Current ice melt rate in Pine Island Glacier may go on for decades
A study of the Pine Island Glacier could provide insight into the patterns and duration of glacial melt.
The Pine Island Glacier, a major outlet of the West Antarctic Ice Sheet, has been undergoing rapid melting and retreating for the past two decades. But new research by an international team including researchers from Lawrence Livermore National Laboratory shows that this same glacier also experienced rapid thinning about 8,000 years ago.
Using LLNL’s Center for Accelerator Mass Spectrometry to measure beryllium-10 produced by cosmic rays in glacially transported rocks, Lawrence Livermore researchers Bob Finkel and Dylan Rood reported that the melting 8,000 years ago was sustained for decades to centuries at an average rate of more than 100 centimeters per year. This is comparable to modern-day melting rates.
The findings indicate that modern-day melting and thinning could last for several more decades or even centuries. The research appears in the Feb. 20 issue of Science Express.
“Pine Island Glacier has experienced rapid thinning at least once in the past. Once set in motion, rapid ice sheet changes in this region can persist for centuries,” said Finkel, one of the authors of the new findings.
Ice mass loss from the Pine Island-Thwaites sector dramatically contributes to the sea level of the West Antarctic Ice Sheet. The Pine Island Glacier is currently experiencing significant acceleration, thinning and retreat. The rate of thinning from 2002-2007 on the grounding line (the part where the glaciers export the ice down the continent and lose contact to the ground and become a floating ice shelf) was between 1.2 meters per year and 6 meters per year.
The change is likely tied to the increased influx of warm water to the cavity under the ice shelf at the glacial front.
Dramatic changes over longer timescales — from centuries to millennia — are somewhat limited, so there is considerable uncertainty associated with model projections of the future evolution of timing and ice loss of the Pine Island Glacier. Current geological research is tied to the grounding line retreat across the continental shelf. However, little is known about the terrestrial thinning history and how the ice stream evolved from 8,000 years ago to the onset of present-day thinning.
The team found that there was a direct correlation from glacial-geological samples consisting of cobblestones and granite boulders from the Hudson Mountains to rapid thinning in the Pine Island Glacier system about 8,000 years ago.
“The melting of the Pine Island Glacier at a rate comparable to that over the past two decades is rare but not unprecedented,” Rood said. “Ongoing ocean-driven melting of the glacial ice shelf in current times may result in continued rapid thinning and ground line retreat for several more decades or even centuries.”
Other institutions involved in the research include: The British Antarctic Survey; Durham University; University of California, Berkeley; University of California, Santa Barbara; Alfred Wegener Institute Helmholtz-Centre for Polar and Marine Research; Berkeley Geochronology Center; Lamont-Doherty Earth Observatory; and Columbia University.
I thought Antarctic glaciers were expanding?
It has all happened before.
This weekend there was a fascinating programme on BBC(4) about the Inca Tiwanaku civilisation that dominated the region of lake Titicaca, 12,000 feet up in the Andes. It evolved an advanced communial agricultural economy, fed by Andean melt waters, that thrived for the better part of the first millenium AD, with astounding monumental architecture. It disappeared at the end of the first millenium because of declining precipitation in the mountains, over a period of some four centuries.
NATURAL Catastrophic Climate Change,
Yet another overhyped press release about a scientific paper. The paper itself appears to be solid bread and butter research on the history of the Pine Island glacier. But of course that isn’t exciting enough for the press release which tries very hard to link it all to climate catastrophe and dire predictions for the future. It is very “dramatic”.
Dramatically! Wow! But since the sea level changes at pretty much the same rate around the West Antarctic Ice Sheet as it does in other places, this is very puzzling. Something isn’t quite right here. A little less attention paid to drama and a little more paid to accuracy and precision might have helped.
Wasn’t the sea level like 300 ft lower at that time?
The sea floor must be being scoured away by this glacier as it pushes out to sea. So the sea floor could be lowered over time and then the glacier floats and breaks away at a line further in. Then new deposits build up and the sea floor comes up again?
Just thinking..
@Lou: 7000 years ago it was only around 4 metres lower than present while 8000 years ago it was 15 metres lower. The last time it was 100 metres lower looks to have been about 14000 years ago near the end of the last ice age. I hope I’ve got those figures about right.
hmm, you take 6 months of satellite data in 2006 and compare it with two completely different land based sets from 20 and 40 years ago, and what do you get? rapid melting! 73% more since 1974!
http://www.ess.uci.edu/researchgrp/erignot/files/RignotGRL2008.pdf
8000 years ago? how about the last 20 years!
8000 years ago the coal fired power plant, the SUV, the wood burning stove and other modern industrial age accoutrements of the planet destroying human race were invented .
This first industrial revolution caused the Pine Island Glacier to begin melting – as the CONSENSUS has determined. But the folks at Lawrence Livermore make no mention of this at all!
I smell a rat here!!! Big bad oil is once again funding a bogus, self-servicing study.
LL researchers should be banned, prohibited from publishing any of their work or speaking at any
“Serious” climate conferences.
Further, any papers they have disseminated must be immediately collected and burned in one massive AGW-NACHT bonfire.
All together now AGW patrons, repeat after me: SIEG HEIL!! SIEG HEIL!! SEIG HEIL !!
Haven’t read the full paper, but the abstract represents a much less alarming situation (“show that this thinning was sustained for decades to centuries at an average rate of 100 cm-1, comparable to today’s thinning rates.”) than an earlier 2008 GSA paper ( http://epic.awi.de/16986/1/Joh2007b.pdf ) on the same subject by three of the same authors.
That paper stated: “Dramatic changes (acceleration, thinning, and grounding-line retreat of major ice streams” in the Amundsen Sea sector of the West Antarctica Ice Sheet (WAIS) have been observed in the past two decades, but millenial-scale context for these changes is not yet known. … Our data provide the first evidence that puts into context recent rates of thinning of the WAIS in the Amundsen Sea Embayment and demonstrates that these are unusually rapid.”
Seems that this 2014 paper provides more of the “millenial-scale context” and current thinning isn’t as bad as was thought previously. And since “This region is critically important because changes are happening faster here that anywhere else in the West Antarctica Ice Sheet (WAIS). In addition, this sector has long been identified as the “weak underbelly” of the WAIS (Huges, 1981), and has the potential to raise sea level by as much as ~1 m (Holt etal., 2006; Vaughan et al., 2006).”
For once, it isn’t as bad as we thought. The beginning of less alarmism as the “hiatus” persists? Let’s hope.
finishing my next to the last paragraph: “… (Vaughan et al., 2006).”, then it’s not as likely that present sea level rise from this area will be any more rapid that previously either.
I am not convinced that it is particularly reassuring that the Pine Island Glacier is now shrinking at a rate comparable to the major melt period at the end of the last glacial period when temperatures were climbing and sea level rose by around a foot per decade during the A1 meltwater pulse.
Why no mention of volcanic influence??
… Or is that an inconvenient truth..
http://www.livescience.com/2242-buried-volcano-discovered-antarctica.html
melting 8,000 years ago was sustained for decades to centuries at an average rate of more than 100 centimeters per year. This is comparable to modern-day melting rates.
The findings indicate that modern-day melting and thinning could last for several more decades or even centuries.
Of course it “could”, but isn’t this a non sequitur?
Why exactly should it do the same now as it did 8000 years ago?
(In the caption A massive crack rus about 29 kilometers presumably should be “runs”)
[Done. Thank you. Mod]
It would also be a non sequitur to see a similar rate in the past and assume that because it happened before naturally there is no human influence this time nor reason for concern.
The point really is that the bedrock geometry and ocean currents in this region make it more sensitive to changes, natural or otherwise. Given the amount of ice in the catchment, it is yet another good reason to be extremely cautious about the planetary scale experiment on the atmosphere and climate we are currently performing.
Leo Geiger says:
February 24, 2014 at 6:06 am
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You forgot the /sarc tag
Don’t tell Mosher.
izen says:
February 24, 2014 at 5:37 am
Izen, could you break that long sentence-paragraph down into a number of subject/predicate pairs so that we can understand what you think that you do?
From the article:
Hmmmmn.
So, we get entertained by excited press releases and convoluted explanations from lots of professional CAGW-funded organizations when an existing Antarctic glacier thins by 1.2 meters a year, when an existing glacier gets a crack in it (but doesn’t thin or go anywhere but “might” go somewhere in a few years.
But ….
When the Antarctic sea ice is ABOVE its historical normal by 1.2 Million square kilometers – an area the size of Hudson Bay and right at half the size of Greenland itself … We hear nothing.
Yet, just last October, the Antarctic sea ice anomaly was not only “above average’ it was “above average” so much that it reflected more sunlight than half of Greenland, at the same average latitude as Hudson Bay.
And nobody said anything. To the CAGW religion, increasing sea ice by massive amounts didn’t support their agenda, so, it didn’t happen.
to measure beryllium-10 produced by cosmic rays in glacially transported rocks, [they] reported that the melting 8,000 years ago was sustained for decades to centuries at an average rate of more than 100 centimeters per year.
How’s that again? Glacially transported rocks get moved, and moved again, again and again. The age control on the dating is remarkable. Not to mention the implied precision on rates. Be-10 dating of the rocks require many assumptions about pre-exposure history. What is the cosmic ray attenuation per 100 m of ice? From where did the samples come?
There are many degrees of freedom to be accounted for.
The reality is these glaciers ground and then unground all the time. When they unground the flow will increase because of the buildup during the time it was grounded. All that is happening is the flow that was restricted now occurs. We know from measurements of the south polar atmosphere and the Southern Ocean that neither one is warming. Hence, there is nothing man made about these changes. It is either just normal variation or geological.
Greenland’s northern shore was getting pounded by waves generated in an ice-free Arctic Ocean at about the same time. Surprising, thus, that the Holocene Climatic Optimum doesn’t receive a mention. I hope I won’t upset anyone by thinking in this way.
@- Réaumur
“Why exactly should it do the same now as it did 8000 years ago?”
Because similar processes are in operation. Global warming.
Specifically the sea surface temperature is rising and that heat is getting into the deeper ocean currents which are now melting the underside of several Antarctic ice sheleves.
Last time, 8000 years ago, it was down to the timing of perhelion in the terrestrial year, now its the rise in CO2.
It has been shown that when doomsday prophecy fails as, will the CAGW prophecy, the irrefutable failure of a prophecy does not cause true believers (people who have committed themselves to a belief both emotionally and by their life choices) to reconsider. They, the zealots, become even more fervent, and proselytize even harder.
So, we see the political machine with likes of the U.N., Mr. Kerry, Mr. Gore and other thieves, using all the doomsday support money being poured into the collective research centers and colleges with the intent to sway the dumb-downed public with propaganda produced from of bad science.
The glaciers are going to come and go. Expand and retract. Proof that the weather changes with or without our help. Recall the notion to spread black soot on the north pole region to melt it…save the planet!
“The change is likely tied to the increased influx of warm water to the cavity under the ice shelf at the glacial front.”
WUWT? How can the glacier be “held back” or accelerated on the continent by the floating section, warm water or cold. Am I missing something here? Can someone explain?
Question:
Since Antarctica has much higher Ice accumulation that average and is very cold, why is there glacial retreat these days? One would think that the glacier would be at a stand still or growing?
Paul Westhaver says:
February 24, 2014 at 8:13 am
Question:
Since Antarctica has much higher Ice accumulation that average and is very cold, why is there glacial retreat these days? One would think that the glacier would be at a stand still or growing?
=========================================================================
The Pine Island Glacier is on or near the Antarctic peninsula which extends far enough north that it is partly outside the antarctic circle. That entire region of Antarctica is warmer than the rest of the continent.
MattS says: February 24, 2014 at 8:25 am
… That entire region of Antarctica is warmer than the rest of the continent.
No kidding!?
I am going to look into that. Much obliged.
Lou at 4:27 and cynical_scientist at 4:46
Here is a link. These are called “art” but, at the resolution used, seem to be reasonably accurate.
http://www.globalwarmingart.com/images/1/1d/Post-Glacial_Sea_Level.png
It is used in this paper:
http://www.fws.gov/slamm/Changes%20in%20Sea%20Level_expanded%20version_template.pdf
In this one, also, is a chart for Maine showing the effect of the Laurentide and other ice as it grew and then melted. (p. 15)
Page 23 has a few IPCC predictions from 2007 and there is another set for 2009. The presentation seems undated so that last date is an indicator; namely after 2009. The author is using info from others to discuss planning issues along the Maine coast. Predictions are not his. He accepts the uncertainty.
They recently found an ACTIVE VOLCANO under Pine Island. How thick are these scientists? Gee…I wonder why the water under the sea ice is is WARMING!!! *forehead smack* Oh…wait….I forgot…oceans can ignore basic thermodynamic laws where heat always rises…so that heat would stay deep beneath the surface. Silly me.
Paul Westhaver asks:
Since Antarctica has much higher Ice accumulation that average and is very cold, why is there glacial retreat these days?
Good question. It shows that we don’t know everything about glaciers.
Glaciers advance, and glaciers retreat. Around the world both are happening right now. But if global warming was the central cause, all glaciers would be retreating, more or less together.
There are many reasons that glaciers act the way they do. Cherry-picking only those glaciers that retreat is a typical tactic of the climate alarmist crowd. But so far, that gang has not made one correct prediction, from glaciers, to CO2 is gonna getcha, to accelerating global warming, to disappearing frogs, to ocean ‘acidification’, to accelerating sea level rise, to… well, you get the picture. They have been wrong in every prediction they’ve made.
When rational folks are wrong about everything, they re-assess their conjecture per the Scientific Method, and try to understand why they were so completely wrong. But catastrophic AGW believers don’t think like that. The Scientific Method doesn’t seem to apply to them. Blind faith in their belief seems to be sufficient.
But faith is not enough here at the internet’s ‘Best Science’ site. We want reasons; either plausible reasons, or preferably, reasons based on verifiable data. But so far the alarmist crowd’s entire argument seems to be, “Because global warming!” That’s not good enough.
izen says:
February 24, 2014 at 7:59 am
Because similar processes are in operation. Global warming.
Specifically the sea surface temperature is rising and that heat is getting into the deeper ocean currents which are now melting the underside of several Antarctic ice sheleves.
Last time, 8000 years ago, it was down to the timing of perhelion in the terrestrial year, now its the rise in CO2.
Fascinating. So CO2, which has been on a 17-year break on warming the atmosphere has now decided to warm the deep oceans which of course we can’t measure, but nevermind. And of course, how the heat we can’t measure even got there is unknown, but nevermind that either. Because the important thing is to blame CO2. Right?
Paul Westhaver,
The west Antarctic peninsula has been warming.
Also, the Antarctic has not warmed for many years.
Paul Westhaver says:
February 24, 2014 at 8:39 am
MattS says: February 24, 2014 at 8:25 am
… That entire region of Antarctica is warmer than the rest of the continent.
No kidding!?
I am going to look into that. Much obliged.
=============================================================================
Look up older articles on this site on various studies trying to show that Antarctica is warmer. The general criticism is that they accomplish this by smearing the warming from the peninsula area to the rest of the continent.
One possible source for the warmth in that part of Antarctica is as other commenters have mentioned the fact that the region is volcanically active.
Antarctic ice cover is currently higher than both it’s short term and long term averages.
As usual, the late, great John Daly makes sense of the ice issue.
Also, it is interesting to note that the currently ice-bound Arctic was essentially ice free several thousand years ago, when CO2 levels were very low.
Finally, we can see here that the sea level changed quite a bit before human emissions had any effect.
Coincides with the melting of 8,000 years ago, huh.
Well gee, 8,000 BP was the “high point” of the Holocene Optimum
To wit, the proxy graph:
http://upload.wikimedia.org/wikipedia/commons/c/ca/Holocene_Temperature_Variations.png
Gary Pearse says: How can the glacier be “held back” or accelerated on the continent by the floating section, warm water or cold. Am I missing something here? Can someone explain?
A stable ice shelf acts like a cork that resists the flow from the glaciers upstream. An example of this was the Larsen-B (floating) ice shelf. The glaciers that fed into it were observed to accelerate and thin after it collapsed.
MattS says: The Pine Island Glacier is on or near the Antarctic peninsula which extends far enough north that it is partly outside the antarctic circle. That entire region of Antarctica is warmer than the rest of the continent.
Pine Island Glacier is not on the Peninsula. It is along the coast of West Antarctica by the Amundsen Sea. It is at a higher latitude (farther south) than nearly all of both the East Antarctica and the Peninsula coastline.
Only recently we had this: Lead author, Dr Pierre Dutrieux, from British Antarctic Survey (BAS) said: “We found ocean melting of the glacier was the lowest ever recorded, and less than half of that observed in 2010. This enormous, and unexpected, variability contradicts the widespread view that a simple and steady ocean warming in the region is eroding the West Antarctic Ice Sheet. These results demonstrate that the sea-level contribution of the ice sheet is influenced by climatic variability over a wide range of time scales.”
http://www.sciencedaily.com/releases/2014/01/140102142010.htm
MattS says: One possible source for the warmth in that part of Antarctica is as other commenters have mentioned the fact that the region is volcanically active.
Volcanic activity won’t cause a regional change in air or water temperature. In this context, it adds additional warmth locally to the base of the ice sheet creating an increase in melt water that could help lubricate the base and allow the glacier to flow faster. But the changes in the Amundsen Sea region are larger and more widespread than can be reasonably explained with volcanic activity causing basal melting alone. From some British Antarctic Survey press releases on Pine Island Glacier research:
and
Stephen Skinner says:
February 24, 2014 at 4:32 am
That exact process is happening to a glacier in Alaska.
http://wattsupwiththat.com/2012/11/27/alaskas-columbia-glacier-expected-to-halt-retreat-in-2020/
The Precautionary Fallacy Raises Its Ugly Head — AGAIN
— Along with its mentor, Ignorance.
!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!@!
“… yet another good reason to be extremely cautious about the planetary scale experiment on the atmosphere and climate we are currently performing.”
(Leo Geiger pompously quavers at 6:06am today)
Mr. Geiger, fear not. An experiment must be at least somewhat controlled. There is no evidence at all that HUMANS HAVE ANY CONTROL over the climate of the earth. ZERO. Any experiments we might do, e.g., you jumping up and down for 3 days straight to try to create an earthquake, are fatally flawed due to all the independent variables. Say, in all your trembling and quaking, perhaps you could not hear me… . AHEM! Once again: there is no evidence (NONE) that human effects can cause any significant change in the climate of the earth. Moreover, there IS evidence that our puny little emissions are easily OVERWHELMED by a magnitude of 3 by natural sources and sinks such as vast grasslands and jungles and ocean evaporation and currents and volcanic eruptions. Human emissions are, thus, irrelevant.
If you are a genuine seeker of truth and not mere poseur, watch this lecture of a world-class expert on the “experiment” about which you are trembling above. If you are not a scientist — no worries! It is (watch it more than once) readily understandable by a non-scientist.
(Note: after the introductory remarks, the lecture is in English)
Dr. Murry Salby, Hamburg, Germany (2013)
FYI: Here is where a key fact for you comes in the above video (if you are wise, you will watch the entire lecture):
[36:34] Native Source of CO2 – 150 (96%) gigatons/yr — Human CO2 – 5 (4%) gtons/yr
[37:01] Native Sinks Approximately* Balance Native Sources – net CO2
*Approximately = even a small imbalance can overwhelm any human CO2
**************************************************************
The only rational (immoral, but, rational) people pushing the human-emissions-control-earth’s-climate junk science are those who use it
to dec1eve
to make
money.
They are not fooled — you are.
After testing the above vid link which has ALWAYS turned into a Youtube control window whenever I posted it until today, it just WORKED on “Test”
so, SECOND ATTEMPT AT SALBY VIDEO post:
shrug — I am sorry for what-EVER I did to make that failed link happen… .
I saw recently a map of global ocean currents including the deep THC. Some areas were identified as locations of formation of deep cold water. This process releases heat from enthalpy so at these places significant heat is released at the sea surface.
One of these places is the west peninsula of Antarctica. Another is near to Greenland. Climate scientists need to engage in system 2 rather than system 1 thinking in regard to apparent warming at these sites.
“Lawrence Livermore research shows that the glacier’s recent melt may go on for decades or
centuries.”
I thought glaciers braking off into the sea was a sign of expanding, not melting ice. This would
suggest colder, not warmer regional weather. You take a large mass of ice like this and if it
continues to expand, it will brake off due to it’s own weight.
I would bet that the crack on the near side of the glacier roughly follows the topography of
the lands end (For the warmers out there, where the land meets the sea.)
The A1 meltwater pulse was around 14000 years ago. 8000 years ago is well into the Holocene and the melt is nearly finished.
In any case, this is the Antarctic peninsula we are talking about. That isn’t what was melting and causing sea levels to rise back then, so this isn’t a repeat. What happens to this glacier is dictated by local conditions which seem to have more to do with the state of the volcano underneath it than what is going on in the rest of the world.
Cynical Scientst says: In any case, this is the Antarctic peninsula we are talking about…
Once again, Pine Island Glacier is not on The Peninsula. It is on the coast of West Antarctica along the Amundsen Sea. Maybe a map would help:
http://en.wikipedia.org/wiki/File:AmundsenSea.jpg
izen says:
I am not convinced that it is particularly reassuring that the Pine Island Glacier is now shrinking at a rate comparable to the major melt period at the end of the last glacial period when temperatures were climbing and sea level rose by around a foot per decade during the A1 meltwater pulse.
Dear Izen
The 1A (not A1) meltwater pulse was 14,000 years ago, not 8,000. For your information 8,000 years ago is mid-Holocene about 3,700 years after the end of the last glacial period.
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John McNaff says:
February 25, 2014 at 9:40 pm
I believe that all of this is caused by global warming and that maybe we can fix it by cutting our oil drills and driving more economic cars like a Prius or the Leaf.
OK.
Now, please go ahead and explain your conclusion there. And, by the way, explain all of your logic too. And please start by providing evidence of each of your statements too.
See, for the past 17 years CO2 levels have been steadily increasing worldwide. And, for the past 17 years, global temperatures have been steady.
Thus, not only have there been NO measurable increase in air temperature around the Antarctic that can be traced to ANY levels of CO2 increase worldwide, there have not even been any increases in air temperatures near the particular glacier in question that might have caused its recent movement!
[ Don’t waste your time, he’s just another fake commenter with a fake email address. He’s been snipped for that and using two different screen names here. -mod]
Thank you sir.
Let us leave my reply in place for the moment.