RENEE MONTAGNE, host:
Now to that glacier. Another in our series Climate Connections with National Geographic, examining how we're changing the climate and how the climate is changing us.
Today, a trip to the Tibetan plateau. It's been called the roof of the world and the third pole for its ice-covered peaks. Global warming is happening there faster than at lower altitudes, and that has serious consequences for hundreds of millions of people.
NPR's Louisa Lim accompanied a team of international scientists to study that one shrinking glacier on the edge of the Tibetan plateau.
LOUISA LIM: This is the sound of a looming environmental crisis. Water trickles from an enormous dirty, craggy, mass of ice wedged in a mountain valley. This is China's lowest glacier, the Mingyong glacier at 8,900 feet above sea level, and it's melting and retreating up the mountain as it melts faster than experts can believe.
Dr. BARRY BAKER (The Nature Conservancy): It's truly amazing how much it's traveled. When I first got up on the (unintelligible) it's just unbelievable.
LIM: Barry Baker from the Nature Conservancy has been tracking the glacier's retreat for the past five years. It's been two years since his last visit, and he's flabbergasted.
Dr. BAKER: The change is actually really remarkable. The glacier - it looks like it's gone back up the valley at least 300 feet in just the last two years.
LIM: That would be 150 feet a year. I mean, how typical is that?
Dr. BAKER: It looks like it's actually increasing at an exponential rate. When we first started observing this glacier, it was retreating at about 80 feet per year, and now it looks like it's doubled.
LIM: So how would explain the change?
Dr. BAKER: As in places in the world, temperatures are increasing. We've see 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 studying, that this region is warming faster than some of the other parts of China. In fact, from the day that we have, this particular is region is warming almost twice as fast as China.
LIM: Scrambling over the rocky debris known as the moraine, left behind after the ice has melted, the scientists moved 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've banned people from touching or stepping on the ice. So that rules out normal scientific practices like removing ice cores and sinking stakes into the ice to measure its retreat.
Dr. BAKER: So what we're doing now is we're just trying to get some measurements. We're recording the date, the time...
LIM: So the scientists have to depend upon GPS measurements and repeat photography. In this they're lucky since explorer Frank Kingdon-Ward snapped pictures of the glacier as early as 1913. Anecdotal evidence indicates the glacier has retreated one and a half miles since the late 1800s, when its tongue was close to Mingyong Village.
On this trip the scientists note more crevasses in the ice, 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 this leads to what's known as the albedo effect explained by The Nature Conservancy's head of climate change, Dominique Bachelet.
Dr. DOMINIQUE BACHELET (The Nature Conservancy): On the Tibetan plateau there's a lot of snow that has been reflecting light for a long time 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're 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.
LIM: That means the dripping of the glacial melt turns into a roar as the waters gather pace downstream, and Barry Baker says that's the reason why the world cannot afford to ignore what's happening in this far-off village on the edge of the Tibetan plateau.
Dr. BAKER: In Northwest Yunnan, we have the upper reaches of the Yangtze River, the Mekong River, the Salween and the Irrawaddy. 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.
LIM: As they pack up to go back down the mountain, the scientist can really only guess what's happening in the upper forbidden reaches of the glacier. Ma Jian has worked from this project for four years. Given what he has seen and heard from the villagers, he's pessimistic.
Mr. MA JIAN (The Nature Conservancy): It's a hard to tell, but maybe 10 years later the glacier would be totally gone.
LIM: That may be the worst case scenario. One famous Chinese glaciologist estimates almost two-thirds of the country's glaciers will have melted by 2050, and that could bring ecological catastrophe for the 300 million people downstream.
Louisa Lim, NPR News, Mingyong glacier, Northwester Yunnan.
MONTAGNE: Tomorrow on MORNING EDITION, what the glaciers retreat means for the economy, the culture and the religion of villagers down in Mingyong. And more stories on the impact of falling landscapes can be found in this month's National Geographic magazine and at npr.org/climate. This is NPR News.