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Ice Sage: An Expert’s View on Antarctic Climate Change

Ice Sage: An Expert’s View on Antarctic Climate Change
 

The Antarctic Peninsula, a spectacular 700 mile long peninsula separated from South America by the Drake Passage is one of the most rapidly warming regions of earth.  A decade ago, when I first began my studies as a marine biologist at Palmer Station on the central western Antarctic Peninsula, the adjacent Marr Glacier would calve a house-sized chunk of glacial ice about once a week.  Now the loud sounds of the calving glacier have become a daily occurrence.

Up and down the length of the Antarctic Peninsula, some eighty-seven percent of the glaciers are under retreat.  Major ice shelves are disintegrating.  Indeed, in just the past thirty years there have been eight major ice-shelf break-outs along the peninsula.  Among them, the Larson-B Ice Shelf, a chunk of real estate the size of Rhode Island, and more recently, the Connecticut-sized Wilkins Ice Shelf dangling by a figurative thread of ice.  While the demise of these peninsular ice shelves does not contribute directly to global sea level rise, glaciologists have discovered that the ice shelves serve an important role as barriers to glacial ice flow.

Land based glaciers formerly barricaded by ice shelves are now flowing into the sea two to three times faster, joining Greenland’s glaciers as contributors to global sea level rise.  The annual sea ice along the western Antarctic Peninsula is also receding – over the past thirty years it has become forty percent less extensive in both its seasonal duration and extent offshore.

The ecological ramifications of this loss of sea ice are profound.  Adelie penguins that depend on the annual sea ice as a platform to access rich offshore krill feeding grounds are disappearing.  So are Weddell seals that depend on the presence of sea ice to bear their pups.  And juvenile krill, the very essence of Antarctic food webs, are suffering as they depend on the micoalgae that grows on the underside of the annual sea ice for their nutrition.

It is imperative that humankind take note of the dramatic climate-change induced impacts underway along the Antarctic Peninsula – for these fundamental changes are not only important unto themselves, but portend ecosystem changes elsewhere on the planet.

James B. McClintock is the Endowed University Professor of Polar and Marine Biology at the University of Alabama at Birmingham.  He is the author of a forthcoming book on the ecological impacts of climate change on the Antarctic Peninsula.


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