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Some Antarctic glaciers reached a tipping point in 2009 SARA PHILLIPS ABC Environmen t22 MAY 2015

THE FIRST SIGNS Antarctic glaciers have reached some kind of melting ‘tipping point’ have been noticed by scientists from Europe.

The group of eight scientists, led by Dr Bert Wouters from the University of Bristol used sophisticated satellite measurements of the Antarctic glaciers that empty into the Bellinghausen Sea, on the Southern Antarctic Peninsula which reaches up almost to South America.

Glaciers are in effect, frozen rivers of snowpack, moving incrementally towards the ocean. These glaciers have existed in their current form for at least 5,000 years.

The scientists found that the height of the glaciers had dropped — some by as much as four metres. By analysing years of data, they could rule out the snow becoming more compact or a reduction in snowfall as the cause. This left only one possibility: that the glaciers were sliding faster towards the sea.

“The most likely explanation is that the glaciers have accelerated because the temperature of the ocean water has increased in the area, which we know from measurements. These warm waters will melt the floating ice shelves and the glaciers where they enter the sea from below and cause them to lose more ice,” said Dr Wouters, Marie Curie Research Fellow at the University of Bristol.

As the sea ice holding back the glaciers melts away, the glaciers slide faster into the sea. Last week researchers warned that elsewhere in Antarctica, the Larsen C ice shelf could collapse this century and what remains of the Larsen B ice shelf would be all gone by 2020, the majority of it having collapsed in 2002.

A tipping point

Curiously, the glaciers studied were relatively stable until 2009. After then, Dr Wouters said the glaciers appeared to have reached a “tipping point” with the glaciers studied simultaneously starting to slip into the sea…….http://www.abc.net.au/environment/articles/2015/05/22/4239285.htm