The New Danger of Significant Sea Rise

Erosion by warming waters has caused the submarine ice around Antarctica to shrink by 1,463 sq km in six years

Section though ice sheet in 2010

Section though ice sheet in 2016

Ocean

Ice shelf

Hidden erosion by

warming waters has

caused the base of the

ice sheet to shrink

Previous extent

of ice sheet

Ice flow

Increased

ice flow

Ice sheet

Ocean floor

Grounding line

Grounding line

Guardian graphic. Source: Nature

Underwater melting of Antarctic ice far greater than thought, study finds

Hidden underwater melt-off in the Antarctic is doubling every 20 years and could soon overtake Greenland to become the biggest source of sea-level rise, according to the first complete underwater map of the world’s largest body of ice.

Warming waters have caused the base of ice near the ocean floor around the south pole to shrink by 1,463 square kilometres – an area the size of Greater London – between 2010 and 2016, according to the new study published in Nature Geoscience.

The research by the UK Centre for Polar Observation and Modelling at the University of Leeds suggests climate change is affecting the Antarctic more than previously believed and is likely to prompt global projections of sea-level rise to be revised upward.

[T]he new study found even a small increase in temperature has been enough to cause a loss of five metres every year from the bottom edge of the ice sheet, some of which is more than 2km underwater.


“What’s happening is that Antarctica is being melted away at its base. We can’t see it, because it’s happening below the sea surface,” said Professor Andrew Shepherd, one of the authors of the paper. “The changes mean that very soon the sea-level contribution from Antarctica could outstrip that from Greenland.”

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The study’s lead author, Hannes Konrad, said there was now clear evidence that the underwater glacial retreat is happening across the ice sheet.

“This retreat has had a huge impact on inland glaciers,” he said, “because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”

The two locations of enough melting ice to produce serious increases in sea level are Greenland and the Antarctica.  I've already posted about Greenland being past a tipping point.  But it's only now with this new study that we see that Antarctica is passing it's own tipping point.

Whatever we do about global warming, however much we are able to bring the flow of carbon dioxide and methane into the atmosphere, sea level are going to rise to serious levels.  Goodbye Miami, Goodbye New Orleans, not to mention sea coast cities all over the world.  And there is nothing we can do about it now.