The Message From the Glaciers – Orville Schell
It was not so long ago that the parts of the globe covered permanently with ice and snow—the Arctic, Antarctic, and Greater Himalaya (“the abode of the snows” in Sanskrit)—were viewed as distant, frigid climes of little consequence. Only the most intrepid adventurers were drawn to such desolate regions as the Tibetan Plateau, which, when finally surveyed, proved to be home to the planet’s fourteen highest peaks. The majestic arc of mountains that compose the Greater Himalaya begins in Inner Asia with the Tianshan range in western China and wraps around the western tier of the Tibetan Plateau as it becomes the Hindu Kush in northern Afghanistan. It then joins the Karakorum in northern Pakistan and becomes the Himalaya above Nepal, Bhutan, and India, before ending with the Hengduan range in southwestern China. Because these mountains encompass the largest nonpolar ice mass in the world—and, since time immemorial, have held water in frozen reserve for the people of Asia—they have come to be known as the “Third Pole.”
There was a time when the immensity of such larger-than-life features of our natural world as oceans, deserts, mountains, and glaciers evoked awe and even fear. These days, however, these once seemingly eternal and invincible aspects of our planet’s architecture are on the defensive. Only belatedly are we beginning to understand how fragile and interconnected they are with myriad other elements of planetary life. Scientists are now warning that we could see a 43 percent decrease in ice-covered landmass in these mountains by 2070. In numerous and complex ways, this loss will affect Asia’s ten major rivers—the Yellow, Yangtze, Mekong, Salween, Irrawaddy, Brahmaputra, Ganges, Indus, Amu Darya, and Tarim. It is here, among the huge modern-day populations of Asia, that the melting of the Greater Himalayan glaciers will have the most significant impact over the coming decades and centuries. The United Nation’s Intergovernmental Panel on Climate Change concluded that because “more than one- sixth of the world’s population live in glacier- or snowmelt-fed river basins and will be affected by the seasonal shifts in stream flow,” a serious downstream problem is unfolding.
Glacial ice-melt from the Greater Himalaya provides Asian river systems with important seasonal flows of water. But what makes glacial melt so critical, even when it is a relatively small percentage of a river’s annual flow, is its timing. If these flows of glacial meltwater come during the hot, dry spring and fall months—the so-called shoulder
seasons just before and after the monsoon—they are welcomed, as they keep the volume of river water constant. However, any disruption of these flows—especially when a monsoon is late, weak, or fails—significantly disturbs not only agriculture but also industry, fisheries, transportation, and many other aspects of life for hundreds of
millions of people downstream. Until now, the world’s formidable glaciers hardly seemed vulnerable. While they may appear immobile, they are actually “rivers of ice,” as the great Swiss geologist Louis Agassiz described them, and they are constantly shifting downward from their “accumulation zones” high on mountainsides, carving out whole valleys as they move. A glacier’s lower reaches are known as its “ablation zone,” because it is there that the glacier “calves,” or sloughs off, giant pieces in a process that can give off unearthly noises—like a giant door creaking open or a cannon shot. After these terrestrial icebergs break off, the ice begins the final stage of its long odyssey to the sea, as meltwaters flow into the river systems of the vast and populous Asian continent. As long as the buildup of new ice in a glacier’s accumulation zone remains greater than the losses in its ablation zone, “mass balance,” or equilibrium, is maintained. But most of the world’s “reference glaciers”—those two-hundred-plus that have been under observation over the past sixty years by the Switzerland-based United Nations World Glacier Monitoring Service—have begun to record significant losses.
The glaciers have been put in jeopardy by man’s voracious appetite for energy, and only now are we starting to realize the critical links between the thirsty, riverine lowland population centers of East, Southeast, and South Asia and the high-altitude ice fields of the Greater Himalaya. When we think of glaciers, we usually conjure images of pristine, white leviathans of mountain ice, radiant in the sunlight, sweeping down spectacular alpine valleys to
produce streams of cold, pure water. When we think of fossil fuels, on the other hand, we envision very different images—of dark, grimy coal mines and pitch-black oil gushers and spills that despoil nature. While, at first blush, glaciers and fossil fuels may seem opposite and unrelated, in reality, they are intimately connected.
It was coal that, by providing the primary source of energy, fueled the industrial revolution in Europe, the development of America as a great manufacturing power in the twentieth century, and the rise of China as an engine of global export in the twenty-first century, in the process catalyzing most of the advances of the modern world. Currently, coal generates approximately half of all electrical energy in the United States and roughly 80 percent in China. But coal also has emitted the lion’s share of carbon dioxide into the world’s atmosphere, triggering what we now know as climate change.
By interfering with the planet’s ability to reflect incoming solar heat from the Earth’satmosphere, greenhouse gases, such as carbon dioxide, have caused an average rise in global temperature of three-quarters of a degree centigrade over the past century. But scientists who construct models of global warming to predict future outcomes also believe that because of an ongoing, delayed reaction, existing greenhouse gas emissions (those released before 2005) alone—quite apart from future emissions—will cause an additional increase of approximately 2.4 degrees centigrade during the next century. Furthermore, the scientists contend, unless current emissions rates are radically curbed, future average temperatures could rise by as much as 4.3 degrees centigrade.
A few degrees here and there may not seem like much to a layman; but ecosystems, especially those involving ice, are so delicately balanced that even shifts of a degree or two can have profound impacts. What is more, when it comes to the Greater Himalayan region, climatologists tell us that global average temperatures are a deceptive measure. Far greater temperature rises occur as a result of global warming in certain high-altitude regions than elsewhere. On the Tibetan Plateau, warming has increased at upwards of three times the global average.
Two of the world’s leading glaciologists, Lonnie Thompson, a professor at the Ohio State University’s Byrd Polar Research Center, and Yao Tandong, director of the Chinese Academy of Sciences’ Institute of Tibetan Plateau Research, concluded that temperatures in these mountains are likely to rise as much as 5 degrees to 6 degrees centigrade over the next hundred years. Needless to say, such a precipitous rise would only accelerate melting, leading to an even more drastic loss in ice mass, as well as an increase in potentially catastrophic outbursts of water from glacial lakes, downriver flooding, and, eventually, diminished flows and periods of drought affecting human
communities both upstream and down. As Zheng Guoguang, head of the China Meteorological Bureau, put it, “If the warming continues, millions of people in western China will face floods in the short term and drought in the long run.” As important as rising temperatures are in understanding what is happening to Tibetan Plateau glaciers, another major factor is at work causing damage: black carbon. Atmospheric brown clouds are aerosol suspensions of very small particles created by the inefficient combustion of coal, kerosene, and diesel oil, as well as biofuels from
home cooking fires. This particulate matter causes the brown clouds that regularly hang like a pall over densely populated areas of the Indian Subcontinent and China. Atmospheric brown clouds have reflective properties that momentarily decrease warming because their sulfate and nitrate particles act as little mirrors, reflecting incoming heat back into the atmosphere. At first, one might be relieved to learn this rather counterintuitive fact. But because the heat-reflecting particles in atmospheric brown clouds are very short-lived in the atmosphere, falling back to Earth after a matter of weeks, whereas greenhouse gases from the burning of these fuels remain in the atmosphere for decades, the gain is only temporary. At the same time, the dust and black carbon soot particles absorb heat, thus increasing global warming. James Hansen, director of NASA’s Goddard Institute of Space Studies, and Chinese glaciologist Yao Tandong have been doing research and fieldwork on how the black carbon that was once immobilized deep beneath the ground now affects the snowy surfaces of high-altitude glaciers and will become “a significant contributing factor to observed rapid glacier retreat.” While airborne atmospheric brown clouds can migrate across oceans, making one country’s pollutants another’s problem, black carbon from India is more immediately deposited on Himalayan glaciers via warm, moisture-laden, southerly monsoon winds that sweep it up onto the Tibetan Plateau. The moist monsoon air condenses into rain and snow, and when the soot-laden snow lands, more of it melts quickly, before new snow can bury it and compress it into glacial ice. So, as new layers of freshly fallen snow melt, concentrations of black soot build up, turning the surface of glaciers into giant collectors of solar heat.
On the accumulation zone of one glacier in the Qilian Mountains in western China, Hansen and Yao found that “fresh snow melted within two days, exposing dirtier underlying snow with black carbon concentration seven times greater than the fresh snow.” They concluded that the soot burden, which has increased markedly since 1990, is now “sufficient to affect the surface reflectivity of the glaciers” by increasing their “effectiveness in absorbing sunlight.” With their natural reflective and self-protective ability, or “albedo,” impaired by soot, and with temperatures continuing to rise, scientists such as Hansen and Yao now fear that “most glaciers, worldwide, will be lost this century, with severe consequences for fresh water supplies.”
We have only recently become aware of the potential for “cascading effects” across ecosystems, creating chain reactions of disturbed relations between ice, water, plants, animals, and people in a complex web of cause and effect that scientists have hardly begun to probe. As global temperatures rise, the vast expanse of permafrost beneath much of the grasslands on the Tibetan Plateau’s northern tier is now at risk of thawing. This affects the watershed that feeds the Yellow and other rivers. It also accelerates desertification and degrades the pasturelands on which nomads have long depended. Stores of methane gas are released by the decomposition of once-frozen carbon-rich
organic matter in the area’s soil. Is it possible to keep the delicate ecology of these crucial Asian mountains from being pushed further out of balance in ways that will ripple through the larger environment and downward through some of the most populous places in the world? Only if we find a way to reduce greenhouse gas emissions and carbon soot levels in the atmosphere.
Not long ago, it would have seemed extreme for respected scientists to warn so overtly of environmental apocalypse. But now we quite regularly hear the likes of NASA’s James Hansen warn that “continued ‘business-as-usual’ emission of greenhouse gases and black soot will result in the loss of most Himalayan glaciers this century, with devastating effects on fresh water supplies.” Or we hear Chinese scientists, such as glaciologist Yao Tandong, bluntly caution that “studies indicate that by 2030 another 30 percent [of the Himalayan glaciers] will disappear; by 2050, 40 percent; and by the end of the century 70 percent,” and that “the full-scale glacier shrinkage in the plateau
regions will eventually lead to an ecological catastrophe.”
Still, even as the scientific evidence of human impact on this defiant but delicate region piles up around us and we see these glaciers melt away before our eyes, we remain strangely reluctant to acknowledge how radically we have altered our relationship to the natural world.
Surely it is one of the great ironies of our age that even in the midst of the information technology revolution, which daily inundates us with vast quantities of information that are supposed to inform and liberate us, we are still unable to synthesize it so as to galvanize ourselves for action. There are many links in the chain of cause and effect that stretch from the coal mines to the melting glaciers of the Greater Himalaya to the Indian or Chinese peasant who relies on the waters of the Ganges or Yellow River to survive. We confront a very dangerous prospect, with no adequate effort under way to find the missing link between the knowledge that we already have and action.