News Review by Kip Hansen – 16 February 2020
Several media pieces have followed up on a study about the Thwaites Glacier in Antarctica. Even the (in)famous climatologist who shares my last name pulled out this story for the press in Australia. Newsweek ran with it as part of a catastrophe article: These Five Cities Are Vulnerable to Rising Seas, Including Miami and New York. Phys.org carried this: New study models impact of calving on retreat of Thwaites Glacier.
What are they saying?
“The Thwaites Glacier is about the size of a U.S. swing state and holds enough ice to raise sea levels by about 10 feet. This alone is scary enough to justify its nickname, the Doomsday Glacier, but there’s more. The Thwaites sits along a 75-mile stretch of shoreline in Antarctica that serves to partially shield the vast West Antarctic Ice Sheet from the warm ocean waters. The WAIS has enough ice to raise the seas by 200 feet.”
“These projections carry some uncertainty, but one thing seems pretty clear: the next century will be tough for coastal city dwellers. Sea levels are rising about 3 millimeters each year. By the end of the century, the oceans could rise at least 2 feet over 2005 levels, according to a 2018 study in the Proceedings of the National Academies of Science. Michael Mann, a climate scientist, told NBC News that unless emissions of greenhouse gases are abated, by the end of the century more than 650 million people will be living on land that is under water all or much of the time.”
— Newsweek
“We think that possibly in a few years or decades, we don’t know yet, the remainder of the ice shelf in front of Thwaites might be gone,” explained Hongju Yu, an assistant specialist at the University of California, Irvine and lead author of the new study.
If the ice shelf disappeared, it would no longer provide resistance to the glacier’s flow, allowing the glacier to accelerate. The glacier would then begin losing mass mainly through increasing breakup of chunks of ice at its leading edge—a process called calving. The aim of the new study was to simulate how much Thwaites’ retreat would accelerate through calving once the ice shelf disappears.”
If Thwaites collapsed, it could raise global sea level by more than half a meter (nearly two feet) and lead to a domino effect of further glacier collapse in West Antarctica. Worst-case scenario, it is going to be gone in less than a century,” Yu said. “But it may also take much longer.” — Phys.org
That’s a lot of scary talk. What is it all about?
The Thwaites Glacier is one of the many West Antarctic glaciers.
Thwaites is inside the Red Box on the left, in West Antarctica. It is not the largest of the glaciers in Antarctica, but there has been long term concern about Thwaites because it is flowing faster than many others.
Part of the concern with Thwaites is the “grounding line” – will Thwaites retreat from the grounding line and thus allow the main glacier to flow faster into the sea?
The Thwaites story is part of the ongoing controversy over Antarctic ice gain/loss that has been being fought in the journals for the last five or ten years. NASA supports a variety of views — 1) NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses ; 2) Antarctica’s contribution to sea level rise was mitigated by snowfall ; 3) Ramp-up in Antarctic ice loss speeds sea level rise
The first study, Zwally (2017), claims Antarctica is gaining mass — not losing. The second claims that even though Antarctica is getting more snow, it isn’t gaining overall. And the third claims “Ice losses from Antarctica have tripled since 2012, increasing global sea levels by 0.12 inch (3 millimeters) in that timeframe alone”. The controversy has spawned articles such as “What to Believe in Antarctica’s Great Ice Debate”, written by freelance science journalist, which says “In 2015 a study was published claiming that East Antarctica is in fact gaining mass, contrary to the majority of studies conducted thus far” [the study was done in 2015 but published in 2017] but fails to mention that the study is from Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, which was published on Oct. 30 2017 in the Journal of Glaciology and which is still headlined on the NASA website. The Scientific American article was rushed into publication 4 days before the Zwally study appeared in the Journal of Glaciology.
In recent years, the media has often gone way overboard about Thwaites and Pine Island glaciers. “But if carbon emissions continue to track on something resembling a worst-case scenario, the full 11 feet of ice locked in West Antarctica might be freed up, their study showed.” [according to DeConto and Pollard]
The controversy hinges on whether the floating ice shelf of Thwaites will continually retreat and eventually lead to it losing its buttressing effect on the bulk of the glacier. Then if the buttressing is removed, will the bulk of the glacier then rush into the sea? Hongju Yu and his team do not think so: “…removing the ice shelf abruptly does not have a long-lasting impact on the retreat and cumulative mass loss of the glacier.” [study conclusions] – and yet Hongju Yu is seemingly quoted to the contrary in the media.
OPINION: Personally, I think Hongju Yu has been carefully interviewed into saying things that the study itself does not support – subtly coerced into statements desired for the narrative of climate alarm.
Interested readers can plow through the conflicting studies for themselves but the bottom line is that there is a “consensus” opinion, backed by many studies intended to confirm what may be the “prevailing bias in the field” and then there are other studies that find the opposite or show greatly reduced long-term concern.
What does the featured study really find?
The study being spoken of is “Impact of iceberg calving on the retreat of Thwaites Glacier, West Antarctica over the next century with different calving laws and ocean thermal forcing” [.pdf] by Hongju Yu et al. published in Geophysical Research Letters.
Its published conclusions are:
“We investigate the impact of calving on the evolution of Thwaites Glacier, West Antarctica over the next century without its buttressing ice shelf. Our simulations suggest that removing the ice shelf abruptly does not have a long-lasting impact on the retreat and cumulative mass loss of the glacier. We calibrate a von Mises calving law with Haynes Glacier, which does not have an ice shelf. Within the calibrated range of the calving parameters, we find a considerable enhancement of the retreat of the glacier compared to the case where the glacier is only experiencing ice shelf melt. The retreat rate varies significantly depending on the selection of σmax. Conversely, we find that a buoyancy driven calving law does not influence the retreat by more than 20% and ice front melt by the ocean modulates the retreat by 15% to 50%, with the highest increase associated with a maximum thermal forcing of 4°C. Based on our experiments, we conclude that Thwaites Glacier will raise global sea level by 13-19 mm if the grounding line stabilizes on the western ridge; otherwise, its collapse will proceed and raise global sea level by 50 mm within this century.”
What was said in the media:
2 FEET — “By the end of the century, the oceans could rise at least 2 feet over 2005 levels,”
10 FEET — “The Thwaites Glacier is about the size of a U.S. swing state and holds enough ice to raise sea levels by about 10 feet.”
200 FEET — “The WAIS has enough ice to raise the seas by 200 feet.”
650 MILLION UNDER WATER – “…by the end of the century more than 650 million people will be living on land that is under water” — Michael Mann
ACTUAL MODELLED PREDICTIONS:
13-19 mm = 0.5 to 0.75 inches by 2100
Worst Case — 50 mm = 2 inches
(Of course, both of these scenarios are “IFs” based on a lot of computer modelling. )
Bottom Line:
We will have to wait on Thwaites to see what it is going to do. We don’t really understand the dynamics involved with Antarctic glaciers yet – what makes them speed up and slow down. But in any case, even Hongju Yu’s worst case conclusion only minimally adds to expected sea level rise of about 12 inches ( other opinions vary but possible values over 2 feet are extremely unlikely) by 2100.
# # # # #
Author’s Comment:
I have emailed Professor Hongju Yu and asked him about the apparent disconnect between his study’s conclusions and the statements attributed to him in the media. If he responds, I’ll either add it to Comments or the main body of the essay.
Despite repeated assertions of Antarctic ice melt and glacier collapse, the sea level record does not show discernible effects – global sea levels still rising at their centuries long 2-3 mm per year as the Earth climate warms from the Little Ice Age.
The study of the Antarctic is a valid scientific endeavor – but not if its only purpose is to attempt to raise more and more alarm about climate change.
# # # # #
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Whole WAIS makes about 12 feet. The whole Antartic might not exceed 200 ft. This is BS.
Ya got yerself a good BS-O-Meter there
It’s tuned well against the
Profits of Doom
Yes, its BS exceeds the size a swing state or Hillary’s behind.
Hey, that’s not fair! I mentioned the size of Michelle Obamas’ behind and got snipped for it (by ctm, the maniac with a machete) and Scissor mentions Hillary’s behind and no pasa nada! What gives?
How were you able to fit the number into a single comment?
Must have been using exponential notation, eh?
;-\
Chaswarnertoo ==> I wouldn’t worry about it…the last time Antarctica was possibly melted was 90 million years ago.
Chas Warner,
This is exactly what I was going to say.
All of the ice on Earth melting would raise sea level 212 feet.
The numbers cited in these article are not consistent with each other or the facts.
All of WAIS melting adds <12 feet.
All of Antarctica including WAIS adds <200'
But this article lists Thwaites alone as 10'
That is nearly as much as Greenland would add, and is the bulk of the <12' from the whole WAIS
And it says WAIS would raise the sea 200', but that is the total for the whole continent melting!
It needs to be emphasized how wrong the numbers in the opening part by Newsweek are.
They have mixed up Thwaites contribution with the whole WAIS, and the WAIS with all of Antarctica.
There is no chance of 100% of any of those masses of ice melting. It has been far warmer than now at various times in this interglacial, and during the whole of other interglacials.
And they never melted then.
It is frigidly cold there, far below freezing even in Summer.
How many warnistas point out how wrong these numbers are?
None.
The Gretas of the world have no ability to think for themselves.
The alarmist propaganda machine have seen to that very effectively.
Alarmist malarkey and extreme lying like this Newsweek crappola blend together in their minds, and no one in their circle of trusted so-called "experts", who are the only ones they even pay vague attention to, ever clarifies anything…instead they reinforce it.
So we wind up with politicians declaring an emergency, when in fact nothing is happening.
It is all fever dreams and lies.
It should make everyone very angry these sick jerks get away with scaring kids and the uneducated.
And in this area of knowledge, it seems most of the world is highly uneducated, and in fact misinformed.
Misinformed is worse than ignorant.
The misinformed have anti-knowledge clogging their minds.
They know things that are not so.
Take a step back and add it all up, and climate science in the year 2020 is actually the opposite of knowledge, not merely the opposite of science.
It is a giant propaganda machine, making people stupider than if their minds were completely blank!
The whole of the work of the lowlifes in this field are actually dedicated to making everyone stupid and scared fools!
And that is no exaggeration.
It is an understatement.
And then there’s the big deal they’re trying to make about Esperanza Base’s “record high”. Esperanza has only been there since ’53. Not much of a temperature record…and the high really doesn’t mean much because it’s summer down there. Every place I know of seems to set another record high during the summer. Doesn’t mean the climate is changing. And Esperanza Base is closer to South America than the South Pole. I’m sure they get warm ocean breezes – and probably pick up some of the volcanic heat in the area – like that of nearby Deception Island’s volcanic hot springs. But they can’t say anything about that – the people wouldn’t panic. And there are a great number that responded to that record high over on Twitter with “We’re destroying the planet”. Where are these people getting their educations these days?
https://wattsupwiththat.com/2020/02/09/medias-horribly-dishonest-antarctica-propaganda/
Thwaites glacier has 91 volcanoes beneath it or near it. That is the reason for any melting. Nothing to do with human. See my web site.
Hey, you danged ice chucking volcanoes! Stop chucking my ice!
HAhahaha!!
That’s one of the very few funny commercials.
The 91+ volcanoes are scattered along the rift zone spanning the entire coast of West Antarctica. The highest geothermal heat fluxes, though, lie under the frozen “headwaters” of Thwaites.
“The highest geothermal heat fluxes, though, lie under the frozen “headwaters” of Thwaites.”
That is disputable. There has been two recent papers on the subject. Their results were remarkably discordant:
https://www.researchgate.net/publication/319110385_Crustal_heat_production_and_estimate_of_terrestrial_heat_flow_in_central_East_Antarctica_with_implications_for_thermal_input
https://www.researchgate.net/publication/320901105_Heat_Flux_Distribution_of_Antarctica_Unveiled_Antarctic_heat_flux_unveiled
I won’t admit to being current on the topic. I was working from this heat flux map.
http://strangesounds.org/wp-content/uploads/2017/11/antarctica-heat-flux-map.jpg
Looking great icisil!
Could you add a table/legend that shows estimated kilocalories by color?
Anybody have the conversion of mW/M2 to Hiroshima bombs?
tty, I read both cited articles, the first is not relevant as the authors don’t comprehend the irrelevance of crustal composition versus rift dynamics, however, the second, by authors Martos and Jordan is right on the topic. They utilize depth to Curie Point, the temperature wherein magnetic properties are eliminated (hotter) or detectable (cooler), which is a temperature of around 275 deg C under most crustal conditions. The Curie Point at equal to or less than 10 kilometers is very high heat flow, similar to the heat flow from the younger rifts in Nevada, which control all of the geothermal energy projects. I have processed a magnetic anomaly map for Nevada utilizing controlled Gaussian stretching downward, and the shallow Curie Point is quite apparent and striking. So, I have no doubt that the rifts in Antarctica are producing a very high heat flow, to include geothermal springs below the ice fields.
That clinches it…I is heading south and opening a spa!
Steamy Nick’s Doomsday Dayspa and Bottom Of The World Last Chance Bar And Grill.
Hey if you use it as the “right temperature” and Krig the areas around it you will be surprised how big you can get the hotspot 🙂
The Jim Hansen standard is to impose/share that heat over 1,200 kilometers.
Oh, wait; there was already an Antarctica study that kriged a few surface thermometer readings across the continental depths of Antarctica.
If they can do that with the few kilocalories necessary to raise a thermometer’s temperature, imagine what they can accomplish with an active rift’s heat flow?
Terri ==> The generally accepted view is the the Thwaites ice shelf is being affected by “warm” water from below, thinning the ice shelf and leading to its more rapid break up at the leading edge — this relatively warm water is called Circumpolar Deepwater, shown in the diagram in the essay.
There are active volcanoes under the Antarctic ice, and some underwater off-shore — but none directly under Thwaites.
Absolutely, on the under ice warming!
Rifts do not stop and start. They are sinuous and continuous, even if the highly active areas are widely separated.
The volcanic/tectonic images show the rift running right under the Thwaites.
Your summation is spot on that the sub-ice warming is the active melt mechanism for Thwaites. Or at least, the current knowledge attributes Thwaites melting is due to warm water from circumpolar currents.
J. Curry’s web site has an Antarctic graphic, linked by Mike Jonas, shows at least one volcano right where the Thwaites meets the edge of the continent. And that graphic clearly states “some of the 91 volcanoes”.
A magnetic anomaly map, such as Ron Long describes, might be clearer. Past aerial Antarctica magnetic anomaly mappings that I remember seeing, were very macro versus fine grained local zones.
Good article Kip!
Not all 91 volcanoes, but certainly lots. There’s a map in …
http://joannenova.com.au/2018/12/far-southern-ocean-cools-kiss-goodbye-to-polar-amplication-around-antarctica/
… which also suggests that massive sea rise from Antarctic melting is a wee bit unlikely. Rather less than a wee, actually.
A few observations.
The Holocene Maximum 8,000 years ago was 2 degrees warmer than now, at the poles, and there does not seem to have been a dramatic (4 meter) rise in sea levels at that time.
Roman and Greek ports all around the Med appear to be about half to one meter above the current sea level (the Med does not have tides). Suggesting the Roman warm period did result in some limited polar melting. (I don’t think Med land levels are rising at that rate, to create these raised ports.)
Cliff undercuts all over the Med (and in the Philipine basin) appear to be on the current sea level. In the Med these undercuts are at least 500 years old, and we can be certain of this because of the thick stalactites hanging on the cliff-face.
In short, I have not seen any evidence for huge sea level rises in the post interglacial warming era (in the last 10,000 years).
Ralph
Here are the Mediterranean unduecuts.
https://ibb.co/ysxKknq
And the Phillipine undecuts.
https://ibb.co/PwmLp0K
R
Rafellis,
Wonderful point, geology and its signature indicts change or the lack of change.
I read an interesting article, Fairbanks, AK was not under miles of ice 18kbp. The evidence was the lack of glacial impact on regional mountain slopes.
Given the fall in global ocean level, due to the closing of the Bering Strait and glacial growth in the past, shouldn’t we find undercutting at far deeper depths?
No, and as far as I know nobody has claimed that it was. Much of Alaska was never glaciated – it was too dry in the rain shadow north of the Alaskan range. The map in the link below shows the maximum Pleistocene glaciation – the 20 (not 18) KA BP Wisconsinan maximum extent was considerably smaller, particularly in the Brooks range:
Note however that lack of “glacial impact” on the landscape does not by itself prove that there has been no glaciation. A “cold-based” ice-sheet (one that is frozen to its bed) often leaves no trace except a thin layer of meltout till.
The true reason that NE Asia was not glaciated, is it was too close to the Gobi desert. The Gobi coated this region with gigatonnes of dust, which lowered the albedo of any ice and allowed it to melt. Ice sheets are modulated by dust and albedo, not CO2.
R
Google “loess edoma”. The ice did not melt. As a matter of fact it is still there. It is however mixed with loess into a very peculiar “rock” formation known as “edoma” or “yedoma” in russian.
It seems that sea ice would have been far south of currents limits as well. This might have limited any moisture in the air.
And a continent sized ice mountain two miles high must have deflected the jet streams.
I think for all that ice to have accumulated there must have been weather patterns locked in place that pumped moisture up from low latitudes across the Gulf of Mexico and east coast of N.A.
I do not think paleo climatologists have a correct idea of how different were the weather patterns that allowed ice sheets to form and then to rapidly melt.
Incremental changes in isolation at high latitudes will not do it, IMO.
For one thing, TSI at TOA was unchanged (or at least that is the prevailing presumption), and any lowering of insolation in the northern hemisphere was matched by a equal gain in the southern hemisphere.
Dust, changes in cloudiness, altered wind flows and hence altered heat and moisture flows…these all must have had a role.
It does not take much snow to cover up dust, and for half the year Alaska has no Sun to melt any ice no matter how much dust there was.
Much less heat must have flowed polewards from the tropics at those times of full glaciation.
And what heat flow there was had to have been bypassing the ice sheets or they would never have got there or been so tall or persisted so consistently.
I suspect the wind flows where far different than anything we see in interglacial periods like now.
They had to have been, in my view.
Any ideas of the dynamics have to explain all the facts and the sequences of events…like how that first year of snow not melting happened, and how all the ice just changed mode to melting away so suddenly.
Incremental and gradual changes simply cannot explain shifting modes from stable conditions like now, to rapidly accumulating vast thicknesses of ice, to rapid melting of entire sheets that are miles thick.
And then there are the periods of sudden changes that just as suddenly reversed…the D.O. events.
Got to ‘splain it all in a coherent picture.
Wind pattern modes different than anything we are familiar with do so.
It does, but generally pretty small ones due to the extreme delay in water moving through the straits of Gibraltar. In some places like Venice, however, they can be as much as a metre (3 feet).
As I am 80 years old and as a helicopter pilot traveled the world ( 11 passports full) what happened 50-60 years ago is almost forgotten. BUT ! I remember long ago an iceberg off the cost of Australia reported to be more than 100 miles across. No seawater rise.
People that have not traveled have a hard time imagining what the oceans are, but if you wanted to fly from London England to Auckland New Zealand ( 24 + hours ) you could do so without passing over land (and water in places 6+ miles deep
George ==> You are right there — human society has a very short memory and forgets things that happened even within their own lifetimes.
Icebergs, no matter how large, do not add to sea level when they melt as they are already displacing an equal amount of water while floating.
Thank you Sir, for confirming what I have been arguing with the local green nutters for years- I began to doubt my sanity! They go on and on and on about Arctic ice melt raising sea levels, and how my family which lives at the coast, (some 50ft above sea level), will be under water in my lifetime. There seems to be no limits to their hysteria…..
Andy ==> You can safely leave your home to your grandkids — as long as you don’t live at the top of a sand cliff.
Thank you, Sir, for your long memory and observations. I was thinking in the one depiction above, it appears that this particular glacier is already below the water line. If it breaks off, it likewise should not raise the water level any either.
This conflicting situation among glaciation scientists studying Antarctica is getting silly now. We are told Antarctica is gaining ice mass but its threat of melting is causing sea levels to rise?
The science sounds very Mickey Mouse to me, or is it Mickey Mann, so hard to tell these days…:)
How right you are, Rod Evans : It is all getting silly now. It is just so silly that we human beings even worry about those glaciers. We are stupendously ignorant about what will happen to this (or other) glaciers. And all the wise research and the conflicting reports are presupposing that humankind can do something about it by a concerted effort to “fight climate change”.
Public money should not be spent on any glacier research yet. All we can and should do these days is to collect data about everything that is happening. Then, after perhaps a couple of hundred years of storing these data some bright fellow can perhaps draw some really useful conclusions about the behaviour of glaciers and their likely effect on global sea levels.
Not fight it…tackle it!
Grab it by the ankles and bring it down like a ton of bricks!
And not scientists…politicians.
Geoengineering?
Nope…raising taxes to impoverish us all.
Yuppers, thatoughtadoit, alrighty!
They cannot count votes, cannot stop single drop of rain or warm up a single hard freeze by a degree, no…no they cannot, and they will not claim to be able to.
But they can change the weather of the whole planet to *Persistently Perfect* , which of course happens to mean cold as the Little Ice Age, and they can do it no problem and toot sweet, if we skeptics shut our yaps , and we all vote for the two stupidest morons in government and just let them handle it.
AOC might not know that plants grow out of dirt, or where tax money comes from,or be able to discern the inscrutable mysteries of the insinkerator, but gosh darn it she can rearrange and rebuild and fix all that is wrong with our energy infrastructure and industrial economy while she eats an orange while making a Twitter video, dumbasses that the rest of us are!
Now, overlap that map of the Antarctic hot spots with maps of volcanic activity (including known submarine activity) and ocean currents…
https://www.theguardian.com/world/2017/aug/12/scientists-discover-91-volcanos-antarctica
From the link: “The big question is: how active are these volcanoes? That is something we need to determine as quickly as possible.”
LOL Why do we need to determine that as quickly as possible. Do we have some new fangled volcano eliminator?
Saint ==> It is unlikely that these volcanoes suddenly appeared since the start of the Modern Industrial Period.
Maybe Captain Nemo could go down in the Nautilus and flip the OFF switch?
The Saint,
Best laugh of the week so far.
Yeah man…not a moment to spare…we gots to know!
Although to be fair, I think they probably meant right after the we * tackle* the Zombie Apocolypse Wuhan Bat Flu Sniffle Pandemic, but before the Last Day Of The World in 10.9 years.
And counting.
“Part of the concern with Thwaites is the “grounding line” – will Thwaites retreat from the grounding line and thus allow the main glacier to flow faster into the sea?”
Question: If the glacier starts to flow faster, wouldn’t the leading edge hit the grounding line again causing the glacier to slow back down?
But a warmer atmosphere carrying more humidity causes faster snow accumulation which adds mass thus causing the glacier to accelerate. Plenty here to speculate with. When is the National Enquirer going to start publishing climate science news. Michael Mann, Editor at Large.
The New York Times is the new National Enquirer.
The Epoch Times is the new New York Times.
The World has moved on.
The truly amazing thing is, with so many and multiple readily apparent incipient catastrophes, here we all are.
Big News in current events is how many electoral votes his own party screwed Bernie out of this week.
Best we can muster when it comes to world altering events is it was kind of chilly in Omaha last night.
“If the glacier starts to flow faster, wouldn’t the leading edge hit the grounding line again causing the glacier to slow back down?”
Not necessarily, a faster flow also means that the glacier becomes thinner which can cause a continued grounding line retreat. However this requires that the glacier bed dips fairly steeply inwards (=inland) from the glacier front. This is quite rare but does happen under parts of Thwaites glacier, hence its star status in the media.
MarkW ==> In the real world, we only have GUESSES about how all this works. Hongju Yu’s work relies on another glacier that has no floating ice shelf, and does not find that glacier flowing faster as a result.
There are many opinions. There are possibly more than one reality — in that each glacier may have its own unique as-yet-not-understood dynamics.
OK Mark, that is a very inconvenient question, causing much angst and sideways glances from our betters.
They want us way up in the cheap seats to shut the hell up now.
Some geological features of West Antarctica may be relevant.
https://tambonthongchai.com/2020/02/09/antarctica-threatens-florida/
https://tambonthongchai.com/2020/02/09/antarctica-threatens-florida/
Oops sorry.
Don’t know how i did that.
Same link in there twice.
Chaamjamal ==> Just lucky, I guess.
It is possible that sub-ice sheet volcanoes are affecting the flow rate of Thwaites — lubricating the ice-rock interface.
I don’t think the jury is in on that yet, though.
Kip – When I did my study on ocean surface temperatures around Antarctica (the one rejected because “we don’t need yet another paper critical of the models“), There were two very small hot spots “up” the coast some way from Thwaites, and a lesser one at or very close to Thwaites itself. Certainly, the parts that were warming were only off the line of coast with volcanoes. I didn’t have enough information to be sure that the volcanoes played a role, but it certainly does look like there is warm water coming in below the surface. It’s worth noting that deep water around Antarctica is degrees warmer than the surface water, so any subsurface current is likely to be warm by Antarctic standards. ie, it can be argued that no volcano is needed to explain it.
Mike ==> I’d love to read your paper — you can email it to me at my first name at the domain i4.net.
The circumpolar deepwater is known to be warmer than surface waters and it upwells along the West Antarctic coastline, coming up under the ice shelves.
Whether undersea volcanoes specifically heat that water flow is not know to me.
Re: “The circumpolar deepwater is known to be warmer than surface waters and it upwells along the West Antarctic coastline, coming up under the ice shelves.” But is that due to Global Warming? Or is it not an inherent characteristic of the circumpolar deepwater?
JCalvertN(UK) ==> We don’t really know that much about it….like most things, we have some data (ARGO buoys) and such.
The circumpolar deepwater flow is not obviously connected to warming surface waters (if they are warming there.)
If a) these glaciers are being melted by the circumpolar deepwater. But b) the circumpolar deepwater isn’t warmed by the greenhouse effect, then c) the melting of these glaciers is NOT being caused by global warming. QED!
Isn’t it remarkable how “selective” the circumpolar deepwater is! It somehow manages to target these two glaciers more than any of the others – despite the fact that they are located in deep bays therefore somewhat removed from general circumpolar current circulation?
Kip and JCalvertN(UK) – You can reach the rejected paper through
https://wattsupwiththat.com/2019/04/10/the-curious-case-of-the-southern-ocean-and-the-peer-reviewed-journal/
and the “Kiss Goodbye” reference in it. [I tried to put the link in my earlier comment, but I must have stuffed up the html tags]
The deep water around Antarctica is of the order of +3 deg C (to do with water density, nothing to do with global warming), while the surface is of the order of -1 deg C. Globally, the THC (Thermohaline Circulation) runs mainly N-S at depth, so upwellings take place irregularly around Antarctica – thus providing the water needed for the globally mainly S-N flow at and near the surface. So, JCalvertN(UK), it is indeed an inherent characteristic of the circumpolar deepwater. The fact that these glaciers are located in deep bays may well remove them from general circumpolar current circulation, but maybe not from the deeper N-S THC.
Mike ==> Thanks, I’ll check it out.
The Thermohaline Circulation (THC) is a misnomer. It is also called the Meridional Overturn Circulation (MOC). But really, it is just the Deepwater Circulation. The Deepwater Circulation has several drivers – of which the thermohaline effect is just one. It lacks power and has no influence on the surface water current circulation – which is 100% wind-driven. Conversely, the wind-driven surface water current system *does* have a significant effect as one of the other drivers of the deepwater circulation.
But if there are areas where the thermohaline effect does play a significant role, they are around the polar regions. But these are thought to be sites of *downwelling* – not upwelling!
In the late Fall and early Winter, when the sea-ice refreezes, salty brine is produced as a by-product of freezing salt water. This cold saline water is more dense and sinks – i.e. downwells. So, I don’t think the THC/MOC can be playing much of a role in melting the Pine Island and Thwaites Glaciers.
PS: I have tried to crash-educate myself on this subject and found Carl Wunsch’s website extremely useful (and scientifically sound, in my opinion). http://puddle.mit.edu/~cwunsch/
Wunsch’s website also includes a useful reference book. Checkout Chapter 5 and Figure 5.11 in particular.
https://ocw.mit.edu/resources/res-12-000-evolution-of-physical-oceanography-spring-2007/part-1/wunsch_chapter5.pdf
JCalvertN(UK) – There really is upwelling around Antarctica. No matter what the cause of their northerly travel, when surface waters reach the Arctic, they sink. What goes down must come up, and come up it does – much of it in the Antarctic several hundred years later. The THC/MOC may not have much speed, but it does have strength, and its waters would supply the deep currents off Antarctica including any that pushed in towards Thwaites.
The THC/MOC is not uniform around Antarcica (that’s myunderstanding aanyway) and upwells irregularly. Polynyas I think would be an example of that. They do sometimes reappear in the same places, probably because of sea-floor configuration, but not regularly.
I’ll see if I can look up some of this and get back to you.
Kip,
Undersea volcanoes at West Antarctic coastline:
https://www.google.com/search?client=ms-android-huawei&sxsrf=ALeKk02A2NsUcWk3sl_3X-P-cCwAYUdstw%3A1583032372441&ei=NChbXv3DGpWFwPAP__qmuAU&q=Undersea+volcanoes+West+Antarctic+coastline&oq=Undersea+volcanoes+West+Antarctic+coastline&gs_l=mobile-gws-wiz-serp.
/ sure carrying water to the well
The calving of the glacier happens a great distance off shore, well into the ocean waters. If that part of the glacier melts tomorrow it would not add as much as a micron to sealevel. There was a Greek guy in Syracuse two thousand years ago who had figured that out. Those calved off icebergs make no difference at all.
Apart from that, the hypothesis that shelves like Thwaites ‘buttress’ the flow of the land ice into the sea is just that, an unproven hypothesis. Personally I think it is nonsense. After all, what remains of the Rhone glacier in the Swiss Alps is still shortening through melt, but not sliding down to the foot of the mountain in one piece. And there is nothing ‘buttressing’ it on the slope.
If the floating ice was buttressing the glacier, it should be under compression. Therefore, I would not expect tension cracks, which is where icebergs are formed. The floating ice has mass, which will resist acceleration. However, as Newton observed, a mass in motion will continue at the same velocity unless acted upon by some outside force.
The entire glacier on land has significant friction at the base. The alarmists would have us believe that a floating shelf of ice can have more impact on the motion of a glacier than the bedrock friction. There may be a slight impediment of ice movement upstream from a grounding line, but that is just a minuscule fraction of the total resistance encountered by the glacier. It is the nearly frictionless boundary between ice and a skater’s blades, created by the water interface, that allows a skater to move so effortlessly. I think that this whole “buttressing” issue is another acorn falling on the head of Chicken Little.
When the Larsen B shelf collapsed the effect on the glaciers inboard of it was closely studied. Several did accelerate, but the effect was short-lived (less than a year), and some glaciers weren’t affected at all.
Ergo, ice-shelves do have some effect, but it is minor.
tty
So, if both possible outcomes were observed, how can they be certain is wasn’t coincidence? Was there a correlation between the size of the glaciers and the rate of acceleration?
No, but the topography seems to be important. The acceleration was most pronounced for glaciers calving into deep troughs.
Clyde,
Please avoid “rate of acceleration” when simply “acceleration” is sufficient and correct in this instance. Cheers. Geoff S
Geoff
Should I have said “Magnitude of acceleration?”
rate of THE acceleration
tty
An alternative hypothesis that should be considered is that it was the accelerating glaciers that were responsible for the Larsen B shelf to detach. In other words, cause and effect would be reversed from what is assumed.
It would be distinctly unusual for the cause to come after the effect.
tty ==> You must be new to Climate Science…..
Wot, like CO2? This is Climate Scientology, remember!
tty
You said, “It would be distinctly unusual for the cause to come after the effect.” My point exactly!
tty
Something else to consider is that most if not all glaciers exhibit surging, some notably more than others. The slower surging is typically interspersed with quiescent periods. So, it may have just been coincidence that some glaciers ended their quiescent period about the time that Larsen B broke off.
I suspect that all glaciers exhibit surging, with the phenomenon ranging from high-frequency chattering, similar to the dragging of fingernails across a chalkboard, to lower frequency surges resulting from shearing off bedrock protrusions to intermittent water lubrication of the bedrock contact. The point being, the forward motion of glaciers is not uniform, but varies on different time scales.
Clyde,
I agree with your comments about the friction at the base of the glacier and the other comments about glaciers surging. A common tactic used by alarmists is to make vague statements such as “the glacier will accelerate without the ice shelf buttressing it.” These comments are then quickly followed by stating scary facts, such as the glacier holds enough ice to raise sea level by 10 feet.
Most studies claim ice mass related SLR is 0.35mm/yr.
https://science.sciencemag.org/content/315/5818/1529
Most studies attribute the bulk of this 0.35mm/yr to Greenland – but we can say Antarctica contributes 0.15mm of the 0.35mm total. Even if Thwaites contributes 1/3 of Antarctica’s SLR (it is probably much less), then it contributes 0.05mm/yr. If the calving doubles from the loss of the ice shelf (it is probably nowhere near a 100% increase), then Thwaites contributes an additional 0.05mm/yr to SLR.
Doomsday Glacier???
Kip: I commend your efforts to get in touch with Professor Hongju Yu and to ask him your clarifying question. As I recall, such informed and polite questions when posed to members of Judith Curry’s group led to her reconsideration of her original position of CAGW.
bernie1815 ==> Overall, I have a pretty good record at getting a response — but not always the one I hope for. Sometimes I get answers to my questions. Sometimes I get “I’d rather not comment on the work of others.” Sometimes I get “I didn’t say that — but don’t quote me on that.”
“The controversy has spawned articles such as “What to Believe in Antarctica’s Great Ice Debate”, written by freelance science journalist, which says “In 2015 a study was published claiming that East Antarctica is in fact gaining mass, contrary to the majority of studies conducted thus far” [the study was done in 2015 but published in 2017] but fails to mention that the study is from Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, which was published on Oct. 30 2017 in the Journal of Glaciology and which is still headlined on the NASA website. The Scientific American article was rushed into publication 4 days before the Zwally study appeared in the Journal of Glaciology.”
“https://www.scientificamerican.com/article/what-to-believe-in-antarctica-rsquo-s-great-ice-debate/
###################################################
KIP : “but fails to mention that the study is from Jay Zwally”
The article:
“There is no doubt that the 2015 study, led by Jay Zwally, a glaciologist at NASA’s Goddard Space Flight Center, flew in the face of previous research and even assertions made by the United Nations Intergovernmental Panel on Climate Change (IPCC). Zwally’s study remains the only one to firmly conclude that Antarctica is growing.”
#################
KIP
“but fails to mention that the study is from Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, which was published on Oct. 30 2017 in the Journal of Glaciology and which is still headlined on the NASA website. The Scientific American article was rushed into publication 4 days before the Zwally study appeared in the Journal of Glaciology.”
“The Scientific American article was rushed into publication 4 days before the Zwally study appeared in the Journal of Glaciology.”
#############
SciAmerica article published
By Shannon Hall on July 6, 2017
The Zwally paper was published in 2015, In PRINT.
and published ONLINE July 10th 2017.
Not Oct 30. July 10.
the publication (IN PRINT) was in 2015. This explains how STEVE MCINTYRE DISCUSSED IT IN 2015
https://climateaudit.org/2015/12/02/antarctic-ice-mass-controversies/
and explains how many others commented on it
https://www.researchgate.net/publication/301900649_Comment_on_Zwally_and_others_2015-Mass_gains_of_the_Antarctic_ice_sheet_exceed_losses
https://blog.hotwhopper.com/2015/11/antarctic-ice-growing-or-shrinking-nasa.html
Nasa, 10/31/2015
https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses
So. you screwed up
The article mentioned Zwally. Zwally was published in 2015. IN PRINT.
It was discussed online by Mcintyre and others in 2015
In 2017 it was OPENLY PUBLISHED ONLINE, on July 10th.
***650 MILLION UNDER WATER – “…by the end of the century more than 650 million people will be living on land that is under water” — Michael Mann***
Michael Mann screwed up.
Yeah. The stupidity of that statement is astounding . Unless they’re living under water.
As usual, Mosher goes off on a completely irrelevant tangent!
Credibility is not a tangent
Further, this told me early on that Kip really doesn’t follow the science as everyone knows McIntyre
covered it in 2015.
Its hard to have less credibility than the MSM but Kip managed it.
he cant get the dates right, I dont trust him to get the science right
Mosher ==> I stand corrected — but the Scientific American piece was clearly timed to appear simultaneously (in fact, four days before), the online publishing, which would bring it into the public view once more.
When I checked back on this for this essay, I found a truncated version of the SciAm piece — which in the lede, does not mention that Zwally was was/is a NASA scientist — and the piece was a direct effort to denigrate the Zwally paper. (see the title of the SciAm piece.)
clearly timed? that’s some projection.
Do you know when the story was filed?
Did you do any checking?
Nope
Mosher ==> You are free to come up with your own interpretation of events . . . I’ve stated mine.
OK, Steve Mosher, so it was 4 days before the paper went ONLINE, not 4 days before it was physically published. But think about how many more people can and will no doubt access it after it goes online. 4 days looks suspiciously like it was deliberately got out there before the paper went online. You say “stuffed up”, but I think that’s pretty (actually, un-pretty) harsh given how your “side” defend real stuff-ups.
Kip said the article didnt mention Zwally. It did
Kip doesnt follow the science or he would have known, as I did, that it was covered in
blogs and responded to in 2016.
Kip got the dates wrong.
and Kip assumed, as you do, on no evidence, that it was RUSHED to publication. tell that
to the layout guys and printers.
SciAmer appears to go to layout 30 days in advance of the Publication, as Ads close more
than 30 days in front of the Street date. If you looked at the media Kit for the magazine
you would see that. But you never checked. Had you ever placed ads in a print magazine
you would know that articles are finished in advance of the street date. There is no “rushing”
to a published street date
Mosher ==> You are fighting a battle about interpretations of events. No truly scientific journal would title an article “What to believe….” The SciAm article appeared (online) four days prior to the online publication of the Open Access version of Zwally. I only bring it up to highlight the controversy over Antarctic ice science.
Thanks Kip. Very interesting.
I’ve nothing to add, but do encourage folks that can — to visit a glacier – although I have only been to valley glaciers.
We walked on the melting front of the Athabasca Glacier (1972 or ’73) and learned of its long melt-history. I’ve worked on trails in Mt. Rainier National Park and helped with the, almost yearly, rebuild of the crossing of the White River – outflow of the Emmons Glacier (northeast facing one). I’ve been to within about 100 yards of the ice front there, where chunks of ice were falling from the roof of the tunnel.
{Recent storms have trashed the main road into Mt. Rainier, and the Park is closed. What has been done to the trails is still a mystery, buried under snow.}
The Columbia Icefield/Athabasca glacier is the most easily accessible major glacier in North America.
Two other major icefields that are fairly easily accessible to ordinary tourists are the Patagonian Icefield in Argentina/Chile and Vatnajökull in Iceland. Both are excellent places to see how glacial landforms are created.
However it is not safe to walk on a major glacier without a competent guide. Crevasses is a constant danger. On steep glacier slopes icefalls/avalanches also occur.
The Bagley ice field is a beautiful sight in southern Alaska, second largest in North America. Easy to see and arrange fly overs when combined with a visit to Wrangell/St. Elias National Park, the largest and possibly one of the least visited national parks in the US. Other ice fields such as the Harding are similarly accessible without too much trouble. Flying low over an ice field is an amazing experience, seeing only the tips of mountains 12k feet tall emerging from the ice, or seeing a dozen glaciers of the hundreds flowing from the ice field, converging together as a river of ice rushing toward the sea, only the lateral moraines helping to show the fact that they started as separate glaciers
“If the ice shelf disappeared, it would no longer provide resistance to the glacier’s flow, allowing the glacier to accelerate. ”
Whoever wrote this obviously does not understand the physics of glaciers. The assertion that maritime glaciers will ‘slide into the sea’ if shelf ice at their terminus no longer ‘holds back’ the rest of the glacier. This is utter and total nonsense! The position of the terminus of a glacier is governed by the rate of accumulation of snow and ice in the upper part of a glacier and the rate of melting or calving near its terminus. Period.
AWashington Post headline stated “Research casts alarming light on decline ofWest Antarctic Glaciers” and goes on to say that “a rapidly melting section of the West Antarctic ice sheet appears to be in an irreversible state of decline, with nothing to stop the glaciers in this area from melting into the sea” and “the region’s mile-thick ice sheet could collapse and raise sea levels as much as 11 feet.The consequences of such an amount of sea-level rise for the United Stateseor for any other coastal regiondare staggering to contemplate.12.8 million Americans live on land less than 10 feet above their local high-tide line.$2.4 trillion worth of property is occupying this land, excluding Hawaii and Alaska.The cities that would be most affected include Miami, New Orleans, and New York. Within 100-200 years, one-third of West Antarctica could be gone. The effects of climate change are outpacing scientific predictions, driven in part, scientists say, by soaring levels of greenhouse gases in the atmosphere.”
In a paper titled “Widespread, Rapid Grounding Line Retreat of Pine Island, Thwaites, Smith, and Kohler glaciers, West Antarctica from 1992 to 2011,” Rignot et al. (2014) contend that increased flow velocity of several small outlet glaciers of theWest Antarctic Ice Sheet as a result of increased rates of calving into the sea will lead to “unstoppable collapse” of the entireWest Antarctic Ice Sheet and raising of sea level by 4 ft, which will displace tens of millions of people from coastal areas around the world. According to Rigot, an electrical engineer, “Warm ocean currents and geographic peculiarities have helped kick off a chain reaction at the Amundsen Sea-area glaciers, melting them faster than previously realized and pushing them ‘past the point of no return’.The system [becomes] a chain reaction that is unstoppable, [with] every process of retreat feeding the next one.The glacial retreat there appears unstoppable.” Curiously, Rignot asserts that “heat makes the grounding line retreat inland, leaving a less massive ice shelf above. When ice shelves lose mass, they can’t ‘hold back’ inland glaciers from flowing toward the sea.” Apparently he believes that the terminal area of the glacier acts like a dam, “holding back” the rest of the glacier, and if it is removed, the glacier will essentially slide into the sea. That’s a false premised every glaciologist knows that where a glacier terminates is determined by its mass balance between the amount of accumulation of new ice every year and the amount of ice loss by melting or calving. Thus, an important factor for the Rignot “unstoppable collapse” of the West Antarctic Ice Sheet is based on a false premise.
In a paper titled “Marine Ice Sheet Collapse Potentially Underway for the Thwaites Glacier Basin, West Antarctica,” Joughin et al. (2014) also infer that the entire West Antarctic Ice Sheet will soon disappear, resulting in a sea level rise of up to 10 ft. The authors contend that recent retreat of the Pine Island and Thwaites glaciers has occurred because warm ocean water has caused melting of ice on the underside of the glaciers, causing them to thin and calve more rapidly. Because the base of most of the West Antarctic Ice Sheet lies below sea level, the authors contend that ocean water will melt its way up several small embayments under the ice sheet, which is more than 1000 miles across, and cause it to collapse abruptly. They refer to this as “unstoppable” because the glacier base is below sea level and they claim that there is nowhere that the glacier can ground, resulting in total collapse of the ice sheet into the sea.
The thickness of the West Antarctic Ice Sheet. Most of the ice sheet is more than 6000 ft (2000 m) thick and in places, reaches up to 10,000 ft (3000 m) thick. The importance of ice thickness is that virtually all of the ice sheet is considerably thicker than the depth below sea level to bedrock, so the ice is grounded and will not float. The Pine Island outlet glacier drains only a relative small portion of the West Antarctic Ice Sheet, so it is difficult to see how events there could result in collapse of the entire Antarctic Ice Sheet.
All of the forecasters of “unstoppable collapse of the West Antarctic Ice Sheet” assume that recent accelerated ice flow and calving has been caused by melting from warm sea water beneath the ice. They did not consider geothermal heat as a possible cause. In a paper titled “Evidence for Elevated and Spatially Variable Geothermal Flux Beneath the West Antarctic Ice Sheet,” Schroeder (2014) presented evidence of elevated geothermal heat flow beneath the Thwaites glacier that “is likely a significant factor in local, regional, and continental-scale ice sheet stability. Thwaites Glacier is one of the West Antarctica’s most prominent, rapidly evolving, and potentially unstable contributors to global sea level rise. Uncertainty in the amount and spatial pattern of geothermal flux and melting beneath this glacier is a major limitation in predicting its future behavior and sea level contribution. Geothermal flux is one of the most dynamically critical ice sheet boundary conditions. We show that the Thwaites Glacier catchment has a minimum average geothermal flux ofw114 10 mW/m2 with areas of high flux exceeding 200 mW/m2 consistent with rift-associated magma migration and volcanism. This supports the hypothesis that heterogeneous geothermal flux and local magmatic processes could be critical factors in determining the future behavior of the West Antarctic Ice Sheet.
The distribution of melt and geothermal flux includes several regions with high melt that are closely related to rift structure and associated volcanism. These include the entire westernmost tributary that flanks Mount Takahe , a subaerial volcano active in the Quaternary and several high-flux areas across the catchment adjacent to topographic features that are hypothesized to be volcanic in origin We also observe high geothermal flux in the upper reaches of the central tributaries that are relatively close to the site of the West Antarctic ice sheet Divide ice core (Fig. 7.10, location B), where unexpectedly high melt and geothermal flux have been estimated.
Our results produce high melt values adjacent to known volcanoes and structures that are morphologically suggestive of volcanic origin. We believe that both the magnitude and spatial pattern of geothermal flux we present reflect the geologic and glaciological reality of the Thwaites Glacier bed and that contrary to previous modeling, our results show regions of high geothermal flux that are in substantial agreement with levels inferred from the ice core drilling site near the ice divide for the Thwaites catchment.
This evidence shows that (Easterbrook, 2016):
1. The West Antarctic Ice Sheet makes up only about 8% of Antarctic ice, and the Pine Island glacier makes up only about 10% of the West Antarctic Ice Sheet. Most of the West Antarctic Ice Sheet lies SE of the Pine Island glacier and at its SW margin is about 1000 miles from the Pine Island and Thwaites outlet glaciers.
2. The Pine Island and Thwaites outlet glaciers drain less than half of the West Antarctic Ice Sheet, so it is not
plausible that they could cause collapse of the entire ice sheet.
3. The Pine Island and Thwaites outlet glaciers are only about 30 miles across, so draining 2.2 million km3 of ice through their narrow channels or sending sea water 1000 miles under the ice sheet is not plausible.
4. Most of the ice sheet is much thicker (2500 m [8000 ft]) than the depth of the subglacial floor below sea level (1000 m [3300 ft]), so the ice will not float and sea water will not extend under the ice.
5. Almost all of the West Antarctic Ice Sheet subglacial floor is less than 1000 m (3300 ft) below sea level. The ice is mostly more than 2500 m (8000 ft) thick, so the ice sheet will not float in 1000 m (3300 ft) of water nor will sea water melt its way under the ice.
6. Studies of subglacial geothermal heat flow show that the area under the Thwaites glacier is unusually high and is the most likely cause of subglacial melting, rather than ocean water.
7. The West Antarctic Ice Sheet is NOT collapsing, the retreat of these small glaciers is NOT caused by global
warming, and sea level is NOT going to rise 10 ft.
(Edited, for formatting) SUNMOD
Thank you. One of the most informative and enjoyable reads I’ve had in a long time. Would it really be that difficult for a major news outlet to provide this kind of insight into the actual dynamics in the region?
The volcanic/geothermal heat cause of melting of the Pine and Thwaites glaciers was documented in several publications half a dozen years ago, but you will never see any reference to them in the scare papers put out by some engineers who obviously don’t know anything about glacier physics.
Thank you, Dr Easterbrook for injecting some geologic and glaciological reasoning. I find it appalling that these sorts of alarmist papers make it through peer review.
And, localized heating would explain why some glaciers accelerated and others did not after the detachment of the Larsen B shelf, as tty commented.
“Whoever wrote this obviously does not understand the physics of glaciers. The assertion that maritime glaciers will ‘slide into the sea’ if shelf ice at their terminus no longer ‘holds back’ the rest of the glacier. This is utter and total nonsense! The position of the terminus of a glacier is governed by the rate of accumulation of snow and ice in the upper part of a glacier and the rate of melting or calving near its terminus. Period.”
wrong
the physics
https://youtu.be/BsVNwqWgXI0?t=1770
Mosher
The analogy with the spreading pancake batter is fundamentally flawed. It doesn’t explain glacial polishing of bedrock, or the deep grooves often left by boulders dragged across the bedrock.
Also, he isn’t saying what you think he is saying. Note that before he gets off on his flying buttresses that he shows a cross section of the ice shelf and makes the valid point that that a key to the behavior of the shelf ice is the grounding line where there is actually some friction. However, it is probably overstated because these grounding lines are usually former terminal moraines that are unconsolidated. That is, they don’t offer the same resistance as indurated bedrock.
Fundamentally, the rate of movement down-slope from the zone of accumulation is a function of thickness (the ice doesn’t behave plastically under its own weight until it reaches a thickness of about 50 meters. The movement is then controlled by slope, friction at the bedrock contact, and ice shearing when the friction is very high. The base can be lubricated by water, significantly reducing friction, which is why thermal hot spots may have a significant impact.
The terminus is an equilibrium between the rate of supply and the rate of ablation. If more snow accumulates, the forward motion will increase (accelerate). Alternatively, a decrease in friction, such as from water, or shearing off a bedrock obstruction, will allow acceleration. The terminus may move forward at such times. If the rate of wastage at the terminus increases, the terminus will move up-slope. That has happened in the past, which is why the grounding lines created from terminal moraines are present.
Again, the key to buttressing should be the absence of tension cracks. Tension cracks imply that the ice is moving forward faster than it is being supplied. At the terminus, the ice is often thin enough that it is responding in a brittle manner. But, what happens at the terminus is not communicated up-slope.
There was another factor that probably contributed to the accelleration of the Larsson, once one piece broke off. It really looks like the islands sticking out of the shelf were physically holding back the ice flow, unlike an ice shelf with no islands and only water. If you look at the sequence of the pieces that break off, over the years, starting in, I think I remember, 2000, and check where the breaks occur after, it looks like the islands play a significant roll in what happens. If it has slowed lately, you might see that the shelf is now once again being butressed by the island or islands. I think the shelves are called A and B because they are on either side of a major island, and it breaks off either side of it now and then, clearly because of the island. The build up of pressure against the islands looks like it accumulates and then make the ice shelf suddenly shatter, probably during some huge swell that tips the balance and initiates it.
“Climate Science” has devolved into a laundry list of catastrophic tipping points…just take your pick, folks.
What is the evidence that the events occurring in and around the Thwaites glacier are new or a result of increased carbon dioxide in the atmosphere?
From my file of factoids, quotes and smart remarks:
Observing something for the first time, doesn’t mean it has never happened before.
How can so many people be so easily convinced that events which have always occurred and are extensively documented, are in fact wholly new and unprecedented?
From the article:
“Bottom Line:
We will have to wait on Thwaites to see what it is going to do. We don’t really understand the dynamics involved with Antarctic glaciers yet – what makes them speed up and slow down. But in any case, even Hongju Yu’s worst case conclusion only minimally adds to expected sea level rise of about 12 inches ( other opinions vary butn possible values over 2 feet are extremely unlikely) by 2100.”
And on top of that, no matter what the Thwaites glacier does, there is no demonstrated connection between what it does, and CO2 accumlations in the Earth’s atmosphere.
Thank you for some common sense in pointing out whatever is happening under the oceans cannot be due to CO2 in the atmosphere.
But mah zettajoules…
Good read and educational. Thanks
Troe ==> You’re welcome.
“by the end of the century more than 650 million people will be living on land that is under water all or much of the time.”
Then it’s not land? Assuming this happens then I really hope people won’t just stay put and watch the water rise. As well as not being able to breath under water, fridges, televisions, cookers or any domestic electronics don’t work under water, or cars and trains or the sewers! Mind you, if we’ve de-carbonised and gone back to hunter gathering it won’t matter.
Any ice shelf that opens out onto the sea is not buttressing anything. There is nothing pushing back against WAIS as it floats free.
Regarding these claims:
“2 FEET — “By the end of the century, the oceans could rise at least 2 feet over 2005 levels,”
10 FEET — “The Thwaites Glacier is about the size of a U.S. swing state and holds enough ice to raise sea levels by about 10 feet.”
200 FEET — “The WAIS has enough ice to raise the seas by 200 feet.”
650 MILLION UNDER WATER – “…by the end of the century more than 650 million people will be living on land that is under water” — Michael Mann”
Two of them are about total sea level rise, not the part of the sea level rise that would result from melting of the Thwaites glacier.
Lessee if I have this straight. People living on land that is under water:
A. Developed gills
or
2. Rely on SCUBA gear
or
iii. Spent a lot of money on a submersible dome
or
D. Kept their property rights and anchored a houseboat their property.
It’ll take a lot of getting used to living on land that is under water.
H.R.===> My first thoughts, exactly. Well played, sir ( or ma’am).
One word – Stilts.
If Mann is right, you’ll never regret putting everything you have into stilts futures.
P.S. Over the years I have mentioned Mrs. H.R. a few times. “Sir” was my father and his peers. I’m just some dumb ol’ retired engineer dude.
Actually if the whole West Antarctic ice sheet would melt, it would only raise the sea level by about 11 feet.
Whoever wrote this nonsense seems to have overlooked that most of the WAIS is below sea-level, so the meltwater would mostly be used up to fill out the space where the ice was. Also (cold) seawater is 13% denser than glacier ice, so even part of the ice above sea level would be needed.
For example if the glacier bed is 1000 meters below sea-level, only the ice >130 meters above sea-level would cause a net raise of the sea-level.
Yeah I would love to see the source of the 200 ft claim because if you melted every bit of ice on the entire planet you get 240 foot, that is the max sea level rise actually possible without crust restructuring. So someone had a bad mathematics day out.
“If the ice shelf disappeared, it would no longer provide resistance to the glacier’s flow, allowing the glacier to accelerate ”
Good grasp of the physics of glaciers and floating ice shelves there. I know about this; you see, we have a floating dock at our country place. If that dock wasn’t there to hold it back, the shore behind it would surely collapse into the river. The principle is the same.
/sarc
Seriously, an ice shelf can slow down a glacier if it has other grounding points to hold it back. But they would have to be very substantial ridges. I’ve spent enough years in glaciated hard-rock terrain to know how easily moving ice can around, or over rocky obstacles.
Smart Rock
It isn’t generally appreciated that an ice sheet can have a dominant direction of movement, but at ground levels may be moving in all compass directions. I have observed and recorded glacial striations in all compass directions in New England. In Greenland, I have observed first hand, at the Camp Tuto tunnel, vertical shearing of the ice over ridges. There is no resemblance to a slide in a children’s playground with a big block of ice at the bottom.
Glacial striations in different directions are usually also of different ages.
Glacial flow varied a lot, just during the last ice-age.
Yes, I have noticed for years that either the people being alarmist over Antarctic ice and glaciers do not seem to know much about the subject of glaciers, or much about Antarctica.
What happens when a glacier runs into another accumulation of ice?
A few things are possible, and none of them are that the glacier stops.
Piedmont glaciers, like Malaspina:
Merging glaciers, showing that a stream of flowing ice will not be slowed down even by a far larger and thicker stream of ice:
_(20991435353).jpg)
They seem to think that these ice sheets and glaciers only exist because of the ice shelves.
I wonder if any of them have even determined the temp of all that ice, and how much the ocean would cool if enough ice was dumped into it to raise sea level 10′?
Nicholas,
You said: “I wonder if any of them have even determined the temp of all that ice, and how much the ocean would cool if enough ice was dumped into it to raise sea level 10′?”
Thanks for the lead-in. I was just working on those numbers. I’m borrowing from my article/paper presented here:
https://wattsupwiththat.com/2019/04/25/basic-science-4-keys-to-melt-fears-about-ice-sheets-melting/
Expanding the calculations presented here: https://wattsupwiththat.com/wp-content/uploads/2019/04/Ice-Atmosphere-Ocean-Energy-20190407-1.xlsx
I don’t think Thwaites holds 10ft of SLR potential, but using that number and USGS stated 260ft total ice mass SLR potential, Thwaites holds ~4% of global ice mass. Assuming -25°C ice temp, melting that ice to liquid water at 0°C requires 5.28E+23 J. The energy to melt the ice would come from the ocean water, but we know the atmosphere and oceans are coupled. We can analyze each independently.
The atmosphere is below 0°C above 2.5km altitude and unable to melt ice. The atmosphere below 2.5km would have to decrease by ~290°C to provide the energy to melt that ice mass. Of course, that is absurd (but lost on Alarmists). The average global atmospheric temperature between 0-2.5km is ~8°C. If we could magically extract all of the energy from the atmosphere above 0°C and exchange it with the ice (such that it only went to melting ice and not warming the meltwater), then at most we could raise sea level by 3.4 inches. The atmosphere would now be at or below 0°C, which is ~6°C colder than at the depth of a glacial period.
If we constrain the energy to melt the ice to the top 100ft of ocean water, the ocean water temp would have to decrease by 22.5°C. If the energy came from the top 1000ft, the temp ∆ would be 2.25°C.
In over 100 years of “global warming,” we have an atmosphere that is ~1°C warmer and oceans that are perhaps a few tenths of a degree C warmer (above the thermocline). [I’m discounting the OHC claims as I think this is just where the mythical Earth Energy Imbalance is hidden – not measured.] So where is the energy to come from to support these scenarios?
Alarmists seem to think melting ice comes for free (no energy required). A simple application of basic physics shows that their catastrophic scenarios cannot happen – they certainly cannot happen quickly. The oceans contain enough energy to melt the ice mass in question if given enough time. Large icebergs have been known to float around Antarctica intact for over 30 years. The mass of ice in this scenario dwarfs that. I’d speculate that the result would be to bring on another mini ice age before any catastrophic SLR would result.
“Despite repeated assertions of Antarctic ice melt and glacier collapse, the sea level record does not show discernible effects – global sea levels still rising at their centuries long 2-3 mm per year as the Earth climate warms from the Little Ice Age.”
‘We have used a combination of historical tide-gauge data and satellite-altimeter data to estimate global averaged sea level change from 1880 to 2014. During this period, global-averaged sea level rose about 23 cm, with an average rate of rise of about 1.6 mm/yr over the 20th Century.’
https://www.cmar.csiro.au/sealevel/sl_hist_few_hundred.html
You’d be lucky to measure that in much less than a decade and I’d suggest the tide gauges at Fort Denison and Port Arthur in Australia are a couple of the best indicators of Antarctic ice melt effects you’ll find in the Southern Hemisphere. Australia’s coastal RE prices would be another good indicator of the doomsters tipping point and their Noah’s Ark re-run.
Any reasonable long term tide gauges at similar or lower southern latitudes in South America or Southern Africa to compare with?
Try these links:
https://www.sealevel.info/about.html
Coastlines – Grouped by Continent:
http://www.sealevel.info/coastline_by_continent.html
NOAA’s 2016 list of 375 long term trend tide stations:
http://www.sealevel.info/MSL_global_thumbnails5.html
The last link is convenient but the data ends in 2016.
Not much except for the Sputniks and their true believers-
http://sealevel.odinafrica.org/
and the Caribbean where those mad dogs and Englishmen ventured-
https://www.fig.net/resources/proceedings/fig_proceedings/fig2010/papers/fs04i/fs04i_sutherland_davis_et_al_4614.pdf
But you do get the drift the CSIRO were on the right track with their 1.6mm estimate of global SLR for the 20th Century with that quote-
‘In the twentieth century, global sea level rose by 10-20 centimetres, averaging 1.7 ± 0.3 mm yr-1 with an acceleration of 0.013 ± 0.006 mm yr-2’
Pretty much accepted science but where would we be without the bogeyman rider to scare the Gretas?
‘ …this rate is expected to accelerate over the next century (Church and White 2006). According to the IPCC, the sea level will rise 9-88 centimetres in the next 100 years, with a mid-estimate rise of 50 centimetres. This translates into 5 millimetres per year, which is two to four times faster than during the twentieth century’
Hang about. 9 cms estimate is 90mm a century or 0.9mm/yr average and that’s pretty much the same as the CSIRO’s 0.85mm/yr average at Port Arthur for over 150 years. Gondwanaland with its tide gauges is obviously floating up with the dire Antarctic ice melt and warming expanding seas methinks as who could doubt the venerable IPCC with 5mm average a year? I must be getting seasick again.
Kip,
“The first study, Zwally (2017), claims Antarctica is gaining mass — not losing”
Irrelevant. Zwally is not “varying” on the subject of Thwaites. His first statement in your link says:
“We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,”
Nick ==> The purpose of bring up Zwally is not to counter opinions about Thwaites.
Thwaites is doing whatever it is doing.
I bring up Zwally and the other two studies just to show that there is a controversy about Antarctic ice mass in general, and that as usual in CliSci, anyone daring to arrive at findings counter to the disaster narrative is attacked and denigrated.
Kip, Stokes knows that. But True-Believers feel compelled to stick their feet out in front of anyone or anything that doesn’t goose-step in-time with the current mantra.