Mountain Glaciers Melting Faster Than Ever, Expert Says
Blake de Pastino in San Francisco, California
National Geographic News
|February 16, 2007|
Mountain glaciers are melting faster than ever, a leading climate expert
announced yesterday, and eerie effects of the thaw are being seen from
the summits of South America to the highest peak in Africa.
In Peru alone, ice fields are disappearing so quickly that giant lakes have formed where meadows recently stood.
And retreating glaciers are exposing ancient plants that haven't been seen in 5,000 years.
Lonnie Thompson, an expert in ancient climates at Ohio State University, announced his findings yesterday at a meeting of the American Association for the Advancement of Science in San Francisco, California.
Thompson's latest research has focused on measuring glaciers in the Andes mountain range, which spans seven South American countries, and on Mount Kilimanjaro in eastern Africa.
"One of the things that's very clear is that the climate changes in those areas are unusual—unprecedented—in the thousands of years of history that we can look at in these places," Thompson said.
Kilimanjaro's glaciers are melting so quickly, he said, that the mountain lost nearly a quarter of its ice from 2000 to 2006.
Meanwhile, some glaciers in the Andes are melting ten times faster than they did just 20 years ago.
The massive melts are among the most provocative evidence yet that the world is getting too warm too fast to be the result of natural forces alone, Thompson said.
"If you look at what's happened to these glaciers, they're not just retreating, they're accelerating [their retreat]," he said. "And it raises the question of whether this might be a fingerprint of [human-caused global] warming."
Ancient Plants, Instant Lakes
Thompson is also studying ice fields in the Himalaya mountain range in central Asia.
Previous research has shown that glaciers there are in fast retreat, prompting the Nepalese government to set up remote monitoring stations in the Himalaya to assess potential threats.
In all corners of the world, Thompson said, the effects of rapid mountain melts are uniformly grim.
So much of Peru's giant Qori Kalis glacier has vanished, for example, that the retreating ice has exposed patches of 5,000-year-old cushion plants, a kind of wetland vegetation typically found in valleys.
"It's only because of the recent warming and the retreat of the glaciers that they've been exposed again," Thompson said. "And by dating this material you can actually say when's the last time this glacier's been as low as it is today."
"I think this is happening in glaciers around the world," he added.
In Tanzania, home of Mount Kilimanjaro, the mountain's meltdown could take a heavy economic toll.
"Twenty-five thousand tourists go [to Kilimanjaro] every year," Thompson said. "But there's a discussion in the parliament today on how many people are going to come when there's no longer glaciers on this mountain."
The most imminent threat posed by the thaws, however, is the sudden formation of giant mountain lakes, Thompson said.
"I can tell you that at Qori Kalis [in Peru], there's a lake that formed there that didn't exist until 1991. But the lake now covers 84 acres [34 hectares] and it's 200 feet [61 meters] deep."
Runoff from rapidly decaying glaciers collects into these newborn lakes, which can overflow to create torrential floods, he explained.
He's seen evidence of such a disaster first-hand.
On March 23, 2006, an avalanche of ice crashed down from Qori Kalis, causing the lake at its base to spill over and flood the valley below.
"We talked with the local people, and it turned out it was the only valley that [the flood] occurred in," he said.
"As these high-altitude glaciers retreat, these lakes are forming, and they form a risk for this kind of flooding."
Hazards From Himalaya to California
Other scientists at the meeting agree that fast-melting mountain ice presents a growing global threat.
John All, an environmental policy expert at the University of Western Kentucky, said the threats posed by rapidly forming lakes have become issues of international concern.
"The UN and other organizations are actively trying to find ways to stabilize these things, because you've essentially got populations in lowland areas and gigantic dams holding billions of gallons of water above them," he said.
In 1994, All said, a deadly flood struck a community in the central Asian nation of Bhutan after a glacial lake high above the town collapsed.
California should also prepare for the escalating effects of mountain melt, said Henry Diaz of the U.S. Office of Oceanic and Atmospheric Research.
The flooding of Yosemite National Park in 1997 and 2005 were signs of things to come, he said, as warm seasonal rains begin to regularly melt California's heavy mountain snows.
"These kinds of things are likely to occur more frequently in the future," Diaz said.
For his part, Thompson, the Ohio State scientist, holds out little hope that the fate of the world's mountain glaciers will improve.
In many cases, he said, the melting is accelerating so quickly that the damage is irreversible.
"It's too late for some of these glaciers," he said. "People will have to adapt to change. That's all."
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