Giant West Antarctic iceberg disintegrates

December 1, 2017
Animation showing satellite images of the disintegration of the ice berg that calved off Pine Island Glacier in September 2017. Credit: British Antarctic Survey

An animation of the giant iceberg that calved off the Pine Island Glacier in West Antarctica just over two months ago shows an unexpected break up.

Satellite images revealed a 100-square-mile calving from Antarctica's Pine Island Glacier (PIG) in September. The calving event did not come as a complete surprise, but is a troubling sign for future sea-level rise. Scientists expected the iceberg to drift far out into the Southern Ocean before breaking up. However, it got stuck, probably impeded by thick sea ice, before it started to disintegrate into many smaller icebergs.

Dr Robert Larter, a marine geophysicist at British Antarctic Survey, who flew over the PIG rift last season during his research cruise with the German Alfred Wegener Institute, explains:

"What we're witnessing on Pine Island Glacier is worrying. We're now seeing changes in the calving behaviour of the , when for 68 years we saw a pattern of advance and retreat resulting in the calving of a single large iceberg which left the ice front to approximately the same place. The calving of icebergs in 2001, 2007 and 2013 are well-documented. Each calving event returned the ice front to more or less the same position and the ice shelf flowed into the sea again. But with continuing thinning it was clear that sooner or later there would have to be a change to this pattern – and this is what we are witnessing now.

"What's both interesting and of concern is the lines along which the iceberg has broken follow the pattern of crevasses developed in the ice shelf that it calved from. This change of behaviour might reflect the crevasses within the ice shelf having an increasing influence on the spacing and pattern of iceberg calving as a result of the thinning that has taken place over the past few decades."

Pine Island Glacier is the fastest melting glacier in Antarctica—one that's responsible for a quarter of the frozen continent's ice loss, around 45 billion tons of ice each year. Satellite images taken since 26 September show an open-water gap emerging between the ice shelf and the iceberg, which is about two thirds the size of the Isle of Wight (103 square miles or 267 square km).

This calving is significant because, despite the fact that the ice shelf has been thinning for decades, until two years ago there had been no systematic retreat of the ice front since it was first observed in 1947.

Dr Larter continues: "If the ice shelf continues to thin and the ice front continues to retreat, its buttressing effect on PIG will diminish, which is likely to lead to further dynamic thinning and retreat of the glacier. PIG already makes the largest contribution to of any single Antarctic glacier and the fact that its bed increases in depth upstream for more than 200 km means there is the possibility of runway retreat that would result in an even bigger contribution to sea level."

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Parsec
4.6 / 5 (10) Dec 03, 2017
I can tell you beyond a shadow of a doubt that this entire image is a fake because we we all know the Vikings raised cows in Greenland in the middle ages.

Or something.
Captain Stumpy
4 / 5 (4) Dec 03, 2017
I can tell you beyond a shadow of a doubt that this entire image is a fake because we we all know the Vikings raised cows in Greenland in the middle ages.

Or something.
LMFAO
10 stars! for that epic preempt of shooty's Greenland idiocy!

I don't care who you are: that's funny right there!

daqddyo
4 / 5 (4) Dec 03, 2017
Has any study been done on the different ocean currents flowing under this calved ice section that might explain the appearance of what look like tension cracks in the ice?
Captain Stumpy
3.7 / 5 (3) Dec 03, 2017
@daqddyo
Has any study been done on the different ocean currents flowing under this calved ice section that might explain the appearance of what look like tension cracks in the ice?
Yes - Antarctic currents have been studied since at least the 1970's that I know for sure - likely they started this earlier

https://scholar.g...mp;btnG=

Bart_A
1 / 5 (5) Dec 04, 2017
Fair and balanced. That is what scientists want, right?
A couple comments for balance.

(1) The article states that Ant. yearly ice loss is 45 billion tons of ice each year.
What it doesn't state is that, according to NASA,
https://www.nasa....n-losses
Ant. has a mass gain from the thickening of East Ant. of 200 billion tons per year.

So when you take these two number into account, Ant. has a NET GAIN of billions of tons of ice per year.

(2) The article states that PIG already makes the largest contribution to sea-level rise of any single Ant.glacier.

What the article does not state is that the annual billions of tons of snow that fall in Ant. actually offsets all of this and more. So Ant. actually is contributing to a yearly sea-level drop!

No, I am not making this stuff up!
But want to give you a balanced view.



mackita
1.8 / 5 (6) Dec 04, 2017
MIT Global Warming Study Based On Speculation The study from MIT that linked recent Hurricane Harvey to global warming didn't actually examine Harvey."
Captain Stumpy
3.7 / 5 (3) Dec 04, 2017
@zeph
The study from MIT that linked recent Hurricane Harvey to global warming didn't actually examine Harvey."
from your own link
Emanuel's study is based on thousands of climate model runs
just because you don't understand science doesn't mean no one else does

do you run real-world experiments and have you isolated your nonexistent aether?

idiot
barakn
5 / 5 (3) Dec 06, 2017
Nonexistent? Zephir's aether form ripples in his bathtub every day while he plays with his rubber ducky and his soap.
leetennant
5 / 5 (3) Dec 06, 2017
(1) The article states that Ant. yearly ice loss is 45 billion tons of ice each year.
What it doesn't state is that, according to NASA,
https://www.nasa....n-losses
Ant. has a mass gain from the thickening of East Ant. of 200 billion tons per year.

So when you take these two number into account, Ant. has a NET GAIN of billions of tons of ice per year.
No, I am not making this stuff up!


No, but you're wilfully misunderstanding it. Firstly, you're confusing land and sea ice. Secondly, you're not taking into account ice thickness or age, and thirdly you're deliberately misusing NASA releases from over two years ago. That article clearly states that Antarctic gains will quickly reverse in the future. Well, this is the future!

https://www.nasa....th-poles
TrollBane
5 / 5 (3) Dec 08, 2017
How long will it be before Sh****ist comes along to tell us all that the polar bears that don't exist in this region will be fine?

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