ABCs are made up of a variety of particles that have the capacity to both absorb and reflect solar heat. Since dust and black carbon soot particles absorb heat, they increase global warming. (Ramanathan and Feng estimate that such absorption causes as much as 50 percent of the warming of the atmosphere.) But ABCs also decrease warming, because they contain sulfate and nitrate particles, which act like little mirrors reflecting incoming heat back out of the atmosphere, resulting in lower temperatures at ground level. Ramanathan and Feng believe that this “dimming” or “surface cooling effect” has “masked a significant fraction of the warming effect of the GHGs blanket.”
At first, one might feel relieved to learn this rather counterintuitive fact. But as scientists go on to point out, because heat-reflecting particles in ABCs are very short-lived in the atmosphere (falling back to earth after emission in a matter of weeks), while the GHGs from the burning of these fuels last in the atmosphere for decades, the gain is only temporary. What is more, if mankind does find a way to clean up these toxic clouds, these scientists say it would be “like removing the mask.” Very quickly thereafter, because their “dimming effect” would be lost, “the climate may play catch-up to compensate,” causing the planet to experience a rapid leap of approximately 1.6°C in additional warming. In other words, as serious as the planet’s already warmed state is, should ABCs ever be eliminated we will be in for a significant, unexpected, and unwelcome further jump in temperature.
Of course, none of these sources of additional warming are good news for glaciers. But the most immediately harmful effect on Himalayan ice from ABCs comes from yet something else: the black carbon soot that migrates up onto the Tibetan Plateau, carried by precipitating monsoons.
When we think of glaciers, we usually evoke 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 imagine 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, and one important link is black carbon soot.
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 ABCs 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. When cooled at high altitudes, this moist monsoon air condenses into rain and snow. However, because of increasingly warmer high-altitude temperatures, once the soot-laden snow lands, more of it now quickly melts before new snow can bury it and compress it into glacial ice. So with successive meltings of new layers of freshly fallen snow, 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 had markedly increased since 1990, had now become “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 like Hansen and Yao now fear that “most glaciers, worldwide, will be lost this century, with severe consequences for fresh water supplies.”
On a trip I made recently to the Tibetan Plateau in Yunnan province to observe the Yongming and the Baishui #1 glaciers, what was striking was just how gritty both their surfaces were. This is not unusual, but here it was a reminder that the wages of soot, along with warming, are speeding these two glaciers on their way to being among the fastest melting in the Greater Himalayas. It is hardly surprising, then, that while between 1950 and 1980 only 50 percent of the glaciers in the Tibetan region were in a state of recession, during the early part of this century that figure rose to 95 percent.
The Permafrost Melt
As global temperatures continue to rise, moreover, the vast expanse of permafrost beneath much of the grasslands on the Tibetan Plateau’s northern tier is also now at risk of thawing. This will have effects on the watershed that feeds the Yellow and other rivers. It will also accelerate desertification and degrade the pasturelands on which traditional nomads have long depended. But the most profound global impact of this thawing, which has already begun, will be the enormous amounts of methane gas—roughly twenty times more potent in heat-trapping capacity than CO2—that will be released by the decomposition of once-frozen carbon rich organic matter in the area’s soil. Indeed, continued thawing threatens to turn what has been a major carbon-sink—sequestering about 2.5 percent of the world’s soil carbon—into a huge new source of emissions.
Ice in the Rest of the World
The Greater Himalayas are, of course, not the only place in the world where ice is melting. According to the World Glacier Monitoring Service, average annual glacier global melt rates “appear to have doubled after the turn of the millennium, in comparison with the already accelerated melting rates observed in the two decades before.”
The ice on Mount Kilimanjaro, which a century ago was twelve square kilometers in size, has now been reduced to less than 1.5 square kilometers, and is predicted to be completely gone within two decades. In Montana’s Glacier National Park, the spring season—as measured by temperature—now starts forty-five days earlier than when the park was established in 1910. Then, the park had 150 glaciers, whereas now only twenty-five remain, and park staff predicts that even these will be gone by 2030. And most of the Rhône Glacier in the Swiss Alps, a major water source for Europe’s Rhone River, is now expected to be gone by the end of the century.
Global warming is also having serious effects on Arctic and Antarctic ice systems. Summer Arctic ice has shrunk from 7.5 million square kilometers in the late 1970s to 4.5 million square kilometers in 2007. As Alun Anderson, author of After the Ice, put it in a recent article, “The Great Melt”:
For millions of years, the great dome of brilliant white ice at the top of the planet has reflected the 24-hour polar summer sunlight back into space, helping cool the entire globe…. We are almost certainly too late to reverse the disappearance of Arctic ice—even if drastic cuts are made in greenhouse gas emissions.
Another large concern is that melting glaciers on the Tibetan Plateau, and other climate change–induced disruptions, will have “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.
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 out through the larger environment and downward through some of the most populous places in the world? Only if we find a way to reduce GHG emissions and carbon soot levels in the atmosphere.
Such reductions would require not only new transnational strategies, but new regional organizations. Countries like India and China have at last begun to discuss the issue of glaciers, and an awareness of the consequences of climate change has been advancing rapidly in both countries. But the Indian minister of environment and forests, Jairam Ramesh, recently released a report questioning whether glaciers in the region are actually melting in a precipitous manner, and the two countries have yet to take joint action. Yet this is not a national but an international problem. And since UN-sponsored international discussions on climate change ended in a stalemate at Copenhagen in December 2009, only isolated responses—some impressive in their ingenuity, but ineffective in terms of any grand solution—have actually been undertaken.
An enterprising road-builder from Ladakh in northern India, Chewang Norphel, launched an unusual effort in response to a retreating glacier in northern India that farmers had relied on for centuries to irrigate their spring planting. The glacier had retreated to such a high altitude that the meltwaters, which had traditionally begun to flow in March, did not start until May (when it is too late to plant and still harvest before winter). Noticing that there was water gushing from a pipe left open during the winter to keep it from freezing, Norphel began using the water to flood a small field, in effect slowly creating, as it froze, a small artificial glacier that could be counted on to melt in March when it was needed.
“People laughed when I first presented the idea,” he told Science. But when spring came and these same people saw water flowing to their fields, they started helping. Ultimately, his artificial glacier grew to be two kilometers long and Norphel, now known as “Glacier Man,” went on to create nine other such synthetic glaciers.
Norphel’s ingenious project got attention in the press. But it did little to remedy the larger challenge: that the lives of hundreds of millions of people across Asia are going to be affected because of what is happening in the remoteness of the Tibetan Plateau.
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, like glaciologist Yao Tandong, bluntly cautioning 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.” Moreover, scores of reports are now pouring out of NGOs, also sounding alarms.
“This mountain system [the Himalayas] is extremely vulnerable to global warming,” warns a recent report from the Kathmandu-based International Centre for Integrated Mountain Development. “Uncertainties about the rate and magnitude of climate change and potential impacts prevail, but there is no question that [climate change] is gradually and powerfully changing the ecological and socioeconomic landscape…. Business as usual is not an option.”
Still, even as the scientific evidence of human impact on this defiant but delicate region piles up around us and we see the patrimony of these glaciers melt away before our eyes, we remain strangely reluctant to acknowledge how radically we have altered our relationship to this part of the natural world. Why, wonders Craig Dilworth in his invigoratingly pessimistic new book, Too Smart for Our Own Good: The Ecological Predicament of Humankind, do we make “no serious attempt to remedy the situation, despite our being aware of it?”
There are, of course, many answers. But 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 stretches from the melting glaciers of the Greater Himalayas to the Indian or Chinese peasant who relies on the waters of the Ganges or the Yellow River to survive. And many more studies should be undertaken to scientifically clarify all these links. But there is already enough information for the world to know that we confront a very dangerous prospect, with no adequate effort underway to find the missing link between the knowledge we already have and action.
—Beijing, April 26, 2010
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‘The Message from the Glaciers’ July 15, 2010