More evidence from the cryosphere

2008-03-17

in Science, The environment

A new study of 100 glaciers has shown that ice loss in 2006 was unprecedented. Between 1980 and 1999, average rates of loss were 30cm per year. In 2006, 1.5 metres were lost.

Overall, the data is not encouraging:

During 1980-1999, average loss rates had been 0.3 metres per year. Since the turn of the millennium, this rate had increased to about half a metre per year.

The record annual loss during these two decades – 0.7 metres in 1998 – has now been exceeded by three out of the past six year (2003, 2004 and 2006).

On average, one metre water equivalent corresponds to 1.1 metres in ice thickness. That suggests a further shrinking in 2006 of 1.5 actual metres and since 1980 a total reduction in thickness of ice of just over 11.5 metres or almost 38 feet.

Glaciers play a critical role in the fresh water cycle. They help to conserve winter snowfall, contributing to river flow in summer. They also affect patterns of downwind precipitation, especially past the Himalayas.

In his infamous address to the White House Press Corps, Stephen Colbert joked about how “your grandchildren will have no idea what a glacier is.” If these trends persist, that might be an accurate prediction.

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{ 8 comments… read them below or add one }

Milan March 17, 2008 at 11:24 am
Sarah March 17, 2008 at 8:39 pm

This is pretty disastrous, both on a global scale (ie. affecting many water sources and ecosystems) and from the rather selfish perspective of a mountaineer for whom glaciers provide beautiful landscapes and a surface on which to walk & sleep. More outdoor education is needed so that people not only understand the trends, but feel a real sense of love and loss regarding the landscape affected.

. March 18, 2008 at 11:52 am

The world’s glaciers are melting quite rapidly and will likely cause all sorts of environmental problems, according to data from the World Glacier Monitoring Service. The WGMS tracks the health of 30 “reference” glaciers throughout the world and has said that their rate of melt has sped up significantly in recent years. Between 1980 and 1999, the glaciers shrunk an average of 11.8 inches; between 2000 and 2006, they dwindled by 4.9 feet on average. Wilfried Haeberli, director of WGMS, said that most of the world’s roughly 160,000 glaciers are receding “at least” as much as the reference glaciers, if not more. Rapidly melting glaciers are likely to cause avalanches and severe flooding in the short term, and in the long term could lead to sea-level rise as well as extreme drought and food shortages in many places that depend on them for their water supply. “There are many canaries emerging in the climate-change coal mine,” said Achim Steiner of the United Nations Environment Program. “The glaciers are perhaps among those making the most noise and it is absolutely essential that everyone sits up and takes notice.”

Anon March 18, 2008 at 1:41 pm

Artic sea ice is also suffering

Every year, more of the overall amount has been less than a year old.

From this page

Anon March 18, 2008 at 1:46 pm

This picture is also startling. The old parts of the Arctic have been crammed up into one area.

. March 18, 2008 at 2:06 pm

The melting of ice sheets due to global warming may trigger massive earthquakes, a new study finds.

Scientists have speculated that heavy ice sheets essentially weigh down the land, building up pressure and energy. But as those ice sheets melt and release the built-up pressure, faults in the crust under the ice sheets have more room to move and energy to do so, causing earthquakes.

The new study, which will be published in the journal Earth and Planetary Science Letters, used sophisticated computer modeling to simulate the effect melting ice would have on pressure in the Earth’s crust and along faults that are normally not prone to slippage and earthquakes.

The researchers, led by Andrea Hampel of Ruhr University Bochum in Germany, also found historical evidence of massive earthquakes occurring after significant melting periods.

One of their examples focuses on a series of essentially inactive faults in Scandinavia. These faults rarely exhibit any earthquake activity, but around 10,000 years ago — roughly the same time as the melting of thick ice sheets at the end of the last ice age — a series of large earthquakes shook the region, moving northward as the ice sheets retreated.

Looking at the rocks’ displacement, the scientists can recreate the timing and size of the faults. Using this method, the Scandinavian earthquakes are estimated as magnitude 8, roughly the same magnitude as the quake that hit the coast of Peru last fall.

The paper warns that melt-induced earthquakes are not just a thing of the past, however. The researchers attribute the recent increased number of earthquakes in Alaska to ice melting there and warn that if warming continues to melt ice in the polar regions, larger and more frequent earthquakes could shake normally stable areas like Antarctica and Greenland.

“The frequency of earthquakes should increase in the future if the ice continues to melt,” the authors write in the paper (Mason Inman, National Geographic News, March 14).

. March 19, 2008 at 1:23 pm

Canada’s largest International Polar Year research project has been forced to switch gears because the ice south of Banks Island in the Western Arctic is melting more quickly that anyone had foreseen.

The project had planned to run continuous measurements and experiments starting this month at a semipermanent base on the ice. The Canadian Coast Guard ship Amundsen, crammed with labs and exotic scientific instruments, arrived in the Western Arctic in October to allow researchers to carry out the first-ever investigation of the changes in ice, water and atmosphere spanning four seasons. Scientists had intended to travel to the base by snowmobile from the Amundsen, which was supposed to be moored nearby, safely sheltered in the fixed ice behind an ice bridge.

But the bridge — which normally forms across 80 miles of the Amundsen Gulf as drifting ice becomes trapped at a chokepoint between two land masses — has not formed this year because ice is passing freely through the chokepoint, which is relatively unclogged because of the shrinkage in the ice pack. Scientists estimate that an unprecedented 800,000 million square miles of ice disappeared in the summer of 2007 from the permanent Arctic ice pack, the zone that remains ice-covered at the height of summer.

The biologists, oceanographers, chemists and physicists are probably going to instead have to settle for brief flying visits once a week to a makeshift camp in Prince of Wales strait. That is roughly 100 kilometers from a new position that the Amundsen may attempt to reach later this week.

“We won’t have as much information to follow biological processes that are changing over time out on the permanent ice,” said Tim Papakyriakou, a professor at the University of Manitoba, which is leading the circumpolar flaw lead system study.

Now at the halfway point, the 10-month study involves 200 investigators from Canada and a dozen other countries, including Norway, Germany, the United Kingdom, France and Russia (Peter Calamai, Toronto Star, March 17).

. July 24, 2008 at 11:01 am

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