No Sign Yet of Himalayan Meltdown, Indian Report Finds
NEW DELHI—Are Himalayan glaciers beating a rapid retreat in the face of global warming? That would seem to be the case, according to a flurry of recent reports by BBC and other mass media. But the picture is more complex—and poses scientific puzzles, according to a review of satellite and ground measurements released by India’s Ministry of Environment and Forests earlier this week.
The report, by senior glaciologist Vijay Kumar Raina, formerly of the Geological Survey of India, seeks to correct a widely held misimpression based on measurements of a handful of glaciers: that India’s 10,000 or so Himalayan glaciers are shrinking rapidly in response to climate change. That’s not so, Raina says. Even if it were, other researchers argue that severe loss of ice mass would not entail drastic water shortages in the Indian heartland, as some fear. Both concerns were cited in the Asia chapter of the U.N. Intergovernmental Panel on Climate Change’s (IPCC’s) 2007 Working Group II report, which asserted that Himalayan glaciers “are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate.”
Some glaciologists hew to IPCC’s view, disputing Raina’s conclusions. Any suggestion that the retreat of Himalayan glaciers has slowed is “unscientific,” charges Syed Iqbal Hasnain, a senior fellow at the Energy and Resources Institute in New Delhi. He says the Indian government has an “ostrichlike attitude in the face of impending apocalypse.”
However, India’s environment minister, Jairam Ramesh, told Science, “We don’t need to write the epitaph for the glaciers, but we need a concentrated scientific and policy focus on the Himalayan ecosystem since the truth is incredibly complex.” India, he says, needs to measure and monitor Himalayan glaciers as a matter of national security.
With ice and snowfields covering more than 30,000 square kilometers, the Himalayas are often called the “third pole.” Records that began in the 19th century show that most glaciers advanced through that century as the Little Ice Age that gripped the Northern Hemisphere tapered off. Glaciers began to retreat in the early 20th century. Since 1960, almost a fifth of the Indian Himalayas’ ice coverage has disappeared, says Anil V. Kulkarni of the Space Applications Centre in Ahmedabad, who has mapped more than 1000 glaciers using satellite data.
Raina’s report, Himalayan Glaciers: A State-of-Art Review of Glacial Studies, Glacial Retreat and Climate Change, concurs with that assessment. But it questions a link to global warming. Findings in the past few years, it states, demonstrate that “many” Himalayan glaciers are stable or have advanced and that the rate of retreat for “many others” has slowed. The report does not enumerate glaciers in either category.
The Raina report draws on published studies and unpublished findings from half a dozen Indian groups who have analyzed remote-sensing satellite data or conducted arduous surveys at remote sites often higher than 5000 meters. The report revises perceptions of a number of glaciers, including two iconic ones. For example, the 30-kilometer-long Gangotri glacier, source of the Ganges River, retreated an average of 22 meters a year and shed a total of 5% of its length from 1934 to 2003. But in 2004 and 2005, the retreat slowed to about 12 meters a year, and since September 2007 Gangotri has been “practically at a standstill,” according to Raina’s report, which cites, among other observations, field measurements by ecologist Kireet Kumar of the G. B. Pant Institute of Himalayan Environment and Development in Almora. Even more stable is Siachin glacier in Kashmir, where Indian and Pakistani forces are stationed eyeball to eyeball at 6000 meters. Claims reported in the popular press that Siachin has shrunk as much as 50% are simply wrong, says Raina, whose report notes that the glacier has “not shown any remarkable retreat in the last 50 years.”
Several Western experts who have conducted studies in the region agree with Raina’s nuanced analysis—even if it clashes with IPCC’s take on the Himalayas. The “extremely provocative” findings “are consistent with what I have learned independently,” says Jeffrey S. Kargel, a glaciologist at the University of Arizona, Tucson. Many glaciers in the Karakoram Mountains, which straddle India and Pakistan, have “stabilized or undergone an aggressive advance,” he says, citing new evidence gathered by a team led by Michael Bishop, a mountain geomorphologist at the University of Nebraska, Omaha. Kenneth Hewitt, a glaciologist at Wilfrid Laurier University in Waterloo, Canada, who just returned from an expedition to mountain K2, says he observed five glacier advances and a single retreat in the Karakoram. Such evidence “challenges the view that the upper Indus glaciers are ‘disappearing’ quickly and will be gone in 30 years,” Hewitt says. “There is no evidence to support this view and, indeed, rates of retreat have been less in the past 30 years than the previous 60 years,” he says.
Why are many Himalayan glaciers bucking the trend of rapid retreat seen in the Alps, for example, or at Mount Kilimanjaro as reported in the Proceedings of the National Academy of Sciences last week? “Glaciers at lower elevations are going to respond faster to a warming climate than those at the highest elevations,” says Richard Armstrong, a glaciologist at the National Snow and Ice Data Center in Boulder, Colorado. Snowfall patterns are more important to Himalayan glacier stability than temperatures, adds Rajinder Kumar Ganjoo, a glaciologist at the University of Jammu in India. “If rising temperatures were the real cause for the retreat, then all ice masses across the Himalayas should be wasting away uniformly,” he says. “At issue in scientific circles,” Kargel notes, “is how lengthy the response time is, and how it varies among glaciers.”
The bottom line is that IPCC’s Himalaya assessment got it “horribly wrong,” asserts John “Jack” Shroder, a Himalayan glacier specialist at the University of Nebraska, Omaha. “They were too quick to jump to conclusions on too little data.” IPCC also erred in its forecast of the impact of glacier melting on water supply, claims Donald Alford, a Montana-based hydrologist who recently completed a water study for the World Bank. “Our data indicate the Ganges results primarily from monsoon rainfall, and until the monsoon fails completely, there will be a Ganges river, very similar to the present river.” Glacier melt contributes 3% to 4% of the Ganges’s annual flow, says Kireet Kumar.
Atmospheric scientist Murari Lal, chair of the Climate, Energy and Sustainable Development Analysis Centre in New Delhi and coordinating lead author of the 2007 IPCC report’s Asia chapter, rejects the notion that IPCC was off the mark on Himalayan glaciers. But he acknowledges that the report’s 10-author team relied on unpublished work when assessing the status of the glaciers. India’s U.N. delegation had objected to the wording, Lal recalls, but in the IPCC plenary session the analysis got wide support.
Raina’s report is by no means the last word. The surprising stability of some glaciers may be a temporary phenomenon, says Hewitt: Melting may have been reduced by a change in summer weather, such as increased cloudiness, and possibly unusually heavy snowfall, he says. “There needs to be a lot of research on [Asia's] mountain glaciers,” adds glaciologist Lonnie G. Thompson of Ohio State University, Columbus. “Truly, we know less about them than any other place on Earth.” Both sides of the debate agree on one point: Forecasts hold little water, so only a robust observation campaign will reveal whether the third pole’s resistance to climate change is durable—or ephemeral.
Copyright 2009, AAA
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