This article appeared in Climbing, No. 208, on December 15, 2001. The magazine did a great job producing it; there were some excellent photos. I recommend getting a hold of a copy if you can … or maybe they’ll post it on their site … ?

I am posting it now because it is playing a role in an odd little tempest in a teapot that was initiated by the Telegraph in England on Sunday. I hope to post another entry about that episode shortly.

I’m still quite happy with the article, even though I wrote it a long time ago. Obviously, the political situation has changed. The science still holds up pretty well, although I do point out a few minor errors below.

Canaries in a Coal Mine

As the Earth warms, its mountain glaciers are disappearing. How will climbers-and life-be affected?

By Mark Bowen

Topher Donahue, 29, has been climbing and hiking in Rocky Mountain National Park since his childhood. He remembers that Mills Glacier, at the base of the east face of Longs Peak, used to be covered in soft white snow year-round. Now, it reverts to hard gray ice every August.

Last September, he and some friends walked in to climb the short ice flows that form near the base of the east face. The climbs were in, but the glacier had changed significantly.

“We walked to the base of the wall without stepping on ice once,” he says. “It used to be that you walked for the last quarter-mile on ice.”

Other formerly permanent snowfields, near Jim’s Grove on the trail to Longs, and on the hills above Trail Ridge Road, now disappear completely for a few weeks every summer.

Gerry Roach of Boulder, Colorado, has climbed El Pico de Orizaba, the highest of Mexico’s three big volcanoes, once in each of the last five decades. In the 1950s and 1960s, he recalls, Orizaba’s south side was covered with soft, sun-cupped snow. Now, you can climb to the summit without stepping on snow once. He says the loss of ice is “dramatic” on all three volcanoes, and says he almost cried 10 years ago when he saw how fast it was going on Iztaccíhuatl, the third highest. “I probably won’t go back to that mountain again, it was such a mess. Everything was dripping. I don’t know whether we’ll live to see [the snow's] complete disappearance, but it will be mostly gone in our lifetime. That’s sad, because volcanoes look prettier with a snowcap on them.”

In 1970, when Roach first climbed Chimborazo, the highest mountain in Ecuador, he followed the route Edward Whymper had used in 1880 on the first ascent. By the time he returned in 1981, however, the snowfields below the prominent “red wall” had retreated to reveal what he calls “a very nasty rock slope” of slabs covered with loose rock. Thus, on about the 100th anniversary of Whymper’s ascent, his route fell out of favor, not only because of the rock slope but also the seracs and crevasses that had opened up on the shriveling glacier above. The hut was moved west to give better access to the Direct Route. Since then, even that route has changed: You used to walk straight up the tongue of the Thielmann Glacier, but it, too, has retreated, and its margin has steepened. Climbers are forced along its edge, with the Scylla of rock cliffs on one side and the Charybdis of hanging seracs on the other. The approach has been changed twice in the last year-and-a-half. Both new lines are more dangerous than the original.

When Lloyd Athearn, deputy director of the American Alpine Club, visited Ecuador in 1998, he carried a 1994 photo that had appeared in Climbing six months previously. In the photo, Illiniza Sur’s North Face Direct appeared to be a steep but straightforward snow climb. In real life, it was out of the question. The distinctive hourglass in the middle of the face, where a smooth glacier once squeezed between two rock buttresses, had shrunk to a crevasse-riven icefall, and much newly exposed rock was poised above it, ready to drop.


We know conditions change from year to year. People in Ecuador told Athearn that the rainy season had been light the year he visited. It so happens La Niña set in that year. She brings drought to the equatorial Andes-sometimes for two or three years running. Her big brother, El Niño, brings increased rain and snow.

But climbers are bringing back stories from around the world of mountains losing the snow and ice that not only makes them prettier, but also easier, safer and more appealing to climb. These accounts are anecdotes, and many of us are quick to dismiss them. Scientists, on the other hand, have lots of solid evidence that the snows really are disappearing, and most believe this is one of the first signs that global warming, caused by human activity, has truly begun.

The only true ice cap in the tropical zone blankets the Quelccaya massif in the mountains above the ancient town of Cuzco, in southern Peru. Lonnie Thompson, a climatologist at Ohio State’s Byrd Polar Research Center, has been observing it since 1974. He first noticed a dramatic retreat of Qori Kalis, the cap’s main tongue, between the summers of 1983 and 1984. “Then we started to look around at ElectroPeru’s records of the retreat of these glaciers,” he says. “You could see this acceleration in the retreat rates kicking in in the late 1970s.” He began supplementing the power company’s records with stereoscopic photographs, to map the glacier in three dimensions. In 1991, he showed that Qori Kalis had retreated three times faster in the last eight years than it had in the previous 20. Volume loss, which takes the thinning of the ice into account, had grown by a factor of seven. From 1995 to 1998, the rate increased again by a factor of three, to more than 500 feet per year.

North of Quelccaya, in the climber’s paradise of the Cordillera Blanca, stands Huascarán, the highest mountain in Peru. Roach has been there, too-in 1968 and 1974. “The difference in those six years was tremendous,” he says. As the ice retreated more than a thousand feet, basecamp was moved accordingly, from a spot in the forest to a stark location on yet another slope of bare rock and rubble revealed by retreating ice. Mark Richey of Massachusetts, who has climbed in Peru since the 1970s, believes that of all the peaks there, Huascarán has changed the most. The standard Garganta Route has gotten harder, and the ice in the huge col between the mountain’s twin summits more crevassed. With the higher south summit increasingly difficult to reach, climbers generally opt for the north. Some years, no one reaches the actual summit of Huascarán at all.

The Garganta Route has never been especially safe, but Cèsar Morales Arnao, editor of the Peruvian Magazine of Andinism and Glaciology since 1953 and former president of the Peruvian Federation of Andinism and Winter Sports, believes it has seen more accidents in recent years. He says nearly all of them occur on a 45-degree rock slab low on the route. Donahue, who guides there, agrees, “It seems like people are getting cleaned out on the standard route on Huascarán yearly.”

Below the equator, of course, northern and western exposures see the most sun. According to Richey, the Northwest Ridge of Alpamayo, which used to be the standard and easiest route up one of the most beautiful mountains in the world, has turned to rock and been abandoned. What Donahue calls “literally a chunk of the mountain” recently fell out of Alpamayo’s lovely, fluted southwest face, leaving a dark hole. Richey says many of Peru’s north and west faces are “just black-devoid of ice and snow-and the rock in Peru is not all that high-quality.”

When he visits Quelccaya, Lonnie Thompson still camps in his original site by a large boulder that Qori Kalis was pushing downhill in 1974. Now, a 10-acre lake lies between the boulder and the glacial margin. He believes the whole ice cap, which 25 years ago covered 27 square miles and was 500 feet thick at its 18,000-foot summit, will disappear completely in about 15 years. Moreover, he believes every glacier in the tropical zone will be gone in 50 years. That means all of Peru, Ecuador, Bolivia, Venezuela, and the half of Mexico that includes the volcanoes-not to mention New Guinea and Africa. I have climbed Africa’s Kilimanjaro with Lonnie twice. Based on historical maps and his aerial photographs, he’s predicting that its fabled snows will fade into memory between 2010 and 2020.

Glaciers that lie above 5000 meters, or 16,000 feet, sit in what is probably the most sensitive layer of the atmosphere. In fact, according to a computer model developed at the National Center for Atmospheric Research in Boulder, the altitude that will see the greatest temperature change in a greenhouse world is precisely 8000 meters, a resonant phrase to Himalayan mountaineers.

Ice is especially sensitive to such effects. Glaciers tend to retreat to the level where yearly temperatures average 32 degrees Fahrenheit [zero Celsius]. Worldwide, according to Thompson, the melting level is rising at about 15 feet per year. In Peru it is rising at twice that.

“Mountain glaciers are a good canary in a coal mine-going both ways,” he says. “They respond to change. For detection, that’s good; but, because they’re sensitive, you have to realize that they do amplify the signal. You don’t want to overreact, because what if [temperatures go in] the other direction two years from now, and suddenly these guys start growing? But since the early 1980s, at least, it’s been going one way, and it’s been accelerating.”

Thompson (profiled in [Climbing] No. 177), has taken more than 40 expeditions to the great ranges of the world. His main interest is ice-core drilling. By analyzing the layers of ice that have been laid down annually, like tree rings, over the millennia, he can study past climates and climate change in remarkable detail. In a core from China’s Dunde ice cap, on the boundary of the Tibetan Plateau and the Gobi Desert, he has found that the last 50 years, which correspond precisely to the period of skyrocketing fossil-fuel use, have been the warmest in the last 40,000. [Note: This statement did reflect current knowledge when it was written. However, subsequent analysis of the Dunde ice core suggested that it didn't reach quite as far back as Lonnie's research team originally thought. They now state conservatively that the last fifty years have been the warmest in the last 10,000. - Mark] His cores from the Garganta col on Huascarán, the summit of Sajama (Bolivia’s highest mountain), the Dasuopu ice cap on the Tibetan side of Xixapangma, the Firn Plateau in the Pamir, the Tien Shan in Kyrgyzstan, and the Antarctic Peninsula all show signs of the same recent warming.

Sunlight streams into the earth mainly in the form of visible and ultraviolet radiation-at short wavelengths. The surface absorbs it, heats up and sends energy back into space-mostly at longer, infrared wavelengths. So-called greenhouse gases in the atmosphere, such as carbon dioxide, which is produced by fossil fuel burning, let the sunlight in but absorb the infrared going out, re-emitting half outward and half back toward the surface. As a result, temperatures at the surface and in the lower atmosphere rise. The greenhouse effect is not purely a bad thing. If it didn’t exist, Earth’s average temperature would fall roughly 63 degrees, to below zero Fahrenheit.

Perhaps the most conclusive evidence that the effect is real came in 1998, from a 2-mile ice core retrieved at Russia’s Vostok Station in East Antarctica. It shows that temperature has tracked the level of carbon dioxide in the atmosphere for the last 420,000 years. The present level also happens to be the highest in that time frame.

Carbon dioxide is the second-most effective greenhouse gas. Water vapor is first. The danger is that a rise in carbon dioxide concentration, in warming the air, allows the air to hold more moisture, for the same reason that it is more humid in summer than in winter. Increased water vapor raises temperatures again, allowing more vapor to enter the atmosphere, temperatures to rise again, and so on. This is called “water vapor feedback.” The uncertainty about the precise amount that temperatures will rise as we continue to load the atmosphere with carbon dioxide comes mainly from the difficulty in estimating the combined strength of the innumerable feedbacks in the system. It also makes the problem interesting.


In 1988, many nations were pushing forward on the policy front, heeding scientists’ warnings that carbon dioxide was rising to potentially dangerous levels. The Reagan Administration, seeing it was about to be left out, called for a full assessment, and the Intergovernmental Panel on Climate Change (IPCC), which consists of some 2500 scientific, economic, and policy experts and operates under the aegis of the U.N., was formed.

The IPCC issued reports in 1990 and 1995, and again this year. Although these reports may be the most peer-reviewed in scientific history, and the wording of the experts has been watered down by many governments who assert that a reduction in their use of fossil fuels would damage their economies, each report has been more ominous than the last.

The 1995 report stated delicately that “the balance of evidence suggests a discernible human influence on global climate.” While this may not seem like a strong statement, it effectively ended the scientific debate. At that time, the panel estimated that temperatures stood to rise as much as 6.3 degrees in the coming century. In the 2001 report, the estimate is 10.5 degrees-about one degree more than the difference between today’s temperatures and those at the end of the last ice age. This year’s report also states confidently that changes in greenhouse gas levels, caused by humans, have “contributed substantially to the observed warming over the last 50 years.”

The scientific community has responded with surprising unanimity to a very complex problem. As the New York Times put it, “Many panel members said that the summary represents the closest thing to a consensus possible in science, which is generally driven more by questioning and challenges than by esprit de corps.

The overwhelming majority of climate scientists believe there is a reasonable chance that Earth will warm enough in this century for many ecosystems, the species they support, and countless human lives to be threatened or destroyed. The latest IPCC report points out that most of these lives will come from developing nations in places like Africa and South America. “The most widespread direct risk to human settlement,” it says, “is flooding and landslides.”

These are the primary dangers faced by the millions who live in the arid coastal plain below the Cordillera Blanca, especially the very poor, as they watch their range turn from white to black. The glaciers store water, to be metered out during the long dry season for agriculture and hydroelectric power. Without them the monsoon will cause deadly floods and landslides, and the dry season will bring crop-killing drought. In 1998, with the heightened stress of a record-setting El Niño-which many scientists see as another effect of global warming-lack of ice on the peaks around Machu Picchu led to a landslide that buried the region’s hydroelectric plant.

There will be winners and losers in the greenhouse, but the IPCC expects many more losers overall. More than a billion people live the same marginal agricultural existence their ancestors pursued for thousands of years-in ecosystems now pushed to the brink by the population explosion. Slight changes in their yearly water budget stand to cause massive famines.


Mark Dyurgerov, a Russian glaciologist at The Institute of Arctic and Alpine Research at the University of Colorado, Boulder, has been monitoring the size of mountain glaciers around the world for more than four decades. He says they are shrinking almost everywhere, with a few maritime exceptions, such as the Blue on the Olympic Peninsula and one or two in Norway. These few are growing because a warmer world is a wetter world, with more precipitation, but the fact that most are shrinking is a sign that Earth is warming enough for melting to overwhelm the increased accumulation.

Dyurgerov’s data shows that the accumulation zone, where snow tends to build during the year, is becoming a smaller fraction of the area on most glaciers. Dirt-filled, gray or brown ice is gaining in percentage even as the total area shrinks. Dark ice may absorb
five times as much of the sun’s heat as a crisp new snow surface, which makes for positive feedback: The smaller they get, the faster they go.

Dyurgerov estimates that mountain glaciers have lost almost a thousand cubic miles of water-equivalent snow in the last 37 years. This figure represents a much larger volume of snow, which is less dense than water. He sees an abrupt transition to faster melting, worldwide, beginning precisely in 1977. Similarly, the recent IPCC report states that the human effect on climate first became clear in about 1980. [Note: I made a mistake here. Actually, the 2001 report made note of a world-wide shift to melting in 1980. - Mark]

One of the smoking guns convincing the scientists of the IPCC that humans are causing the change is its geographic pattern. Computer models say that rising greenhouse levels should cause the polar regions to warm preferentially. They have. While the Earth’s average temperature has risen less than two degrees in the last century, the Antarctic Peninsula has warmed about seven degrees, and Alaska has warmed an astounding five degrees in the last 20 years.

Alaskan tundra that has been frozen for more than 100,000 years is melting to produce “sinkholes,” which have damaged roads and undermined buildings. (In melting, the permafrost also releases many tons of sequestered carbon dioxide-another positive feedback. [Note: A minor mistake: the permafrost releases more methane-also a powerful greenhouse gas-than carbon dioxide. - Mark]) Many of the state’s hundreds of glaciers have begun to retreat. Between a third and a half of Alaska’s white spruce have died in the last 20 years, from the direct effects of the changing climate and from the proliferation of tree-eating insects.

One might expect warmer weather to help Alaskan agriculture, but oddly, it has not. More snow is falling in winter, but less rain is falling in summer. Even with the longer growing season, there is often insufficient water to sustain crops. On the other hand, the state’s economy has been helped by the longer tourist season, and prospects exist for easier shipping, perhaps even the opening of the legendary Northwest Passage.

Gerry Roach climbed Alaska’s Mount Saint Elias in both 1984 and 2000. On the first trip, he found Icy Bay, the fjord below the mountain, covered with sea ice. Sixteen years later, it had retreated 20 miles, and he could paddle to within eight horizontal miles of the 18,000-foot summit. The retreat of the ice gave the mountain the greatest vertical relief of any by the edge of the sea.

Roach’s partner on the second trip was Chris Holland, a climber from Ridgway, Colorado, who has another story to tell, this one from the bottom of the Earth. In 1998, on a traverse of northern Patagonia, Holland encountered a lake 10 miles long that was shown as a glacier on his map. No surprise to the scientists who have seen the south Patagonian ice sheet lose almost 200 square miles in the last 50 years.

Stories pour in from all quarters: The Tasman glacier below New Zealand’s Mount Cook has retreated two miles since 1971. Almost three-quarters of the glaciers in Central Asia were retreating in the 1980s. The Tien Shan range has lost almost a quarter of its glacial ice volume in the last 40 years. Glaciers in the European Alps have lost 50 percent of their volume since 1850.


And what of the greatest range of all? In 1989, Steve Van Meter, Gil McCormick, and Jim Nowak, all of Colorado, attempted the unclimbed west ridge of 23,400-foot Pumori, on the Nepal/Tibet border about three miles west of Everest. They set up a camp at 19,500 feet by the base of a 65- to 70-degree ice slope, then fixed ropes up the slope and camped in a 21,000-foot saddle at the start of the ridge proper, a wandering snowy crest that they climbed to a bivy about 600 feet below the summit.

Disaster struck early on the day of their summit bid. McCormick was hit by a rock that embedded a shard from his glasses in his eye.

“Game over,” recalls Nowak. He and Van Meter carried out a high-altitude Himalayan rescue, one or the other literally carrying McCormick all the way down. On the descent, they rappelled down the fixed ropes on the ice slope and left them there. They saved McCormick’s life, but not his eye.

In 1998, Nowak returned to Pumori with his wife, Kim Reynolds, and two other couples, one being Chris Holland and his wife, Sarah Ballantine. When Holland and Nowak reached the site of the 19,500-foot camp and looked up at what had once been a steep ice slope, Nowak could not comprehend what he was seeing. “There was this dead vertical [rock] wall on the left side of a gully, and the [fixed] lines were like a tramway up there. It was like, €˜Well, did they stretch?’ and then, €˜Well … wait a minute … The belay anchors are in the exact same spots.’ They were pins and wires in rock.” The fixed lines, waist level nine years before, were now 10 feet overhead.

Holland and another companion struggled up the gully to the 21,000-foot saddle and got a view of the once dreamlike ridge, now more like a nightmare. The snow was nearly gone. They would have needed rock gear to climb it, but they had come prepared for snow and ice. Game over again.

Elizabeth Hawley, of Kathmandu, who has been briefing and debriefing climbing groups for decades, says, “The Khumbu glacier [on Everest] retreated 100 meters this spring, from 6000 to 6100.” Scientists have shown that the eastern Himalaya have lost one quarter of their 10,000 glaciers in the last century. [Note: For a more recent-and vivid-sense of the retreat of the glaciers around Mt. Everest, go here. -Mark]


Chris Holland, witness to changes in Patagonia, Alaska and the Himalaya, says, “I have a new daughter, and knowing she’s not going to experience all the beauty I did is awfully disheartening.” Others voice an added urgency to climb those classic routes, especially in the Andes, before they disappear altogether.

They might want to start packing their bags. The speed and scope of past changes conjure terrifying visions in the minds of Lonnie Thompson and others who have studied climate’s erratic history. Small changes in the air or oceans can cause dramatic responses. Ice cores from Greenland show that the last big cold spell, 12,000 years ago, receded in just 10 years, raising temperatures there by 18 degrees and doubling annual precipitation. This is a fantastic change in climatological terms: It would make Chicago as warm as New Orleans. Wallace Broecker, of Columbia University, calls climate “an ornery beast which overreacts even to small nudges.”

Human beings first took up agriculture and animal husbandry at the start of the unusually stable period that began with that sudden rise in temperature. This stability has made our planet a congenial home for the rise of civilization. Paleoclimatologists fear that the goose we are administering to the “ornery beast” might bring back the instability that reigned for more than a million years before that.

“When I go to the mountains,” says Jim Nowak, “I’m repeatedly reminded how fragile things are. What we’re doing on a personal level here has an impact [worldwide]. It’s sad. It makes me feel sad … and then I feel mad about the attitude that the United States is taking.”

Indeed, in July, President George Bush stepped away from international talks aimed at forging a treaty to limit greenhouse gas emissions. (Instead, like his father and Ronald Reagan before him, Mr. Bush called for more research-relatively little, in fact.) A treaty was soon signed by 178 nations. The United States, which accounts for one-quarter of global emissions, did not sign.

Nowak is right about our impact. The average American sends about 27 tons of carbon dioxide into the air every year-five times the global average. Lonnie Thompson points out that one gallon of gasoline, about seven pounds, produces 22 pounds of carbon dioxide-three times the weight of the liquid fuel. That’s 440 pounds from a 20-gallon tank. Returning to Boston after rock climbing in Acadia National Park over Memorial Day, I sat in a traffic jam on the Maine turnpike and calculated that my car was belching about half a ton of carbon dioxide into the air on that trip. I now try to share the driving.

Our greatest contribution to the greenhouse comes from coal-burning electric power plants. Pound for pound, coal has a stronger greenhouse effect than gasoline. The Gavin plant in southeastern Ohio, for instance, burns 7.5 million tons of coal a year and sends 46 million tons of carbon dioxide into the air. One of the complaints President Bush has about the recent treaty is that it exempts developing nations, particularly China and India, from emission limits. But China, which is second to the U.S. in emissions, has reduced its own by 17 percent since the mid-1990s-more than the treaty would require of us-mainly by converting old coal-burning plants to natural gas. At the same time they seem to have belied the conventional wisdom linking carbon emissions to economic vitality: their economy has grown. Meanwhile, utilities in the U.S. lobby against converting or even improving the efficiency of outmoded coal plants.

When you consider the magnitude of the burning, it is not hard to believe that humans might be as powerful a geologic force as the action of the tides, say, or volcanoes. Almost all the carbon around: in the air above, the coal and oil below, trees, plants, you, me, the diamond in your ring, was originally spewed into the atmosphere by a volcano. All the volcanoes on earth produce somewhere between 300 million and a billion tons of carbon dioxide in a year. Fossil-fuel burning produces five to 10 times that-6 billion tons a year! In this century, carbon dioxide could reach its highest level in 50 million years. The last time it was that high, alligators and flying lemurs lived on Ellesmere Island, north of the Arctic Circle.

Lloyd Athearn, from the AAC, says that climbers have always been in the forefront of wilderness preservation. “We wouldn’t have wilderness, or it would be very different, if it hadn’t been for people like John Muir being climbers. They would go to these remote areas and be fundamentally changed by them and then return and fight for their protection.”

Mountaineers are encountering the first signs of a great change. Perhaps it is time we followed Muir’s lead.

Mark Bowen, Ph.D. (physics, MIT), has been climbing for more than 20 years. He is working on a book about Lonnie Thompson.


The following correction appeared in the next issue of Climbing, no. 209:

In “Canaries in a Coal Mine,” the yearly emissions from the Gavin Plant in Ohio were overestimated by a factor of two. It burns about 7.5 million tons of coal per year, which produces 23 million tons of atmospheric carbon dioxide, not 46 million. In the second-to-last paragraph, the total emissions from fossil fuel burning were underestimated by a factor of three. This makes the statement even stronger: Human activity at present sends about 23 billion tons of carbon dioxide into the air every year.

2 Responses to “Canaries in a Coal Mine”

  1. Sorry to hear you are no longer writing about Climate change. I am reading your book “Thin Ice”. I saw a few minor errors and am satisfied that you recognized them and corrected them in this essay. I got the book used and they underlined all the items that did not fall into a neat Anthroprogentic climate change. I used to climb, and work on Niwot ridge and a “glacier /ice field” we called the Arikaree. Probably all the glaciers I’ve been on are gone, except the one in Iceland. Terrific book on the pre-Colombian history of SA. Thanks so much!
    I think someone ought to write an Opera about Jim Hansen’s trouble similar to the Nixon In China or the Opera about Oppenheimer. Maybe that would raise some eyebrows? Could you do the lyrics?

    • An Opera about Jim Hansen? What an idea!

      Could I do the lyrics? I’d say “could” would be the operating word there. It would be fun to try.

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