The Great Antarctic Peninsula Ice Shelf Extinction

Public Release: USGS

Ice shelves disappearing on Antarctic Peninsula

Glacier retreat and sea level rise are possible consequences

Ice shelves are retreating in the southern section of the Antarctic Peninsula due to climate change. This could result in glacier retreat and sea-level rise if warming continues, threatening coastal communities and low-lying islands worldwide.

Click Images to Enlarge!

Southern Portion of Antarctic Peninsula. This image identifies the southern portion of the Antarctic Peninsula, which is one area studied as part of this project. Research on the southern Antarctic Peninsula is summarized in the USGS report, “Coastal-Change and Glaciological Map of the Palmer Land Area, Antarctica: 1947—2009” (map I—2600—C). Source: U.S. Geological Survey

Multi-year ice. ARCTIC OCEAN – A multi-year ice floe slides down the starboard side of the Coast Guard Cutter Healy Aug. 11, 2009, as the ship heads north into even thicker ice. “You can tell that this is a multi-year ice floe by the light blue melt ponds that have formed on top of the floe,” said Pablo Clemente-Colón, chief scientist at the U.S. National Ice Center. Credit: Patrick Kelley, U.S. Coast Guard

Southern Antarctic Peninsula. This image shows ice-front retreat in part of the southern Antarctic Peninsula from 1947 to 2009. The southern portion of the Antarctic Peninsula is one area studied as part of this project, and is summarized in the USGS report, “Coastal-Change and Glaciological Map of the Palmer Land Area, Antarctica: 1947—2009” (map I—2600—C). Source: U.S. Geological Survey

U.S. Geological Survey says its research is the first to document that every ice front in the southern part of the Antarctic Peninsula has been retreating overall from 1947 to 2009, with the most dramatic changes occurring since 1990. The USGS previously documented that the majority of ice fronts on the entire Peninsula have also retreated during the late 20th century and into the early 21st century.

The ice shelves are attached to the continent and already floating, holding in place the Antarctic ice sheet that covers about 98 percent of the Antarctic continent. As the ice shelves break off, it is easier for outlet glaciers and ice streams from the ice sheet to flow into the sea. The transition of that ice from land to the ocean is what raises sea level.

“This research is part of a larger ongoing USGS project that is for the first time studying the entire Antarctic coastline in detail, and this is important because the Antarctic ice sheet contains 91 percent of Earth’s glacier ice,” said USGS scientist Jane Ferrigno. “The loss of ice shelves is evidence of the effects of global warming. We need to be alert and continually understand and observe how our climate system is changing.”

The Peninsula is one of Antarctica’s most rapidly changing areas because it is farthest away from the South Pole, and its ice shelf loss may be a forecast of changes in other parts of Antarctica and the world if warming continues.

Retreat along the southern part of the Peninsula is of particular interest because that area has the Peninsula’s coolest temperatures, demonstrating that global warming is affecting the entire length of the Peninsula.

The Antarctic Peninsula’s southern section as described in this study contains five major ice shelves: Wilkins, George VI, Bach, Stange and the southern portion of Larsen Ice Shelf. The ice lost since 1998 from the Wilkins Ice Shelf alone totals more than 4,000 square kilometers, an area larger than the state of Rhode Island.

The USGS is working collaboratively on this project with the British Antarctic Survey, with the assistance of the Scott Polar Research Institute and Germany’s Bundesamt fűr Kartographie und Geodäsie. The research is also part of the USGS Glacier Studies Project, which is monitoring and describing glacier extent and change over the whole planet using satellite imagery.

Related Info:

• The report, “Coastal-Change and Glaciological Map of the Palmer Land Area, Antarctica: 1947—2009” and its accompanying map is available online at http://pubs.usgs.gov/imap/i-2600-c/.
• The other completed reports in the Coastal Change and Glaciological Maps of Antarctica series can be viewed online at http://pubs.usgs.gov/imap/2600/.
• For photos regarding this release, visit http://gallery.usgs.gov/tags/NR2010_02_22.

Contact: Jessica Robertson
jrobertson@usgs.gov
United States Geological Survey

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Emerging Patterns of Vanishing Ice Shelves

Catastrophic Sea-level Rises Are Almost a 100% Certainty

Wordie Ice Shelf has entirely vanished and the northern section of the Larsen Ice Shelf measuring about 10,000 sq km has disappeared in the last 20 years.

A view of the leading edge of the remaining part of the Larsen B ice shelf that extends into the northwest part of the Weddell Sea is seen in this handout photo taken on March 4, 2008. Mariano Caravaca (Handout via Reuters).

A report by the U.S. Geological Survey and others blames the climate change for what must surely be a prologue to a full-scale catastrophe in the Antarctica. The report and a detailed map of the region are available at  http://pubs.usgs.gov/imap/2600/B/ . The report says:

Antarctica is Earth’s largest reservoir of glacial ice. Melting of the West Antarctic part alone of the Antarctic ice sheet would cause a sea-level rise of approximately 6 meters …

“This continued and often significant glacier retreat is a wakeup call that change is happening … and we need to be prepared,” a USGS glaciologist, who led the Antarctica study, said.

“Antarctica is of special interest because it holds an estimated 91 percent of the Earth’s glacier volume, and change anywhere in the ice sheet poses significant hazards to society,” she said.

Meanwhile …

The Ice bridge that collapsed

A satellite picture reportedly acquired on Saturday showed that a 40 km strip of ice which held the Wilkins Ice Shelf in place was breaking up.

“It’s amazing how the ice has ruptured. Two days ago it was intact,” said David Vaughan, a glaciologist with the British Antarctic Survey, speaking about a satellite image of the Wilkins Ice Shelf on the Antarctic Peninsula, which was taken by the European Space Agency, ESA.

Antarctic Peninsula has experienced temperature rises of up to 3 °C in the past 50 years, the fastest warming rate in the region.

“We believe the warming on the Antarctic Peninsula is related to global climate change, though the links are not entirely clear,” Vaughan said.

Related Links:

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• Antarctic Ice Shelf Collapse Highlights a Fast-Warming World
• Antarctica: The [Formerly] Frozen Continent
• If You Thought Antarctica, Too, Must Be Warming
• Ice Melt in Alaska, Antarctica, Greenland Accelerating

• WILKINS ICE SHELF IS “HANGING BY A THREAD
• Possible Thule Eruption Disastrous for Antarctic Ice
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• Antarctic Ice Sheet
  
• Hidden Lakes Speed Ice Flow Into Ocean, May Disrupt Climate

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Image of the Day: Antarctica

Antarctica: The [Formerly] Frozen Continent

NASA EO image acquired January 27, 2009

Relatively few people have seen Antarctica. A myth until the early 1800s, the ice-covered southern continent is difficult to get to and hostile to most life. But now, the MODIS Rapid Response System is producing daily photo-like images of Antarctica. The images are valuable to scientists studying everything from ice to penguins, as well as to the crews of ships navigating through the southern ice pack.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this composite image on January 27, 2009. Few features are visible on the ice-covered landscape. The surface appears rough where the Transantarctic Mountains curve in a shallow “s” from the shore of the Ross Sea to the Ronne Ice Shelf. The Polar Plateau in the center of the continent is smooth, shaded only by the faint shadow cast by clouds. The Weddell Sea is textured with chunks of sea ice.

Antarctica was enjoying summer when this image was taken. During the summer, sunlight shines on the continent constantly. Winter is dark. For this reason, MODIS can only image Antarctica during the summer. Flying on both the Aqua and Terra satellites, MODIS orbits the Earth from north to south, passing over Antarctica many times every day. This mosaic image of Antarctica was created from data collected on various overpasses throughout the day. Each overpass is a pie-shaped wedge in the image.

More information about the daily mosaic is available from the MODIS Rapid Response System’s Antarctica Project Page.

NASA image courtesy the MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek.

Instrument: Aqua – MODIS