Zone of Peace
Tibetan Glaciers Melting at Stunning Rate (Discovery News)
November 24, 2008
Glaciers high in the Himalayas are dwindling faster than anyone
thought, putting nearly a billion people living in South Asia in
peril of losing their water supply.
Throughout India, China, and Nepal, some 15,000 glaciers speckle the
Tibetan Plateau, some of the highest land in the world. There,
perched in thin, frigid air up to 7,200 meters (23,622 feet) above
sea level, the ice might seem secluded from the effects of global warming.
But just the opposite is proving true, according to new research
published last week in the journal Geophysical Research Letters.
Lonnie Thompson of Ohio State University and a team of researchers
traveled to central Himalayas in 2006 to study the Naimona'nyi
glacier, expecting to find some melting. Mountain glaciers have been
receding all over the world since the 1990's and there was no reason
this one, which provides water to the mighty Ganges, Indus, and
Brahmaputra Rivers, should be any different.
But when the team analyzed samples of glacier, what they found
stunned them. Glaciers around the planet are usually dated by looking
for two pulses pulse of radioactivity buried in the ice. These are
the leftovers from American and Russian atomic bomb testing in the
1950's and 1960's.
In the Naimona'nyi samples, there was no sign of the tests. In fact,
the glacier had melted so much that the exposed surface of the
glacier dated to 1944.
"We were very surprised not to find the 1962-1963 horizon, and even
more surprised not to find the 1951-1952 signal," Thompson said. In
more than twenty years of sampling glaciers all over the world, this
was the first time both markers were missing.
He suspects the reason for this is that high-altitude glaciers,
despite residing in colder temperatures, are more sensitive to
climate change. As more heat is trapped in the atmosphere, he said,
it holds more water vapor. And when the water vapor rises to high
altitudes it condenses, releasing the heat into the upper atmosphere,
where high mountain landscapes feel the brunt of warming.
"At the highest elevations, we're seeing something like an average of
0.3 degrees Centigrade warming per decade," Thompson said. "The
Intergovernmental Panel on Climate Change (IPCC) projects 3 degrees
of warming by 2100. But that's at the surface; up at the elevations
where these glaciers are there could be almost twice as much, almost
"I have not seen much as compelling as this to demonstrate how some
glaciers are just being decapitated," Shawn Marshall of the
University of Calgary said.
Marshall, who studies glaciers in North America, said it's striking
how much worse glaciers near the equator are than those in the
Canadian Rocky and Cascade mountain ranges.
The finding has ominous implications for the hundreds of millions of
people who depend on the waters of the Naimona'nyi and other glaciers
for their livelihoods. Across the region, no one know just how much
water the Himalayas have left, but Thompson said it's dwindling fast.
"You can think of glaciers kind of like water towers," he said. "They
collect water from the monsoon in the wet season, and release it in
the dry season. But how effective they are depends on how much water
is in the towers."
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