MercoPress. South Atlantic News Agency

Giant iceberg changes Antarctic geography

One of the largest icebergs ever seen and drifting in Antarctica, B-15A last week broke a five kilometres piece of the continent after colliding with the Drygalski ice tongue, forcing the redrafting of Antarctic maps.

Iceberg B-15A is 115 kilometres long which originally broke off Antarctica's Ross Ice Shelf in 2000. Scientists predicted an imminent collision of the iceberg back in January, but instead it ran aground and stalled. However last month it broke free.

The European Space Agency in Paris warned that maps of the area covering the seventy kilometres long Drygalski ice tongue in the McMurdo Sound are no long reliable.

European satellite Envisat had a radio photograph of the collision last Friday but only released it today.

The satellite images show how a city size chunk of the Drygalski ice tongue has been let out into the ocean. Further damage from the bottle shaped 2,500 square kilometres iceberg can be expected according to the ESA scientists.

In the maps Drygalski ice tongue sticks out into the McMurdo Sound on the Ross Sea.

B-15A is the largest chunk left of a bigger iceberg, known as B-15 that broke off in March 2000 with the size of the island of Jamaica.

The original a hundred and fifty miles long iceberg then cracked in two between October 7 and 9 in 2003 creating the current B-15A.which drifted into McMurdo Sound blocking ocean currents and causing sea ice to build up, threatening wildlife.

Since calving in 2000 B-15A has made delivery of fuel and supplies to McMurdo Station particularly difficult.

Scientists argue that calving of icebergs from the Antarctic ice shelf is a common phenomenon. As the snow accumulates it turns into ice and a shelf of ice is pushed into the surrounding ocean. Eventually pieces break off the ice shelf and icebergs are born.

However scientists also point out it's unlikely that this particular event is connected to global warming as the advance of the ice sheet is a continual process. Even with the calving of this gigantic iceberg, the edge of the ice shelf has simply returned to where it was half a century ago.