‘Problem of missing ice’ finally solved by movement of the earth’s crust

A new global ice sheet reconstruction for the past 80,000 years


Research News


During ice ages, the global mean sea level falls because large amounts sea water are stored in the form of huge continental glaciers. Until now, mathematical models of the last ice age could not reconcile the height of the sea level and the thickness of the glacier masses: the so-called Missing Ice Problem. With new calculations that take into account crustal, gravitational and rotational perturbation of the solid Earth, an international team of climate researchers has succeeded in resolving the discrepancy, among them Dr. Paolo Stocchi from the Royal Netherlands Institute for Sea Research (NIOZ). The study, now published in the journal Nature Communications, could significantly advance research into the climate of the past and help to make better sea-level predictions for the future.

Paolo Stocchi: “Our new reconstruction revolutionizes what we thought about the global continental ice mass during the Last Ice Age. The total mass of the Last Ice Age glaciers was 20% smaller and accumulated faster than previously thought.”

Growing and melting glaciers

With the alternation of ice ages and warm ages, the glaciers on Greenland, North America and Europe grow and shrink over the course of tens of thousands of years. The more water is stored in the form of ice, the less water there is in the oceans – and the lower the sea level. Climate researchers want to find out how much the glaciers could melt in the course of man-made climate change in the next centuries and how much the sea level will rise as a result. To do this, they look into the past. If one succeeds in understanding the growth and melting of the glaciers during the last ice and warm periods, then conclusions can be drawn for the future.

The “problem of the missing ice”

But this look into the past is difficult because the thickness of the glaciers and the height of the sea level can no longer be measured directly in retrospect. Climate researchers therefore have to laboriously collect clues that can be used to reconstruct the past. However, depending on which clues you collect, the results are different and seem to contradict one another. Previous models and calculations led to the so-called “missing ice” riddle. Geological evidence from ocean areas suggest that sea level might have been 120-140 m lower than today during the last Ice Age 20,000 years ago. The uncertainty of these data is quite large, though. To account for these low sea levels, as much as twice the current mass of the Greenland ice sheet would have to have been frozen worldwide. However, these glacier masses could not possibly have been that large at the time, according to climate models. Also, there is no geological evidence at higher latitudes for such a large mass of ice. How to explain then that the water wasn’t in the sea and at the same time it wasn’t stored in the freezer on land either?

80,000 years of ice sheets and sea level changes accurately reconstructed

This problem has now been solved with a new method by an international team of scientists led by Dr. Evan Gowan (Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, in Bremerhaven). Among them the geophysicist Dr Paolo Stocchi from The Royal Netherlands Institute for Sea Research. “We have found a way to accurately reconstruct the last 80,000 years of ice sheets and sea level changes,” says Dr. Paolo Stocchi, who has contributed to the creation of the novel global ice sheet model by including crustal, gravitational and rotational perturbation of the solid Earth. Their new model explains past local sea levels that are lower than today by incorporating the relative motion of the sea surface and Earth’s crust. In this way, past local sea levels that are much lower than today, can be modelled without requiring an unrealistically large global ice mass. The solid Earth motions would do the trick!

Understanding the behavior of glaciers by looking at the Earth’s mantle

With the new method, the scientists have eventually reconciled sea level and glacier mass: According to their calculations, the sea level must have been around 116 meters lower than today at the time. There is no discrepancy in terms of glacier mass. Unlike the previous global model, the team took a closer look at the geological conditions in the proximity and underneath the formerly glaciated areas, and not in the far-field ocean areas: How steep were the mountain slopes? Where did glaciers reach the sea? Did friction interfere with ice flow velocity? And how much? The new model includes all these local factors. It also accounts for ice- and water-load-induced crustal deformations. The latter are important because they alter the topography of the land, thus affecting the ice flow and eventually the volume of glaciers. “Crustal deformations are regulated by solid Earth physical parameters such as viscosity,” says Paolo Stocchi. The Earth’s mantle, in fact, behaves like a highly viscous fluid on geological time scales and deforms under the weight of a fluctuating ice mass. “By assuming different viscosities of the earth’s mantle, we model different evolutions of the land topography, which then result in different scenarios for the ice masses.” These can now be brought into harmony with the marine geological evidence from the ocean areas, without the need for extra mass.

The established isotope model needs to be revised

The technical article by Evan Gowan and his team takes a critical look at the method for estimating glacier masses that has been the standard in science for many years: the method of measuring oxygen isotopes. Isotopes are atoms of the same element that differ in the number of their neutrons and therefore have different weights. For example, there is the lighter 16O isotope and the heavier 18O isotope of oxygen. The theory says that the light 16O evaporates from the sea and the heavy 18O remains in the water. Accordingly, during ice ages, when large mainland glaciers form and the amount of water in the sea decreases, the 18O concentration in the oceans must increase. But as it turns out, this established method results in discrepancies when it comes to reconciling sea level and glacier mass for the time 20,000 years ago and before.

“The isotope model has been used widely for years to determine the volume of ice in glaciers up to many millions of years before our time. Our work now raises doubts about the reliability of this method,” says Paolo Stocchi. His goal now is to use the new model to quantify the current rates of crustal deformation in the North Sea and Wadden Sea, thus revealing the actual contribution of current climate change to the regional relative sea-level changes.


From EurekAlert!

3.4 15 votes
Article Rating
Newest Most Voted
Inline Feedbacks
View all comments
Richard (the cynical one)
February 23, 2021 10:17 pm

Sounds like modelling works, sort of, and the closer the model’s assumptions are to reality, the more accurate the conclusions. So for something as incredibly complex as our earths climate, the understanding of all the interwoven factors is what? maybe getting close to 1%, erring on the side of generous. (Any higher would be extreme hubris, and the Greek tragedies model the results of that!) So the near 100% prediction failure rate is pretty good, considering.

Reply to  Richard (the cynical one)
February 24, 2021 5:11 am

“the near 100% prediction failure rate is pretty good” – that is one of the clearest succinct statements about climate models that I have seen. And it makes it easy to understand the statement in the article: “these glacier masses could not possibly have been that large at the time, according to climate models”. The models have near 100% prediction failure rate, so of course they are wrong about this too. This never was a climate problem to be solved, it was only ever a climate model problem. Trouble is, they’ve used dumb fixes and the models are now worse than they were before. Still 100% or near 100% failure rate, of course, but the failures are getting larger.

Bill Capron
Reply to  Mike Jonas
February 24, 2021 7:55 am

Climate alarmists are so invested in their models that every failure must be debunked … I don’t recall who said it, but the alarmists aren’t close enough to the truth to be just wrong.

Walter Sobchak
Reply to  Richard (the cynical one)
February 24, 2021 2:51 pm

As John von Neumann said: “With four parameters I can fit an elephant, and with five I can make him wiggle his trunk”.

February 23, 2021 10:50 pm

“The total mass of the Last Ice Age glaciers was 20% smaller and accumulated faster than previously thought.”

So are they saying that the sea levels during the height of Pleistocene did not fall nearly 400 feet? Are they implying that on the geologic time scale the Pleistocene started earlier and the Pliocene ended earlier?

Reply to  rah
February 23, 2021 11:57 pm

100 metres, close enough?

Reply to  Chaswarnertoo
February 23, 2021 11:59 pm


Reply to  Chaswarnertoo
February 24, 2021 12:21 am

They state 120-140m , then under cut lower limit.

“The total mass of the Last Ice Age glaciers was 20% smaller and accumulated faster than previously thought.”

So apparently they have no proxy of what ice volume was, beyond inference from sea level. They have no constraints on how quickly it accumulated and are free to fudge around with mantle viscosity almost at will.

Well I’m sure Van Neumann could get Greenland to wiggle its toosh with that many unconstrained parameters.

Reply to  Greg
February 24, 2021 7:58 am

Aren’t there actual measurements of how low the sea level was during the glacial period? So this paper says that the measurements are wrong?

Clyde Spencer
Reply to  AnonyMoose
February 24, 2021 10:33 am

Empirical evidence is of no importance in modeling. As in the classic sarcasm, “Don’t confuse me with facts. My mind is made up.”

Reply to  rah
February 24, 2021 10:24 am

the sea level must have been around 116 meters lower than today at the time.”

From metricconversions.org:
“116m= 380 feet 6.9 inches”

From the missing ice researcher’s fantasy above where they claim the ice volume is 20% smaller and resulting sea level substantially higher.
Sea level that is 20% lower @ 116 meters, suggests original estimated drops of sea level is roughly 145 meters or 475 feet.

Giving a sea level drop of 380 feet to 475 feet.

It is interesting they do nor reference any of the sea level coastal markers giving the original estimates of sea level drop.

Instead they make statements that they believe their model results over observations as exemplified by:

Paolo Stocchi: “Our new reconstruction revolutionizes what we thought about the global continental ice mass during the Last Ice Age. The total mass of the Last Ice Age glaciers was 20% smaller and accumulated faster than previously thought.”

Reply to  rah
February 26, 2021 7:23 pm

 “By assuming different viscosities of the earth’s mantle, we model different evolutions of the land topography, which then result in different scenarios for the ice masses.”

They are saying the continents rode higher and the ocean basins lower in a sort of reverse isostacy. This sort of thing has been implicated in the extremely low apparent sea levels in the late permian.

February 23, 2021 11:12 pm

Isn’t it wonderful, in this day and age, when over half the world cannot get proper food, the climastrologists have the money to waste on measuring fairy droppings? But then again, science is about interesting, not useful. I believe Tesla paid for his own toys, though…

Reply to  paranoid goy
February 23, 2021 11:57 pm

Half the world cannot get food? Evidence?

Ewin Barnett
Reply to  Chaswarnertoo
February 24, 2021 2:24 am

Meaning the high fat western diet. Pizza Hut, Taco Bell and KFC are not yet everywhere.

Reply to  paranoid goy
February 24, 2021 12:06 am

William Faulkner once said “History is not what was but what is”. I believe that to be the case for not only human history but Natural History also. An accurate portrayal of what has happened before is a key for understanding what is to come and possibly essential for surviving it.

So I do not believe it to be a waste when anyone honestly works to figure out what has happened before.

Reply to  rah
February 24, 2021 12:54 am

Well put. There are questions about sea-level/ice mass that we need answered so if these guys have come up with a way of better reconciling the two then I don’t see how anyone could object to that. Unless you didn’t want to know the answers I suppose.

Reply to  Loydo
February 24, 2021 2:08 am

“There are questions about sea-level/ice mass that we need answered”


Like…… “Why is there SO MUCH MORE ARCTIC SEA ICE now, than there has been for most of the last 10,000 years.

The implication is that we are in a rather COOL period of the Holocene..

Wouldn’t you agree. !

Reply to  fred250
February 24, 2021 2:06 pm

It turns out that even knowing some what some would consider trivial history can be a very good thing.
I suspect everyone here has read or heard about what Coca-Cola has been doing to assert that it is properly “woke”.

Well it turns out Coca-Cola was created by John Pemberton, a Confederate veteran of the Civil War who once owned slaves. IOW a “racist”! Though neither that word or the concept behind it existed back then, that doesn’t matter as we have learned from those that are now “woke”. The Company name is forever stained by this fact!

And since the Coca-Cola Board of Director is requiring all of it’s white employees to attend training in which they are telling their white employees to “try and act less white”, the management must change the company name or be exposed as the fakes they are. 

And then there are all the restaurant chains that have instituted their own programs of “wokeness” and yet still service Coca-Cola! They too will be exposed for the Charlatans they are unless they drop Coke if it doesn’t change it’s name.  

Yes. knowing a little history can be a very good thing and it seems that “counter culture” and “wokeness” can have a price. A very high one for some.

Reply to  Loydo
February 24, 2021 2:33 am

“Climate researchers want to find out how much the glaciers could melt in the course of man-made climate change in the next centuries and how much the sea level will rise as a result.”

Until you know how much climate change is natural and how much us man-made then everything else is just a guess. Just more useless models.

Reply to  JeffC
February 24, 2021 2:43 am

Man-made weather change is mostly restricted to large urban areas.

This DOES NOT affect sea ice in the Arctic.

Reply to  fred250
February 24, 2021 5:03 am

The most pervasive temperature anomalies are in the polar circles that drive up the satellite global temp. . Time and again when I look at the maps I see red over one or both poles while the temperate and tropical regions appear average or even a bit cooler than average. Joe Bastardi shows the maps which show that pattern all the time.

Bruce Friesen
Reply to  Loydo
February 24, 2021 9:57 am

Loydo, a serious question. You state “There are questions about sea-level/ice mass that we need answered.” My question “Why”?

I live in a small beach community. If there is a rapid rise in sea level, my community will be affected. Either new houses will be built on higher foundations, or the community will be abandoned.

My contention is that decision will be based on local trends (sea level is local, within a global average). And the rise will be spread over several lifespans of the average house. Therefore, my contention is a prediction of global sea level a hundred years from now is not a core data point.

Do you have a counter argument?

Clyde Spencer
Reply to  Bruce Friesen
February 24, 2021 10:48 am

Surely you aren’t arguing in favor of ignorance about things just because there isn’t a ‘good reason’ to study something! While applied research is often a response to a perceived need, basic research is often pursued just because someone finds it interesting. And yet, often that basic research has found applications in applied research.

It is one of the modern problems with science that ‘Big Science’ needs the level of funding that only governments can supply. Being accountable to tax payers, legislators are reluctant to provide research money for “pie in the sky” research that might lead to a Golden Fleece award. So, it is the ‘need’ mentality that is responsible for climate researchers to exaggerate the severity of potential problems. We would probably be better off in the long term if a fixed amount of money were made available for researchers for basic research, except for problems where time is of the essence, as in developing a new vaccine or controlled thermonuclear energy.

Reply to  Loydo
February 24, 2021 6:47 pm

In the end: who cares? Their grasping at straws to drum up scenarios to scare people into believing in the climate emergency bullshit, like rising water levels drowning cities and islands – currently only 1.5mm/yr or 12cm by 2100. Ancient Rome’s port is way above the current sea level, so we’re not even up to the temps back then, co2 notwithstanding. Knowledge of history and a firm grasp of logic are your friends.

David A
Reply to  rah
February 24, 2021 3:25 am

Rah, I agree, although claims of “Mystery of missing Ice Solved” may be a bit grandiose, as there are numerous admitted assumptions in their hypothesis.

Yet repeated cycles of glaciation are an interesting puzzle, particularly cogent as we are near a projected end of the current interglacial. So some thoughts…

“Harvard researched the interrelationship between historical increases in land based volcanic activity and the end of ice ages. They limited the scope of their research to land-based volcanoes and land-based glacial ice sheets. The data showed that the end of ice ages, when glacial ice sheets rapidly began to melt / retreat, coincided with dramatic increases in land-based volcanic activity. Based on this information, Harvard theorized that atmospheric warming occurred first and was therefore the root cause of deglaciation. Worked like this:

1. The atmosphere was suddenly and somehow warmed by an unknown energy source.
2. This warmed atmosphere acted to dramatically melt / thin worldwide glacial ice sheets.
3. Thinned ice sheets reduced overburden pressure on previously ice sheet buried land volcanoes effectively “uncorking” / activating them. The uncorked volcanoes spewed huge amounts of CO2 and heat into the atmosphere which acted to further increase atmospheric warming.
Result? End of an ice age period’
( Many ? On the last, no indication CO2 led any part of the atmospheric warming)

Lamont- Doherty study interrelated this way…
“1. When an unknown energy source suddenly and somehow warmed the atmosphere, glacial ice sheets were melted.
2. Large amount of melt water acted to dramatically raise sea levels.
Higher sea levels increased downward pressure on sub-oceanic volcanoes, which acted to “cork” / deactivate sub-oceanic volcanoes.
3. Conversely, when the unknown energy source suddenly and somehow turned off the atmosphere cooled.
4. Cooler atmospheric temperatures acted to rebuild worldwide ice sheets and in the process steal water from the oceans.
5. As sea levels dropped, less pressure on sub-oceanic volcanoes acted to “uncork” / activate deep ocean volcanoes. These volcanoes began spewing CO2 and heat into the ocean.
According to Lamont-Doherty the result of this complex series of events fits well with the Harvard research.

My thoughts vary, yet follow somewhat along these lines…

In the depth of an ice age, geothermal on land is suppressed ( it still occurs, but at a reduced level) by the pressure of massive ice sheets, and geo thermal in the oceans is perhaps released by lower sea levels, and therefore reduced pressure ( not a great deal but an average gradual increase in geo thermal to the oceans, also affected by changes in the Earth’s axial rotation or its solar orbit which may put stress on the planet’s crust, inducing global increases and at times decreases in continental and sub-oceanic volcanic activity (Milankovitch Cycles)

This change of geothermal release points from oceans to land and vice versa may also altar magna flow underneath the crust.

Also the heat loss of the oceans would likely be reduced by far larger sea ice sheets. The oceans, like the atmosphere, release more of their warmth further poleward. If that heat is somewhat restricted by large ice caps, and lower oceans in conjunction with suppressed land geothermal leads to greater geothermal to the oceans and reduced heat loss, possibly further reduced by slower ocean currents, the oceans could undergo a very gradual warming. This gradual ocean warming may be further increased by reduced cloud cover associated with a colder atmosphere, allowing more tropical and subtropical sunshine over the non ice capped global oceans.

The combination,
1. Somewhat suppressed land geo thermal and increased ocean geothermal, ultimately further increased by changes in mantle viscosity flow…
2. Possibly reduced ocean current velocity leading to increased residence time of energy in the oceans
3. Increased solar insolation into the oceans slowly absorbed to depth by the thermohaline current.
4. Reduced ocean heat loss via greatly increased insulating sea ice caps, further increasing the warmth of the thermohaline current taking solar insolation to depth.

All leads to a slowly warming ocean while the atmosphere stays very cool due to Milankovitch Cycles, greatly increased albedo, and the solar energy over the oceans stealing, for a time, that energy from the atmosphere, as the oceans absorb that energy and can’t release it back to the atmosphere as quickly due to expanded poleward ice caps.

The oceans are capable of holding and hiding from the atmosphere immense heat.
If that heat slowly builds and builds, and other factors like Milankovitch cycles harmonise said increase, the warmed oceans could possibly induced a rapid large scale melting of the global oceans sea ice caps, releasing immense heat into the atmosphere. This could be the energy source missing in the Harvard studies.

Thus an interglacial is born, and you have geological reports if immensely warmer waters off Greenland etc…
And you then see a gradual release of said ocean heat over the duration of the interglacial, each ocean release coming in cycles, leading to the warming periods we see over the last 18 k years or so, each warm period cooler then the last, until the oceans have cooled enough, and the Milankovitch cycles harmonises with the cooler oceans, and volcanism slightly suppressed within the oceans, and reduced ocean uptake of solar, all lead to the oceans cooling enough to kick start the next glaciation period.

So, in my conjecture, the oceans are both the heat trigger and cooling factor for both ending and beginning ice age interglacial periods.

Well, nothing wrong with speculation…

Reply to  David A
February 24, 2021 5:49 am

You may want to think how the Sun plays into this. Everyone is looking at TSI being relatively constant, but in fact the wavelengths the Sun puts out during solar cycles vary and have impacts primarily to O3 in the upper atmosphere and the amount of heat absorption into the ocean itself.

Additionally the cycles effect the number of cosmic rays hitting the Earth which effects cloud cover and even magma. And you have the solar wind and CME’s ebbing and flowing which change the electrical components of the atmosphere, deliver energy to Earth and effect weather systems.

And the last thing to consider is the Earth’s magnetic field gaining and losing strength and allowing the electrical energy from the Sun to affect the Earth in different ways.

I’m not sure why the electrical relationship between the Sun and the Earth is never part of the equation when trying to figure out anything climate. Maybe in the next decade a light bulb might go off (no pun intended) on some of these “climate scientists” when they realize just how much energy comes into the Earth from plasma and solar particles. They only have to look at the amount of energy the Carrington Event put into the Earth to see geomagnetic storms do matter.

Clyde Spencer
Reply to  rbabcock
February 24, 2021 11:10 am

Perhaps you could expound on the “electrical relationship” you mentioned. Just what do you mean by that nebulous expression? Are you suggesting that the stream of charged particles from the sun, which is deflected by our magnetosphere, is a significant fraction of the electromagnetic output of our friendly luminous neighbor? Willis says he can find no relationship between the 11-year solar cycle and Earth temperatures.

David A
Reply to  rbabcock
February 24, 2021 9:06 pm

Thanks rbabcock. Yes, I agree the amount of TSI absorbed at the surface into the oceans is an interesting subject. AFAICT nobody knows the ocean residence time of disparate solar wavelength, or how much heat is gained or lost by multi decadal changes in solar cycles. And yes, although total TSI changes only a little, different wavelengths of insolation change to a much greater degree, and thus certainly affects the ocean heat content.

Climate is literally the sum many dozens of different factors exhibiting various length cycles sometimes harmonizing with each other, sometimes inducing negative feedback. An illustration of several dozen teeter – todders of different sizes moving up and down at very different speeds is perhaps illustrative. When enough of them reach the top at a certain time, warming occurs, when enough reach the bottom at the same time, strong cooling occurs.

This helps explain why no single factor is dominate at all time scales. Yet it is undeniably logical that the Sun, as the primary heat source and a variable source it is, and variable ocean heat content, containing at least 1000 times more energy than the atmosphere, are the primary drivers of atmospheric energy.

Reply to  David A
February 24, 2021 10:34 am

If sea level is 120 m lower would that change atmospheric pressure on the sea surface or would the atmosphere as a whole just drop 100 m lowering the temperature at any height by 0’4 ºC. So Mount Everest will be 120 m higher compared to sea level and 100 m higher compared to surface pressure.

David A
Reply to  Robertvd
February 24, 2021 9:11 pm

Hum? My guess is the ladder, the total atmosphere volume would remain about the same, as well as the lapse rate, and so the snow line would effectively lower about 400′

Clyde Spencer
Reply to  David A
February 24, 2021 11:00 am

You opined, “… geo thermal in the oceans is perhaps released by lower sea levels, and therefore reduced pressure …”

It would seem that the majority of the new heat introduced to the ocean bottoms comes from mid-ocean spreading centers. That is lateral movement produced by convection cells in the upper mantle. I don’t see how water pressure is going to be effective in preventing lateral movement of mafic plates, and creating tension cracks that allow magma to rise.

In places like Hawaii, volcanic vents are above sea level and aren’t really strongly influenced by water depth, rocks being roughly three times as dense as water.

David A
Reply to  Clyde Spencer
February 24, 2021 2:04 pm

Yes,400 feet of ocean would be a minor release of pressure at best. However, beyond the mid ocean ridges there are many thousands of likely active below surface volcanoes, many over 2500 high and still beneath a couple thousand feet of water. https://www.iceagenow.info/many-ten-million-underwater-volcanoes/

Yet the land suppression is more intense with glacial ice sheets 4k thick covering much of North America and part of the ROW.

The mantle is obviously very global, so increased resistance in one area, land, and less resistance in another, the ocean floor, could conceivably increase ocean volcanism and affect mantle motion direction. Over 1000 years this may be minor. Yet we have tens of thousands of years for this process to take affect.

Energy is never lost. Also the increased polar IceCaps actually have a net insulation affect on ocean release of energy. Increased residence time within the oceans alone would increase the heat content of the oceans. As to the thermohaline current, if the sub polar IceCaps ocean waters actually warm a bit, this current could slow, again increasing residence time of ocean energy content.

Reply to  rah
February 24, 2021 7:45 am

So I do not believe it to be a waste when anyone honestly works to figure out what has happened before.

Nice belief, except trusting this or any “model” out of academia nowadays is naive & gullible. Everything out of academia has become political, especially “science”.

Reply to  beng135
February 24, 2021 8:32 am

I did not say I trust their model. I did say that I believe their effort to be honest. There was once a time when I rejected any study that used “Climate Change” in it’s title or abstract. But I have come to realize even honest scientists desiring to have their research funded must do so in order to gain and sustain funding.

My “belief” is one backed by the repeated cycles as revealed in our study of history. Repeated ice ages with repeated glaciations for example. In human history in science it seems to me we are repeating in some ways the times of the first great astronomers who’s claims of a heliocentric solar system were quashed by the powers that be. I could outline other cycles but those are some examples.

Reply to  paranoid goy
February 24, 2021 7:06 am
Reply to  paranoid goy
February 24, 2021 6:33 pm

I don’t know why you were down voted, but you are right on! Billions of $ being sucked into renewable subsidies, making electricity ever more expensive; and modelling of chaotic processes that really can’t be modelled – all money wasted when there are much better excuses for taxing people to death.

February 23, 2021 11:39 pm

The ice fields in NWT of Canada must have been massive to show such smooth evidence of movement over the granite.

Nicholas McGinley
Reply to  frank
February 24, 2021 11:07 am

How about to carve out the Great Lakes?
What has long been “known” about the particulars of the ice ages has been gleaned over long periods of time by geologists, and not working from models or hunches or WAGs.
Do questions remain?
Doubtlessly they do.
Are the people that have given us the wonderful world of “climate science” the ones who will answer them?
I sincerely doubt it.
True to form, the first thing they do is throw out any information that does not conform to what they intend to “prove”.

Barney Fife from Fife, WA
February 23, 2021 11:50 pm

This looks like Garbage in -Garbage out to me…

The only model I trust is a super model & I trust her as far as I can throw her…

Reply to  Barney Fife from Fife, WA
February 24, 2021 3:57 am

The only model I trust is a super model & I trust her as far as I can throw her…

You can obviously throw her some way, since she is very skinny…

Reply to  Barney Fife from Fife, WA
February 24, 2021 6:49 am

Perhaps your trust in super models is influenced by related softwear and hardwear.

Reply to  eyesonu
February 24, 2021 7:47 am

Or underwear.

Reply to  eyesonu
February 24, 2021 8:07 pm


Reply to  KAT
February 27, 2021 6:10 pm

He just made you say “under where”!!

February 23, 2021 11:55 pm

The point of this research, announced in this amateurish press release, is contained in the last sentence “thus revealing the actual contribution of current climate change to the regional relative sea-level changes.” This was, no doubt, the original goal as stated in the grant funding request.
Models are software, and as such, can not be independently verified without complete access by a disinterested third party and peer validation.
None of the claims in this article are cited or labeled as confirmed. Even the title asserts the existence of an incomplete hypothesis, that there is a missing unknown ice mass burden in the calculation of geophysical rebound after the end of the ice age.
Even if we stipulat that a reasonable person should “believe” scientists in most circumstances, no reasonable adult should trust the work of media flaks or science journalsts without a lot of verification.

February 24, 2021 12:13 am

“By assuming different viscosities of the earth’s mantle, we model different evolutions of the land topography, which then result in different scenarios for the ice masses.” These can now be brought into harmony with the marine geological evidence from the ocean areas, without the need for extra mass.”

Yet more fiddle factors and tweaking of unconstrained parameters. “Assuming ” convenient values.

This then morphs into being “accurate”.

80,000 years of ice sheets and sea level changes accurately reconstructed

Clyde Spencer
Reply to  Greg
February 24, 2021 11:14 am

It is a legitimate approach to allow a variable of uncertain value to take on different reasonable estimates to see how it is constrained by empirical measurements.

February 24, 2021 1:05 am

 However, these glacier masses could not possibly have been that large at the time, according to climate models”

Climate models?

Reply to  mwhite
February 24, 2021 2:40 am

Yes, that had my GIGO meter twitching as well!

Nicholas McGinley
Reply to  Newminster
February 24, 2021 11:14 am

My GIGO meter is in the shop, but I can tell you that my bullshitometer was pegged to the pinstop from the first word of this to the last.
My lameometer is flat out wrecked.

Philip Mulholland
February 24, 2021 1:10 am

It almost looks like these researchers have just discovered Isostacy.

Reply to  Philip Mulholland
February 24, 2021 6:09 am

Isostasy you mean.

Philip Mulholland
Reply to  tty
February 25, 2021 2:23 pm

That two.

Nicholas McGinley
Reply to  Philip Mulholland
February 24, 2021 11:16 am

I hope you were laughing when you called these people “researchers”.

Philip Mulholland
Reply to  Nicholas McGinley
February 25, 2021 2:25 pm

I was trying to be polite.

Philip Mulholland
Reply to  Philip Mulholland
February 25, 2021 2:42 pm

I was probably thinking of idiocy.

Ben Vorlich
February 24, 2021 1:22 am

This is vaguely Off Topic.

Is there any data on how the salinity of the remaining ocean is affected? Then how is sealife affected by rapid changes in salinity? As a supplementary how does ocean pH change when the world changes between glacial and interglacial conditions?

Reply to  Ben Vorlich
February 24, 2021 2:53 am

The rapid change in salinity wipes out all life in the oceans, just like a 1C degree change does. That’s why we see life dying out on the planet over and over again every 120,000 years or so, then of course life springs back into existence and everything starts over again.

Sarc off now

Reply to  Ben Vorlich
February 24, 2021 5:39 am

Salinity increases by about 3,5 % and pH becomes slightly higher (less CO2, more salt)

Reply to  tty
February 24, 2021 10:55 am

And species sensitive to higher salinity will move further up estuaries and fresh water influxes.

For the rest, a 3.5% salinity change is well within normal fluctuations for salt water life.

From https://lotusarise.com/salinity-of-ocean-water-upsc/;

“The salinity for normal open ocean ranges between 33 and 37″ ppt (parts per thousand).

A 10% range of fluctuation. Which doesn’t include the higher salinity levels of the Persian Gulf, Red Sea, Mediterranean, etc.

Yup, just like a 1 degree C temperature change, higher salinity levels are perfectly normal fluctuations in life and life takes no harm nor withers from them.

Stephen Philbrick
Reply to  ATheoK
February 24, 2021 1:15 pm

I asked this question down-thread before noticing it had already been answered. Thanks.

Nicholas McGinley
Reply to  tty
February 24, 2021 11:18 am

Heck, I’ve known women that get saltier than that when I switch off the bedroom ceiling fan.

Reply to  Ben Vorlich
February 24, 2021 7:44 am

Dropping sea levels by even 400 meters is a pretty small drop in total ocean volume. The affect on salinity will be minor.

Nicholas McGinley
Reply to  MarkW
February 24, 2021 11:22 am

I think somewhere along the line, someone has mixed up meters and feet.
Holocene sea level rise since the last glacial maximum is thought to be on the order of 130 meters.
400 meters is over 1200 feet.

Ed Zuiderwijk
February 24, 2021 2:10 am

The authors would be wise to avoid usage of the word ‘trick’. It has distinct negative conotations when used in anything related to climate.

Ron Long
February 24, 2021 2:13 am

It appears to me that the report uses the term “ice age” when they should use “intra-glacial cycle”. The earth has been in an Ice Age for close to 5 million years, with around 90,000 years intra-glacial and 10,000 years inter-glacial. We are in the Geologic Time known as the Holocene, which starts at the end of the last intra-glacial cycle.

So, they discovered 116 meters of lower sea level during the last intra-glacial cycle. I wonder if they found 40 meters higher sea level during the Holocene Thermal Maximum? Big problem with this study, which is obviously biased toward “send more research money”.

Robert W Turner
Reply to  Ron Long
February 24, 2021 6:26 am

Indeed. Any Earth scientist that cannot properly communicate the difference between ice age and glacial/interglacial should be sent back to Geology 101 at a community college. When you miscommunicate the basic terminology, as if people are too dumb to understand the difference, then you become part of the problem and exacerbate the comic book science prominent in our society today.

Nicholas McGinley
Reply to  Robert W Turner
February 24, 2021 11:44 am

I agree that the accepted terminology is interglacial.
A glacial is defined as a period of advancing ice and colder temperatures within an ice age, lasting many thousands of years.
There are short periods of advancing and retreating ice referred to as stadials and interstadials.
Although it should also be noted that not everyone would agree with the above.
Some people use the words stadial and interglacial more or less interchangeably.

I also feel compelled to point out that most texts define the beginning of the current ice age, called the Quaternary Glaciation, at around 2.58 million years ago.
Not to put too fine a point on it, but this definition is itself incomplete.
The Quaternary is thought to be merely the most recent phase of an ice age that began about 34 million years ago, called the Late Cenozoic Ice Age.
This is defined as such because it is thought to be when the ice sheet began to form on Antarctica.

And also it should be noted that the two most recent glacial periods have been more like 125,000 years long or so, IIRC.

Geoff Sherrington
February 24, 2021 3:27 am

A decade ago I blogged on WUWT and Climate Etc that it was unscientific to assume that the ocean basins were of fixed volume, as small tectonic movement could explain some of the tiny current measured rise in sea level. It surprised me not that we now see this paper modelling related parameters.
CO2 does not cause every anomalous measurement in clmate research.
Geoff S

Ron Long
Reply to  Geoff Sherrington
February 24, 2021 4:49 am

Good comment, Geoff. Another factor of the ocean basins is that creeks and rivers are trying their best to remove mountains and deposit the eroded fraction in the ocean basins. There are other factors, of course, and the topic is very complex and not well documented.

Clyde Spencer
Reply to  Geoff Sherrington
February 24, 2021 11:25 am

Yes, it is well known that the land area was depressed by the weight of the continental glaciers, and is even now still rebounding in the absence of the ice.

Yet, rarely is anything said about how the ocean basins respond to changes in the water volumes. It seems that the unstated assumption is that the basin volumes are fixed and the only response is for sea level to change. Because mantle material is very viscous, there is undoubtedly a significant time lag for adjustment. However, I suspect that eventually the mantle will accommodate the increased volume of water by being depressed in proportion to the depth of the water, thus increasing the basin volume and decreasing sea level.

February 24, 2021 4:10 am

“We have found a way to accurately reconstruct the last 80,000 years of ice sheets and sea level changes,”

Ermm… How do you know it’s accurate? Checked against what?

February 24, 2021 4:25 am

There’s a giant cocktail party going on somewhere.
Who forgot the ice?
If you know the answer to that, you are OLD.

Reply to  bluecat57
February 24, 2021 5:26 pm

I’m barely double digits. What’s the answer?

Reply to  Derge
February 24, 2021 7:02 pm

The party is over. Who forgot the ice? is from a TV commercial for one of the first in freezer consumer ice makers.
I couldn’t find a video or even reference to it, but Frigidaire introduced an in-door ice maker in 1965. That’s where the term “Frig” comes from too.

February 24, 2021 4:33 am

Two Greenlands seems too little to account for the continental ice sheets and glaciers of the Last Glacial Maximum.

Reply to  John Tillman
February 24, 2021 5:41 am

Indeed, it was more like 20. Some idiot communications specialist misunderstood things as usual.

Reply to  John Tillman
February 24, 2021 10:14 am

Continental, that’s the word I missed when I posted about the NWT ice fields Love to hear the professionals weigh in about a paper like this. Like a mini geology 101 course..Pick the view point you like.

Nicholas McGinley
Reply to  John Tillman
February 24, 2021 11:57 am

Yup…Greenland melting would only raise sea level by about 20 feet. 17-23 by most estimates.
Volume of Greenland ice sheet: 2.85 million cubic kilometers.
Volume of Antarctic Ice Sheet: 26.5 million cubic kilometers
Volume of additional ice at last glacial maximum: 52 million cubic kilometers

Nicholas McGinley
Reply to  Nicholas McGinley
February 24, 2021 11:58 am

Note that these are reference values…I am not swearing to them.

February 24, 2021 4:39 am

Once upon a time there was a lotta really frigid ice children and then the good fairy came along…..

Barnes Moore
February 24, 2021 5:00 am

“Climate researchers want to find out how much the glaciers could melt in the course of man-made climate change in the next centuries and how much the sea level will rise as a result. To do this, they look into the past. If one succeeds in understanding the growth and melting of the glaciers during the last ice and warm periods, then conclusions can be drawn for the future”.

So, are they looking into man’s contribution to the growth and melting of the glacier during the last ice and warm periods, or are they looking at natural variability? Looks to me like many other studies that start with – we know man is causing climate change and we will manipulate our data to provie it.

Reply to  Barnes Moore
February 24, 2021 1:32 pm

And of course, completely oblivious to their own statements ” If one succeeds in understanding the growth and melting of the glaciers during the last ice and warm periods, then conclusions can be drawn for the future”.

If it happened in the past, what was the mechanism, why would you assume that mechanism is no longer in effect? Why assume another mechanism is now predominant?

Trying to Play Nice
February 24, 2021 5:06 am

Stopped reading at “However, these glacier masses could not possibly have been that large at the time, according to climate models.”

February 24, 2021 5:26 am

My big takeaway, science is never settled. The isotope theory that has been used for decades is now rendered useless by this new study.

Tell me again why the science behind global warming is settled?

Clyde Spencer
Reply to  DeNihilist
February 24, 2021 11:33 am

One of the strongest arguments for anthropogenic CO2 rising in the atmosphere is from the ratio of carbon isotopes, based on differences in carbon isotopes in plants and coal compared to the atmosphere. However, something that I suspect isn’t adequately accounted for is the fractionation of carbon isotopes when water is evaporated. This article demonstrates that oxygen experiences fractionation. However, I don’t recollect anyone addressing that with respect to CO2.

Perhaps someone like Ferdinand can set me straight about this?

February 24, 2021 5:27 am

Actually this is a rather interesting study, but as usual the press-release and You-reek-alert has mangled things completely.

“To account for these low sea levels, as much as twice the current mass of the Greenland ice sheet would have to have been frozen worldwide”

That is of course utter nonsense, that would only make about 14 meter sea level change, not 140.

To find out what it is really all about you have to read the actual paper:


The interesting things are that this reconstruction has higher sea-levels during the mild mid-Wisconsinan, which fits in with evidence for ice-free conditions in the Hudson Bay area. Their maximum reconstruction -116 meters seems a bit low, but then as far as I can see it does not factor in smaller icecaps and pluvial lakes, so it is probably slightly low.

The other interesting thing is their gravitationally/isostatically adjusted sea level map (fig 3a) which show how much difference this actually makes. This should be of interest to people that try to put a single figure on high sea levels during interglacials, including modern sea-level changes.

They do have a problem with d18O reconstructions that support a lower sea-level during the mid-Wisconsin. Their suggested explanation for this is unconvincing.

Chad W Jessup
Reply to  tty
February 24, 2021 9:18 am

The article was an interesting read in that the entire subject matter and history of sea level studies unfortunately involves a few too many adjustable parameters, and I can’t argue much with their selection of adjustments and rationale for their conclusions, mainly because we just don’t know.

In regard to the question raised concerning doubling the size of the Greenland ice mass to account for a certain lower sea level, just doing some math off the top of my head (which could be a BIG mistake), it seems to me the areas of Canada, Antarctica, and Northern Europe could easily accommodate the extra ice and still fit into the authors’ geophysical conceptions. But just guessing here, and I applaud the authors’ different “take” on the issue.

Clyde Spencer
Reply to  tty
February 24, 2021 12:38 pm

Thank you for supplying the link to the original article.

February 24, 2021 5:41 am

The solid Earth motions would do the trick!

Of course the crust moved. We’re still experiencing post-glacial rebound.

The crust is floating on the mantle. If the crust is pushed down in one place by a mass of ice then it must be pushed up somewhere else because the mantle isn’t compressible.

I presume the land was pushed down and the bottom of the ocean was pushed up. There would thus be a flattening out of the ocean bottom.

If the ocean bottom were flattened, the extent of the oceans would then be increased. That would lead people to believe the oceans contained more water than they actually did.

If people have been over estimating the amount of water in the oceans that would mean the glaciers contained more ice than previously thought.

So, solid Earth motions could do a trick. It just might not be the same trick the researchers thought it was. 🙂


Clyde Spencer
Reply to  commieBob
February 24, 2021 11:41 am

Yes, it seems that these modelers are ignoring what happens to the ocean bottoms. It is known that there were fore-bulges at the leading edge of the glaciers. However, what is being ignored is that as more water was removed from the oceans, the pressure on the mantle, especially in the deeps, would be decreased, allowing the mantle to move upward, decreasing the volume of the ocean basins. The issue is the relative response time of evaporating water versus viscous deformation of the mantle.

Nicholas McGinley
Reply to  commieBob
February 25, 2021 2:01 am

I have a somewhat different perspective on this.
It relates to buoyancy and what happens when you redistribute or add weight to a floating object, like a raft of logs, or a garbage scow, or a continent.
Say we have a football field sized barge floating in a lake, which is itself a few square miles in area.
Now say we pull 100 tons of clams from the bottom of the ocean, or the same amount of ice from the top of the lake, and place it on one end of the barge. I do not think the level of the lake will change much. Or the mud around the perimeter of the lake change much. Or the mud at the bottom.
But one end of that barge will definitely sink down some, and the other end will pop up into the air.
In fact we know that something akin to this very thing occurred when two miles of ice was sitting in a big pile centered over Hudson Bay.
The mantle of the Earth is 1800 miles deep. The crust is varying in thickness by quite a bit, and it is thinnest at spreading centers and thickest over the oldest parts of continents (and where there are mountains of course, and BTW, all the mountains had a lot of ice on them…a whole lot, which I am not so sure these “researchers” took into account. Consider Yosemite). Continents are mostly about 5-25 miles thick and thousands of miles across, and are far more rigid than ocean crust, which is mostly about 3-5 miles thick and also thousands of miles across.
Under the Himalayas, for example, the crust is about 40 miles thick, not counting the solid mantle portion of the lithosphere.
The mantle below the asthenosphere has been described as about the consistency of asphalt.
It is resistant enough to flow, IOW has high enough viscosity, that the surface it supports has huge high and low spots. Granted none of these are on anything like the scale of the ice sheets in question. And the ice sheets, while less dense by far than rock, were a substantial percentage of the thickness of continental crust.
Let’s keep in mind though that the crust of the Earth is only one part of the solid outer part of the Earth called the lithosphere. Oceanic lithosphere is about 50-140 km thick, and continental lithosphere is about 40-280 km thick.
I switched from miles to km, so one needs to know a km is 3/5 of a mile.
And ice is about 1/3 as dense as rock.
Ice is about 0.92 g/cm^3.
Continental crust is about 2.6 g/cm^3
Oceanic crust is about 3.0 g/cm^3
So compared to the lithosphere, the ice was a few km thick but sitting on far greater thicknesses of far more dense and heavy material. The lithosphere sits above the asthenosphere, which is a plastic layer that can be more readily deformed. But the mantle not so much.
No doubt things move under those mass redistributions, but I do not think it was especially large in terms of the total volume of ocean basins.
A large factor is the relative density of rock and ice, and another is the fact that much of the crustal depression was equilibrated by adjacent parts of the continental crust rising.
And is is almost certainly the case that prior to the last glacial advance, there was not enough time for equilibrium to be reached.
Keep in mind that the interglacials are only about 10k years long or so.
There is no time for the Earth to have come back to isostatic equilibrium during at the interglacials.
Each of these factors tends to diminish how much the ocean basin would have had to change in response to continental crust being pushed down by ice sheets.

Too tired to work these last two parts into the above long winded spiel:
There are two stages of post glacial rebound, and one of them is very rapid, more or less immediate. There are also two types of rebound, one of which is continental levering…as I noted in the barge example.

When one reads about post glacial isostatic rebound, it is striking that many authors speak about the crust not reaching equilibrium for at least another ten thousand years, without seeming to ever consider that it is very unlikely to be that long before deep ice is once again accumulating on the continents in the N.H.

Reply to  Nicholas McGinley
February 25, 2021 4:16 pm

So are you saying that crustal movements don’t explain the missing ice?

Nicholas McGinley
Reply to  commieBob
February 25, 2021 9:59 pm

What missing ice?
The missing ice the climate models invented?

Ben Vorlich
February 24, 2021 5:56 am

A couple of days ago there was a comment about DMI Arctic ice data. The problem has been fixed

Tak for din mail.

Jeg skulle gerne mene at dette problem er blevet rettet nu. Tak for din henvendelse.

Med venlig hilsen



Thanks for your mail.
I would like to believe that this issue has been fixed now. Thank you for your inquiry.
Yours sincerely


Jean Parisot
February 24, 2021 6:54 am

” and accumulated faster than previously thought.”

I’m more concerned about this, than sea levels. That the tipping point into a glacial epoch may be even steeper is bad news and makes the need for a high confidence, advance notice greater and longer (more time before we lose central Asian and North American breadbaskets).

Peter W
Reply to  Jean Parisot
February 24, 2021 8:21 am

Having seen charts of several hundred thousand years of ice ages, including especially the past 10 thousand years or so of the current warm period, this is why we moved from NH to FL in 2016. My observation is that the next big ice age is imminent, and I am considering the possibility that the recent Texas cold was a warning shot. Far more than just Texas was cold, and it was not limited to North America.

Jean Parisot
Reply to  Peter W
February 24, 2021 11:36 am

While I’m not ready to move the family to FL (I did open an office there, so we could keep working.), I did notice Niagara Falls has frozen over this year.

Nicholas McGinley
Reply to  Peter W
February 24, 2021 12:22 pm

Yeah, but Florida was mostly oasty-toasty warm, eh.
This time.
It gets cold here, too.
Plenty cold.
I had frost on my car in November, near Fort Myers.
I had freezing rain in Altamonte Springs about ten years back.
And here is shot from my driveway on February 20th of 2015.
Note that none of these times were even particularly notable cold events here.
Back in the 1970s, the first in the series of freezes that lasted for about 20 years or so killed Avocado trees south of Miami that were several decades old…maybe 50 years old or so.
Florida was a major supplier of them before that.
I recall the huge groves of very old orange trees that use line many miles of SR 50 West of Kissimmee.
Many decades old, killed to the stumps in the mid1980s.
After surviving the earlier freezes.
Duration, dew point, wind, and temp have to combine to prevent growers from being able to protect trees by icing them.
It is never the one thing.

But I am curious…why single out the recent weather in Texas?
We have had many surprising cold weather events in the US just in the last ten years.
Like the ocean freezing south of New Jersey a few years back?

Reply to  Peter W
February 24, 2021 1:30 pm

You might want to keep your eye on ocean heat content or SST, that’s where any heating or cooling trend will be most obvious.

Walter Sobchak
February 24, 2021 7:29 am

Mathematical onanism. They plugged some more numbers into their model, and behold a rabbit. No actual facts were harmed in the making of this animated movie.

As John von Neumann said: “With four parameters I can fit an elephant, and with five I can make him wiggle his trunk”. 

February 24, 2021 7:35 am

Meh, models. Even if it’s an honest model, how can anyone trust modellers anymore, especially those working in socialist academia?

Bill Rocks
February 24, 2021 7:39 am

This paper says that the oxygen kinetic isotope effect is problematic. That is a very big statement with vast implications for many things including climate science.

How valid is their claim about the oxygen isotope problem? What is the problem and how does it work? This should be much more important than the ice volume conundrum?

February 24, 2021 8:27 am

“By assuming different viscosities of the earth’s mantle, we model different evolutions of the land topography, which then result in different scenarios for the ice masses.”

They simply updated that 1976 work…

February 24, 2021 10:03 am

Another self satisfaction fantasy model modified until it surrenders and supplies what the designers/programmers believe.

The Earth’s mantle, in fact, behaves like a highly viscous fluid on geological time scales and deforms under the weight of a fluctuating ice mass.”

Start with a gross assumption. Use plenty of scientific words to imply knowledge and experience.

“By assuming different viscosities of the earth’s mantle, we model different evolutions of the land topography, which then result in different scenarios for the ice masses.” These can now be brought into harmony”

Introduce additional assumptions that complicates the scenario.

Adjust the new introduced factors until model results match researcher desires.

N.B. This is not a case where independent researchers/users validate and verify the results of a new model. It is a case of the researchers who built the model claim their new model solves all of the missing ice/sea level problems and validates their research group’s confirmation bias…

Caveat Emptor.

February 24, 2021 10:23 am

Now I would like to know the effect of all the volcanic venting in all the earths oceans. How much is the ocean temperature rising, if any?

Clyde Spencer
February 24, 2021 10:29 am

Did friction interfere with ice flow velocity?

Does a bear forage (or whatever) in the woods?

NZ Willy
February 24, 2021 10:40 am

I should think they could have resolved this by positing that the Arctic Ocean was frozen solid with extra ice heaped on top. No crustal shifting required.

February 24, 2021 11:03 am

You’ll pardon my amateur confusion, after being told, for years, that ice age sea level was 394ft (120m) lower than it is today … https://iceagenow.com/Sea_Level_During_Last_Ice_Age.htm

Comes today these learned boffins who tell us that today, according to this new modeling that the sea was 380ft lower back then..”According to their calculations, the sea level must have been around 116 meters lower than today..”

Granted, 14ft around the globe would add up, but being that far off the mark for decades while the climate ‘science is settled’ leads one to wonder about just how ‘settled’ it is..

Reply to  fred250
February 27, 2021 6:25 pm


Stephen Philbrick
February 24, 2021 11:25 am

I presume that the glaciers are salt free, which means the remaining ocean will have increased salinity (assuming the absolute amount of salt in the ocean has been roughly constant over the period in question). I wondered how significant this would be but my back of the envelope calculations suggest it would be only a 3% increase in salinity. My guess is that this would not be enough to affect the life in the sea but I don’t have very much knowledge in this area. Is that correct?

Jean Parisot
Reply to  Stephen Philbrick
February 24, 2021 11:48 am

I don’t know, but I would expect that difference to be detectable in the geologic record.

Steve Z
February 24, 2021 12:53 pm

There seem to be a lot of unknowns in trying to estimate what the maximum ice volume and minimum sea level would have been during an ice age.

Geologists can estimate the amount of land area which could have been glaciated by noticing the positions of glacial debris left behind when the glacier retreated from its maximum extent. But the maximum thickness of the ice is harder to measure–how do you measure the height of ice that is no longer there?

The problem is more complex for the two existing large ice caps in Antarctica and Greenland, both of which are still more than 90% covered by ice. Their surface area was probably not much higher during the ice age than now, but how can we measure the thickness of ice that has long since melted and is no longer there? During a period of ice accumulation, one can drill ice cores and measure concentrations of gas isotopes trapped in the ice, but once a layer of ice melts and flows into the sea, those isotopes either mix with sea water or are emitted to the atmosphere, and the record is lost.

If the sea level was really 120 meters lower during the last ice age than it is now, how can one measure the location of an ancient shoreline now under 100 meters of water? We can sometimes observe evidence of higher past sea levels by finding fossils of marine animals inland, but do we have to try to find fossils of land animals at the sea bottom? What if these animals didn’t actually live where they are now buried, but may have been swept away to sea and drowned by a flooding river?

The writers of this article may have found a theoretical model that yields a converged mass balance, but lack the evidence to show whether or not it is correct.

Nicholas McGinley
Reply to  Steve Z
February 25, 2021 12:36 pm

We can see where corals are located that lived a when sea level was lower.
The lowest we can find such remnants gives some indication of where sea level was.
That is one way.
There are others.
It can be calculated how thick a ice sheet would need to be to gouge out rock to the depth of Lake Superior, given the known hardness of the rocks gouged out.

I suspect we will never know much of anything if the people organizing our bases of accumulated knowledge erase any parts they do not like, as was done when these guys declared that accepted values should be discarded because their models say it was impossible.
Models only say what they are programmed to say. They are not by themselves evidence of anything:

To account for these low sea levels, as much as twice the current mass of the Greenland ice sheet would have to have been frozen worldwide. However, these glacier masses could not possibly have been that large at the time, according to climate models.”

February 24, 2021 12:57 pm

So they took better account of the fact that our planet is a molten iron liquid balloon of fixed volume, with a thin insulating silicate scum floating on top. On top of that silicate scum over 3/4 of the planet is a layer of water and sometimes ice, that combined with the silicate scum, all obey Archimedes principle. But I think we’ve known this for a while already.

Brian Johnston
February 24, 2021 2:21 pm

The report refers to the negligible ‘man made climate change’. Not off to a good start.

Reply to  Brian Johnston
February 24, 2021 3:25 pm


Do have a link to the evidence that supports that opinion Brian?

February 24, 2021 4:06 pm

How much did the ocean floor rise when the continents were depressed?

Geoff Sherrington
February 24, 2021 4:38 pm

There are reasons to doubt the accuracy of the delta-Oxygen-18 method for sea level studies.
The method, in brief, is here.
“Delta-O-18 changes directly as a result of temperature fluctuations, so it provides a very good record of the climate. Oceanic delta-O-18 values that are high represent cold climates, while lower values indicate a warm climate. This trend occurs because of the effects of precipitation and evaporation. Since it is lighter than 18O, 16O evaporates first, so in warm, tropical areas, the ocean is high in 18O. Additionally, as water vapor condenses to form rain, water droplets rich in 18O precipitate first because it is heavier than 16O. Thus, the cold, polar regions are depleted in 18O as it all precipitates out in the lower latitudes, but they are high in 16O. On the other hand, the Tropics possess a large amount of 18O but have little 16O. This state is not permanent, however, because evaporation and precipitation are highly correlated with temperature. Changes in the climate can greatly affect the ratio of 18O and 16O and can alter their distribution throughout the globe.”
The overall complication is because both are stable isotopes. The method above looks at changes in the ratio, but a change (say positive) in one pace has to be balanced by a change (say negative) in another place. These measurements are done on water and ice. +Water is mixing all of the time, so there is a probability that water from the +ve places will mix in a largely undefined way with the -ve.
In short, there does not seem to be a stable reference point to which other measurements can be related. It all floats around.
When ice is analysed, it has been formed from water evaporated usually elsewhere, then transported. In most cases, one does not know the source of the water, nor its temperature, accurately enough to relate to temperatures.
I have never used this method, so please shoot me down if I am wrong.  Geoff S

Michael S. Kelly
February 24, 2021 5:35 pm

Um, oxygen’s atomic mass is 16, and its isotopes are 11 through 26. Tantalum and Hafnium have isotopes with atomic mass of 180, but oxygen…no, sorry, there are none.

Ed Zuiderwijk
February 25, 2021 4:25 am

What about Antarctica? There is absolutely no way we can know how high the ice was piled up on Antarctica during the last glaciation. So how can we possibly know that there was ‘missing ice’ in the first place?

Ian MacCulloch
February 25, 2021 9:22 pm

Where did the water go? Each glacial period represents a major issue with respect to the reconciliation of the water budget. If we use the last glacial event then the following become apparent from the USGS:

  1. Today ice covers 3.1% of the entire earth’s surface
  2. Land totalling 10.7% of the earth’s surface is covered by ice
  3. During the last glacial maximum the numbers were 8% and 25% respectively
  4. Today the oceans represent 70% of the earth’s surface.
  5. Ocean levels fell by 125 metres
  6. On ratio alone to account for the water transfer to land ice should have reached 291 metres
  7. From 3 above the thickness of the ice equates to 1167 metres on average
  8. According to the logs from the deep ice core holes, there was no change in the rate of accumulation at either Greenland or Antarctica during the LGM
  9. The ice floating in water is a de facto net constant with respect to sea level. At any stage the weight of the floating ice has already displaced its own weight therefore its melting will not contribute to sea level change per se.
  10. The ratio of permanent ice to glacial ice is about 9:1.
  11. Therefore the theoretical height of the ice during the LGM on land reached some 10,000 metres.
  12. Now, this clearly did not happen and while later mapping shows small glaciers the high points of Hawaii these are insignificant in the overall scheme of things.

So we have a huge conundrum. The rate of ice accumulation of the permanent ice as represented by the ever-increasing ice thicknesses in Greenland and Antarctica on the one hand regardless of sea level and weather changes elsewhere around the world and the fluctuating sea levels.
So where did the water go?
Perhaps we should look at the expanding and contracting earth theory as espoused by Dr R Wilson at the University of Illinois, Urbana campus, IL in 1993.

%d bloggers like this:
Verified by MonsterInsights