ANTARCTIC ICE SHEET COULD COLLAPSE DUE TO GLOBAL WARMING, SCIENTISTS WARN
By Louise Gray
The Telegraph
March 18, 2009
Original LinkGlobal warming could cause the collapse of the West Antarctic ice sheet, leading to a catastrophic rise in sea levels, scientists have warned.
Scientists have known for a long time that a rise in temperature in the oceans could cause the South Pole to start melting.
However two studies published in the journal Nature have found new evidence of the Antarctic ice sheets collapsing in relatively short periods of time in the past.
They predict that if there is a rise in temperature of five degrees Celsius or more in the oceans by the end of the century, the huge West Antarctic Ice Sheet would begin melting. This could cause sea levels to rise by up to seven metres within one to three thousands years wiping out wildlife, flooding low lying islands and coastal areas and even changing weather patterns by releasing so much fresh water into the sea.
The studies come as scientists at emergency meeting in Copenhagen last week warned the affects of global warming are worse than previously thought and politicians must act.
The two studies both showed that the WAIS has collapsed several times in the past over geologically short timescales.
Tim Naish and colleagues at Victoria University in Wellington, in New Zealand, looked at ocean sediment drilled from the bottom of the ocean. They found evidence that the WAIS periodically collapsed during the early Pliocene period (three to five million years ago), a time when atmospheric carbon dioxide was similar to, or slightly higher than, present day levels.
David Pollard at Pennsylvania State University, in the USA, used computer models to simulate Antarctic ice sheet variations over the past five million years. The results show that during this time, the WAIS transitioned between full, intermediate and collapsed states in only a few thousand years.
Although the collapse of the ice sheet would happen over thousands of years, he said the new evidence showed how damaging man made climate change could be.
"Before there was doubt [climate change] could melt the West Antarctic Ice Sheet, these studies show it is a distinct possibility but it is not going to happen in the next hundred years it will happen over thousands of years," he said.
"[But] it is something to be concerned about, you cannot just ignore it because it is happening in thousands of years time."
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