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Himalayan Glaciers Retreat

Page history last edited by PBworks 11 years, 5 months ago

Again and again these days we see data coming in from many different

localities and habitat-types, which indicates that the effects of

global warming are occurring at a much faster pace than currently-used

climate models are predicting. This article presents more of the

same...... while temperatures have levelled off in recent years, they

have done so at a very warm level, and the effects are cumulative.

Also, the models seem to be either missing or under-estimating some of

the various feedback processes at work at regional and planetary scales.

 

Ross Mayhew posting in ClimateConcern

 

http://dsc.discovery.com/news/2008/11/24/tibet-glaciers-warming.html

 

Nov. 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 6 degrees."

 

"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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