Monday, December 17, 2007

Worries About Water as Chinese Glacier Retreats

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An image of the Mingyong glacier taken in 1913.
Frank Kingdon-Ward

This image of part of the Mingyong glacier was taken in 1913. Courtesy Royal Geographical Society

An image of the area taken in 2004 shows the glacier's retreat.
Robert Moseley

An image taken in 2004 from the same point, below a Tibetan Buddhist temple, shows the glacier's retreat. Courtsey The Nature Conservancy

The scientists have noted more crevasses and wastage in the body of the glacier.
Dominique Bachelet

The scientists have noted more crevasses and wastage in the body of the glacier, which they say is making it more unstable. A local meteorologist estimates that it has shrunk by one-quarter in 13 years, but the glacier is considered sacred, so normal scientific practices, such as removing ice cores, are not permitted. Courtesy The Nature Conservancy

The glacial melt runs off the ice mass.
Dominique Bachelet

The glacial melt runs off the ice mass. The four rivers that begin the Northwest Yunnan are mostly glacier-fed in their upper reaches. Courtesy The Nature Conservancy

Morning Edition, December 17, 2007 · The Tibetan plateau has been called "the roof of the world" and "the third pole" for its ice-covered peaks. There, global warming is happening faster than at other, lower altitudes, with serious consequences for hundreds of millions of people.

China's lowest glacier, the Mingyong glacier — an enormous, dirty, craggy mass of ice wedged in a mountain valley 8,900 feet above sea level — is melting. And as it melts, the glacier on the edge of the Tibetan plateau is retreating up the mountain faster than experts can believe.

"It's truly amazing how much it's traveled," says Barry Baker of The Nature Conservancy, part of a team of international scientists who recently visited the shrinking glacier. "It is just unbelievable."

Baker has been tracking the glacier's retreat for the past five years. He is flabbergasted by the difference since his last visit two years ago.

"The change is actually really remarkable," he says. "The glacier looks like it's gone back up the valley at least 300 feet in just the last two years."

An Astonishing Increase

Baker says the rate of retreat is increasing quickly.

"When we first started observing this glacier, it was retreating at about 80 feet per year, and now it looks like it's doubled," he says.

To explain the change, he cites an increase in temperatures.

"We've seen just in this area about a 2.2 degree increase in temperature just in the last 20 years. And it's interesting because it seems like, from the climate data that we've been studying, that this region is warming faster than some of the other parts of China. In fact, from the data that we have, this particular region is warming almost twice as fast as China," he says.

The scientists must scramble over the rocky debris, known as the moraine — left behind after the ice has melted — to move closer to the snout, or lower end, of the glacier. Studying this ice mass is extremely difficult because local Tibetans see it as a sacred glacier, and they have banned people from touching or stepping on the ice. That rules out normal scientific practices like removing ice cores and sinking stakes in the ice to measure its retreat.

The scientists have to depend on GPS measurements and repeat photography. In this, they are lucky — because explorer Frank Kingdon-Ward snapped pictures of the glacier as early as 1913. Anecdotal evidence indicates the glacier has retreated 1 1/2 miles since the late 1800s, when its tongue was close to Mingyong village.

Feeling the Albedo Effect

On this trip, the scientists note more crevasses in the ice and more wasting in the body of the glacier. An estimate by one local meteorologist says the Mingyong glacier has shrunk by 25 percent over the past 13 years, while the snowline has risen dramatically. And that leads to what is known as the albedo effect.

"On the Tibetan plateau, there's a lot of snow that has been reflecting light for a long time," explains Dominique Bachelet, The Nature Conservancy's head of climate change. "And we call it the third pole, because it has a huge impact: Reflecting the insulation from the sun means that you don't get as much warming on the globe. And so having less snow means you are going to get a lot warmer a lot faster. And when you walk by the glacier, you see all these rock falls and sediments on top of the glacier that make it dark, and so it's melting even faster now that it's totally destabilized."

That means the dripping of the glacial melt turns into a roar as the waters gather pace downstream. Baker says that's the reason the world cannot afford to ignore what is happening in a far-off village on the edge of the Tibetan plateau.

A Threat for Those Downstream

"In Northwest Yunnan, we have the upper reaches of the Yangtze River, the Mekong River, the Salween and the Irrawaddy," Baker says. "These four rivers deliver water to 10 percent of the world's population. In those upper regions, they're mostly glacier-fed, and so melting of the glaciers will have a significant impact on water for a great many people. There'll be more water for a while, but no one's really sure what's going to happen after that."

The scientists can really only guess what's happening in the upper, forbidden reaches of the glacier. But Ma Jian, who has worked on the project for four years, is pessimistic, given what he has seen and heard from the villagers.

"It's hard to tell, but maybe 10 years later, the glacier will be totally gone," he says.

That may be the worst-case scenario. One famous Chinese glaciologist estimates that almost two-thirds of the country's glaciers will have melted by 2050. That could bring ecological catastrophe for the 300 million people downstream

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