Seawater seep may be speeding glacier melt, sea level rise


Warm seawater that’s seeping under certain glaciers could eventually lead to sea level rise that’s double that of existing estimates.

Peer-Reviewed Publication

GEORGIA INSTITUTE OF TECHNOLOGY

Alexander Robel holds ice used in glacial melt research.
IMAGE: ALEXANDER ROBEL IN HIS LAB. view more  CREDIT: ALEXANDER ROBEL (GEORGIA TECH) AND EARLE WILSON

The melting of ice sheets at the points where they float on and along the world’s oceans is a major climate culprit when it comes to sea level rise. But less is understood about the extent of melting that is due to warm, salty seawater that seeps underneath “grounded” portions of ice sheets along land, as well as what happens when that mix intrudes deep under glacier interiors.  

new study published in The Cryosphere led by Alexander Robel, an assistant professor in the School of Earth and Atmospheric Sciences, may provide some clarity. Robel, who leads the Ice & Climate Group at Georgia Tech, and his team of researchers have developed a theory that finds glacial melt may be happening faster out of sight than previous estimates.

“The paper shows warm seawater can intrude underneath glaciers, and if it causes melting at the glacier bottom, can cause predictions of future sea level rise to be up to two times higher than current estimates,” Robel says. “Put another way, our research showed that the grounding line (where glacial ice meets water) is not the sort of impenetrable barrier between the glacier and the ocean that has previously been assumed.”

Using predictions based on mathematical and computational models, the study shows that seawater intrusion over flat or reverse-sloping impermeable beds may feasibly occur up to tens of kilometers upstream of a glacier’s end or grounding line.

Fresh meltwater stays close to the temperature of the ice it came from, but salty seawater that intrudes under glaciers may also bring heat from the ocean, which researchers say has the potential to cause much higher rates of melting at the glacier bottom.

Robel’s co-authors for the study are Earle Wilson, a postdoctoral scholar at the California Institute of Technology, and Helene Seroussi, an associate professor at Dartmouth College.

The new study uses basic mathematical theory of fluid flow and large computer models run on the Partnership for an Advanced Computing Environment (PACE) high performance computing cluster at Georgia Tech to make its predictions, and builds on a 2020 study led by Wilson which showed how such intrusions could occur through laboratory experiments.

“Past measurement from field expeditions and satellites have hinted that seawater may intrude subglacial meltwater channels,” Wilson notes, “much like how the ocean may flow upstream and mix with river water in a typical estuary. Our study shows subglacial estuaries are not just possible but likely over a wide range of realistic scenarios, and their existence has profound implications for future sea level rise.”

“Simulations show that even just a few hundred meters of basal melt caused by seawater intrusion upstream of marine ice sheet grounding lines can cause projections of marine ice sheet volume loss to be 10-50 percent higher,” Robel explains. “Kilometers of intrusion-induced basal melt can cause projected ice sheet volume loss to more than double over the next century.”

Robel adds that these results suggest that further observational, experimental, and numerical investigations are needed to determine the conditions under which seawater intrusion occurs — and whether it will indeed drive rapid marine ice sheet retreat and sea level rise in the future. The research team will start to look at measurements from past field expeditions to confirm if their theory is true, and are working to secure funding in the next year to go to Antarctica and look for such intrusion in a targeted expedition.

“Overall, this contributes to an important body of current work that tries to estimate how fast ice sheets melt in a changing climate,” Robel adds, “and what physical processes are relevant in driving these rapid changes.”

DOIhttps://doi.org/10.5194/tc-16-451-2022

The Georgia Institute of Technology, or Georgia Tech, is a top 10 public research university developing leaders who advance technology and improve the human condition. The Institute offers business, computing, design, engineering, liberal arts, and sciences degrees. Its nearly 44,000 students representing 50 states and 149 countries, study at the main campus in Atlanta, at campuses in France and China, and through distance and online learning. As a leading technological university, Georgia Tech is an engine of economic development for Georgia, the Southeast, and the nation, conducting more than $1 billion in research annually for government, industry, and society.


JOURNAL

The Cryosphere

DOI

10.5194/tc-16-451-2022 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Layered seawater intrusion and melt under grounded ice

ARTICLE PUBLICATION DATE

8-Feb-2022

From EurekAlert!

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Matthew Bergin
February 10, 2022 2:06 pm

But the sea level is doing the same thing it has always done. There is no indication of any acceleration in the rate of increase in sea level since the little ice age. The male bovine excrement, it stinks

Steve Case
Reply to  Matthew Bergin
February 10, 2022 5:07 pm

Yes there is some acceleration. A survey of the PSMSL Permanent Service for Mean Sea Level shows about 50 tide gauges with 100 years or more of records, and average and median acceleration is around 0.01 mm/year/year. That’s one tenth of the 0.098 mm/year/year the Sea Level Research Group at Colorado University claims.

Yes they actually claim 0.98 not 0.97 nor 0.99, but 0.98 mm/year/year. Apparently Dr. R. Steve Nerem never learned about rounding off meaningless numbers.

Reply to  Steve Case
February 10, 2022 8:06 pm

More false precision masquerading as accuracy.

Whether 0.098mm or 0.01mm, the systems for measuring sea level do not have that capability for accuracy.

David A
Reply to  Steve Case
February 10, 2022 10:12 pm

Or meaningless things a peer reviewed paper postulates-

“The paper shows warm seawater can intrude underneath glaciers, and if it causes melting at the glacier bottom, can cause PREDICTIONS of future sea level rise to be up to two times higher than current estimates.”

I capitalized the operative word. Lots of things can cause “ predictions” of anything to increase. Increased “predictions “ of accelerated SL rise is very different then actual accelerated SL rise. But we live in clown world, so who knows.

W Browning
Reply to  Steve Case
February 11, 2022 1:16 pm

They are measuring sea levels from moving platforms as all land mass is always moving, there are many places where sea level is receding because the land is rising.

Dudley Horscroft(@dudleyhorscroft)
February 10, 2022 2:07 pm

Unless this sub basal intrusion of warmer salt water has only just started – which seems to be implausible – it has been going on for centuries.

And if the latter, then this will not affect the rate of addition of melt water to the oceans, and hence will not increase the rate of sea level rise.

Steve Case
Reply to  Dudley Horscroft
February 10, 2022 5:21 pm

“Unless this sub basal intrusion of warmer salt water has only just started – which seems to be implausible – it has been going on for centuries”

That goes for a lot of Climate Change claims.

Sara
Reply to  Dudley Horscroft
February 11, 2022 4:50 am

But — but–but— Dudley they HAVE TO HAVE something to fuss about, no matter how “normal” it is in the real world, because they can’t control it….

Seawater undermining glaciers at the edges and seeping a little further inland??? That’s been going on for not just a few years but a billion bunch of years, give or take a few gazillion. It isn’t something new, but these overgrown children have to have something to fuss about.

stinkerp
February 10, 2022 2:08 pm

Warm seawater that’s seeping under certain glaciers could eventually lead to sea level rise that’s double that of existing estimates.

Potentially increasing sea level rise an additional 0.5 mm per year over the current average of about 3 mm per year, leading to a possible increase of 1 meter in—wait for it—300 years. Oh no!

The operative word in their doomsaying is “could”. So far every prognostication by the climate cult has been vastly overblown. And according to studies of Antarctic and Greenland ice sheet mass balance, their contribution to sea level rise is about 0.5 mm per year combined. But why assuage public fears with data in context when fearmongering is so much more fun?

Last edited 3 months ago by stinkerp
Rud Istvan
Reply to  stinkerp
February 10, 2022 2:39 pm

See my previous guest post here on “sea level rise, acceleration, and closure”. Greenland is 0.7mm/year, Antarctica total is 0.4, and thermosteric rise is 1.1, total 2.2mm/year with exact closure to dGPS vertical land motion long record tide gauges 2.2 mm/year.

Steve Case
Reply to  Rud Istvan
February 10, 2022 5:29 pm

Thermostatic rise is local. If sea level in the middle of the Pacific warms up and causes a 1.1 mm increase in sea level, will the water level in New York harbor go up too?

Rud Istvan
Reply to  Steve Case
February 10, 2022 5:51 pm

SC, my number was from ARGO last ten (then) years, so probably close to correct

Sara
Reply to  Rud Istvan
February 11, 2022 5:41 am

I’m curious about something, Rud, so perhaps you can help me out, because these attempts to induce panic attacks in the populace are getting sillier and sillier.

Since this “undermelt” goes on all the time and has been since land rose out of the oceans (back before I was born, anyway), why is it that these people act as though these “events” (they really aren’t) are something new and should scare us?

These people seem to be desperate to scare us into something-something-something, until it becomes about as close to a comic episode of the Monty Python guys. I keep hearing that classic song “How Sweet To Be An Idiot” every time I see one of these reports, in which reality is that a 1.1 millimeter overall rise is less of a threat than dropping my buttered toast on the floor.

So are they really this desperate, or what? Just askin’. The geese are coming back from the warmer climes and ice fishing will soon be over.

michael hart
Reply to  Sara
February 11, 2022 10:31 am

A great piece of music, Sara. Oasis later created “Whatever”, and had to then accord credit to Neil Innes for its originality.

Quite ironic, since Oasis openly took from the Beatles without losing a lawsuit (to my knowledge). Yet Innes lost his case to the Beatles for his musical creation of The Ruttles.

Reply to  Rud Istvan
February 10, 2022 8:24 pm

From GPS.gov:

“On April 20, 2021, the global average URE across all satellites was ≤0.643 m (2.1 ft.), 95% of the time.”

Argos are not calibrated at deployment, or during periodic cleaning or maintenance, so fall into this gross accuracy level of measurement.

Still, for those who believe government ocean buoys are frequently calibrated to perfect capability.

“High-end users boost GPS accuracy with dual-frequency receivers and/or augmentation systems. These can enable real-time positioning within a few centimeters”

Even that accuracy is over 1.5 inches for each measurement.

That is before considering measuring a sea level surface that is affected by wind direction, wind speed, storms at sea, barometer changes, water temperature, tidal movement, etc. etc.

Yet, the Feds believe and proselytize that they are accurate within millimeters.

Silly feds.

Last edited 3 months ago by ATheoK
Reply to  stinkerp
February 10, 2022 8:12 pm

Warm seawater that’s seeping under certain glaciers”

“Seeping”!?
Which means the water matches the temperature of the glacier almost immediately.
Or does the glacier jump up and down squeezing out the cold water?

Odds are their model uses very high temperatures and huge volumes of water flowing under the glaciers.

Nick Schroeder
February 10, 2022 2:11 pm

Where is a glacier most likely to melt?
In contact with the -10 C air or out of sight at the 15 C basal boundary?

Brent Wilson
Reply to  Nick Schroeder
February 11, 2022 7:46 am

The basal boundary is nowhere near 15 C. More like 1 to 2 C.

TeddyLee
February 10, 2022 2:13 pm

Funding for a trip to Antarctica.Who would have guessed.
Top quality science from an Ass Prof.

fretslider
February 10, 2022 2:14 pm

“large computer models”

It matters not how big they are when they are patently wrong

Joseph Zorzin
Reply to  fretslider
February 10, 2022 4:48 pm

beat me to it

Rick C
Reply to  fretslider
February 10, 2022 7:20 pm

This one apparently has water flowing up hill.

David A
Reply to  fretslider
February 10, 2022 10:18 pm

It does matter, big computers can generate more wrong numbers more often in a mad race to more frequent funding for increased alarmist peer review dribble.

Tom Halla
February 10, 2022 2:17 pm

Yet more models.

4 Eyes
February 10, 2022 2:21 pm

The model is no good if it cannot tell us why it hasn’t started yet and when it is going to start. I guess that their free trip to Antarctica will reveal that this phenomenon is imminent but more research will be required to confirm the tipping point.

Rud Istvan
Reply to  4 Eyes
February 10, 2022 2:33 pm

The GT posited effect is NOT novel or new. And there have already been other Antarctic expedition papers speculating it could ALARMINGLY happen. The paper PR was a hysterically bad false alarm. See my post “Another Antarctic sea level rise false alarm” concerning the EAIS Totten glacier, a few years ago over at Judith’s Climate Etc.

Rud Istvan
February 10, 2022 2:22 pm

Since sea level rise is about constant for the last century, and isn’t accelerating, simple macro observation says this modeled theory isn’t happening yet.

Of course, Further investigations are needed. More grant money needed.

Sadly to include “The research team will start to look at past field expeditions to confirm if their theory is true…” Which means they have NOT yet done that basic step. A new theory based on ZERO observations. Yup, that’s some more ‘good climate science’ right there.

Curious George(@moudryj)
Reply to  Rud Istvan
February 10, 2022 5:55 pm

The premise of this peer-reviewed publication is “The melting of ice sheets at the points where they float on and along the world’s oceans is a major climate culprit when it comes to sea level rise.”
Peer reviewers never heard of Archimedes’ law. This is equity in science.

Last edited 3 months ago by Curious George
D. J. Hawkins
Reply to  Rud Istvan
February 10, 2022 6:47 pm

Unless they are drilling through the sheets to sample the water at the ice/bedrock interface, looking at field expeditions isn’t going to tell you squat.

Thomas Gasloli
February 10, 2022 2:26 pm

We need to ban government funding of any “research” that consists of creating “models”. This is NOT science.

Johanus
February 10, 2022 2:29 pm

Simulations show that even just a few hundred meters of basal melt caused by seawater intrusion upstream of marine ice sheet grounding lines can cause projections of marine ice sheet volume loss to be 10-50 percent higher,” Robel explains. “Kilometers of intrusion-induced basal melt can cause projected ice sheet volume loss to more than double over the next century.”

“All models are wrong.” George Box wrote in 1976. The useful ones are those that explain and/or predict actual observations in the real world.

Pillage Idiot
February 10, 2022 2:29 pm

“Put another way, our research showed that the grounding line (where glacial ice meets water) is not the sort of impenetrable barrier between the glacier and the ocean that has previously been assumed.”

It does not matter if it is impenetrable! Fresh meltwater has a hydrodynamic head as it works down slope to the meltwater/seawater interface.

The interface is like a “positive pressure” clean room. If the door is open a crack, there is still no entry of air into the clean room.

Greg S.
February 10, 2022 2:45 pm

“It’s worse than we thought!”

Yawn.

Chris Hanley
February 10, 2022 2:48 pm

The research team will start to look at measurements from past field expeditions to confirm if their theory is true …

Climate Change scientific method: devise a theory and search for confirming evidence instead of contrary evidence.

MarkW
February 10, 2022 3:43 pm

Is there any evidence that sea water didn’t slip beneath grounded glaciers prior to 1950?

DMacKenzie
Reply to  MarkW
February 10, 2022 3:50 pm

No, none, so we must assume there was none.

Rud Istvan
Reply to  MarkW
February 10, 2022 3:54 pm

No. They remained grounded. And still are. Simple observation. A grounded glacier flows slowly. An ungrounded glacier flows faster. And we can measure using IceSat the rates of flow of all glaciers since decades. Oopsie for GT.

Dusty
February 10, 2022 3:54 pm

I was writing a long explanation for why this is bunk, but then I realized their scenario would be just as applicable on land where there is no glacier as they claim it MAY occur where there is glacier. I can’t think of an area on land where there is no glacier that this occurs, but there might be. But then I thought, could this possibly occur in an area where there is no glacier but where it does rain at least a little bit 24/7/365, because that, in effect, is what the glacier provides in the way of fresh water melt at the base of the ice and that fresh water is pressurized or easily made to be so if there is resistance to its flow.

Anyway, I just don’t see it.

Mickey Reno
February 10, 2022 3:55 pm

Um, point of order. When I make home made ice cream in an old fashioned churn, I add salt to the ice water in the bucket in order to make it COLDER, not warmer. What if the salty sea water preserves the ice because when salt water absorbs a little bit of the “heat” from the ice, it is able to stay liquid down to 8 to 12 f degrees. Glacial ice next to 10 f degree salt water is NOT going to melt.

Rud Istvan
Reply to  Mickey Reno
February 10, 2022 4:07 pm

Sorry. Your observational facts about making ice cream have NOTHING to do with this new ice/freshwater/salt (sea) water theory. The authors explained that their theory was based only on basic math and models—no experimental evidence allowed. Especially not something as testable as ice cream.

Mickey Reno
February 10, 2022 3:55 pm

Um, point of order. When I make home made ice cream in an old fashioned churn, I add salt to the ice water in the bucket in order to make it COLDER, not warmer. What if the salty sea water preserves the ice because when salt water absorbs a little bit of the “heat” from the ice, it is able to stay liquid down to 8 to 12 f degrees. Glacial ice next to 10 f degree salt water is NOT going to melt.

Curious George(@moudryj)
Reply to  Mickey Reno
February 10, 2022 6:00 pm

Salt melts the ice, making it colder. Sorry.

philincalifornia
February 10, 2022 4:01 pm

Stoppit everyone. Bedwetters have feelings too.

Geoff Sherrington
February 10, 2022 4:16 pm

Per Avogadro, when floating ice melts it scarcely changes the sea level.
The grounding line is defined as being where glacial ice starts to float. Therefore, (broadly) only ice still in contact with rock below it is able to contribute to sea level rise by ice melting under it. There are gradations, as in a cantilever of ice sticking out to sea partly floating and partly sitting on rock below..
However, it is normal for tidewater glaciers to move towards the sea, under a permanent push by the gravity acting on the mobile ice mass. The faster they move, the more they can melt. However, there is also enduring replenishment if ice from snowfall, so any calculations of sea level change have to account for both ice addition and subtraction.
Lastly, as others have noted, for this proposed mechanism to be relevant, there needs to have been a change in the ice melted by basal intrusion of hot water, a change from historical times to now and the future. Because there has been near-zero acceleration of tide gauge sea level measurements, there might not be any such recent change. So, the whole paper is about an idea, one it seems without any factual evidence of it operating, let alone allowing estimates of a doubling of the rate of sea level change.

DMacKenzie
Reply to  Geoff Sherrington
February 10, 2022 7:29 pm

I think you mean Archimedes. Aside…I especially am impressed(actually the opposite) by the exaggerations written about the “doomsday glacier” Thwaites. It’s the size of the UK only its really 120 km by 200km, it drains an area the size of the UK but most of that doesn’t move…it’s 2 km thick, but really only averages 135 meters above sea level…if it melted it would raise the world’s ocean by a meter, except most of it’s volume is already below sea level…it could be gone in 3 years…blah blah….they work serious overtime trying to make plausible Chicken Little stories about a place where nobody cares to check on their Bu11sh’t. It’s disgusting crap they come up with that can be debunked with Google Earth and a calculator but journalists don’t bother.

Last edited 3 months ago by DMacKenzie
Geoff Sherrington
Reply to  DMacKenzie
February 11, 2022 12:23 am

Yep,
Archimedes,Tks.

Walter Sobchak
February 10, 2022 5:22 pm

“Using predictions based on mathematical and computational models”

I stopped there. More mathematical onanism. I will be interested when they actually go out there with ice axes and drills and show that something is really happening.

Michael Elliott
Reply to  Walter Sobchak
February 10, 2022 6:06 pm

Make a prediction, a guess , then call that guess a fact.

Then run that “fact” through a computer, add a mathematical formula, & Walla what do you have.

Yes that’s good enough to take to the IPCC to add to the 97 % already there.

Michael VK5ELL.

Terry
February 10, 2022 6:32 pm

Santa “may” exist and if he does he has the “potential” to bring us gifts. My God will this ever end?

Doonman
February 10, 2022 6:38 pm

…conducting more than $1 billion in research annually for government…

And there you have it. Science by computer models for sale.

February 10, 2022 8:01 pm

Using predictions based on mathematical and computational models”

They did not observe it.
They did not measure it.
They did speculate a lot, then went public with their fantasies.

Defund them!

Jit
February 11, 2022 12:45 am

A prediction: if you give a group of smart people a laboratory, computers and a salary and ask them to do research on something that might be dangerous… they will come back and tell you that yes, it is dangerous.

Perhaps a new survey of the literature is needed: what proportion of papers tell us that things are worse than we thought? 97%? Then we might as well just assume that everything is terrible and cut out the research.

I am too cynical, because we saw a few days ago with the effect of decreasing ocean pH on fish behaviour that there are still scientists out there with integrity.

cerescokid
February 11, 2022 3:50 am

Just like other papers addressing the same dynamics, no mention of warmer water being the problem, but rather intrusion of warm water. Only after they can demonstrate that this is a new phenomenon and they calculate the additional ice sheet loss from each 0.1C increase in OHC, will they be able to link it to AGW.

Joao Martins
February 11, 2022 4:42 am

The new study uses basic mathematical theory of fluid flow and large computer models (…) to make its predictions

Enough said.

Tom
February 11, 2022 5:11 am

“Kilometers of intrusion-induced basal melt can cause…”

I’ll have to admit that I’m only an engineer, and not a vaunted “post-doc” mathematician described here. However, one of the first things you learn at engineering school is that “water runs downhill”. I’ll admit that a few years of experience have tempered that ‘law’ with observations that it excludes capillary action and diffusion. Neither operate over regions of kilometers, however, especially when carrying enough warm BTUs of energy to melt a glacier. The water in the ‘estuaries’ described in the article is level with ocean, not uphill. Were I to be asked, I give a great thumbs down to the requested additional funding.

Bruce Cobb
February 11, 2022 5:26 am

We know this is happening because the new Climate Ice smells different.

Scott snell
February 11, 2022 6:01 am

Quite a stretch to call it “warm” seawater, when it’s likely a fraction of a degree of above freezing, and a fraction of a fraction of a degree warmer than the historical average. Numbers, please.

Scott snell
Reply to  Scott snell
February 11, 2022 6:04 am

And would someone please explain to me how a trickle of seawater isn’t frozen on contact with a block of ice millions of times more massive and 50 or 60 or 70 degrees colder.

Trying to Play Nice
Reply to  Scott snell
February 11, 2022 6:44 am

It’s fortified by CO2 so it constantly gets warmer and never can cool off. Hopefully I don’t need a /sarc off.

Trying to Play Nice
February 11, 2022 6:29 am

Al models. All garbage.

Bruce Cobb
February 11, 2022 6:34 am

If you see seawater seeping, say something.

Slowroll
February 11, 2022 8:46 am

“Models say, simulations say, predictions result….” I detect no intrusions of reality here. Never ruin a good theory with facts.

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