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
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."