May 2, 2010

Antarctica: the pole apart

The Earth's poles are poles apart, and the pun is intended.

While the North Pole is in an ocean surrounded by land, the South Pole is a continent surrounded by the Southern Ocean. Let us focus on Antarctica as it is a big player in Earth's climate systems.

We get occasional sound bites in the news or press about what appears to be happening there, but they are usually brief and leave one hoping for more, for a more clear placement and interpretation of that particular fact. Even Webster's New World dictionary is brief: "land area about the South Pole, completely covered by an ice shelf: c. 5,000,000 sq. mi.: it is almost entirely within the Antarctic Circle: sometimes called a continent." OK, this is a start, but let's dig a little deeper.

Big numbers

How does one describe a continent — especially one whose land mass is 98-percent covered by an ice cap? Get ready for some big numbers. Let's try and construct in our minds' eye what this place must be like. It is huge and at 5.4 million square miles is larger than Europe or Australia and 1½ times the size of the United States. Its highest point is more than 16,000 feet above sea level. The continent holds 90 percent of the world's ice and the ice, up to 10,000 feet thick in places, holds about 70 percent of the planet's fresh water. A satellite photo of Antarctica from Google Earth is stunning, with its pure whiteness surrounded by a blue ocean, and is readily available by a web search.

The map indicated here gives the general outlines of the continent. It shows the two major ice sheets, one in the east sitting largely on land, the East Antarctic Ice Sheet (EAIS), and one in the west (WAIS), resting partly on land and partly grounded on the ocean floor up to one mile below sea level. They are separated by the Transantarctic Mountains. In the upper left is the Antarctic Peninsula, stretching up towards Chile, which is one of the areas whose glaciers are under intensive study by the United States Geological Survey (USGS). This peninsula is the area most often visited by cruise ships bringing intrepid visitors to this ice-bound world.

So what is the issue? It is really quite simple: If climate change causes half of that ice to melt, ocean levels will rise by about 100 feet and Lake Champlain will be connected with the Atlantic Ocean. If it all melts, well, I think you get the picture.

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