"Remember this view," Lonnie Thompson yells into the storm. It's -10 degrees Celsius (14 degrees Fahrenheit) as a fierce wind rips at his old woolen cap. "This glacier will be gone forever in less than 20 years." The 57-year-old researcher hunches down and coughs, struggling with the mountain, the thin air and himself.
He stands in front of an ice wall as tall as a house, and behind him the west flank of Mt. Kilimanjaro plunges more than 3,000 meters (about 10,000 feet) to the valley below. The mountain juts up like an island from a sea of East African clouds, towering over the shimmering Serengeti, a world of zebras, giraffes and elephants so far away that one might as well be seeing it from the window of an aircraft.
Thompson, widely viewed as the pioneer of modern tropical glacier research, is a living legend among climate researchers. He's met with former US Vice President Al Gore to give him his personal assessment of climate change, and music magazine Rolling Stone has celebrated him as an "ice hunter." Where others see nothing but fields of rubble, Thompson uncovers evidence of dying glaciers and the traces of a 300-year catastrophic drought that spelled the downfall of entire civilizations. For Thompson, the ice at the top of Mt. Kilimanjaro is an archive, and he intends to use it to divine both the past and future of Africa's climate.
Working conditions in his open-air laboratory are extreme, to say the least. Though frozen, everything is constantly in flux. The steps cut into the ice yesterday are covered with snow today. Location markers suddenly disappear, blown away or knocked over by the wind. Sometimes, as Thompson lies awake in his tent at night, struggling to catch his breath and suffering the debilitating effects of high altitude headaches, he listens to the glacier's sounds: a cracking in the ice, then silence, followed by a metallic knocking sound and then a rumbling noise. And sometimes he feels as if he were standing on the twitching back of an enormous, wounded animal struggling to stay alive.
Dramatic conclusion; but premature?
The ice mountain at the equator is legendary. As recently as the 19th century, geographers were arguing over whether ice could even exist there. Nowadays, Kilimanjaro's tropical ice is once again the topic of heated discussion among experts. Is it true that the glaciers of Kilimanjaro will soon melt away completely? If so, how fast? Is this the result of global warming? And will streams fed by the glaciers dry up when they disappear?
To answer these and other questions, Thompson and many other scientists are busy studying tropical glaciers, but not all concur with Thompson's conclusions. American climate expert Doug Hardy, for example, who also happens to be climbing around on Kilimanjaro these days, is convinced that his famous colleague's dramatic conclusions are a bit premature.
But before other groups could even analyze their data, Thompson made headlines last week by publishing the results of his latest measurements. The glaciers, he announced, are receding more rapidly than previously thought, losing more than half a meter in thickness each year. Thompson -- in yet another highly controversial claim -- believes that if the ice fields disappear, much of the water supply at the base of the mountain could vanish along with them.
"We have to collect as much data as possible today, even if we're not exactly sure what it means, because in a few decades it'll be too late," says Thompson. More than 80 percent of tropical glaciers, including those on Mt. Kilimanjaro, he believes, have already vanished within the last hundred years.
A few hundred meters away, a crowd of tourists stumble down the mountain. Despite its official elevation of 5,895 meters (19,340 feet), Kilimanjaro's middle summit, a peak known as Kibo, is considered a walk-up, one that even an out-of-shape chain smoker can master. Each year about 25,000 visitors drag themselves up the dormant volcano, spend the night in giant tent camps and slide back down special one-way tracks carved into the lava sand. Generally, the groups are accompanied by vast armies of porters.
Popcorn in the "death zone"
But less than half actually make it to the summit. Those who fail are often kept back by altitude sickness, causing symptoms ranging from headaches, vomiting and insomnia to mental blackouts and cerebral edemas. Each year the mountain claims an average of six lives. Thompson and his three younger assistants, as well as another group of researchers camping nearby, also suffer from the effects of working at this high altitude. Unlike the tourists, the scientists spend about a week living and working at an altitude of about 5,750 meters (18,865 feet), where the air is only about half as dense as it is at sea level.
As brutal as conditions on the mountain are, the researchers can't exactly complain when it comes to meals. A long caravan of more than 40 porters carried the two teams' equipment and supplies up the mountain, an effort that's reflected in their fare: eggs, porridge and toast for breakfast, popcorn and homemade potato chips as snacks before dinner.
Despite the calories, the scientists seem to become weaker as the days pass. At this altitude, the "death zone," -- the altitude at which the human body begins to steadily deteriorate -- begins. After a night of confusing dreams, the scientists often wake up feeling so exhausted that a task as simple as tying shoelaces becomes a challenge. After a few days, their eyes become swollen, their cheeks begin to collapse, their noses are sunburned and jokes become a rarity.
Thompson has been punishing his body like this for the past 30 years. As far back as 1976, he was studying tropical ice samples he obtained from Peru's Quelccaya ice field, at an altitude of more than 5,000 meters (about 16,400 feet).
He's been collecting drill cores from the world's tallest mountains ever since -- more than four tons of material from 15 countries, all stored away at Ohio State University. "In a few decades you'll have to come to my university if you want to see the remains of a tropical glacier," says Thompson. After each sentence, he has to bend over and struggle for air. Despite the fact that he has asthma, Thompson has probably spent more time at such high altitudes than anyone else -- a grand total of more than three and a half years. But he has no interest in alpine sports. "I just don't understand why people would come up here for fun." So what's his motivation? "I guess I'm just stubborn," he says.
"Equator has been woefully ignored"
Thompson was widely derided when he set out for the Quelccaya ice shelf in 1976. Back then climate researchers saw no point in studying tropical ice. One of his first expeditions almost failed when the helicopter carrying the team's heavy ice-drilling equipment began lurching from side to side in the thin air. The pilot immediately turned back, forcing Thompson to make do with porters. But the incident came with a silver lining, as it prompted Thompson to develop a portable solar-powered drill to take advantage of the intensity of sunlight at high altitudes -- an unforgiving 1,000 watts per square meter. Whereas temperatures plunge to polar levels at night, noonday temperatures inside a tent can climb to 40 degrees Celsius (104 degrees Fahrenheit). Thompson once even developed a sunburn on his gums after breathing through his open mouth for too long.
In the end, his Peruvian drill cores proved to be a sensation. They provide precise geological documentation of many climatic events of the past 1,500 years, including the eruption of a volcano, Mt. Huaynaputina, in 1600. Thompson's essays, some of which he wrote in his tent, have appeared in publications such as Science.
"The history of our climate can teach us how global warming will affect the tropics," says Thompson. "That's why it's so important that we obtain the data from glacial ice. The polar regions have been researched to no end, but the areas near the Equator have been woefully ignored."
Thompson developed a reputation beyond the world of climatology when he obtained the first drill cores from Mt. Kilimanjaro in 2000. His results were surprising. The mountain's tropical glaciers, he found, developed about 11,700 years ago. Paradoxically, this was precisely at the time when the last great ice age ended in the north. In other words, the climate of the tropics is "asynchronous" with that of the north; it follows a different cycle.
Like the ebb and flow of ocean tides, the African glaciers have expanded and contracted over the centuries. But beginning in about 1880, tropical glaciers began receding more rapidly and more abruptly than in the past. In places where extensive ice caps reached down to altitudes of 4,500 meters (14,750 feet) only a hundred years ago, all that remains today are narrow glacier strips and isolated chunks of ice in a moonlike landscape of lava sand. Thompson managed to turn Kilimanjaro into a symbol of global warming -- and he has triggered a heated scientific debate in the process.
Part II: Leopards in the Ice and Other Riddles
Climatologist Doug Hardy is among Thompson's adversaries in the world of glacier research. "The phrase global warming is misleading, as are the alarmist reports of the complete disappearance of all glaciers on Kilimanjaro," says Hardy. The American scientist acts as a weatherman of sorts for the ice-capped mountain. And although he and Thompson work closely together, Hardy disagrees with much of what Thompson says, arguing that Thompson's speculations are excessive and his predictions far too premature.
Hardy laboriously works his way through the vertical face of the mountain's northern ice field. After each step he takes with his crampon, he has to rest until the painful stabbing sensation in his head subsides again. Small icicles dangle from his beard.
An athletic man in his late forties, Hardy struggles doggedly into the wind. Suddenly, he stumbles upon a jumble of antennas, solar cells and sensors protruding from the barren icescape. It's Hardy's weather station, which takes readings for snow depth, relative humidity, temperature and incident sunlight, then uploads the data onto the Internet via satellite.
When Thompson drilled his first Kilimanjaro ice samples in 2000, he asked Hardy to set up a station that would enable the scientists to learn more about the conditions under which the glaciers formed. Ironically, the data Hardy's equipment has been supplying ever since contradicts Thompson's theory of the tropical glaciers rapid demise as a result of rising global temperatures.
"Dryness, not warming, is what's causing the glaciers to recede," says Hardy. According to his readings, the average annual temperature at the station is minus seven degrees Celsius (19 degrees Fahrenheit). Hardy believes that what the glaciers lack is enough new snow -- possibly because moist winds coming from the Indian Ocean, 350 kilometers (218 miles) away, are weakening. Besides, he adds, the amount of water from glacier melt is relatively insignificant, because most of the ice is "sublimed" -- it evaporates immediately, bypassing the liquid phase.
Hardy is a fanatic when it comes to gathering facts. This is his seventh expedition to the top of the mountain, and yet he still believes that he and other researchers know too little about its ice fields. If he hears the sound of a hailstorm on his tent during dinner, he pulls out his pad and immediately makes a note of the incident. When a colleague mentions some bold new theory, his usual reaction is a long, drawn-out "hmmm."
Will the mountain's glaciers truly disappear in a few years? "No, that's highly unlikely," says Hardy. "A few hanging glaciers will still be there many decades from now."
Mt. Kilimanjaro is treacherous terrain, in more ways than one. For example, when Hardy co-authored an article criticizing Thompson's theory that global warming is destroying Kilimanjaro's glaciers as "simplistic," climate change skeptics triumphantly misread the statement as evidence that global warming isn't taking place. Hardy hates being misinterpreted and often spends months brooding over an article before approving it for publication.
"Highest point in Germany"
When he's climbing around the glacier, Hardy sometimes thinks about his most famous predecessor, a stern-eyed German with a pince-nez and a moustache: Hans Meyer, the first man to climb Mt. Kilimanjaro. Meyer is often derisively referred to as a colonialist, because he named the snow-covered African peak "Mount Kaiser Wilhelm" in 1889, calling it the "highest point on African and German soil." Tanzania was part of German East Africa at the time and to this day, the mountain's glaciers still bear German names, like Rebmann, Ratzel and Penck. But Hardy has a higher opinion of the colonial geographer than most, and sees him mainly as an incorruptible researcher. Meyer carefully mapped out and surveyed the glaciers, and even noted that they were receding to a small degree. He was the first to describe Kilimanjaro's various vegetation zones, from the savannah ("next to us stood the naked negro, and before us were palm trees") through rain forests and, finally, to the summit where, Meyer wrote, he encountered the "icy air of the poles."
Despite modern technology, studying Mt. Kilimanjaro is still an adventure today, as the climate researchers on Hardy's team discover as they set out to take readings at an electronic weather station near the "Breach Wall." Renowned Austrian mountain climber Reinhold Messner trained on this wall in 1978 before climbing Mt. Everest without oxygen equipment. According to Messner's notes on the experience, "it was gurgling, rattling, crunching and snorting nonstop. The wall was constantly vomiting rock avalanches and spitting out plumes of water. It was the liveliest wall I'd ever experienced."
The researchers suddenly find their steep path blocked by a landslide, evidence of an incident the national park administration has attempted to keep quiet. Local mountain guides say that a group of tourists was trapped by a landslide in early January. The bodies of three US tourists were recovered, and officials say that the bodies of about ten porters still lie buried underneath the loose rock. Apparently the ice that had been holding the rock together melted, causing the landslide.
Climate research in the jungles below
Not everyone is impressed by the extreme nature of doing research at the top of a mountain. "Climbing around on glaciers may be spectacular," says German biologist Andreas Hemp. "But plants tell me more about climate change than ice."
With the sure-footedness of a sleepwalker, Hemp wanders through the underbrush, among red-blooming flame trees, banana groves and ferns the size of trees. He has been studying the region's mountainous forests on behalf of Germany's University of Bayreuth for the past 15 years. Brandishing a machete to clear a path, he frequently sets out to inspect -- in some case centimeter by centimeter -- his 1,400 test sites.
Hemp lives in a colonial-era German mission. The glass windows in the mission's Lutheran church were shipped from Nuremberg, the church bells, likewise imported from Germany, continue to ring every Sunday, and the villagers sing German hymns in the local Chaga dialect.
The binders in Hemp's office are filled with dried plants. To this day, he's constantly discovering new species, usually grasses but occasionally trees. "The climate data collected by the German colonial administration show that precipitation has declined by about a third in the last hundred years," says Hemp. Some mountain streams are little more than thin trickles of water today. But Hemp sees overpopulation as a more serious problem for the region than global climate change.
"In that span of time, the number of people living at the base of the mountain has grown twenty-fold, or to about a million. The forest suffers as a result," says Kemp. "Illegal loggers are assaulting the rain forest from below, and fires have lowered the upper range of the evergreen forest -- by about 500 meters in the last 30 years." Poverty is often at the root of the forest fires, which are set by illegal honey gatherers who burn sticks of wood to protect themselves against aggressive African bees.
The loss of about 150 square kilometers (58 square miles) of mountainous forest in the past 30 years has changed the area's microclimate by making it drier. "The destruction of the forests may be accelerating the loss of glaciers, but not vice-versa," says Hemp. "In fact, all the excitement about melting glaciers has almost become part of the problem." As Hemp sees it, the park administration manages to avoid taking responsibility by blaming receding glaciers and deforestation on global climate change.
Leopards at the summit of Mt. Kilimanjaro
The climatologists working up on top of the mountain are also aware of just how complex the relationships surrounding glacier melt really are. After a long day at the summit, each answer seems to raise two new questions. One scientist even suggests that hot volcanic vapors emerging from fissures could be melting the glaciers.
The teams are constantly finding dead animals -- monkeys, antelopes, leopards -- in the summit zone, prompting them to wonder what could be driving the creatures into the extreme altitudes.
As they debate these and other questions, the researchers listlessly eat chicken and rice cooked with 4,000-year-old glacier water, their questions becoming more expansive as they chew.
According to recent results, drill cores dated about 2,200 B.C. contain an unusually high concentration of salt, possible evidence of dust clouds from dried-up saltwater lakes. According to historical sources, the region was struck by a 300-year drought at about the same time, causing harvests to fail for years and triggering the political downfall of Egypt's Old Kingdom.
"Perhaps we're seeing evidence of the same kind of drastic climate change today," Thompson speculates, "except that this time it's more severe and is happening more rapidly." What if the glaciers on Kilimanjaro do in fact disappear one day? "Then we'll study the ice fields on Mars," says Thompson, defiantly. The man is dead-serious. He's already been in touch with NASA.
Translated from the German by Christopher Sultan