Science has confirmed it. Human-caused warming is killing Antarctica’s massive Pine Island Glacier (PIG). And this week’s release of a chunk of ice larger than Guam into the southern ocean is just one of the many major losses that will occur as part of what is now an inevitable demise of one of the world’s greatest glaciers.
(CNN provides this stunning NASA imagery sequence of the break-off of B-31, a 12×24 mile iceberg from the, now doomed, Pine Island Glacier.)
Heat-Charged Blow to The Soft Underbelly of Antarctic Ice Shelves
As human greenhouse gas emissions caused the world’s oceans to warm, upwelling currents delivered a portion of that heat to the continental shelf zone surrounding Antarctica. A fortress of ice, numerous glacial ice shelves thrust out from this frozen land and drove deep into the sea floor. Ocean-fronting glaciers featured submerged sections hundreds of feet below the sea surface.
The warming currents encountered these massive ice faces, eroding their undersides and providing pathways for ocean waters to invade many miles beneath the glaciers. These invasions subjected the vulnerable ice shelves not only to the heat forcing of an ever-warming ocean, but also to wave and tidal stresses. The reduction in grounding and the constant variable stresses set the glaciers into a rapid seaward motion.
Antarctica’s most vulnerable glaciers lie along its western out-thrust. Two, Thwaites and the Pine Island Glacier, have recently seen very rapid increases in forward speed. Of these, the Pine Island Glacier, according to a recent study, is undergoing the process of an irreversible collapse. What this means is that the glacier’s speed of forward motion is now too great to be halted. Inevitably, even if the climate were to cool, the entire giant glacier will be launched into the world’s oceans where it will entirely melt out.
(Pine Island Glacier underwater melt dynamics. Image source: Nature)
Guam-Sized Chunk of Ice to be One of Many
The Pine Island Glacier is massive, covering a total area of 68,000 square miles and, in some locations, rising to over 2,000 feet in height. It represents 10% of all the ice in the West Antarctic Ice Sheet, holding enough liquid water to raise sea levels by between 1 and 2.5 feet all on its own. And the now destabilized PIG is bound to put added stresses on the adjacent Thwaites glacier together with almost the entire West Antarctic ice system.
Over recent years, PIG’s forward speed has accelerated. Increasing forward velocity by 73 percent from 1974 to 2007. Surveys made since that time show an even more rapid pace. By January of this year, studies were finding that PIG had entered a sate of irreversible collapse. So it is little wonder that enormous chunks of ice are breaking off from this massive glacier and drifting on out into the Southern Ocean.
As of early this week, the immense ice island dubbed B31 measuring 12×24 miles in size (nearly 290 square miles), slid off its temporary grounding on the sea bottom and began its journey out into the Southern Ocean. There it will remain for years, plaguing the world’s shipping lanes as it slowly disintegrates into a flotilla of icebergs. It is just the most recent event in the now ongoing decline of PIG. And we can expect many, many more major ice releases as this vast Antarctic glacier continues its dive to the sea.
Links:
Humongous Iceberg Slowly Drifts Away From Antarctica
Scientists: Warming Ocean, Upwelling Make an End to Antarctica’s Vast Pine Island Glacier
Retreat of Pine Island Glacier Controlled by Marine Ice Sheet Instability
Hat tip to Colorado Bob who’s been tracking PIG since 1994
robertscribbler 
dtlange
/ April 25, 2014Thanks Robert, for keeping us up to date, etc.
The way things are progressing (digressing) I’m starting think of our future not in centuries or decades, but in 18 month increments. Or something like that.
I am worried at the amount of particulate from dust, vapor, and emissions etc. that I see in the atmosphere. The sky is no longer deep blue. It’s mostly a pasty white. And the sun is now huge glare splotch.
The atmosphere is visibly becoming saturated as it malfunctions. I’m surprised this seems to go unnoticed by the populace.
Just a thought, thanks again,
David Lange
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robertscribbler
/ April 25, 2014Warmest regards to you, David. My timetable is rather similar, still hinging on summers when we still see some of the strongest effects of the human forcing, and winters, when polar amplification is at its most extreme.
Just wondering what’s your location. Are you anywhere close to the Asian plume? That thing is enormous and plainly visible in the daily satellite shots.
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dtlange
/ April 25, 2014Thanks, Robert. I’m in the Pacific Northwest (Portland,OR). I see plenty of particle pollution, at ground level, mid level, and high in the atmosphere. Every vista is shrouded in a gray-pink gauze. I’m sure we are getting Asian and Siberian aerosols. Likely ground level ozone from their influence.
The Pacific Northwest may get repeat of 2012 “Smoke from large wildfires in Siberia can be lofted high enough into the atmosphere for winds to push the plumes across the Pacific Ocean to North America. On July 8 and 9, 2012, smoke from Siberia arrived in British Columbia, Canada, and caused ground-level ozone to reach record high levels.” – http://earthobservatory.nasa.gov/IOTD/view.php?id=78515
More later, David
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robertscribbler
/ April 25, 2014Tracking fires and a rapidly receding melt line in Siberia through NASA’s LANCE-MODIS now. From where I’m sitting it looks like the burning is at least comparable to 2012 and the stage could well be setting up for something rather worse.
Will be interested to hear your thoughts.
-R
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Tom
/ April 25, 2014This is amazing Robert. Thanks for keeping us informed. It’s likely that sea level rise will become a problem as the heat already in the ocean continues to work on these glaciers and icebergs, adding their fresh water to the sea. The heat build-up is only increasing, since we continue to blanket the atmosphere with CO2 (and other gases).
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robertscribbler
/ April 25, 2014We get a few more of these giant glaciers in irreversible collapse and it will certainly be a worsening problem.
Best to you, Tom.
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Greyson Smythe
/ April 26, 2014That image looks disturbingly like a genitourinary tract diagram. Perhaps we are gefuckt.
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