A glaciologist sticks to the ‘slow’ science

A glaciologist sticks to the ‘slow’ science
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First Published: Sun, Feb 14 2010. 11 51 PM IST

Paradigm shift: Milap Chand Sharma says the notable thing about the Himalayan glaciers controversy is that it’s brought attention to glaciology. Pradeep Gaur/Mint
Paradigm shift: Milap Chand Sharma says the notable thing about the Himalayan glaciers controversy is that it’s brought attention to glaciology. Pradeep Gaur/Mint
Updated: Sun, Feb 14 2010. 11 51 PM IST
New Delhi: Milap Chand Sharma looks more like a mountaineer than a glaciologist. His tall, muscular frame and rugged looks don’t belong to the small office in New Delhi’s Jawaharlal Nehru University (JNU). Its confines, the stacks of papers, the intermittent ringing of the telephone and the occasional visitor seem to irritate him. He only smiles when talk turns to glaciers.
These might be turbulent times for most glaciologists, but not for Sharma. Apart from a few newspaper clippings that lie strewn across his desk, there’s little evidence in his office of the maelstrom the small, tight-knit community finds itself in.
“It’s less about science, more about research funding,” he says dismissively of the Intergovernmental Panel on Climate Change report on the melting of Himalayan glaciers. Then he turns impatiently to his computer screen, across which snakes the majestic form of the Gangotri glacier. “The controversy has been created by people who have little understanding of glaciers, and have rarely ventured to them.” Glaciology, like the glaciers it studies is, he says emphatically, a “slow and laborious” science, not prone to sudden changes.
Glaciers are more than just distant objects of scientific study for Sharma.
They’re living forms that he grew up with in the “one-house” village of Yangkarting in Himachal Pradesh’s remote Lahaul district. They were the source of water to the surrounding villages and the subject of local folk songs and stories.
His drift towards a formal engagement with them started early. It was intertwined with a love for mountaineering. In school in Manali, Sharma did a course on snow and ice, his “first involvement” as he calls it. In college, he chose to study geography. The choice was easy. “Where I come from nothing is more important than geography,” he says.
At around the same time, he started acquiring the mountaineering skills that he’d need for climbing, measuring and living on glaciers. While in college, he did a course in basic mountaineering at Manali’s Western Himalayan Mountaineering Institute. Later, as a student at JNU, he completed the gruelling advanced mountaineering course.
By the time he’d finished his master’s degree, Sharma was certain that he’d like to focus on glaciers.
He’d hoped to go to the University of London to study Arctic glaciers, but on the urging of his “guru”, glaciologist Lewis Owen, decided to work on Gangotri, the largest glacier in the Greater Himalayan Range. “Its social and historical relevance made it one of the best glaciers to study,” explains Sharma.
Charting the recent changes in the glacier was straightforward. The position of the snout was mapped and compared with previous photographs and records; and stakes were planted to monitor changes in precipitation at different points.
But recreating its history, as he discovered, was far more complicated. “Each glacier is a different creature,” says Sharma animatedly. Each expands and retreats in distinct ways, erodes the mountains it flows down differently, and due to the differences in terrain, each has a different set of markers that provide clues to its habits.
Paradigm shift: Milap Chand Sharma says the notable thing about the Himalayan glaciers controversy is that it’s brought attention to glaciology. Pradeep Gaur/Mint
The best indicators of historic glacial movement, says Sharma explaining the process, are the lateral moraines, or deposits of debris, that accumulate along a glacier’s edge. A technique called optically stimulated luminescence (OSL) allows glaciologists to date when the inner layers of this debris were last exposed to sunlight. That corresponds to the time when the glacier first started retreating from an area.
Sharma used the technique in conjunction with another known as cosmogenic radionuclide (CRN) dating which, in contrast to OSL, is used to determine when a surface was first exposed to sunlight. “It’s best applied to the beautifully rounded polished rocks that glaciers reveal when they retreat,” he says. Dating a rock that once lay in the centre of a glacier’s path, where the accumulation of ice is the maximum, gives the time by which its retreat was complete.
Taken together, OSL and CRN determine the upper and lower time frames of glacial retreat. The challenge, says Sharma, lies in differentiating the moraines from the similar erosion formations and in identifying glacial rocks. “It takes a lot of training to do that,” says Sharma, pointing to a photograph of an assortment of rocks which, to the untrained eye, look much the same.
Using the techniques, Sharma has, among other things, been able to show that the Gangotri glacier retreated from the present location of Gangotri town somewhere between 3,000 and 4,000 years ago.
Creating a complete movement map of Gangotri involved travelling the length of the ablation or melt zone, which extended to 60% of a glacier’s length. It was a traverse of nearly 18km involving almost vertical ascents, negotiating hidden crevasses and nights spent camping in sub-zero temperatures. Each expedition lasted nearly three weeks and required a huge number of porters. “Falls and broken bones were common,” says Sharma matter-of-factly.
An hour into the conversation, Sharma is in his element. Then his mobile phone rings. “The one thing a glaciologist should not have,” he says, shaking his head, “is a family”. His flow of thought is disturbed, but only momentarily.
All the ground measurements were incorporated into a complex overlay of aerial photographs and topographic sheets. “On their own though, neither aerial photographs nor topographic sheets are of any use,” says Sharma. The best available aerial photographs for India, he says, have a resolution of 23.5m, “way too high a margin of error for a glaciologist”; it’s also difficult to distinguish the glacier from seasonal snows in them. And Survey of India topographic sheets are peppered with inaccuracies.
According to him, there’s no replacement for ground surveying. So over the last 20 years, Sharma and his students at the geography department at JNU’s School of Social Sciences have trudged across glaciers around the country, poking, prodding and sliding their way to scientific certainty.
They undertake a couple of monitoring trips every year. A few glaciers such as Gangotri are visited almost every alternate year, others less frequently.
Apart from Gangotri, they’ve been monitoring Menthosa, Sonapani, Hamta and the Miyar group of glaciers in Lahaul, Kafni in Kumaon, Kalapani in Garhwal, Stok Kangri in Ladakh and Zemu in Sikkim. All of them are beautiful, but Sharma’s favourite is Kedar Bamak, a two-day climb from Gangotri.
The group has also been examining local history and habitations for clues about glacial movements. Dating the remains of wooden houses near Tharang village, 2km from Miyar glacier, has helped corroborate the data from OSL and CRN measurements; and in Lahaul, a folk tale from Gushal village, describing a period of drought, has provided indication of glacial melt in the region.
The work might be slow and painstaking, but there’s been plenty of excitement. Sharma has been stalked by giant Himalayan black bears, trapped by snow and rain for weeks on end, and has helped in the discovery of an Indian Air Force plane that crashed on South Dhaka glacier in 1968.
The results? “We’ve got a historical record dating back to 60,000 years for Gangotri and 40,000 years for some of the glaciers in Lahaul,” says Sharma, beaming. Those records have allowed him to compare recent glacial changes with those that took place earlier.
He admits that over the last 20 years most glaciers in the Indian Himalayas have been retreating, but similar (and much bigger) changes, he protests, have occurred many times in the past. The current changes could just be part of a natural cycle.
Many more glaciers would, he believes, need to be studied before any conclusions can be arrived at. “Glaciology is a very nascent science in India,” he says. Of the 9,575 glaciers listed in the inventory of the Geological Survey of India, only 30 or so are tracked on a regular basis.
Sharma seems to be doing his bit. In a life intertwined with that of glaciers, he has already moved on to the next white strand of rock and ice. Over the next few years, he’s going to be working with the National Geographic Society to chart the “past, present and future glaciers” of the Nanda Devi National Park. It’s an area he hasn’t worked in earlier, and his excitement is apparent.
The Indian government is pitching in by establishing the Indian Institute of Glaciology. “The great thing about the current controversy is that it’s brought attention to glaciology,” says Sharma wryly. “Hopefully, some of my students will now finally get jobs.”
akshai.j@livemint.com
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First Published: Sun, Feb 14 2010. 11 51 PM IST