Ice Shelf 'May Collapse without Warning'
By New Zealand Herald
03 December, 2006
The New Zealand Herald
The Ross Ice Shelf, a massive
piece of ice the size of France, could break off without warning causing
a dramatic rise in sea levels, warn New Zealand scientists working in
A New Zealand-led ice drilling
team has recovered three million years of climate history from samples
which gives clues as to what may happen in the future.
Initial analysis of sea-floor cores near Scott Base suggest the Ross
Ice Shelf had collapsed in the past and had probably done so suddenly.
The team's co-chief scientist,
Tim Naish, told The Press newspaper the sediment record was important
because it provided crucial evidence about how the Ross Ice Shelf would
react to climate change, with potential to dramatically increase sea
"If the past is any
indication of the future, then the ice shelf will collapse," he
"If the ice shelf goes,
then what about the West Antarctic Ice Sheet? What we've learnt from
the Antarctic Peninsula is when once buttressing ice sheets go, the
glaciers feeding them move faster and that's the thing that isn't so
Antarctica stores 70 per
cent of the world's fresh water, with the West Antarctic Ice Sheet holding
an estimated 30 million cubic kilometres.
In January, British Antarctic
Survey researchers predicted that its collapse would make sea levels
rise by at least 5m, with other estimates predicting a rise of up to
Dr Naish, a sedimentologist
with the Institute of Geological and Nuclear Sciences, said one day
the drilling team retrieved a core of 83m, far greater than expected,
which contained climate records spanning about 500,000 years.
"We're really getting
everything we've dreamed of. What we're getting is a pretty detailed
history of the ice shelf," he said.
"You go from full glacial
conditions to open ocean conditions very abruptly. It doesn't surprise
us that much that the transition was dramatic.
"Scientists knew from
the collapse of the Larsen Ice Shelf in 2002 that expanses of ice could
collapse "extremely quickly".
Once dating of the sample
was completed, researchers would be able to look at what the ice shelf
was doing during periods when scientists knew from other evidence that
it was 2degC to 4degC warmer than today, Dr Naish said.
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