Antarctica Ice Cracks Could Speed Up Melting

Rifts along the northern shear margin of Pine Island Glacier (upper right of image).

By Andrea Thompson, OurAmazingPlanet Managing Editor

The floating ice shelves of West Antarctica are fracturing increasingly and losing their grip on the rocky bay walls that slow their flow, threatening to speed up the flow of ice from land to sea, a new study finds.

The study looked at 40 years of satellite images of West Antarctic ice shelves, which have seen rapid ice loss over the past few decades. The region has been steadily warming over the past 30 years; one region in particular, the Antarctic Peninsula, is one of the fastest warming spots on the planet.

The West Antarctic Ice Sheet, which is about the size of Greenland, contains about 10 percent of all the ice in Antarctica. All of this ice makes breakoffs and melting particular concerns in terms of potential sea level rise. Scientists estimate West Antarctica contributes nearly 10 percent of global sea level rise from an acceleration in glacier ice melt.

The glaciers that make up the ice sheet slowly flow toward the sea, and there the ice flows out to sea and floats atop the ocean, forming what is called an ice shelf.

The flow of the glaciers is resisted naturally by the seams where the glaciers merge and by the rocky bay walls that the ice shelves attach to, making the shelves act as a sort of doorstop.

But the satellite record shows that in the eastern Amundsen Sea Embayment, the margins of the ice shelves, where the ice grips onto the rocky walls, are fracturing and retreating inland.

The fracturing increases until the ice shelf calves, or spits off, new icebergs that then drift out to sea. Calving is a normal process, but it is changing with these increasing cracks.

As an ice shelf's grip continues to loosen, these already-thinning masses of ice will be even less able to perform their doorstop function of holding back the grounded ice upstream, leading to potentially even faster flow of these already speedy glaciers.

"An accelerating glacier can tear away from its margins, creating rifts that negate the margins' resistance to ice flow and causing additional acceleration," said study co-author Ginny Catania of the University of Texas at Austin that conducted the research.

The research team found that the largest relative glacier accelerations occurred within and upstream of the increasingly rifted margins.

The study researchers, whose findings are detailed online in the Journal of Glaciology, say the ice shelves are poised to disintegrate further.

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Comments

[sunsetter]

06:20 PM on 05/01/2012

The children in the media lap this stuff up don't they?

[Charles John Olesen]

01:45 AM on 04/22/2012

http://youtu.be/tWq2bukeBp0 Strange Creature Found 600 Feet Under Antarctica

[StephenBP]

07:04 AM on 04/04/2012

So one big take away from this information is that if the "doorstep" ice is fracturing, the glaciers in the hills which that doorstep ice was holding back will have an easier time getting to the sea. And when glacial ice hits the sea, it raises the sea level.

So now, glacial ice doesn't have to melt and trickle down to the sea to raise sea level. Now it can just slide in on its melt-water-lubricated bottom to get there.

So it is conceivable that we will be seeing an even more rapid raise in sea level in the near future.

If that is all true, then denialists will have to spin even harder to patch up their bag of anecdotal evidence. Meanwhile , we warmists will be saying "I told you so", and people living in vulnerable margins of the coast will be suffering greatly.

[ubrew12]

12:22 AM on 04/19/2012

We should never have tried to predict the future of a state of matter whose flow characteristics are summarized by the word 'avalanche'. I find it doubtful that glacial ice will flow in any orderly fashion into the ocean.

[Publicola]

11:37 PM on 04/02/2012

U.S. National Academy of Sciences (2010):
-----------------------------------------------------------------------

Human activities are influencing climate. As discussed in the following chapters, scientific evidence that the Earth is warming is now overwhelming. There is also a multitude of evidence that this warming results primarily from human activities, especially burning fossil fuels and other activities that release heat-trapping greenhouse gases (GHGs) into the atmosphere. Projections of future climate change indicate that Earth will continue to warm unless significant and sustained actions are taken to limit emissions of GHGs.

Increasing temperatures and GHG concentrations are driving a multitude of related and interacting changes in the Earth system, including decreases in the amounts of ice stored in mountain glaciers and polar regions, increases in sea level, changes in ocean chemistry, and changes in the frequency and intensity of heat waves, precipitation events, and droughts. These changes in turn pose significant risks to both human and ecological systems. Although the details of how the future impacts of climate change will unfold are not as well understood as the basic causes and mechanisms of climate change, we can reasonably expect that the consequences of climate change will be more severe if actions are not taken to limit its magnitude and adapt to its impacts.

http://www.nap.edu/openbook.php?record_id=12782

[john649]

09:10 PM on 03/31/2012

Propaganda against GLOBAL WARMING originates from ALEC.

ALEC = corporations who meet with REPUBLICANS to plan (via under the table pay offs) to pass state laws to take away our rights and give the corporations carte blanche to do anything they want.

www.alecexposed.org

[pappy50]

09:24 AM on 04/09/2012

How can anybody be against Global Warming. Global Warming, Global Warming. Come on everybody, Global Warming. Does anybody have a drum?

[oldwolf49]

07:59 PM on 03/31/2012

Again, expressing my emotional relief at the realization of something so significant..........DUH!

[jimboy71]

04:35 PM on 03/31/2012

How many times do you have to be told that VOLUME, not AREA is the measure by which melt is measured accurately?

Moreover, this sentence "Antarctic sea ice extent is above normal as is the usual case"... is ridiculous. If the sea ice extent is "above average" it cannot be "the usual case", because the "usual case" is precisely the average.

If it were usual for sea ice to be "above average", well, then the average itself would change. Your statement is gobbledygook.

[john649]

09:02 PM on 03/31/2012

ahhh, the Flat Earth Society has struck again, you must be their secret weapon.

[Jamzhelm]

10:06 AM on 03/30/2012

If you are worried about sea levels, move inland dummy! The ebb and flow of the temperature, complicated by increasing greenhouse gases (both man-made and escaping methane from once-frozen areas) will most definitely cause sea levels to rise. And when that happens, weather patterns will change...oh, wait, they already are...arguing over whether my SUV is complicating things is pointless (of course it is!)

Whether you want to call it man-made or not, it's most assuredly not going to stop just because we decide who did it.... Stop worrying about why and try to figure out what to do to save humanity when it DOES happen.

Jeez, it's like 3rd grade all over again with all this "climate denier" and "warmer" BS!

[palindrom]

10:11 PM on 03/30/2012

So you're saying anthropogenic CO2 is a main driver, but that we should be taking no steps to reduce emissions?

That makes no sense, especially when one considers the other environmental damage and geopolitical vulnerabilities involved with fossil fue.

[Jamzhelm]

10:57 AM on 04/02/2012

absolutely the opposite of what I said, had you bothered to read it.

[Jamzhelm]

12:19 PM on 04/02/2012

actually, my comment was about how ridiculous it is to argue over what/who is to blame for global warming...the argument is idiocy and gets us nowhere. I, of course, believe that we should be using every option available to reduce our carbon footprint.

I appreciate that my lack of clarity caused the confusion....thanks!

--James

[jimboy71]

04:36 PM on 03/31/2012

Not everyone can move, and your comment is typically self-centered and myopic...

[Jamzhelm]

10:56 AM on 04/02/2012

how?

[fishingman]

03:08 AM on 03/30/2012

In 1840 the explorer James Ross was the first person to do a marine survey of what was later named for him, The Ross Ice Shelf. In 1912, Robert Falcon Scott, the second man to lead an expedition to the geographic south pole, also surveyed The Ross Ice Shelf. Both men were chosen to lead their expeditions because of their navigation and marine survey skills. Falcons entire party perished after reaching the pole A noted naturalist of the age was quoted as " lamenting that the Great Ross Ice Shelf has retreated by over 50 miles between surveys 62 years apart. He wished he had seen it it all it's glory". Ross discovered the ice shelf in a sailboat without a steam engine. So the largest Antarctic ice shelf was already receding 1 mile a year when first discovered during the Age Of Sail. I don't pretend to know what was causing this melting of the ice shelf. Unfortunately, man made global warmist claim to know. They blame it on something that did not exist when it was first noted that the ice shelf was retreating. Astrologists say that the earth is wobbling on it's axis and tilting one end toward the sun. If their claims are true it seems to me that this may have more cause and effect on climate change due to ocean and wind current disruption than the politically correct " man made CO2".

[doriath22]

06:26 AM on 03/30/2012

"Astrologists"?!!!!!
And yet you have no problem pronouncing the work of thousands of scientists to be "warmist"?
I'm laughing so hard I almost choked on my coffee
You must have been born under the sign of Alfred E Neuman

[Roadrun]

06:32 AM on 03/30/2012

CO2 is a myth. There is no such thing, man-made or natural.

[jimboy71]

04:38 PM on 03/31/2012

Wait. How do I know?

[Kommonman]

02:21 AM on 03/30/2012

Well since most of the deniers live in the lowlands of the south...they will get flooded out and either drown or move north....If they move north they have to enter more liberal demographics and then their children will get some actual education and leave all that bible/denier bs behind...I for one will take great delight in the educating their ignorance out of existence much to the screaming dismay of there bible thumping parents

[D-Driller]

02:53 AM on 03/30/2012

It doesn't work that way - look at the "Californication" of Colorado. The invaders move in and take over...

[Kommonman]

11:58 AM on 03/30/2012

When I lived in Colorado as a youth the people tended to fairly liberal...but with the rise of evangelicalism the demographic changed as that ideology sought to influence the military...It is good to hear that perhaps the pendulum begins to swing back the other way.

[fishingman]

03:02 AM on 03/30/2012

Before you start educating the ignorance out of anyone, you should learn the difference between "there" and "their".

[MonsterMusician]

06:11 AM on 03/30/2012

Ummm... Grammar usage does not greatly affect an understanding of science. But you fishingman, you might want to learn the difference between ice shelves and land ice. Those are 2 distinctly different kinds of ice formations, and you chose the one that is not significant to the article or the debate.

[palindrom]

07:20 AM on 03/30/2012

As a bona-fide astronomer, I also suggest you learn the difference between astronomers and astrologists.

That is, if you want to have any appearance of scientific competence.

[Aladdin Sane1]

12:12 AM on 03/30/2012

Man, simply knowing middle school basics would erase half the erroneous comments seen here.

Three types of ice: 1) Land ice (glaciers), 2) Ice shelves, 3) Sea ice and icebergs.

The above article does a good job of failing to report about sea ice; that is not what it is about.

Sea ice and ice shelves, if melted, cause sea level rise, but to no noticeable extent. For example: "Therefore, when a mass of floating ice melts, sea levels will increase; however, this effect is small enough that if all extant sea ice and floating ice shelves were to melt, the corresponding sea level rise is estimated to be ~4 cm." [1]

The above article is about land ice, mainly, so info about sea ice and ice shelves is largely irrelevant (except where noted in the above article about ice shelves that come from land ice).

Three main sources of land ice: 1) Antarctica, 2) Greenland, 3) Other glaciers. Land ice causes significant sea level rise when melted ice flows into the sea.

Please take a moment to refresh your sixth grade Earth Science knowledge by reading *just the summaries* of these three articles:

1 http://en.wikipedia.org/wiki/Ice_shelf
http://en.wikipedia.org/wiki/Sea_ice
http://en.wikipedia.org/wiki/Glacier

"A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation (…) over many years, often centuries. … Glaciers form on land, … ."

[palindrom]

07:21 AM on 03/30/2012

Oh, but it's so much more fun to type whatever comes into my head than to read anything!

[jimboy71]

04:43 PM on 03/31/2012

Funny, but when we do that, it still usually makes sense. That is the joy of an education.

[racetoinfinity]

12:08 AM on 03/30/2012

This is obviously a symptom of global warming; only a dupe, a big shareholder in carbon energy, or an uneducated person could think otherwise.

[green34]

02:27 AM on 03/30/2012

Bullshit

[Jeremyewilliams]

09:30 AM on 03/30/2012

Go on...

Continue...

Oh, that's it? Good job little guy *pats green34 on his head*

[HowthCastle]

08:15 PM on 04/01/2012

My, what masery of logic!

[PandaUnbound]

11:42 PM on 03/29/2012

The only thing cracking apart is the desperate greens whose global warming hoax is falling apart. Look at how huffp0 draws you in with their misleading headlines.

[doriath22]

06:30 AM on 03/30/2012

Sure. Just keep telling yourself that putting gigatons of CO2 into the atmosphere for a couple of centuries has no effect.

[palindrom]

07:23 AM on 03/30/2012

"global warming hoax is falling apart."

This is happening only in the right-wng denial-o-sphere, funded largely by oil and coal interests.

In the scientific literature, where these questions are discussed with a deep level of rigor, the question has long been decided.

The idea that you could somehow coax all those scientists into a gigantic 'hoax' -- which would ruin their professional reputations they've built up so hard over the decades -- is preposterous.

[Dave Dave]

11:13 PM on 03/29/2012

Temperature fluctuation have been occurring since the earth was formed 6000 years ago.

[old soil guy]

12:33 AM on 03/30/2012

6000 yrs? Where'd you get that? Did god fake carbon dating for that?

[Sunwyn Ravenwood]

05:02 AM on 03/30/2012

Around 1650 an Irish Bishop used all the begats in the Bible, along with other materials, to conclude that the world was created on October 22, 4004 BC. Simple-minded people have adopted this date in an effort to avoid the painful process of rational thought.

They are joined in their denialism by the members of the Flat Earth Society which uses the same justification for their rejection of astronomy and physics that Creationists use to reject geology, biology, and climatology.

"Modern hypotheses supporting a flat Earth originated with English inventor Samuel Rowbotham who published a 430-page book, "Earth Not a Globe," expounding his views. He also published a leaflet entitled "The Inconsistency of Modern Astronomy and its Opposition to the Scriptures!!" which argued that the "Bible, alongside our senses, supported the idea that the earth was flat and immovable and this essential truth should not be set aside for a system based solely on human conjecture".

The Flat Earth Society recruited members by attacking the United States government and all of its agencies, particularly NASA. Much of the society’s literature in its early days focused on interpreting the Bible literally to mean that the Earth is flat. The society also took the position that the Apollo Moon landings were a hoax, a position also held by others not connected to the Flat Earth Society."

[doriath22]

06:31 AM on 03/30/2012

That, I say that might just have been sarcasm, there, son

[Roadrun]

06:37 AM on 03/30/2012

Actually when it was made the earth was completely covered with ice and has steadily melted off to this point. One day it will be nothing but a burning heck. It's all gawds plan.

[hypnoblonde]

11:10 PM on 03/29/2012

we are due for another polar shift.... it has been noted that the magnetic north pole in the past year has moved 40 miles towards Russia... if the north pole is moving it means the south pole is doing something.

[D-Driller]

02:55 AM on 03/30/2012

What does a magnetic pole shift have to do with Antarctic warming? If the rotational poles were moving, then yes, that might indeed have an affect. Ice doesn't know if it is pointing north or south.

[palindrom]

07:28 AM on 03/30/2012

Magnetism has always had a fascination for folks on the fringes of science (or beyond the fringe); they ascribe all sorts of "gnarly powers"* to it.

* -- Bart Simpson's bus driver, Otto, in an early "Treehouse of Horrors" episode.

[jimboy71]

04:46 PM on 03/31/2012

Ugh. Learn a little geology. There is no concordance between pole shift and ecological disaster. It happens quite regularly, you know.