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Antarctic Peninsula Ice Sheet is Melting Rapidly

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Background

An article in the Buffalo News on March 31, 2016 states that massive icebergs have broken off from the Thwaites Glacier in Antarctica.  The Glacier is probably in the early stages of collapse. A recent study indicates that total collapse is almost inevitable.

                                    

Antarctica Glacier

                                                      Antarctic Glacier - Wikimedia

Introduction

Antarctica is the world’s fifth largest continent, and it is, on average, the highest and coldest continent.  It comprises three ice sheets: the Antarctic Peninsula Ice Sheet, the West Antarctic Ice Sheet, and the East Antarctic Ice Sheet.  We are concerned here with the Antarctic Peninsula Ice Sheet (APIS).  This great ice sheet, larger than Mexico, is believed to be vulnerable to disintegration from a relatively small amount of global warming.  It is capable of raising the sea level by at least 12 feet if it breaks off.  It was thought formerly that this phenomenon would take hundreds, even thousands of years to occur.  Researchers now believe that the disaster could arrive much sooner.  A recent study indicates that high emissions of heat-trapping gases could begin the disintegration of the ice sheet within decades, raising the ocean’s water as much as three feet by the end of the century.  Ice is melting in other regions also, causing the sea to rise by five or six feet by the year 2100.  This finding would create a profound crisis during the lifetime of children being born today.

Sea Levels are Rising

The catastrophe will grow even worse after 2100 when the sea level could exceed a pace of one foot per decade by the year 2150.  The predictions may not be accurate, say the researchers, but there is a great danger and this development should be followed closely in the years to come.  Depleted ozone has also changed wind patterns in the area.

                                    

Antarctic Penguins

                                                    Antarctic Penguins - Wikimedia

Coastal Cities are in Danger

The long-term effect of such a calamity would be the mass erosion of the world’s coastlines, devastating many of our great cities.  New York City, for instance, is 400 years old; its chances of surviving in its present form for another 400 years is highly unlikely.  Other cities that are close to sea level are just as vulnerable as New York City, maybe even more so.  They include Miami, New Orleans, London, Venice, Shanghai, Hong Kong, and Sidney. 

It is possible that coastal defenses might be built to protect these coastal cities, but the American coastline is 95,000 miles long and vast areas would need to be abandoned to the rising sea.

A Computerized Model of Antarctica

Improvements in a computerized model of Antarctica, including its rocks and glaciers, have recognized new factors which are imperiling the stability of the ice.  Scientists were able to reproduce high sea levels of the past, including a period 125,000 years ago when sea levels rose 20 to 30 feet higher than today.  The ability to reproduce past events is considered a stringent test of the merits of any geological model. Scientists were given greater confidence in the model’s ability to project future sea levels, although they admit that their predictions could not be labeled definitive.  There is always hope that unanticipated factors could emerge that would help to stabilize the ice sheet in a warming climate.

Carbon Emissions and Greenhouse Gases Must be Curtailed

These latest findings are unlikely to be the last word on the fate of western Antarctica.  Efforts by a U.N. panel to assess the risks of sea level rise highlighted the urgent need to bring emissions of carbon dioxide and other greenhouse gases under more control.  It is now widely recognized that in the absence of rapid alleviation of carbon emissions, we will face a large sea level rise at faster rates than were once foreseen.  A better understanding of the Antarctic ice could affect these estimates.

                                        

Antarctica - Royal Navy Ship

                                              Antarctica - Royal Navy Ship - Wikimedia

Warmer Temperatures in Antarctica

To add to the crisis, temperatures around the Antarctic Peninsula are warming at a rate that is approximately six times the global average, resulting in ice-shelf collapse and glacier recession.  Some of these ice shelves have collapsed for the first time.  Although Antarctic glaciers are beautiful and awe-inspiring, numerous volcanoes exist underneath the icy exterior.  A recent ice core from James Ross Island shows that warming in this region began around 600 years ago and then accelerated over the last century. This rate of warming is unusual, but not unprecedented.  Changing pressure patterns result in flow anomalies, with cooling over East Antarctica and warming over the Antarctic Peninsula in the west.  Each side of the continent is therefore quite different.

The Antarctic Peninsula is particularly vulnerable to climate change due to its small size and northerly latitude.  80% of the Peninsula is covered in ice.  It consists of a relatively long, thin-spined, Alpine-style mountain chain, 43.5 miles wide.  These mountains form a significant barrier to the persistent westerly, moisture-laden winds.  It receives high snowfall but high melt, with a large number of days above 32 degrees Fahrenheit in the summer months.

Glaciers are Thinning

A recent study concluded that the majority of the glaciers around the Antarctic Peninsula are likely to have been thinning for decades.  It has been noted that 87% of the glaciers around the Antarctic Peninsula are receding.  Once warm ocean water is able to access the underside of a glacier, melting from below exacerbates thinning from above, resulting in increased and rapid glacier thinning.  Concomitantly, global sea levels are currently rising at a rate of about 3 millimeters per year.

Collapse of the Larsen Ice Shelf

The Larsen Ice Shelf on the east coast of the continent collapsed dramatically and very rapidly in 2002, and glaciers that previously fed into the Larsen Ice Shelf have since accelerated, thinned and receded. The ice shelf disintegrated very rapidly, with the main event happening over just one warm summer.  This is the first time it has collapsed in the last 10,000 years.

                                                         

Admiral Richard E. Byrd

                                                              Admiral Richard E. Byrd                                                                                                                                            Wikimedia

Explorers James Cook and Admiral Richard Byrd

Captain James Cook crossed the Antarctic Circle for the first time in January, 1773. Too much ice blocked Cook’s way to find the continent of Antarctica and eventually his ships headed for warmer waters to the east.

Thus it was that on November 28, 1929, Admiral Richard Byrd launched the first flight to the South Pole and back.  On his second expedition in 1934, Byrd spent five winter months alone in Antarctica operating a meteorological station.  His third expedition, in 1939-1940, was the first one on which he had the official backing of the U. S. government.  The project included extensive studies of geology, biology, meteorology, and exploration.

Teams of scientists now travel to Antarctica on a regular basis.  Some stay a few months, but  others have made it their permanent home. Read an interesting article about average people living their lives and doing their jobs on the continent of Antarctica.

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Alone on the Ice: The Greatest Survival Story in the History of Exploration
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(price as of Apr 5, 2016)
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Comments

Apr 5, 2016 11:07pm
HLesley
Your article brings attention to an extremely serious issue which with a potential worldwide impact. Yet, just like Nero fiddling while Rome burnt, the fossil fuel industry continues to pump out carbon while climate change deniers keep their heads in the sand.
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Bibliography

  1. Justin Gillis "Model Predicts Rapid Melt-Off of Antarctic Ice Sheet." The Buffalo News. 31/03/2016.
  2. Bethan Davies "Glaciers and Climate Change." AntarcticGlaciers.org. 11/07/2014. 5/04/2016 <Web >
  3. Bethan Davies "Antarctic Peninsula Ice Sheet." AntarcticGlaciers.org. 16/02/2014. 5/04/2016 <Web >
  4. "Richard E. Byrd." Wikipedia. 5/04/2016. 5/04/2016 <Web >

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