thighs of the Statue of Liberty. No responsible person is saying that New York is going to suffer the fate of Atlantis any time soon. But there is concern that even a little melting in the wrong places could be devastating. During hurricanes and typhoons, for example, places like Florida and Bangladesh could be hit by storm surges more massive than any ever seen. "Right now, nobody knows whether these ice sheets are growing or shrinking," says Ellen Mosely-Thompson of the Byrd Polar Research Center. Mosely-Thompson spent much of the spring drilling ice cores in central Greenland. The warming of the air may be melting the ice in some areas of Greenland and Antarctica, and bringing more snowfall to other regions, she says. "Finding the balance of this account is a huge problem. And we're not going to work it out in a year or two." Bill Krabill, a high-tech surveyor from Maryland, leads a team of NASA scientists who are trying for the first time to measure the entire mass of Greenland's ice sheet. About 10 years ago, Krabill had the idea to mount state-of-the-art lasers, radars, satellite-navigation devices and computers inside a refurbished 1962-vintage Navy submarine chaser and fly the length and breadth of the sheet to see whether it is growing or shrinking. NASA came up with the money, and since 1993, Krabill and his team have surveyed all of Greenland twice, flying about 2,000 miles a day during four 15-day missions.
During each flight, the pilots use a computer and signals from satellites to keep the plane cruising at about 1,500 feet above the ice and as close as possible to the middle of a straight, 200-foot-wide corridor. About 3,000 times a second, all along the corridor, a laser measures the distance from the plane to the ice surface.
In July 1998, five years after their first survey of southern Greenland, Krabill's team flew along the same corridors to see what the ice had done. This March, Science published the team's results. The ice in southeastern Greenland, a region long thought to be frozen tight, has thinned rapidly. The ice in some regions has shrunk by as much as 33 feet. The ice balance for the entire southern half of Greenland is in the red.
The NASA team crisscrossed Greenland's northern half this May, flying hour after hour over the vast, featureless cap. "The real action is along the edges," Krabill says as he gazes out the window of the plane. "It's still only a piece of the puzzle, and satellites will eventually take over this job." The plane dashed down and across rivers of ice that tumble into the sea, including Jakobshavn, one of the world's fastest-moving glaciers, whose output could bury an area the size of Columbus, Ohio, under 400 feet of ice in a single year. NASA's computers will need three months to calculate the new measurements and compare them with data collected five years ago. In the meantime, Krabill will spend his off hours tending a farm his family has kept on Maryland's Eastern Shore for decades. Its elevation, coincidentally, is about 25 feet above sea level. His neighbors may want to keep an eye out to see whether the place goes up for sale.
If pollution has not warmed the air so far, most climate scientists say, it is only a matter of time before it does.
The bulk of the gases discharged into the air today comes from the United States and the other major industrialized nations together with Russia and the former Communist states of Eastern Europe. The U.S. emitted 5.2 billion metric tons of carbon dioxide in 1995, Russia placed second with 1.8 billion, and Japan scored 1.1 billion. In another 15 years, however, poorer developing countries are expected to produce more pollution than the industrialized world. If business as usual continues, by about 2060 the amount of carbon dioxide in the atmosphere is expected to rise to 600 parts per million, more than double the highest concentration in the half-million years before the Industrial Revolution.
Predicting the world's climate a century in advance is fraught with hazards. It requires making huge assumptions about things like population increases, economic growth, the destruction of forests, urban sprawl, technological advances and the kinds of energy societies will use in coming decades. Eleven years ago, an international treaty set up the Intergovernmental Panel on Climate Change and secured for it the help of about 2,000 scientists. The IPCC's job is to provide accurate information and reasonable projections about air pollution and its effects for the world's policy-makers. All of the complexities involved did not deter the IPCC's scientists from forecasting in 1995 that the speed and extent of the warming during the next 100 years will far outstrip that of the 20th century. In fact, the panel said, the cataclysmic effects will be unlike anything mankind has experienced in the last 10,000 years.
The IPCC is now drawing up new emissions forecasts based on fresher information. A few months ago, Tom Wigley, a senior climate scientist at the National Center for Atmospheric Research in Boulder, got the IPCC's permission to examine its preliminary estimates and use them in a paper he wrote for the Washington-based Pew Center on Global Climate Change, an organization working to enlist large corporations in a campaign to curb air pollution. From these preliminary estimates, Wigley concluded that the IPCC's 1995 temperature forecast was too optimistic. Global temperatures will rise between two and seven times faster in the next 100 years than they did during the last, Wigley projected, and the rate of warming over the United States will be faster than the rate over the globe as a whole. Wigley also estimated that sea level will rise by one to three feet. "This kind of increase is unknown territory," says Wigley. "I don't wake up in the middle of the night shaking with fear. But I do worry about my children and their children. They're the people who are going to really have to cope with this problem."
Some of the IPCC's forecasts already appear to be panning out. Kiribati, an island nation in the South Pacific, is complaining that parts of its territory have sunk beneath the waves; the island's government has appealed to the outside world to hold back emissions and has begun a resettlement program to move a few families from low-lying atolls. The World Wildlife Federation issued a report on June 9th warning that rising temperatures have already begun disrupting the plankton that form the base of marine food chains. Sharks and other fish that mainly inhabit warmer southern seas are migrating northward in greater numbers. Coral, migratory seabirds and penguins, as well as whales and seals, are also showing effects.
The evidence is even more visible in the polar north. Ninety miles from the Arctic Ocean, in a Canadian town called Inuvik, the temperature peaked at a record 91 degrees on June 18th. "We were down to our T-shirts and hoping for a breeze," says Richard Binder, a fifty-year-old local whaler and hunter. Binder's people, the Inuits, have inhabited this frostbitten corner of the Northwest Territories for about 1,100 years. His generation, however, has felt a lot of unusual heat. Summers have arrived earlier and winters later. Hillsides and shorelines have collapsed as the warmer air melted subterranean ice. Along the Mackenzie River, Binder says, "hillsides have moved even though you've got trees on them. The thaw is going deeper because of the higher temperatures and longer periods of exposure." Near Inuit villages on Herschel Island, just above the northern coast of the Yukon, the sliding ground opened up traditional graves, Binder says. The people had to rebury the remains of some of their ancestors. Last summer, the Arctic coastline, which is usually locked in by a sheet of sea ice until July, was navigable in mid-June. The Inuits killed their first whale weeks earlier than normal. The whalers had never heard of the ice breaking up so soon. Binder consulted the tribe's elders, but they couldn't recall anything like it. Tribal legends, the repository of Inuit history and wisdom, couldn't explain it either.
The Politics: Bogged Down
As gases and heat fill the air and the Inuits watch the thaw around them, the international effort to reduce gas emissions has slowed to a pace so lethargic that even some energy corporations are voicing concern.
For decades, these companies have campaigned against proposals for limiting emissions of heat-trapping gases. They have funded research aiming to prove that there is no pollution-driven warming — and have even promoted the benefits of increased levels of carbon dioxide in the atmosphere just like tobacco companies once promoted smoking as a health-enhancing activity. Within the past year, however, the unity of this bloc has fractured.
Some energy-company executives now refer to their naysaying colleagues as troglodytes and caution that the mounting evidence of a link between air pollution and the warming air should be taken as a warning. One of these companies is the multinational oil giant BP Amoco. "Science by definition is generally not definitive," says Michael McAdams, an associate group-policy adviser at BP Amoco. "Rather than wait for some ironclad answers, BP concluded that it made good business sense and good sense for our customers and our employees to take progressive actions now, actions that we could all see are a step in the right direction." BP is now the world's largest solar-energy company, and it has launched a campaign to reduce emissions at its refineries and bring clean fuels, like compressed natural gas, to its pumps.
American Electric Power Company, one of the largest producers of carbon dioxide in the United States, has also recognized a need for change. "You can't help being alarmed by the temperature record of the last two decades," says Dale Heydlauff, the company's vice president for environmental affairs. "There are enough warning signs out there that we recognized we needed to do our part to begin looking at options for solving this problem."
Still, the political leaders are balking. Developing countries like China, Brazil and India, which have huge populations living in squalor, say it's immoral to demand that they retard their economic growth to curb pollution before the United States, the European Union and other big, rich polluters like Japan do something. These rich polluters, meanwhile, are squabbling among themselves over the Kyoto Protocol, reputedly the most complicated international agreement in history, which commits its signatories to making significant cuts in gas emissions. The Clinton administration signed the protocol. But during a rules-drafting conference in Germany earlier this summer, it squabbled with European Union delegates over limits on "emissions trading," a process that would allow rich countries to score points toward their emissions targets by helping poorer countries to reduce pollution. The U.S. accused the Europeans of trying to renegotiate the protocol; then the U.S. called for postponing finalization of the rules until after the 2000 presidential election.
Scientists and environmental groups are calling for the United States and the other rich nations to get on with it. "There is an unbelievably unhealthy strain of politics that runs through this issue right now, and it is preventing any serious discussion of any reasonable solution," says Steve Cochran, legislative director for the Environmental Defense Fund. "In Congress, you've got a pretty good-size contingent of the flat-earth society." The Senate, which must ratify any treaty the United States signs, has passed a resolution saying it will not consider any agreement on emissions reductions that doesn't include "meaningful participation" by developing countries, he explains. "When the administration looks at Congress, it says it can't get anything done up there."
Ironically, the political deadlock in Washington and the squabble with the European Union come at a time when the rich nations are richer than ever and changes would be less costly than in harder times. "These are not only good times," Cochran says, "these are times when there are a lot of good choices. They are not being taken advantage of, and they will not be around forever.
"It's a classic dilemma for the representative government we have," Cochran concludes. "How do you have the courage to look ahead and act with foresight? On this one, if we get it wrong, there will be some very serious consequences out there. This is the environmental issue. If we get this one wrong, the work done on all the other environmental issues goes right down the drain."