Life and Death in a Dry Land
At the cusp of the seasons in late May, as the austral summer gave way to winter, something unusual happened in Lima, the capital of Peru. It rained. Although perhaps even that statement needs to be qualified. There was precipitation, the thinnest of drizzles, just enough to leave a slick of moisture on the pavement.
I was standing on a concrete barrier above the Río Rímac, which supplies the city with four-fifths of its water, in the company of an engineer named Oscar Sánchez, a 30-year veteran of the state water authority, SEDAPAL. Nearby, a group of neatly uniformed schoolchildren were learning how the flow of the Rímac is handled here at the city’s gigantic water treatment plant, La Atarjea -- removal of solid waste, filtration, chlorination, and so forth. Sánchez nodded approvingly as the kids asked questions. "People have to start learning where their water comes from and how scarce it is here," he said. "It’s not just a question of turning on the faucet."
Lima gets less than half an inch of precipitation a year, he told me. Most of this comes in the form of the garúa, a dense sea mist that for the next six months would envelop this already unprepossessing city in a clammy, gray murk. But this is only the beginning of Peru’s climatic weirdness -- and its global significance.
The source of the garúa is the Humboldt Current, a powerful flow of cold water that moves from Antarctica up the western edge of South America. When warm tropical air meets this current, the result is a blanket of water vapor. Every few years, at unpredictable intervals, the Humboldt Current reverses direction -- the so-called El Niño Southern Oscillation, or ENSO. (El Niño -- The Child -- was given its name by Peruvian fishermen because it often occurs around Christmastime.) Weather patterns are turned on their head, often with devastating effects: as warm water pools in the ocean, Peru’s coastal desert is swamped by torrential rains, and the normally wet highlands are wracked by drought. To complicate matters further, a related phenomenon called La Niña turns the ocean current abnormally cold; when this happens, the aridity of the coast increases while the sierra gets heavier rain and snow.
The impact of these turbulent events is not just local. The onset of El Niño in Peru affects the intensity of Asian monsoons and Atlantic hurricanes as well as rainfall in places as far apart as Australia, Tibet, and the Nile Valley. Some scientists even believe that El Niño cycles explain the "seven years of plenteousness" and "seven years of famine" in Genesis. Understanding El Niño, in other words -- and particularly the millennia of evidence left behind in Peru’s glaciers and interpreted by an American scientist named Lonnie Thompson -- gives us unique insights into the past, present, and likely future of our global climate.
City of the Kings
From our vantage point above the river, Sánchez gestured upstream into the garúa. The Rímac rises in the icy peaks of the Cordillera Central, he explained, at about 16,000 feet. On its steep 100-mile rush to Lima, the modest river must serve the needs of countless farms, villages, and small towns and meet the demands of the copper, gold, zinc, and silver mines that are Peru’s principal source of exports -- and of water pollution. In addition, a string of hydropower plants on the Rímac supplies Lima with two-thirds of its electricity. These plants have no storage reservoirs, Sánchez explained, and this, coupled with profligate water use and poor management, explains why 40 percent of the meager flow of the Rímac ends up in the ocean without being captured for human needs.
Upstream, a swirl of water from a deep holding pool was being channeled into the treatment area. Downstream, this being the tail end of the dry season, there was nothing but a broken shelf of concrete and a few stagnant puddles in a dry bed of gravel, like a dilapidated version of the Los Angeles River. Beyond the puddles, invisible in the fog, the city stretched away for more than 10 miles to the Pacific.
Francisco Pizarro and his Spanish conquistadores established Lima, or La Ciudad de los Reyes, as it was first known, in 1535, in one of the world’s driest deserts. By the eve of World War II, Lima was a city of 300,000. Since then, successive waves of rural migrants have swelled that number to nine million. Almost a quarter live in vast, sprawling shantytowns, the asentamientos humanos, most of which have no running water. In the next quarter-century, at the current rate of growth, Lima’s population will balloon to 15 million. Demand for water will double.
Two-thirds of Peru’s population of 28 million live on the arid western side of the Andes, but this area has only 2 percent of the country’s water, and that amount is steadily diminishing. Whether this dilemma remains just insanely stressful or threatens the very viability of the country will depend largely on the fate of the glaciers of the high Andes.
The Andes contain 99 percent of the world’s tropical glaciers (which sounds at first like an oxymoron, but altitude is everything). Peru alone accounts for almost three-quarters of them. These glaciers are not only an indispensable water source, storing and releasing the precious liquid on a seasonal cycle, nourishing depleted rivers during the long dry season; they are also an invaluable data bank on climate change.
As early as 1943, the Peruvian glaciologist Jorge Broggi theorized that the first signs of glacial retreat were related to a warming climate. That correlation is now beyond argument. According to the latest government estimates, between 1970 and 2006 fully one-third of the ice cover disappeared, and the rate of loss has increased. Within 10 years, all the ice below 5,000 meters (16,400 feet) -- which includes virtually all of the glaciers that feed the Río Rímac and Lima -- is likely to be gone. This pattern of accelerating retreat is occurring in every glaciated area in the world, from Antarctica to the Tibetan Plateau, from the European Alps to the North American Rockies.
Rising temperatures will be accompanied by radical changes in annual precipitation. In some parts of the Andes, rain and snowfall will decline by as much as 20 percent, greatly reducing the flow of the rivers that run to the parched Pacific coast. As the glaciers melt away, however, there will be a temporary illusion of bounty that will tempt water users into reckless assumptions about the future -- making, for example, extravagant new investments in unsustainable agriculture. By 2050, the government predicts, Peru may have lost 40 percent of its water.
But enough of statistics. Why does any of this matter to the rest of us? Isn’t the future of Peru, as the British Prime Minister Neville Chamberlain famously said of Hitler’s attack on Czechoslovakia, "a quarrel in a faraway country about a people of whom we know nothing"? The answer is no. The assault of climate change on Peru affects all of us. To see why, however, requires a journey not just to the thirsty slums of Lima and the snow peaks of the Andes but to the unlikeliest of places: a freezing basement in Columbus, Ohio; the ruins of a sixth-century pyramid; and the produce aisle of your local supermarket.
In the Death Zone
If Lonnie Thompson was not recognized as one of the world’s great climate scientists (technically he is a paleoclimatologist), he would surely be considered one of the world’s great explorers. He is said to have logged more hours in the planet’s oxygen-thin "death zone" -- elevations above 18,000 feet -- than any other human being. At 62, he continues to ascend to these places at least once a year, often for weeks at a stretch and sometimes for months, while supervising the transport by porters and mules of tons of ice-drilling equipment and managing teams of often fractious colleagues, not to mention coping with his crippling asthma.
Stepping up to the podium at a seminar at Ohio State University in Columbus in late March, Lonnie (his modesty of manner seems to encourage everyone to call him that) was introduced by his wife, Ellen Mosley-Thompson, who is the director of the university’s Byrd Polar Research Center. She too is an expert on ice, but while Lonnie’s specialty is tropical glaciers, hers is Antarctica and Greenland. "That combination has worked well for us, especially while we were raising our daughter," Lonnie told me later. "It meant that one of us was always home."
Lonnie is a man of medium height, with receding hair and rimless glasses. He speaks softly, with strong remnants of his native West Virginia accent. His manner is somewhat owlish, with flashes of dry humor. Today he was wearing an unremarkable gray suit. A row of pens and a pocket protector would not have seemed out of place. He conforms to no one’s idea of Indiana Jones on ice.
I alluded to this, diplomatically I hoped, when his talk was over. He grinned and suggested that since our schedules in Peru would not coincide, I might look at a couple of documentaries of his work. I did so later. There he was, crouched in an ice cave at 20,000 feet with several colleagues, wearing mountain gear and a watch cap. None of them had shaved in a while. The image brought to mind something that was once said about glacier fanatics by a member of Lonnie’s inner circle of collaborators, the aptly named Australian Keith Mountain: "We’re not pretty. We smell a lot and we have horrible bodily habits."
Lonnie’s core philosophy is simply expressed. To discover something new, you go to a place where no one has ever been before; once you get there and look around, you are certain to make new discoveries. His goal in choosing these perilous work sites is to gather and analyze as much high-altitude ice as he can while the glaciers are still there and he still has the stamina. His findings will then form a mosaic with parallel discoveries from tree rings, lake and ocean sediments, coral reefs, speleotherms (mineral deposits in caves), and other so-called climate surrogates, which cumulatively will give us the fullest possible picture of the world’s climate and its likely future.
In his presentation at the Byrd Center, Lonnie described the three basic indicators of the health of a glacier. The first and most easily measured is the shrinking of its surface area. The second is something called mass balance, which calculates the relationship between the accumulation of ice and its ablation -- that is, the loss of volume through melting and through the transformation of ice into a gaseous state without passing first through a liquid stage. The third indicator is the thinning of the ice from the top down. Unlike the loss of surface area, mass balance and thinning can’t be measured with satellites and aerial photography; you have to delve into the ice itself. "Thinning, in particular, is absolutely critical," Lonnie told me. "On Kilimanjaro, for example, we found that the glacier is losing as much through thinning as it is through retreat at the margins. So it’s actually even worse than it seems."
He gave his audience some of the most salient statistics about Peru’s vanishing ice, showing dramatic before-and-after slides that depicted the recession of particular glaciers over time. And he shared a favorite quotation, by the University of Michigan geophysicist Henry Pollack: "Ice asks no questions, presents no arguments, reads no newspapers, listens to no debates. It is not burdened by ideology and carries no political baggage as it changes from solid to liquid. It just melts."
It does, however, generate all manner of questions, arguments, and political debates. Lonnie is one of a small but growing number of glaciologists who have come to believe that the study of climate change has to move out of the bastion of pure science. All kinds of social forces -- agribusiness, industry, subsistence farmers, energy utilities, city residents -- lay claim to the water that drips from the glaciers, and their demands will escalate as the supply diminishes. Already, half of all the social conflicts that are serious enough to be recorded by Peru’s ombudsman’s office derive from disputes over scarce water.
This article was made possible by a generous grant from the Larsen Fund.