News Brief by Kip Hansen — 16 January 2024 — 1100 words/5 mins
Antarctic ice melt has been an ongoing scientific controversy for more than a decade. Oddly, the warring parties are all at the same U.S. Federal Agency. The war, which involved salvos of papers between the NASA’s GRACE Ice Mass team and H. Jay Zwally and his team.
Here’s the background:
The current NASA Vital Signs of the Planet web page [NASA’s climate crisis propaganda section] for Ice Sheets carries this message boldly across the top one third of the page:
In 2021, I wrote about this issue in Antarctic Ice Mass — Alternate Sources, which featured these two contrasting images (but not together):
Here is today’s Vital Signs Antarctic Ice Sheets graphic:
It is important to remember that both the NASA’s GRACE Ice Mass team and Zwally et al. use the same data sets to determine their estimates of losses and gains. The differing results are then an indication of the different approaches to interpretation of that data, which may include biases.
NASA’s climate.gov doesn’t quite agree with Zwally et al. yet. But the Vital Signs graphic is for “Antarctic Ice Mass in Gts” . . . and that total ice mass has been level since turn of the century, with a lot of variation.
Compare Zwally’s 2021 estimate of -12 GT a year with the GRACE figure of -137 GT a year (in the two panel image, on the right). Zwally’s runs through the end of 2016.
Don’t think for a moment that Jay Zwally is some kook on the shady fringes of NASA – he is one of their top flight scientists and led the 2003 ICESat mission. He presented one of NASA’s famed MANIAC talks in 2019. And he has firmly stated that his Antarctic Ice Mass work is not a repudiation of climate science—it is just solid evidence that Antarctic Ice Mass is not plummeting as the Climate Crisis Team claims. (One might rightly ask why, then, don’t the creators of the Vital Signs Ice Sheets page present his results alongside of those of the GRACE team.)
So what’s the news?
The news is that some clever scientists — Collin M. Schohn, Neal R. Iverson, Lucas K. Zoe , Jacob R. Fowler, and Natasha Morgan-Witts — had decided that instead of blindly following the long-standing formulas for glacier ice flow, maybe they ought to find out, using real experiments, if those formulas actually reflect what happens in the physical universe where glaciers, ice under pressure, are flowing and melting. It took them ten years.
The story is covered in this SciTechDaily article: Glacier Experts Uncover Critical Flaw in Sea-Level Rise Predictions.
Disclosure: I am not a glaciologist. I know next to nothing about the physics of ice melting under pressure. Therefore, I report only what SciTechDaily says.
The article is a press release from Iowa State University (the by line is theirs). It says:
“New research shows temperate glacier ice flows more steadily than previously thought, leading to lower projections of sea-level rise.
Neal Iverson started with two lessons in ice physics when asked to describe a research paper about glacier ice flow that has just been published by the journal Science.
First, said the distinguished professor emeritus of Iowa State University’s Department of the Earth, Atmosphere, and Climate, there are different types of ice within glaciers. Parts of glaciers are at their pressure-melting temperature and are soft and watery.
That temperate ice is like an ice cube left on a kitchen counter, with meltwater pooling between the ice and the countertop, he said. Temperate ice has been difficult to study and characterize.
Second, other parts of glaciers have cold, hard ice, like an ice cube still in the freezer. This is the kind of ice that has typically been studied and used as the basis of glacier flow models and forecasts.
The new research paper deals with the former, said Iverson, a paper co-author and project supervisor.”
The press release is about Iverson’s new paper Linear-viscous flow of temperate ice (Schohn et al. 2025). (paywalled and too new for my usual paywall-work-arounds).
“The paper describes lab experiments and the resulting data that suggest a standard value within the “empirical foundation of glacier flow modeling” – an equation known as Glen’s flow law, named after the late John W. Glen, a British ice physicist – should be changed for temperate ice. …. The new value when used in the flow law “will tend to predict increases in flow velocity that are much smaller in response to increased stresses caused by ice sheet shrinkage as the climate warms,” Iverson said. That would mean models will show less glacier flow into oceans and project less sea-level rise.”
How much less? Can’t read the paper, so I don’t know. [If anyone has access to the paper here, I’d love a copy].
But here is Iverson’s sketch of the experimental equipment which was all contained in a temperature-controlled freezer:
The press release further states:
“Resetting n to 1.0
Glen’s flow law is written as: ε ̇ = Aτn.
The equation relates the stress on ice, τ, to its rate of deformation, ε ̇, where A is a constant for a particular ice temperature. Results of the new experiments show that the value of the stress exponent, n, is 1.0 rather than the usually assigned value of 3 or 4.
The authors wrote, “For generations, based on Glen’s original experiments and many subsequent experiments mostly on cold ice (-2 degrees C and colder), the value of the stress exponent n in models has been taken to be 3.0.” (They also wrote that other studies of the “cold ice of ice sheets” have placed n higher yet, at 4.0.)”
Most of us might want to check the Wiki for an explanation of Glen’s Flow Law. The key is that the exponent n is just that, an exponent and not a mere multiplier. Thus, the call to re-set that exponent to “1” makes a rather huge difference.
The Bottom Line:
New research shows temperate glacier ice flows more steadily, linearly and not exponentially, contrary to our previous understanding, and this leads to far lower projections of future sea-level rise due to any glacier melt in Greenland and Antarctica.
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Author’ Comment:
We have to admire a group that spends ten years, working through all the failures and development, to discover something closer to the real-world truth about something as hard to measure as “glacier ice flow” – the flow of ice under tremendous pressures – and the melting that takes place.
Hopefully, we will see the findings translated into better, more reasonable and less hysterical projections of future sea level rise that might result from the melting of the glacier ice of Greenland and Antarctica.
Comments meant for me should begin with “Kip—“ or some such.
I can be reached by email at my first name at the domain i4.net.
Thanks for reading.
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I’m ‘out of the office’ until mid-morning Eastern time tomorrow — I’ll get to your comments then.
I seem to remember a graph in one of Willis’ articles comparing the estimated ice loss of Greenland’s glaciers, with the estimated amount of ice in those glaciers. The loss was microscopic in relation to the total mass. Equivalent to losing a few more skin cells each day than usual.
The overall theme around Al Gore’s Warming is, all change is bad. It’s even worse now that it can be measured and quantified without the basis for a baseline with any meaningful time frame.
You mean like this ? 🙂
Right. So Greenland has approx 2.6 quadrillion tons. And the annual loss is either 12 or 137 billion. Less than trivial.
Antarctic one is rather similar. 🙂
Antarctica total ice mass
24.4 million gigatons
Annual loss 150 gigatons
All ice gone in 160,000 years
If interglacial continues for 160,000 more years
(someone please check the math)
A gigaton is one billion tons
“Giga” in the metric system means one billion, so a gigaton is equal to one billion metric tons.
Like I said above, less than trivial. Essentially a rounding error.
The article came across my Google feeds and I was saving it for an open thread.
I agree with admiration for the group that stuck with the research and publishing anything that runs contrary to the Kool-aid/consensus.
“That would mean models will show less glacier flow into oceans and project less sea-level rise.”
But Iverson doesn’t seem to have done the modelling, so we don’t know how much less. There are 2 reasons to be sceptical:
First, Glen’s is an empirical Law, and has to fit observations. If the exponent is reduced, the multiplier A must rise.
Second, so the net effect will be a less steep stress gradient, but the stress difference is the same. The lubricated layer will be thicker. How much does that matter? The models will tell us.
I love the smell of desperation in the morning!
Kinky !!
I always flush & open the window. (:-))
We do know that general long-term sea level rise is somewhere around 2mm/year.
So we know that we are talking about totally trivial numbers.
At the top end of 137GT of ice that is 4.5 Penta Joules just to melt it from zero to water. I don’t care what model you show me to get that to exponentially increase is just ridiculous.
Leon ==> Remember, this is about ice flow under stress,under tremendous pressure, think at the bottom of a massive heavy glacier….
Eventually we might need some dykes.
No, that was L.A.’s problem. Too many dykes and not enough reservoirs,
Tsk Tsk….
I can see this is going to turn into an ongoing inside joke. But I think it’s going to be an appropriate response to a lot of things.
Yep, the forum seems to being flooded by dyke jokes.
No reality will tell you … models will say whatever you want them to say.
+ 100
“. . . Glen’s is an empirical Law . . . .”
All scientific laws are empirical.
“Glen’s is an empirical Law, and has to fit observations.”
You mean theoretical Laws don’t?
Scarecrow ==> They have made NEW observations, which call for a re-writing of Glen’s Law. That’s the whole point which some seem to miss.
Yes nick, they waisted 10 years doing experimental science when they could’ve just programmed a model to give them the desired results. Maybe you can help determine the desired results.
I believe the data is more likely to tell us than the models as the models only tell us what the writer of it wants to tell. Absolute sea level has been rising at a steady and currently unchanging rate of 1 to 2 mm/yr since before Abraham Lincoln was elected President. One USGS researcher even concluded from the study of coastal peat bogs and river sediments that it has been rising at this average rate, with lots of ups and downs, for the past 6,000 years! You can see sea level gauge data yourself Nick at PSMSL.org. Go to “The Battery” sea level gauge on the southern tip of Manhattan. Mounted on bedrock, its as good a gauge gets. And don’t forget to deduct from Relative Sea Level the rate at which Manhattan is sinking (about 1/2 the relative rate.) And yes, it is only one gauge but sea level does seek a common level and this gauge has been reading it for approaching 200 years. Or you could look at any other sea level gauge data from among the thousand or so shown on this site; The Battery being the longest record. And yes, there is a difference between Atlantic and Pacific sea level caused by consistent winds and currents which have seemingly been operating steadily for at least those 200 years. Thus, whatever the contribution to sea level rise from melting ice is, if any, has been steady for centuries. And yes, NASA’s satellite measurements of sea level show faster sea level rise rate surprisingly initiating exactly at the time their measurements began, but sea level gauges, thousands of them all across the world see it differently. Who to believe? The hysteria about sea level, promoted by climate change enthusiasts, including those in some Government agencies, is just one of many many phenomena twisted by the true believers into false predictions is leading to the currently common belief by all so many that the Government cannot be trusted, perhaps not on any subject at all.
Denis ==> Schohn et al. (including Iverson) only set out to discover, by actual experiment, how temperate ice flows under pressure — checking Glen’s Law by experiment. Audacious, yes. (How dare they!)
The idea, recognized by Schohn et al. in the abstract of their paper, and in the university’s Press Release, is because their experiment showed that Glen’s Law had to be modified, future projections of SLR would be substantially lower.
Nick ==> The Iverson/Schohn team are not ice modelers….The models might tell us something, at least maybe give us an idea, but the projected ice mass loss will be far less than previous projections using the corrected Glen’s Flow formula using the stress exponent of 1 instead of 3 or 4.
The point is that they have found that in more realistic physical experiments, the formula for Glen’s Law is incorrect because it was based on incorrect observation. Now,with the new experiments, they have found that empirical ice flow is linear…and the exponent in the original Glen’s Law should be 1, not 3.
If you have access to the full paper, you can fill us in on the details.
Models tell us nothing unless every single assumptions is identified and properly qualified by experimentation and measurement.
Models tell us nothing unless all tolerances and uncertainties are identified and properly quantified and propagated through the model.
Under normal circumstances I would agree the implemented equations need to close review, I am not sure that is a safe approach in this case.
typo s/b: need no close review.
You’re right. Therefore it has no real predictive power, especially when the state is outside of observations that have been made thus far.
Same for clouds in GCMs.
Nick ==> I have a copy of the paper I could email to you if you are interested. Let me know. My first name at the domain i4.net.
🤣🤣🤣
I am not sure there ever was a hysterical projection there are several made up AGW junk about it.
The numbers are basic sea level rises by around 200 foot (60m) if you melt all the ice. Now pick a time-frame that you think that is possible lets say 1000 years. So sea level would have to rise at 2.4 inches (60mm) per year to do that.
Its nothing like that current rate is 0.102 inch (2.6mm) per year so it would take 20000+ years to melt all the ice at current rate.
You can see the sort of time frames we are talking about and not sure anyone alive or there children has anything to worry about.
Leon ==> How many times have front pages of newspapers and magazine featured the Statue of Liberty half submerged….that’s hysterical.
It also makes a difference if it is glacial ice or sea ice. Melting sea ice does not change the sea level.
Whew! I am much relieved by this result. I have friends in Tampa, Houston, and Eureka. I was not looking forward to cleaning stuff out of the spare bedrooms for their displacement and arrival here.
Has the supposed Antarctic ice mass loss supposedly anything to do with the warming atmosphere attributed in part to the increasing well-mixed global CO2 concentration attributed in part at least to human CO2 emissions?
If so the pattern of the lower troposphere atmospheric temperature trend over Antarctica since 1979 is very puzzling.
Chris ==> There are a lot of climate-ish things that are puzzling –because there is so much that we (humans) simply do not yet understand [the alternate view is that we misunderstand them].
This news brief shows us that Glen’s Law, which has been used “forever” to project glacier ice flow (thus long-term melting) was simply incorrect.
Not puzzling at all
More CO2 causes a negative greenhouse effect for most of Antarctica because of the permanent temperature inversion. The exceptions are the small peninsula and two ice shelves affected by sea currents and underseas volcanoes There is zero risk of accelerating sea level rise from Antarctica ice melting. And that is 90% of all of Earth’s land ice. The melting of Antarctica is 99% hoax and1% reality.
This is good news! I’m only 2000 feet from the Atlantic and about the same from the ICW. As I’ve said before, I’d rather live 200 feet from the ocean but I can’t afford it.
Jim ==> I have been up and down the ICW many times — some sections are great. When we are in a hurry, or conditions are good (wind and waves), we go out and around.
It should be pointed out that no-one sane, who looks at actual real data, has ever “panicked” about sea level rise.
Only AGW-crazed modelling loonies do that.
bnice ==> Aw, come on now — be nice.
Grace is a gravity based measurement system
iirc, Zwally showed that East Antarctic ice mass was actually increasing..
… while the West Antarctic region directly over the major active volcanic area might have been losing mass.
Or was it moving magma that Grace was measuring.
bnice ==> Basically, Zwally et al. found that glacial ice loss was mostly offset by new snow->ice, making the total ice mass change near zero (give or take a dozen or so Gigatons).
I should have gone back and found the actual paper to get the comment correct. 🙂
bnice ==> There are papers that submit that ice loss over East Antarctica may be due to volcanism.
What i would like to know is where this sea level rise is supposed to be occurring. After all, we’re told relentlessly that all the ice melting in Greenland will swamp pacific islands but heaps of Greenland ice has already melted and the pacific islands are actually getting bigger and as I look out my window at the beach the water is where it’s always been. If the sea level is going to rise, it’s taking its damn time about it.
Tony ==> Humans are only interested in sea level where it hits land of interest to us. This is called Relative Sea Level (RSL). RSL is measured by Tide Gauges where the sea meets the land. It is different in every place it is measured because the land and the structure on which the tide gauge is mounted also move up and down.
But, all in all, when we look at all the tide gauges, and subtract that Vertical Land (and structure) movement, it appears that the seas are rising steadily across the last couple of centuries at about 2 or 3 mm per year.
There is no reason to believe that that situation is going to change.
Thanks, Kip. Subsequent to that, do we know what is causing this change? (I had initially asked a whole series of questions subsequent to the subsequent question, but I had so many that I bailed out, fearing that I would look like a total idiot.)
And Al Gore bought another ocean front mansion.
Nicely done, Kip!
Antarctica averages more than 40° below zero. A few degrees of warming won’t melt it. Because physics.
Zwally, et al. (2021) reported that Antarctica’s ice mass trend is −12 ±64 Gt/yr. That’s a fancy way of saying zero, because the confidence interval straddles zero. But even if the confidence interval were ±0, it still wouldn’t matter, because 12 Gt/year adds up to only 0.1 inch of sea-level rise per century.
Antarctica loses ice by sublimation, by gravity-driven ice flow onto floating ice sheets & consequent periodic iceberg calving, and by melting below the waterline. It gains ice by snowfall. The net sum of those processes is so close to zero that we don’t even know the sign.
GRACE gravimetry only measures gravity. So it cannot tell the difference between ice mass change and vertical land-motion beneath the ice sheets (GIA).
That’s a big problem for GRACE-based studies. When magma shifts as the Earth’s crust rises or sinks, perhaps due to changes in the loads upon it, it affects the Earth’s gravity field just like ice accumulating or diminishing does. So the GRACE-based studies must adjust their gravity measurements to account for GIA.
Unfortunately, GIA is not reliably measurable beneath ice sheets. So they use model-derived estimates of what they think GIA probably should be. But those models are not testable.
Altimetry-based studies are based on different evidence. They’re based on radar measurements of the surface height of the ice sheets. They’re also affected by GIA, but much less so than GRACE, because rock is nearly three times as dense as ice. So vertical land motion affects gravity readings much more than it affects altimetry readings.
Thus errors estimating GIA corrupt GRACE-based studies 3× as much as they corrupt altimetry-based studies. (OTOH, the altimeters also have challenges due to varying snow and ice densities, which don’t affect GRACE.)
The differences between altimetry-based studies (which reported Antarctica losing no ice, or even gaining small amounts of ice mass) and GRACE-based studies (which reported Antarctica losing small amounts of ice mass) offered clues to help correct the GIA estimates. That’s what Zwally’s team took advantage of, to reconcile the two lines of evidence.
Greenland is very different from Antarctica. It actually is losing ice, most years. The current average rate of Greenland ice loss is 200 to 250 Gt/year (depending on whose study you trust). At that rate, to lose all of Greenland Ice sheet would take 100 to 150…
…you thought I was going to say “years,” didn’t you?
No, not years.
Not decades, either.
Centuries. 100-150 centuries!
What’s more, Greenland’s ice loss is not detectably accelerating.
Nor is there any good reason to expect Greenland ice loss to significantly accelerate. We know that during the Medieval Warm Period Greenland was substantially warmer than it is now. (We know that because Norse settlers grew barley there, and the growing season is now too short for that; they also buried their dead is soil that is now permafrost.) Yet despite those warmer temperatures a millennium ago, there was not enough ice loss from the Greenland Ice Sheet to notably affect sea-level, elsewhere in the world. There’s nothing in the historical records to suggest that the MWP was accompanied by a worrisome surge in sea-level.
Dave ==> Thanks for giving readers a good backgrounder on Greenland (not the 51st state) and Antarctica ice sheets. Appreciated.
For readers who don’t know: Dave is the proprietor of the extremely informative web-based sea level resource:
SeaLevel.info
Were Greenland ice to melt, should we expect its bowl (or canoe) shape to be less via isostatic rebound? How might this impact the available space for the ocean?
John ==> Interesting question.Greenland is already moving upward – away from the center of the Earth – due to isostatic rebound. Too many other things would have to happen simultaneously to cause all of Greenland’s ice to melt that I would not be willing to make a guess.
Kip, there is a similar finding about sliding ice on land glaciers regarding Greenland ice sheet.
Researchers know that the small flows of water from surface melting are not the main way GIS loses ice in the summer. Neil Humphrey explains in this article from last year Nate Maier and Neil Humphrey Lead Team Discovering Ice is Sliding Toward Edges Off Greenland Ice Sheet
“There has been some debate as to whether ice flow along the edges of Greenland should be considered mostly deformation or mostly sliding,” Maier says. “This has to do with uncertainty of trying to calculate deformation motion using surface measurements alone. Our direct measurements of sliding- dominated motion, along with sliding measurements made by other research teams in Greenland, make a pretty compelling argument that no matter where you go along the edges of Greenland, you are likely to have a lot of sliding.”
The sliding ice does two things, Humphrey says. First, it allows the ice to slide into the ocean and make icebergs, which then float away. Two, the ice slides into lower, warmer climate, where it can melt faster.
While it may sound dire, Humphrey notes the entire Greenland Ice Sheet is 5,000 to 10,000 feet thick.
“In a really big melt year, the ice sheet might melt a few feet. It means Greenland is going to be there another 10,000 years,” Humphrey says. “So, it’s not the catastrophe the media is overhyping.”
Humphrey has been working in Greenland for the past 30 years and says the Greenland Ice Sheet has only melted 10 feet during that time span.
My Synopsis
https://rclutz.com/2020/08/21/greenland-ice-varies-dont-panic/
Ron ==> Thanks for the input and the references — including the link to you site. Always good to hear from you.
Everything you always wanted to know about the macro-scale motions of massive amounts of ice but were afraid to ask:
A. C. Fowler (2024) Glacier and ice sheet flow, Geophysical & Astrophysical Fluid Dynamics, 118:4, 251-386, DOI: 10.1080/03091929.2024.2346588. To link to this article: https://doi.org/10.1080/03091929.2024.2346588
M. Ranganathan, B. Minchew, A modified viscous flow law for natural glacier ice: Scaling from laboratories to ice sheets, Proc. Natl. Acad. Sci. U.S.A. 121 (23) e2309788121, https://doi.org/10.1073/pnas.2309788121 (2024).
The former is an extensive history to the max: n.b., ca. 200 equations and an uncountable number of literature citations.
The latter is a deep look into details of the motions and mathematics of that.
The Google, plain and Scholar, will find hundreds for you.
Dan ==> Thanks for the references And, yes, there has been many studies on glacial ice, sliding, melting, moving. The Schohn et al. experiment is, nonetheless, a new piece of the puzzle and potentially modifies much of that older work if based on Glen’s Law.
A big Thank You to a reader who has forwarded to me a full copy of Schohn et al.. This is very helpful and much appreciated.
You know who you are and can take credit here if you wish.
Thanks again.
How many university “chairs” can be attributed to the global warming scare?
Danley ==> Too many….
This is going to kill ticket sales for my SE Michigan ark
Richard ==> I like boats and have half-a-lifetime of experience. Let me know if you need a skipper.
Not long after WUWT was launched, I made 2 comments that stick in my mind.
First was the calculation of thousands of years for Greenland ice to melt, causing many other readers to say wow, why all the bother?
Second was a summary of tide gauge data plus a graph showing no change in a slow rate of rise over the last 6,000 years.
These matters should have moderated concern about sea level change in general, but alarmist comments abound. Put them in the class of “then a miracle happens” and get stuck into the many pseudo-scientists who believe in miracles. They are sick people, filling the receptive minds of our youngsters with drivel, causing Science to be disrespected and showing a lack of moral integrity by failing to confess that they were and are wrong.
As others have noted, the miracle bit makes parallels credible, climate change myths and religion. Geoff S
Geoff ==> The reasons that these odd views stick around have been exposed in these pages, and by philosophers of science for more than a decade.
My example today is that NASA Vital Signs only shows the GRACE Team Antarctic Ice Mass Loss graphic, despite the contrary data from one of their brightest scientists, H Jay Zwally, who once headed the ICESat team that gathers the data.
Gravimetry in earth sciences was shown to me by colleagues in mineral exploration in the 1970s. A major problem was the tiny size of the perturbation of the Earth gravity field caused by variations in rock density, tiny compared to the natural gravity field. Instruments had to be very sensitive, noise was a major enemy and interpretation was difficult because the rocks causing gravity signals were often unable to be sampled to measure their actual density. Often a density was assumed.
However, gravimetry was and is a valuable part of the tool kit and improvements and innovations are welcomed.
The use of gravimetry to model ice and basement rock properties is highly challenging. Same reason, tiny signal compared to ever-present natural Earth gravity. When used from a satellite base, there are extra complications from measurement of altitude above surface. In short, the real uncertainty of measurement is high. It might even be high enough at present to make some applications invalid. The credibility of a paper depends on honest uncertainty estimates. We are at a stage of development when Grace type work should continue, because there are some signs that it is useful, but scepticism about uncertainty estimates is prudent. Geoff S
A most interesting discussion – Carbonate rocks behave similarly under elevated temperatures and pressures and will flow.
With this discussion one of the most interesting omissions in all of this is the actual age profile of the ice itself at its various locations. For example, in the deep ice core holes we know that the age of the ice at the base can reach 1,000,000 years BP. However, the ice forming the glaciers and flows is much younger but by how much. No one seems to know or has done this mundane but most important work. Jeff Alberts’s comments below hint at this conundrum.