Ice bridge ruptures in Antarctic
David Vaughan says the breakage is a 'really strong indication' of warming
An ice bridge linking a shelf of ice the size of Jamaica to two islands in Antarctica has
snapped.
Scientists say the collapse could mean the Wilkins Ice Shelf is on the brink of breaking away,
and provides further evidence of rapid change in the region.
Sited on the western side of the Antarctic Peninsula, the Wilkins shelf has been retreating since
the 1990s.
Researchers regarded the ice bridge as an important barrier, holding the remnant shelf
structure in place.
Its removal will allow ice to move more freely between
Charcot and Latady islands, into the open ocean.
The ice bridge has splintered at its thinnest point
European Space Agency satellite pictures had indicated
last week that cracks were starting to appear in the
bridge. Newly created icebergs were seen to be floating in
the sea on the western side of the peninsula, which juts
up from the continent towards South America's southern
tip.
Professor David Vaughan is a glaciologist with the British
Antarctic Survey who planted a GPS tracker on the ice
bridge in January to monitor its movement.
He said the breaking of the bridge had been expected for
some weeks and much of the ice shelf behind was likely to
follow.
"We know that [the Wilkins Ice Shelf] has been completely or very stable since the 1930s and
then it started to retreat in the late 1990s. But we suspect that it's been stable for a very much
longer period than that," he told BBC News.
"The fact that it's retreating and now has lost connection with one of its islands is really a
strong indication that the warming on the Antarctic is
having an effect on yet another ice shelf."
While the break-up will have no direct impact on sea level
because the ice is floating, it heightens concerns over the
impact of climate change on this part of Antarctica.
Over the past 50 years, the peninsula has been one of the
fastest warming places on the planet.
Many of its ice shelves have retreated in that time and six of them have collapsed completely
(Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and the Jones Ice
Shelf).
Separate research shows that when ice shelves are removed, the glaciers and landed ice behind
them start to move towards the ocean more rapidly. It is this ice which can raise sea levels, but
by how much is a matter of ongoing scientific debate.
Such acceleration effects were not included by the UN's Intergovernmental Panel on Climate
Change (IPCC) when it made its latest projections on likely future sea level rise. Its 2007
assessment said ice dynamics were poorly understood.