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Glaciers

Terrestrial Tour: Glaciers

If all land ice melted, most of it would end up in our oceans, mixing with undrinkable salt water and raising sea level by about 230 feet. Such a large influx of cold, fresh water will also affect the world's ocean currents and therefore Earth's climate.
Credits

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory.

All images, illustrations, and videos courtesy of NASA except:
 
except:
·       Photo of Tasman Lake in New Zealand courtesy of Wikimedia user Avenue
·       Sea creature illustration copyright The National Library of Israel, Shapell Family Digitization Project _and The Hebrew University of Jerusalem, Department of Geography – Historic Cities Research Project
·       Athabasca Glacier photo courtesy of Lucy Albert
·       Snowflake photos by Wilson A. Bentley
·       Electron-microscope image of a snowflake from the Electron Microscopy Unit, _Beltsville Agricultural Research Center, U.S. Department of Agriculture
·       Photo of snow-covered field courtesy of Emmanuel Boutet
·       Photo of melt pools from the collection of Dr. Pablo Clemente-Colon, Chief Scientist, National Ice Center
·       Photo of snow crystals courtesy of Alex Bakharev
·       Photo of ice crystals courtesy of Petr Dlouhý
·       Photo of Mt. Kilimanjaro’s southern ice field courtesy of Wikimedia user Chris 73 / Wikipedia Commons
·       Larsen B Ice Shelf images courtesy of Ted Scambos, National Snow and Ice Data Center, _University of Colorado, Boulder, based on data from MODIS
·       Statue of Liberty illustration courtesy of ClipArts101.com
·       Photo of boat in front of Eqip Sermia Glacier courtesy of Michele Koppes, University of British Columbia
·       Bear Glacier IKONOS image courtesy of DigitalGlobe
 
Music courtesy of Associated Production Music
Written by Andrea Gianopoulos
Designed by Marc Lussier
Transcript

(SPEECH)
[UPBEAT MUSIC]
 
(DESCRIPTION)
Text, Glaciers; Rivers & Seas of Ice.
 
A cove of icy water flanked by two snow-capped mountains.
 
(SPEECH)
[GENTLE MUSIC]
 
(DESCRIPTION)
Distinctly shaped snowflakes in free fall.
 
Text, Snow falls as beautiful, feathery, ice-crystal flakes.
 
Close up of snowflake shows a symmetrical hexagonal shape. Snow blankets the ground in mounds.
 
Text, When accumulated snow sits on the ground for a while, it may partially melt and then refreeze.
 
Islands of ice float in bright blue water. A close-up shows sharp and rugged ice crystals.
 
Text, Over time, it loses its feathery texture and becomes granular.
 
A large wall of ice topped with smooth snow.
 
After many many years of accumulation, the granules compress into ice.
 
Eventually, the ice layer becomes large enough to begin flowing under the influence of gravity.
 
Bright blue ice floats between two patches of land.
 
These flowing rivers and seas of ice are called glaciers.
 
(SPEECH)
[LIGHT MUSIC]
 
(DESCRIPTION)
Planet Earth with shifting ice at the pole surrounding Greenland.
 
Text, Petermann Glacier, Greenland. July 5, 2003.
 
When a glacier extends over the ocean, the warmer water can melt and weaken the glacier.
 
An aerial view shows where ice has split into two.
 
Petermann Glacier, August 16, 2010.
 
In 2010, a large chunk broke off the floating ice "tongue" of Petermann Glacier.
 
A crack on the sheet of ice is highlighted.
 
Text, A large crevasse slicing across the glacier hinted at the potential for further breakup.
 
Text, Nearly two years later, just such a breakup occurred. Side by side of three images, July 16, 2012, 10:25 UTC, July 16, 2012, 12:00 UTC, July 17, 2012, 9:30 UTC. On each image, the same area is highlighted to show how the ice increasingly broke off.
 
Text, Petermann Glacier, Greenland. July 21, 2012. Icebergs littered the water in the ice island's wake.
 
(SPEECH)
[ENERGETIC MUSIC]
 
(DESCRIPTION)
The continent of Antarctica.
 
Antarctica. Some of the fastest changing glaciers are in Antarctica, where ice is disappearing at a rate of more than 100 billion metric tons per year.
 
Map zooms in on northwest corner of Antarctica and the Weddell Sea.
 
Text, Larsen B Ice Shelf, Antarctica. January 31, 2002. Weddell Sea. In January 2002, the Larsen B Ice Shelf began a 35-day period of rapid disintegration, which resulted in an expanse of ice larger than Rhode Island collapsing into the Weddell Sea.
 
A series of dated images begins, February 17, 2002; February 23, 2002; March 5, 2002; March 17, 2002; and February 18, 2005. Beginning in February 2002, the shoreline rounds off as a chunk of ice falls to the sea, In March 2002, ice which floats in the black sea rejoins the shelf, and by February 2005, a larger block of ice disappears from the shoreline, leaving a more jagged ice shelf.
 
Text, Just three years later, open water lapped along the shoreline where Larsen B once stood.
 
(SPEECH)
[SOFT MUSIC]
 
(DESCRIPTION)
Crane Glacier, Antarctica. April 6, 2002. The loss of the Larsen B Ice Shelf accelerated the flow of surrounding glaciers into the bay.
 
In April 2002, two months after the ice shelf's collapse, Crane Glacier extended into the bay that once held Larsen B.
 
A time lapse shows how the shoreline of ice once fanned out and is now concaved.
 
Text, Crane Glacier, February 20, 2003. By February 2003, much of the lower Crane Glacier had crumbled into the Weddell Sea. Its fan-shaped terminus became a C-shaped cove filled with icebergs.
 
The shoreline continues to move inward while chunks of ice remain in the sea.
 
Crane Glacier, February 24, 2012. Crane Glacier continued its retreat in the following years.
 
A ship in the water next to a tall wall of ice.
 
(SPEECH)
[GENTLE MUSIC]
 
(DESCRIPTION)
Text, As our planet warms, so do our oceans.
 
An ocean temperature only slightly above the freezing point of water can melt glacial ice at a rate of several feet per day, or hundreds of feet over the course of one summer.
 
Glaciers hold 75% of the world's fresh water.
 
If all land ice melted, most of it would end up in our oceans, mixing with undrinkable salt water and raising sea level by about 230 feet.
 
Such a large influx of cold, fresh water will also affect the world's ocean currents and therefore Earth's climate.
 
An animation of the north pole where icy shorelines shift in and out.
 
Text, Earth's climate is a complex system with many interconnected parts.
 
When one component of the system changes, it starts a chain reaction that affects everything else.