During the Mid-Holocene, when CO2 concentrations were stable and low (270 ppm), Antarctica’s massive Ross Ice Shelf naturally collapsed, adding the meltwater equivalent of 3-4 meters to sea levels.
Because CO2 concentrations changed very modestly during the pre-industrial Holocene (approximately ~25 ppm in 10,000 years), climate models that are predicated on the assumption that CO2 concentration changes drive ocean temperatures, ice sheet melt, and sea level rise necessarily simulate a very stable Holocene climate.
In contrast, changes in ocean temperatures, ice sheet melt, and sea level rise rates were far more abrupt and variable during the Holocene than during the last 100 years.
Modern ocean changes are barely detectable in the context of natural variability
Image Source(s): Rosenthal et al., 2013; Climate Audit
The temperatures of the global ocean have changed by just 0.1°C in the last 50 years, and just 0.02°C during 1994-2013.
According to Levitus et al. (2012), the global ocean’s 0-2000 m layer warmed by 0.09°C during 1955-2010, while the 0-700 m layer warmed by 0.18°C during that span.
In the context of the Pacific Ocean’s 0-700 m temperature changes during the last two millennia (Rosenthal et al. 2013), that 0.18°C change in 55 years is barely detectable.
Mid-Holocene centennial-scale sea level fluctuations were much higher than today’s
During the Early Holocene, when continental ice sheets were still in the process of melting, sea levels rose at rates that ranged between 10 to 60 mm/yr, or 1 to 6 meters per century (Ivanovic et al., 2017; Zecchin et al., 2015; Hodgson et al., 2016).
During the Mid- to Late-Holocene, when relative sea level was about 2 meters higher than today’s levels, sea levels rose and fell at rates of a half-meter to a meter per century, with 13 mm/yr reached on decadal timescales.
Image Source: Meltzner et al., 2017
Image Source: Mörner et al., 2011
In contrast, the modern record indicates that sea levels only rose at a rate of 1.5 mm/yr during 1958-2014, or about 0.15 of a meter (6 inches) per century.
Image Source: Frederikse et al., 2018
Widespread collapse of ice sheets from 5000-1500 years ago
A new paper (Yokoyama et al. ) suggests that the Antarctic (and/or Greenland) ice sheets melted to such an extent around 5000 years ago that they added between 3 and 4 meters to sea levels.
The Ross Ice Shelf (Antarctica) underwent “widespread collapse” during this period (Yokoyama et al., 2016), subjected to rates of retreat and sub-ice shelf water temperatures much higher than present.
These melting events occurred while CO2 concentrations were a low and quiescent 270 ppm.
Image Source: Yokoyama et al., 2019
Image Source: Yokoyama et al., 2016
22 responses to “New Paper: Widespread Collapse Of Ice Sheets ~5000 Years Ago Added 3-4 Meters To Rising Seas”
Is this your main point in this article? Ice melted when CO2 was low thus we should not worry about CO2 today?
Yes, ice melted when this planet came out of the ice age and continued to melt for quite some time. Also, putting the word “just” in front of datapoints doesn’t make them magically smaller. Please do us a favor and convert those temperatures into Joules. What kind of (average global) forcing would be necessary to cause those fast changes you write about? What could have caused those? Internal variability? CO2 forcing is weak, but steady for a long period of time. Even if we’d stop emitting CO2 tomorrow it would take many decades/centuries until the human caused element in the climate equation fully returns to zero.
It wouldn’t be a “favor” to anyone but you who think that if we use Joules we can mask the minimal nature of changes in OHC during the last 50 years (0.1°C).
During the Holocene, the 0-1000 m fluctuated by 2°C/200 years. In contrast, the last 200 years of 0-1000 m changes are “below detection limits”. The former occurred without any change in CO2 concentration. The tiny latter change occurred with +50 ppm CO2.
Indeed, especially for Antarctica: <0 to 1 W m-2 - and "comparatively weak" for Greenland.
And Kenneth Richard,
The assumption that it takes centuries for CO2 levels to decline back to natural levels (when humans stop venting so little) presupposes that we know exactly how, where, and why the CO2 levels fluctuate as they do, and that human are venting a significant amount — which we do not compared to nature.
SebH’s final statement to this effect (it take centuries) is just an assertion. As this graphic shows http://co2science.org/subject/other/figures/co2amp.jpg , in any year the overall CO2 levels move about a fair bit, sometimes up, sometimes down. And why? Because that is how NATURE does it. Maybe its all just the termites https://phys.org/news/2018-11-year-old-termite-mounds-brazil-visible.html 🙂
Not that it matters much, as studies have found that historically Temperatures, Sea Levels, Climate Dynamics ‘Have No Apparent Relationship To Atmospheric CO2’ as shown before in https://notrickszone.com/2017/11/23/2-new-papers-temperatures-sea-levels-climate-dynamics-have-no-apparent-relationship-to-atmospheric-co2/ .
Of course the big problem for cAGW alarmists is why global temperature do not exactly track the atmospheric CO2 levels.
Expressing a change in heat content in Joules is the natural way. Since the ocean is clearly not warming uniformly by a temperature X, it is kind of misleading to express this as a temperature. It makes sense to do that for reconstructions however since they derive (likely) temperatures.
Come on, I hope you realize how weak of an argument that is. So the “variability in foraminifer something is below the detection limit” and you infer from this that we 0-1000 m changes are “below detection limits”? Also note that their explanation is more internal variability, not a swing representing 2°C within 200 years of the heat content of the entire ocean.
One can only wonder why you use papers like this one trying to downplay the development of the heat content in modern times.
So? I also have no heater in the hallway, yet it is warm there. But what you are getting at with this remark, is of course not what I meant by writing this and you probably know it, right?
I thought about replying to your comment in detail, but let’s just agree to disagree. Not one thing you wrote is what is really happening and I suggest you revisit that co2amp.jpg and think about what is displayed there again 😉
If you want to learn more about CO2, please visit:
I assure you it is not termites.
“If you want to learn more about CO2, please visit:
Interesting link you supplied me (not).
I wonder which version of ECS you think they would find correct (https://object.cato.org/sites/cato.org/files/wp-content/uploads/gsr_022714.gif) — oh, that’s right it would be the least realistic one, the IPCC guess at ECS.
So your link in one quick look is shown not to be even close to reality, just more duff computer games with presumptions, assumptions and guesswork. A huge waste of money but useful as it keeps the dull and unemployable off the streets.
It must be a main point, since you so eagerly picked up on it. Is your questioning about the importance of this point your main objection? I wonder why you might object to this being the main point, when it is an important point to make.
So, you agree that Earth’s ice melted, even with lower CO2 levels than today. How is it, then, that you still see CO2 as any sort of driver of this? Lower CO2 than today, and ice still melted. Higher CO2 than back then, and ice still melts. This indicates that something other than CO2 is the driver. If you cannot see this, then explain why.
You are right. The word “just” has no effect on the meaning of the data points. Rather, the word, “just” qualifies how small the data points are that alarmists magically inflate to alarming proportions. Clear communication, using appropriate words, is not magic. The magic is in taking small data points and graphically inflating them to look larger than they actually are.
See my above comment, which describes exactly what your favor-request amounts to — “Please make the data points look more terrifying by representing them in units that have a lot more places before the decimal point.” That’s what you are asking. In the time it took me to write this sentence, I aged 10,000,000,000 nano-seconds. I invested all this time in giving the obvious answer.
You don’t even attempt to resolve the questions that lead up to your thereby baseless conclusion about “the human caused element”. In fact those questions of yours are precisely what are up for investigation — investigation that is not pursued because of widespread manic obsession with proving human CO2 has anything at all to do with climate change.
That’s what they all do. They’re alarmists.
Here’s a particularly poignant example from the Washington Post’s journalist/climate alarmist:
9,103 gigatons of ice loss sure sounds scary. So does submerging the U.S. highway system with 98 ft of water 63 times over.
What’s the meltwater equivalent/addition to sea levels for 9,103 gigatons of lost ice? One inch.
It’s lying with numbers.
I am not objecting to this being the main point.
Yes, of course. What kind of question is that?
I’d go out on a limp and say not a single climate scientist is saying that CO2 is the driver of Holocene ice melt coming out of the last ice age 😉
CO2 is the driver now.
See my reply to Kenneth when it eventually appears. There is no inflation happening when using the proper unit for heat content instead of trying to express it with a temperature that corresponds to an uniform ocean warming.
I hope you know that all units can be prefixed with modifiers. Use Petajoules, if you need to. Or put differently, when I turn a device on that adds a few Kilojoules to the skin on your left hand, would you then also express this event as a 0.00x °C change in temperature of your whole body in an effort to downplay the significance of the event?
That is not a conclusion that comes from resolving any questions in the paragraph you quoted. The questions you quoted are about what caused past changes.
Nope Kenneth, it’s using the correct units and comparing numbers to what humans can understand. Nobody can understand a heat content change of 10^20+ Joules, nobody can understand what it means when the entire ocean volume would have uniformly warmed by 0.x°C.
Anyway, you guys have fun with “lying with numbers” allegations while you do everything to downplay what is happening and magically explain away reality. If that works for your niche and makes you happy, good for you. It’s however not very scientific, don’t you think?
I’d like you guys perform experiments on your theories like the flat earthers in the documentary “Behind the curve” did. Maybe you’ll design an experiment that once and for all shows that CO2 doesn’t do what science says it does, good luck! 😉
CO2 is the driver now.
So, never in the geologic time extent of Earth was CO2 the driver, even though it has been both lower and incredibly higher, but somehow magically CO2 has become the driver now?
How is “now” CO2 imbued with powers that “back then” CO2 did not have?
There is no inflation happening when using the proper unit for heat content instead of trying to express it with a temperature that corresponds to an uniform ocean warming.
I think you are not looking at it from the proper perspective. The reason you say you choose energy units is not the effect that you want those units to have on a person reading the figures. You want people to read a big number and fail to realize that it translates into a minuscule temperature difference, which is what human senses detect and judge their existence by. Humans do not perceive joules, and they do not live their realities in joules.
Temperature anomalies that are all the rage in the big warnings are not given in joules — why is that? — because “global average temperature anomalies” do not properly account for joules.
That’s one reason why the very concept of a “global temperature” is questionable — it deals in a unit of measure that conceals the specific energy dynamics that enables the degree-reading.
In short, you are trying to choose your units of measure to misrepresent the reality to people who do not ordinarily deal in those units. This is underhanded.
Seb, it seems clear that it is you who are the liar here, as you attempt to choose units that confuse rather than educate. You’ve got this scam game down to an art form, I have to admit. (^_^)
SebastianH also prefers the unit “Hiroshima bombs of heat” for ocean temperature changes. Because, you know, CO2.
So if you’d ever want to, go ahead and indulge him by using his favorite heat unit that he learned from SkepticalScience. He’d like that.
Then, there’s the emerging GigaMegaGarganJoules unit. That’s only recently started to become popular among the Disciples of Gavin.
Of course, it was. There are many high CO2 events in Earths history. None of which were caused by humans though 😉
It’s not. That’s entirely your imagination.
Nope. But feel free to fast-drink a cup of water that increases your average body temperature by “just” 0.1°C instead of referring to an event like that with the amount of Joules applied to a very small area of your body and wondering if that would be healthy. It’s about science, not about impressing people. The ocean is not warming uniformly by 0.x°C degrees.
See, you are making the exact same point I am making. Expressing warming as a global temperature is not wrong, but what’s really going on is an increase of the heat content and that doesn’t get distributed uniformly all over the globe (obviously).
I think this is also why skeptics can imagine that there was a warming pause when surface temperatures didn’t increase as much for a period of time. They are completely ignoring what is going on with the heat content and instead take comfort in a huge mass “just” warming by some small amount of degrees uniformly.
You just wrote “global temperatures” are questionable. Make up your mind! Why aren’t they questionable for the total mass/volume of the oceans?
I still don’t get how using the correct units is a form of lying. Very scientific reply from you …
Looks like my reply to you got buried. I know who is “lying” with numbers here, Mr. “below the detection limit” 😉
Sebastian, the title of the report by Rosenthal et al. 2013, is “Pacific Ocean Heat Content During the Past 10,000 Years”.
You stated “Please do us a favor and convert those temperatures into Joules.” Did the title of the report not give you pause before you put your fingers into motion?
The full report is behind a pay wall, therefore I could not access it. Perhaps you were able to do so, but surely you must have wondered why a study of ocean heat content reports its conclusions in terms of ocean temperature trends.
Fortunately you are not the first who tried to exploit that report for advocacy reasons. We can and must be grateful to Steve McIntyre for having evaluated the report and various interpretations of its findings, both by objective climate scientists as well as by proponents of catastropic anthropogenic global warming, man-made climate change.
The link to Steve McIntyre’s assessment and its results is indicated at the top of this discussion thread, in the caption for the first image, right after the link for “Rosenthal et al. 2013,” namely “Climate Audit,” which latter, as you probably know, is Steve McIntyre’s blog. That link will take you directly to Steve McIntyre’s report on his efforts and conclusions regarding his assessment of “Rosenthal et al. 2013” and related claims.
Just as he did in all of his examinations that identified the baselessness of Michael Mann’s Climate Hockey Stick, Steve McIntyre calmly and objectively presents his assessment of how “Rosenthal at al. 2013” expressed the case of calculating ocean heat content in terms of Joules and converting it to temperatures in °C.
Have a look at what Steve McIntyre found. If nothing else, even the most obstinate objector can learn from it what a real scientific assessment and criticism looks like when it is done objectively. You should have done so anyway, before you made your unfounded request.
You really should give it a rest, but I for one welcome your constant objections. They make one take a second, deeper look at what you object to, to see whether your objections are far off the mark or on target. Overall, the best that can be said of your efforts is, you are a prolific sniper but not a good marksman. You could learn from Steve McIntyre what you need to do to hit your mark, but that would be a lot of work and not so much fun, right?
“…prolific sniper but not a good marksman.” – Walter Schneider
Excellent addition to the troll’s resume!
Reply with the links to not-paywalled Rosenthal 2013, the 2017 version and correct usage of Joules by Rosenthal for heat content display, didn’t get through? Hmm …
I find it a bit fascinating that Walter Schneider seems to be under the impression I would somehow disagree with Rosenthal or that I am saying something completely different. Anyway, … IWT (intermediate water temperatures) aren’t directly comparable to a conversion of heat content changes into a global uniform ocean warming temperature.
Have fun while imaginging I wouldn’t hit targets here 😉
FYI, Walter – Here are the two blog posts by McIntyre.
The activist nuisance asks…
“Is this your main point in this article? Ice melted when CO2 was low thus we should not worry about CO2 today?”
It has been repeated here so often that not only has ice melted when [CO2] was low, but that a lot of ice has also formed when [CO2] was very high. Temperature does not correlate well to [CO2]. Therefore he has long had the answer to the question of the involvement of CO2 to warming – little to none. But he asks it anyway. Only a troll asks questions he knows the answer to, and in belittling ways that he hopes will annoy his readers.
Aggressive distraction, deflection, dishonesty and logical fallacies galore. That’s all SebH has ever had, and probably ever will have.
Well, it does. As ocean heat content and sea levels decline, CO2 rises.
LOL – “why, I oughta…!” 🤨
(PS – Was there supposed to be a link in your 2nd sentence, or did you just color it for emphasis?)
Don’t know why mine didn’t work. Here it is by itself.
As ocean heat content and sea levels decline, CO2 rises.
That’s fascinating, actually.
Colder oceans are supposed to absorb more CO2, not emit it. Assuming that’s where the CO2 they claim is rising came from. Did the authors speculate on it’s source?
CO2 rise in those cases seems to have begun before the sea levels and their heat content fell, and it continued for the duration.
Also, from you article above, we have “A new paper (Yokoyama et al. ) suggests that the Antarctic (and/or Greenland) ice sheets melted to such an extent around 5000 years ago that they added between 3 and 4 meters to sea levels.”
I guess that might be the blip in the sea levels at or just before 5ka in this link?
Interesting can of worms you have there, Kenneth, at least for warmists who want [C02] to be the driver of environmental change. Not so good for them when it appears to be racing out of control in reverse.
What I was referring to, as you probably guessed, was the paleo record, during which we find every possible correlation (-,0,+), implying [CO2] isn’t causative of anything.
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