UNIVERSITY OF WASHINGTON
VIDEO: THE ICE SHELF ON ANTARCTICA’S PINE ISLAND GLACIER LOST ABOUT ONE-FIFTH OF ITS AREA FROM 2017 TO 2020, MOSTLY IN THREE DRAMATIC BREAKS. THE TIMELAPSE VIDEO INCORPORATES SATELLITE IMAGES FROM… view more
CREDIT: JOUGHIN ET AL./SCIENCE ADVANCES
For decades, the ice shelf helping to hold back one of the fastest-moving glaciers in Antarctica has gradually thinned. Analysis of satellite images reveals a more dramatic process in recent years: From 2017 to 2020, large icebergs at the ice shelf’s edge broke off, and the glacier sped up.
Since floating ice shelves help to hold back the larger grounded mass of the glacier, the recent speedup due to the weakening edge could shorten the timeline for Pine Island Glacier’s eventual collapse into the sea. The study from researchers at the University of Washington and British Antarctic Survey was published June 11 in the open-access journal Science Advances.
“We may not have the luxury of waiting for slow changes on Pine Island; things could actually go much quicker than expected,” said lead author Ian Joughin, a glaciologist at the UW Applied Physics Laboratory. “The processes we’d been studying in this region were leading to an irreversible collapse, but at a fairly measured pace. Things could be much more abrupt if we lose the rest of that ice shelf.”
Pine Island Glacier contains approximately 180 trillion tons of ice — equivalent to 0.5 meters, or 1.6 feet, of global sea level rise. It is already responsible for much of Antarctica’s contribution to sea-level rise, causing about one-sixth of a millimeter of sea level rise each year, or about two-thirds of an inch per century, a rate that’s expected to increase. If it and neighboring Thwaites Glacier speed up and flow completely into the ocean, releasing their hold on the larger West Antarctic Ice Sheet, global seas could rise by several feet over the next few centuries.
These glaciers have attracted attention in recent decades as their ice shelves thinned because warmer ocean currents melted the ice’s underside. From the 1990s to 2009, Pine Island Glacier’s motion toward the sea accelerated from 2.5 kilometers per year to 4 kilometers per year (1.5 miles per year to 2.5 miles per year). The glacier’s speed then stabilized for almost a decade.
Results show that what’s happened more recently is a different process, Joughin said, related to internal forces on the glacier.
From 2017 to 2020, Pine Island’s ice shelf lost one-fifth of its area in a few dramatic breaks that were captured by the Copernicus Sentinel-1 satellites, operated by the European Space Agency on behalf of the European Union. The researchers analyzed images from January 2015 to March 2020 and found that the recent changes on the ice shelf were not caused by processes directly related to ocean melting.
“The ice shelf appears to be ripping itself apart due to the glacier’s acceleration in the past decade or two,” Joughin said.
Two points on the glacier’s surface that were analyzed in the paper sped up by 12% between 2017 and 2020. The authors used an ice flow model developed at the UW to confirm that the loss of the ice shelf caused the observed speedup.
“The recent changes in speed are not due to melt-driven thinning; instead they’re due to the loss of the outer part of the ice shelf,” Joughin said. “The glacier’s speedup is not catastrophic at this point. But if the rest of that ice shelf breaks up and goes away then this glacier could speed up quite a lot.”
It’s not clear whether the shelf will continue to crumble. Other factors, like the slope of the land below the glacier’s receding edge, will come into play, Joughin said. But the results change the timeline for when Pine Island’s ice shelf might disappear and how fast the glacier might move, boosting its contribution to rising seas.
“The loss of Pine Island’s ice shelf now looks like it possibly could occur in the next decade or two, as opposed to the melt-driven subsurface change playing out over 100 or more years,” said co-author Pierre Dutrieux, an ocean physicist at British Antarctic Survey. “So it’s a potentially much more rapid and abrupt change.”
Pine Island’s ice shelf is important because it’s helping to hold back this relatively unstable West Antarctic glacier, the way the curved buttresses on Notre Dame cathedral hold up the cathedral’s mass. Once those buttresses are removed, the slow-moving glacier can flow more quickly downward to the ocean, contributing to rising seas.
“Sediment records in front of and beneath the Pine Island ice shelf indicate that the glacier front has remained relatively stable over a few thousand years,” Dutrieux said. “Regular advance and break-ups happened at approximately the same location until 2017, and then successively worsened each year until 2020.”
###
Other co-authors are Daniel Shapero and Ben Smith at the UW; and Mark Barham at British Antarctic Survey. The study was funded by the U.S. National Science Foundation, NASA and the U.K. Natural Environment Research Council.
Since NSIDC shows sea ice in Antarctica as normal for this time of year, could this possibly be something else i.e. volcanoes?
Or was that not considered?
The paper is here
Yep. Volcanoes.
And for those that insist that “climate scientists wouldn’t lie or misrepresent the facts”, I’m pretty sure that the British Antarctic Survey were the guys that discovered the volcanoes, yet they neglect to mention them. Go figure.
If they had brought in the volcanic aspect, I doubt that they would have been published. Far too inconvenient for Big Brother to tolerate.
That little island in the southern ocean called Antarctica, is surrounded by undersea volcanoes, most reasonably active beneath the waves, according to a report on WUWT a few years back!!!
I know mate, that’s way I raised it š
Indeed, I well recall that, many years ago, the synthetic aperture radar on the US Space Shuttle (about 30 years ago) demonstrated the large field of active volcanos under the glaciers that showed “ice stream” activity. That activity showed the center of the glacier was moving at up to ONE METER PER DAY, and the cause became known once the SAR data was processed. It was opined that if one or more of those buried volcanos erupted, the entire glacier could end up in the sea in weeks or months, raising sea levels several meters in that time.
No AGW needed.
This was in Science News magazine, a publication I subsequently canceled because of their overt support for the dunderheads who insisted that man is destroying the Earth.
Specifically an active volcano directly beneath Pine Island Glacier
Evidence of an active volcanic heat source beneath the Pine Island Glacierhttps://www.nature.com/articles/s41467-018-04421-3
According to this geothermal heat flux map the highest heat fluxes (pale purple circles) are underneath Pine Island (-100 longitude) and the headwaters of Thwaites (-110 longitude).
Geothermal heat flux map
https://www.researchgate.net/figure/New-heat-flow-map-of-Antarctica-based-on-revised-data-sets-For-details-see-the-text_fig2_340086938
The mere fact that they did not mention the Volcanic activity invalidates their paper.
Two interesting things mentioned in that research paper:
1) Geothermal meltwater feeds the hydrologic network crossing the grounding line (as would be expected), meaning it’s discharged underneath the floating ice shelf.
2) Volcanic heat is estimated to be about 1/2 that of the active Grimsvƶtn volcano in Iceland.
Magnificent Photos of Grimsvoetn Volcano Eruption in Icelandhttps://www.amusingplanet.com/2011/05/magnificent-photos-of-grimsvoetn.html
How much longer till griff or one of our other trolls pops up to declare that heat flow from volcanoes never changed before CO2 started increasing.
Is there any evidence heat flow from volcanic heat source beneath the Pine Island Glacier (or any nearby) has changed since CO2 started increasing? Emphasis on the word changed.
If so please link to it.
This is a really nice paper, very well written:
https://www.nature.com/articles/s41467-018-04421-3
Thanks for having me do your work for you. I enjoyed reading that. It doesn’t answer your question directly, but it has some partial answers (Fig. 3, for example). It was the first Google hit and don’t have time to read more.
It would have to be a person very removed from science and general reality, who would think that volcanic activity in a high-activity volcanic area didn’t change. Oh ….. hold on a sec.
Thanks Phil,
“It doesnāt answer your question directly…” Surprise, surprise.
Ok so I will – there is no evidence that there are any changes to the flux. And if there are no changes… then obviously, obvious that is to anyone not removed from science and general reality, obviosly that means such geothermal heat plays no role in the decadal fluctuations mentioned in the post. So no, nothing whatsoever to do with volcanos. The heat coming from below probably hasn’t changed very much for a million years.
Oceanic heat advected around the glacier is the correct answer…from your link:
“Presently, the greatest contributor to ice shelf instability around Antarctica appears to be an increase in ocean heat supply to the cavities of Antarctic ice shelves19. Circumpolar Deep Water (CDW) is the primary heat source for melting glacial ice and its increased presence on the Amundsen Sea continental shelf has been implicated in the rapid melting and grounding line retreat observed beneath the Pine Island Glacier19,20,21 and in the atmospheric warming along the western Antarctic Peninsula
Nothing new there.
Your committing a classic fallacy of bad science. The Antarctic environment is so harsh and inaccessible that geothermal flux is not something that can be easily measured, so long-term data don’t exist. That means there is no way to know anything about changing geothermal heat flux at Pine Island via measured data.
The fallacy states that since there is no evidence heat flux changes it must remain steady. But that’s simply an assertion without evidence. Without evidence there’s no way to know.
But we can reasonably conclude that if Pine Island is an active volcano, which the study above evidences, then heat flux does fluctuate because that happens with all active volcanoes.
So at least with the geothermal melt position there is some evidence that volcanic heat flux varies, but there is no evidence that it remains steady, ergo only ocean heat can be responsible for changed ice shelf melting.
And you and your zombie-myth, volcanists are committing a classic fallacy of willul delusion. Higher water temps are observed, ice tongues are shrinking entirely predictably as a result of warmer Circumpolar Deep Water.
With zero evidence: “Must be volcanoes, yup”.
Nope.
Circular reasoning
I thought that the movement indicates the glacier is growing.
Alexy, right on! Notice they never provide data on what’s happening in the recharge zone of the glacier, where snowfall is compacted into ice and moves downslope toward the ocean? Show me the balance between increased load above versus reduced resistance below versus glacier speed. Easier to sit in your office and look at satellite images? Than examine, on foot, the snow accumulation conditions in the upper recharge zone?
Quote “leading to an irreversible collapse,”
It formed so that is a pretty good indication that it isn’t irreversible.
They struggle with English.
Not just English but logic.
Dunning Kruger central.
https://en.wikipedia.org/wiki/Marine_ice_sheet_instability
You’re a sad sack.
Wikipedia is the last place to go for any topic that could be at all controversial.
By the way if you think by insulting me you will gain an advantage in an argument you are especially delusional.
What a tosser.
āIf it and neighboring Thwaites Glacier speed up and flow completely into the ocean, releasing their hold on the larger West Antarctic Ice Sheet, global seas could rise by several feet over the next few centuries.ā
If.
and If a comet hits Earth tomorrow, who cares?
and If Cthulhu rises out of the ocean…
“and If Cthulhu rises out of the oceanā¦”
Call me, I will put him back on his leash. Sorry about that.
Yes, I know, destroyer of worlds and all that stuff.
But he is really not all that bad when you get to know him.
https://www.youtube.com/results?search_query=calls+for+cthulhu+episode+1
Cthulhu for President. Why vote for the lesser evil?
I may need to make a shirt with that slogan.
Yep, I think that thought might have crossed the bad boy’s mind. He could do way more damage to humanity and the planet as a democrat.
Back in the real world, Antarctic sea ice is in rude health:
Cold air recently broke out of Antarctica north to Australia covering half the country in snow āļø:
https://www.bbc.com/news/av/world-australia-57425931
Antarctica is cooling and leading the world slowly toward glacial inception.
Yep. Glaciation is coming.
Could we really be seeing this in our lifetimes, the Antarctic landmass cooling, the Sun apparently in shut-down mode with very low activity, a shuddering combination, good job I have my thick woollen sweaters still in the draws in my bedroom!!! I’ll do some research into wool investment projects, might boost the pension a tad!!!
Investing in wool, sorry will be a sad loss. Farmers in NZ get penalised for unshorn sheep.
During the Korean war wool in NZ was worth a pound a pound and townies were going out and plucking it from barbed wire fences.
It is a way better product than most synthetics but price wise it can’t compete and sadly it is oil that is to blame.
mate wools getting 10$ or so a kilo last 2+yrs
wools rather good income now
and sheep at 300 or so Each..its a very expensive lamb roast for Aussies right now, half a leg $48 this week in butchers
It may be getting subsidised in Aussie but it isn’t in NZ where you get penalised for selling stock that is unshorn because it isn’t worth shearing them. Shearing for wool has as good as become a cost instead of a profit.
I’ll admit Aussie probably has more merino which gets a higher value but most of NZ is not suited to merinos.
A scrawny leg of lamb here is now worth over NZ$50. My butcher no longer gets in mutton because hardly anyone knows how to cook it so he gets too may complaints.
My dad served in the US Navy at the end of WWII and always said he HATED the mutton they served on his ship. Apparently they didn’t know how to cook it.
Being from the US I have never eaten anything but lamb, either leg or chops, usually from NZ. We roast L of L at home and eat chops/rack at Outback Steak House, almost a cheep to buy at the restaurant as a meal then to buy the rack and cook it ourselves.
Too many people try and cook it in an hour or so whereas it should be cooked at a lower temperature, depending on the size for two to three hours.
I cook mine at 160c and the last three quarters of an hour I take the lid off and turn it up to 180c.
Put a little bit of fat on top or if you don’t like fat just enough water in the pan until the juices run and give it a dusting of flour.
A romney/south down cross four tooth wether in my view is the ultimate mutton.
I was presser in a shearing gang and had to cook lunch which often included mutton and never had a complaint apart from one time when lunch was late. A real no no.
Ate NZ leg of lamb last week. All gone within a few days.
The week before we ate lamb stew using USA raised lamb.
Of course, I can only afford the stew meat. But that has been available and lamb stews were more common on my table this past winter.
I haven’t had real lamb chops in a decade or more. Not since my butcher bought several 4H lambs at my request.
The “lamb chops” commonly sold in grocery stores hereabout are shoulder or ham cuts; not steak or loin cuts.
4H raised lambs fetch a decent price for the kids that raise them, but a pittance compared to what the middlemen get for choice meats.
Which is why it is near impossible to buy inexpensive good meats this past year.
Laws meant to allow easier carcass reduction into food, now allow significant percentages of added water, bone chips, cartilage and something commonly referred to as “pink slime”.
Hamburgers with too high a percentage of pink meat cook into hockey pucks if anywhere near well done. Chewy through the last bite.
High levels of added water, included at cost per pound of meat, are evident when meats/hamburger oozes red water for days.
The recent meat prices during 2020 COVID-19 year are not reflected in significantly higher prices at the farm/ranch level.
Instead, middlemen and grocers used the COVID excuse ratcheted preferred meat prices high during the pandemic.
Which is why I’ve been eating more lamb since 2019.
āSince floating ice shelves help to hold back the larger grounded mass of the glacier, . . . ā
Do these clowns actually get paid for writing this nonsense? By definition, floating ice shelves are, well, floating!
They hold back nothing. They float. They move up and down with the tides. Eventually, they get pushed so far out to sea, they snap off, often close to the shore, and then – float away!
Florid comparisons to the buttresses of Gothic cathedrals, uttered by clueless journalists are symptomatic of the deranged pseudoscience foisted on the gullible masses.
Do these idiots also claim the ocean holds back a river? After all, a glacier is just a river of ice! Geez.
“They move up and down with the tides.” Ah, so you admit that the sea levels are rising, at least twice a day!!! ;-)) PS don’t mention falling tides, it’ll only confuse them!!!
Right and that just brings the moon into play and that only serves to set their heads a spining.
Four large non-tidal sea level fluctuations between April and June led to the breakup of the Wilkins ice sheet in 2008. There don’t appear to be any tide stations anywhere near the Pine Island glacier, so we can’t check that possibility here.
“It is already responsible for much of Antarcticaās contribution to sea-level rise, causing about one-sixth of a millimeter of sea level rise each year,”
Be still my beating heart. They can’t even measure SLR with that accuracy.
Exactly. I am sick of hearing of measurements to one hundredths of a degree when a person in the past would not have cared about a single degree when they were out in negative degree temperatures.
I always understood in science that you didn’t use a number that was greater then the least precise number. Sadly today that doesn’t count.
“Itās not clear whether the shelf will continue to crumble”.
That seems like the really important bit.
There was a Russian scientist I followed about twenty years ago that said that by about 1930 the world would be cooling and that it was all to do with the sun.
I have more faith in him than all these other wallies.
2030?
‘the ice shelf holding back the glacier’?? Wot?
There is not a shred of evidence for that hypothesis and oodles for the opposite. Just go to Switserland and admire the Aletsch glacier. It’s been up there for donkeys years and it’s moving ‘fast’.
But where is the ice shelf keeping it up? How on earth does it stay up?
A load of utter bollocks.
How does this compare with the ice loss over the period 1917-1920 and 1817-1820?
Pretty sure glas\ciers moving faster is an indication of more ice forming at the “top” end pushing the glacier. Volcanic activity beneath is just gravy.
Can someone please explain to me why less ice is a ācatastropheā?
What will you put in your Gin, Bourbon, Whisky etc?
If the Antarctic glaciers all start to melt, the rate of sea level rise will increase. That could result in problems if it happens and if it continues over many years.
That’s why they are so desperately looking for evidence that the Antarctic glaciers are melting.
Need sweaters for penguins.
Climate Change, nope its just nature taking care of its own as its always been and will be.
Pine Island = 180 TRILLION aka 180,000 E9 or Gt or 0.18 E6 Gt
A76 is 4,320 km^2 or 0.03% of the total ICE CAP.
Antarctica covers 14.2 E6 km^2 (NBS equivalents: 20 * Texas, 2,768 * Delaware or 163,218 * Manhattan) with an average ICE CAP thickness of 1.9 km for a volume of 2.698 E7 km^3.
Ice has a density of 9.2 E11kg/km^3.
The Antarctic ICE CAP (NOT sea ice!) contains 2.482 E19 kg of ice, 2.482 E16 tonne, 24.82 E6 Gt.
Between 2002 and 2012 the Antarctic ICE CAP supposedly ālostā about 1,200 Gt or a decrease of 0.0048%, 48 ppm, per decade.
At that rate the ICE CAP will be all gone in 206,850 years.
I donāt plan on waiting around.
You?
Every year the SEA ICE swings from around 3E6 km^2 during summer to 14E6 km^2 (doubling the polar coverage) during winter.
Thwaites glacier is 192,000 km^2 or about 1.3% of the ice cap.
Yawn!!!!!
Version 1.0 061221
“So, 100 Gt of cryo melt would raise sea level 2.77 E-4m, .277 mm.”
190,000/100 * .277 = 498.6 mm or .498 m.
Reference:
Ice Sheets and Sea Level Rise
By: Claire L. Parkinson, Oceans and Ice Branch, Code 971, NASA Goddard Space Flight Center,
Greenbelt MD 20771 e-mail: clairep@neptune.gsfc.nasa.gov
From: The PUMAS Collection http://pumas.jpl.nasa.gov
Thank goodness for scientific notation. There would be a whole lot of zeroes in your post without it.
This will never be the case when the stratosphere descends into the troposphere in winter.
https://www.timeanddate.com/weather/antarctica/concordia-station/historic
Icebergs around Antarctica can melt gradually even into late summer, brilliantly cooling the ocean surface in the area.
It is not uncommon for glaciers to exhibit surging, or abrupt changes in their speed. The reasons are usually not evident. This surging may destabilize the shelf ice in front of the glacier. Thus, the calving would be a result of, and not the cause of, the acceleration.
Assuming that the ungrounded shelf ice actually has a significant ābuttressingā effect, which I doubt, one should extrapolate with caution. If all the floating shelf ice were to calve or melt, then the glacier would transition to a regime where the basal, bedrock-friction would dominate its movement. It should stabilize (except for transient surging) and not accelerate further.
This is interesting to glaciologists and geologists. However, one should be cautious about assigning more importance for the general public than can be verified.
Surging. Correct and there is so much they donāt know about all the dynamics involved Iām not sure anyone is in a position to infer anything given such a short period of observation. The basal hydrology and the influence of topography are fascinating but the science is in its infancy. Does anyone know this kind of behavior hasnāt been going on for thousands of years? I doubt it. Lloydo above dismisses geothermal activity because it might not have changed in recent decades. That misses the point. It could have an influence in ways we donāt yet understand. Temporal variability on a short scale might not, in itself be significant. But there are many papers showing geothermal accelerates ice stream flow. How does that play out over hundreds of years. Still an unknown.
Press release nonsense.
Sea ice is no longer part of the glacier and it’s breakage into icebergs is normal.
Sea ice is incapable of “hold back” glaciers.
Glacier sea ice breakage is typically where the tide affects the sea ice.
Glaciers speeding up causes are manifold. Additional ice/snow deposition rates are substantial contributors to glacier movement.
“UW Applied Physics Laboratory. ā
Applied Physics is ….Engineering (Engineering Physics) by definition. Applied Chemistry is Chemical Engineering. All the branches of Physics … Electricity and Magnetism is Electrical Engineering and Electronic Engineering.
The oxymoron Rocket Science (er that would be Rocket Engineering), is historically the first brazen example of the trend that followed over decades of co-option of engineering by sciences in near stasis after its golden Age was winding down. The Space Age was a crowning development and everyone wanted a shiny piece of it. And before this stunning achievement had gone far, the electronic marvel lit up the world.
Oh yes, the phenomena underpinning these achievements were the fruit of theoretical sciences. Give us more and let’s take the world and the Universe up to the dizzying heights.
“If it and neighboring Thwaites Glacier speed up and flow completely into the ocean” – but they don’t flow. They extrude from weight above. They don’t flow to oceans. The bizarre misunderstanding means it’s written by someone that doesn’t understand even basic concepts.
Pine Island Glacier By Bethan Davies ā Last updated 21/10/2020 Calving IcebergsPine Island Glacier ice shelf periodically calves huge icebergs. The ice shelf currently loses around 62.3 Ā± 5 Gigatonnes per year of ice through calving, and loses 101.2 Ā± 8 Giga tonnes per year through basal melting24. It calved a large iceberg in 2001, and in 2011 a huge rift developed on the ice shelf. This iceberg was finally calved in July 2013. Itās about eight times the size of New York, or half the size of Greater London, at 720 km2.
However, this iceberg calving event is a natural process, part of how the ice shelf regularly calves ā this ice shelf spawns huge icebergs every 6-10 years. Releasing a huge iceberg, by itself, is a normal process, unrelated to warming
It seems that the glacier is capable of very rapid recession within millennial timescales27
A collapse of Pine Island Glacier could occur within 1000-2000 years, raising sea levels by up to 1.5 m, but it is unlikely to contribute to more than 2.7 cm of sea level rise over the next 100 years
.-
It does seem a worry that she thinks this could melt in a Millennials or two time span
[Millennials, also known as Generation Y or Gen Y,]
Or not.