Thin Ice

Unlocking the Secrets of Climate in the World's Highest Mountains

Mark Bowen

A John Macrae/Holt Paperbacks Book

Thin Ice
The Aymara are descended from the Tiwanaku, a mysterious pre-Incan people who once ruled an empire encompassing most of present-day Chile, Peru, and Bolivia from a city on the shores of Lake Titicaca, an inland sea on the high Altiplano. Like their ancestors, many of today's Aymara revere the snow-covered mountains as gods, for they produce the rare trickles of water that make life possible in this inhospitable land. The Aymara believe water is to the land as blood is to the body--the sacred essence of life and fecundity--and that mountain spirits show their wrath through ferocious storms or by holding the water back, in the sky. In the eerie, looming presence of Sajama, one can understand and even share in this belief.
Modern society also treats Sajama with respect. Commercial jets are forbidden from flying overhead, for the mountain's core contains an enormous magnet that may twist the needle of a compass more than twenty degrees away from true magnetic north.
When Lonnie Thompson arrived in small Sajama village, a few miles west of the mountain, with twenty-odd scientists, a fleet of outfitters from La Paz, the five Peruvian mountaineers who have supported his high-altitude work for decades, and six tons of equipment, the villagers decided they did not want him disturbing the local deity. Similar visitors from the University of Massachusetts, Lonnie's collaborators, had set up a satellite-linked weather station on the summit the previous year, and the subsequent growing season had been poor. The villagers were afraid alarger expedition might induce more severe retribution. Impassioned negotiations ensued.
Bernard Francou remembers the bargaining as the most engaging cultural experience of his six years in Bolivia. It fell to Lonnie to convince the people of Sajama--more baleful an assemblage than any grant review committee back in the States--that his work was relevant to their own lives.
He told them that the ice on their mountain could give him information not only about Bolivia's changing climate but also about El Niño, the mysterious change in the weather that visits the Altiplano every two to seven years. Their mountain and their dry vegetable plots, which provide a marginal existence even in the best of years, feel El Niño's effects quite directly.
Since it generally appears at around Christmastime, the phenomenon was named for the Christ child by anchovy fishermen living less than a thousand miles northwest of here, in the coastal villages of Peru and Ecuador. They noticed that the cold waters that they fished, normally one of the most productive fisheries on earth, rose in temperature with El Niño, and the anchovy disappeared. This disrupts the entire aquatic food chain and the economy based upon it. Seabirds, which feed off the anchovy and produce the mountains of guano that the local farmers use as fertilizer and export all over the world, disappear as well. And while the sea withholds its bounty, it drives huge thunderheads into the skies above the equatorial coastal plain, normally one of the driest places on earth, producing storms, flash floods, and the occasional deadly landslide.
Simultaneously, more than nine thousand miles to the west, New Guinea, one of the wettest places on earth, experiences drought, as do Australia and the Indonesian archipelago. The Asian monsoon generally fails, while, farther west, the Horn of Africa receives torrential rain.
El Niño's sister, La Nina, who usually visits on his heels, makes Peru even drier than usual and New Guinea even wetter. This climatic seesaw, which scientists have named the "El Niño/Southern Oscillation," or ENSO, spans the Pacific and has immediate collateral effects nearly everywhere on earth.
And ENSO is just one--though perhaps the most notorious--of the myriad oscillations and seesaws known to climatologists. Seesaws and oscillations, either in time or in space--some real, some perhaps imagined and the subject of intense debate--are the basic stuff of climatology. A cycle may span years, as with El Niño, decades, several centuries, or hundreds of millennia. Only a few have El Niño's global reach.
To find a particular cycle, a climatologist must generally tease it outfrom among dozens of others. Consider the motion of the sun across the sky, which can change temperature by as much as sixty degrees in a single day; the hourly or weekly changes we call weather; the seasons; subtle changes in our orbit around the sun, having periods of tens or hundreds of thousands of years; sunspots and other cycles in solar output--and all of these have different strengths at different latitudes and longitudes. It's like a kid playing with a yo-yo, bouncing on a pogo stick, in a car on springs, zooming along on a roller coaster--worse, actually.
The devastation wrought by the last few El Niños has made the phenomenon a household name in recent years. Its east-west, transpacific seesaw has become relatively well known; but Sajama, in Bolivia, stands at the southern end of a second, lesser-known, north-south seesaw with equatorial Peru. When El Niño brings storms to Peru, Sajama experiences drought; when La Niña brings drought, Sajama receives rain.
AT THE NEGOTIATING TABLE, LONNIE EXPLAINED THAT IF HE COULD FIND BETTER WAYS to predict the onset and strength of these climatic siblings he might help the people of Sajama choose appropriate crops for the corresponding wet and dry years. For some inscrutable reason, however--perhaps out of caution, for they are not yet entirely confident in their predictions--he and Bernard did not reveal that the Southern Oscillation Index was dropping and an El Niño was on the way.
But they did point out that a global change of another sort was taking place, that Sajama's glacier was retreating (as the locals had already observed), and that every glacier in the tropical zone will probably disappear within fifty years. Sajama lies just inside the southern edge of the tropics--the main reason Lonnie wanted to drill there. Its high glacier should outlast the others, which are generally lower and nearer the equator, but the odds are that it, too, will disappear while the children, playing as he spoke in the streets of that village, are still alive. And since Sajama's snow is their primary source of water, its disappearance stands to have a dramatic effect upon their lives.
Lonnie happened to have some idea just how dramatic that effect might be. Two ice cores he had recovered fifteen years earlier, on the summit of the Quelccaya massif on the northern Altiplano, in Peru, had shown that climate change had played a major role in the births and deaths of numerous Andean civilizations five hundred and more years ago--the ancestors of these very people among them.
Archeologists have long known that the Tiwanaku abandoned their city by the lake shortly after A.D. 1000. They had no written language, and there was no explanation for their demise until the Quelccaya ice coresrevealed that a severe drought had set in on the Altiplano just before the Tiwanaku disappeared. The drought persisted for about four hundred years, and when it withdrew, the first Aymara city-states emerged. Furthermore, the drought commenced about a century after a warm spell began on the Altiplano, and its span coincides with an event that is sometimes called the Medieval Warm Period, in which temperatures in many parts of the world, including northern Europe, rose for about four centuries. Based on this evidence, one might expect the present warming to cause another devastating drought in this arid land.
You can tell just by looking that the people of the Altiplano are tough--not threatening, strong in the face of adversity. The Aymara of today grow the same crops, tuned to the Altiplano's cold, dry climate, that the Tiwanaku farmed more than a thousand years ago: tubers like potato, oca, olluco, and mashwa, and the unique, cold-adapted grains quinoa and caniwa. Their way of life and animist belief system have withstood the Incas, the Spanish conquistadors, and--at least until now--the lure of the city. But a few bad years might change that. Already El Alto, the slum by the airport on the Altiplano above La Paz, is swelling from a steady trickle of migrants across the high, windswept plain.
WHEN THE SCIENTISTS FINALLY WORKED OUT A DEAL WITH THE PEOPLE OF SAJAMA, A delegation from the village joined them at base camp to conduct a ceremony similar to those that had taken place ten and more centuries earlier in the city of Tiwanaku. They gathered together in a circle around a bonfire and passed around an endless supply of coca and legía, chasing them with shots of grain alcohol. (One scientist testifies that his head went completely numb.) Two yatiri, or holy men, offered songs and prayers to Sajama and Pacha Mama ("Lady Earth"), seeking fertility for their families and fields and forgiveness for the transgressions they planned. Lastly, the yatiri laid a white llama on a smooth stone, used before for this purpose, and slit its throat. They spilled blood, the magic elixir, into a ritual ceramic cup. Singing songs and scattering figurines of humans and animals in the fire, they sprinkled the animal's blood on the sand.
Lonnie reached the summit two days later.
Copyright © 2005 by Mark Bowen