Antarctica - Melting Ice Sheets

The burning of forests and fossil fuels has resulted in a 25 per cent increase in the carbon dioxide deposits found in Antarctic snow since the 1970s. 'Greenhouse gases' like carbon dioxide, which is produced by burning fossil fuels trap some of the sun's heat and warm the atmosphere, causing global warming.

Over the past 50 years, the west coast of the Antarctic Peninsula has been one of the most rapidly warming parts of the planet.  The Peninsula is particularly sensitive to small rises in the annual average temperature  and it is causing sea ice to melt.

Warmer ocean temperatures are making ice shelves increasingly susceptible to breaks and collapses, and already some have collapsed.  Icebergs are created as great chunks of ice break off the edges of ice shelves.

The Larsen Ice Shelf is a long ice shelf in the northwest part of the Weddell Sea, extending along the east coast of the Antarctic Peninsula.  In January 1995, the Larsen A ice shelf collapsed and in 2002 the majority of the Larsen B ice shelf collapsed dramatically.  Just recently, in July 2017, one of the world's largest icebergs broke off from Antarctica's Larsen C ice shelf.

There has been no significant loss of ice from the 96% of Antarctica that is not the Peninsula.  It is so cold here (average surface temperature of continental Antarctic is about -37ºc, compared to -5ºc for the warmest places on the Peninsula), that even if temperatures were to rise by the same amount as they have on the Peninsula, there still wouldn’t be any melting. 

Recently, however, it has been discovered that the East Antarctic ice sheet is more vulnerable to melting than was first thought. A new paper in the journal Nature suggests that a large part of it collapsed only 400,000 years ago and this change happened during an extended but relatively mild warm spell. The greenhouse gases that humans have produced to date may have already locked in 42 feet of eventual sea level rise from all of the glaciers predicted to melt in the coming centuries, including the ones in East Antarctica.