Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Alaska’s Columbia Glacier continues on disintegration course

08.12.2005


Glacier has shrunk by nine miles, now at midpoint of retreat


Columbia Glacier, September 2005



Alaska’s rapidly disintegrating Columbia Glacier, which has shrunk in length by 9 miles since 1980, has reached the mid-point of its projected retreat, according to a new University of Colorado at Boulder study.

Tad Pfeffer, associate director of CU-Boulder’s Institute of Arctic and Alpine Research, said the glacier is now discharging nearly 2 cubic miles of ice annually into the Prince William Sound, the equivalent of 100,000 ships packed with ice, each 500 feet long. The tidewater glacier -- which has its terminus, or end, in the waters of the Prince William Sound -- is expected to retreat an additional 9 miles in the next 15 years to 20 years before reaching an equilibrium point in shallow water near sea level, he said.


Pfeffer presented his latest findings at a news briefing at the fall meeting of the American Geophysical Union Dec. 5 to Dec. 9 in San Francisco. Pfeffer, CU-Boulder doctoral student Shad O’Neel and other researchers from CU-Boulder and around North America have been monitoring the glacier with time-lapse photography, aerial photography, satellites, seismometers, lasers and other instruments.

The Columbia Glacier is now the single largest glacial contributor to sea level in North America, producing about 10 percent of the water volume entering the sea from all Alaskan glaciers each year, said Pfeffer. Sliding roughly 80 feet a day, the Columbia Glacier is among the world’s fastest-moving glaciers and the last of Alaska’s 51 tidewater glaciers to exhibit a drastic retreat.

The glacier’s retreat appears to be due to a combination of complex physical processes, he said. "The start of the retreat in 1980 is not the direct result of global warming, but was triggered by longer-term warming," said Pfeffer. "The Columbia Glacier, like all Alaska glaciers, is melting at an increased rate, but the enormous volume of loss accompanying the retreat is much greater than melt alone."

The retreat of the Columbia Glacier and Alaska’s other tidewater glaciers are believed to be influenced by a slow warming trend that began in the Northern Hemisphere about 500 years ago, he said. The Muir Glacier in Alaska’s Glacier Bay, for example, began its retreat in the late 1800s, according to researchers.

But the Columbia Glacier, which is about three miles wide in places and up to 3,000 feet thick, has thinned up to 1,300 feet in places during the past 25 years. The thinning is believed to be caused, in part, by seawater pressure floating the submerged glacier terminus slightly and "stretching it like taffy" as the glacier speed has increased, he said.

"When tidewater glaciers thin to a critical level, they seem to reach a point where they speed up discharging ice into the ocean and can’t slow down," said Pfeffer, who is also an associate professor in CU-Boulder’s engineering college. Pfeffer said he believes the ongoing retreat of the Columbia Glacier will eventually create a vast fjord rivaling the spectacular Glacier Bay.

The ongoing research on the Columbia Glacier retreat can be used as a model for the current behavior of glaciers in Greenland and Antarctica, where more than 90 percent of the Earth’s ice is locked up, he said. Greenland and Antarctica are believed by scientists to be major contributors to global sea rise.

"Up until about 50 years ago, the perception was that Greenland and Antarctica were essentially monolithic pancakes of ice," he said. "We now understand that these large ice masses are made up of very different sub-regions that respond uniquely to climate forcing."

The Columbia Glacier has been under intense scrutiny since the late 1970s, when the U.S. Geological Survey determined that a marked increase in its calving rate might pose a threat to shipping lanes in Prince Williams Sound, site of the devastating 1989 Exxon Valdez oil spill. The initial USGS studies were begun by glaciologist Mark Meier, who came to CU-Boulder in 1986 as INSTAAR’s first director and who remains on the faculty as an emeritus professor.

While climate-forcing events like the warming underway at high latitudes of Earth may appear to be occurring in small steps, the ultimate response of glaciers and other parts of the environment may be significantly larger and faster, Pfeffer said. "High latitudes respond to climate change in tricky and very unpredictable ways."

Tad Pfeffer | EurekAlert!
Further information:
http://www.colorado.edu

More articles from Earth Sciences:

nachricht Impacts of mass coral die-off on Indian Ocean reefs revealed
21.02.2017 | University of Exeter

nachricht How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>