Melting Antarctic ice and sea levels

By Dave Armstrong - 09 May 2014 14:41:0 GMT
Melting Antarctic ice and sea levels

Our knowledge of the huge continent has been limited to coasts and island. Now we are starting to discover what the interior Antarctic massif, including these Transantarctic Mountains (TAM to you!) hold in store for us. They separate the west of the continent from the great expanse of the east, which includes some significant chunks of ice; Antarctic image; Credit: © Shutterstock

The recent news from the Antarctic is that the eastern ice shelf, 5X greater in volume than the west, is liable to melt. The biggest area of marine ice in the east is likely to be released despite the cold air temperatures, confirming the worries about the effect of melting Antarctic ice on global sea levels. Global warming may have its biggest effect here. A new paper has more than confirmed this.

Both west and east Antarctica have inland-sloping rock beds. When the coastal Larsen Ice Shelf collapsed in 1998 and 20002, alarm bells rang. The Wilkes Basin is inland, with subglacial troughs connecting the largest ice volume in the east. It is now regarded as susceptible to melting of the ice lip or plug that connects it to the ocean. Using new topographic measurements and computer simulation at Potsdam University's Institute for Climatic Impact Research, the paper's authors, Matthias Mengel and Anders Levermann , have reached alarming conclusions about the effects in - Nature: Climate Change.

They present the long-term prospect of unavoidable sea-level rises of 3-4 metres or 11.5 feet. If the whole of Eastern Antarctica melts, a 19m global sea-level rise is possible, but the effect of this lesser rise would still be catastrophic to both cities and agricultural land, apart from immediate loss of human lives. If we can prevent this small coastal plug on the edge of the Wilkes shelf from melting, all is well, but once it has melted, there seems no way of preventing the whole shelf from a self-sustaining melt, even if miracles somehow slowed the current emissions causing global warming.

The only saving grace is that it could take a century to reach the critical stage. Sighs of relief could well be the only response, until we weigh the evidence. What if the simulations have failed to account for new factors. What do our descendants believe when they notice that we knew this would happen? They will probably be unable to stop the process, but we can do it quite simply, by preserving that plug.

Suggestions on a postcard to those who will probably not care one jot!