An attempt to link past ice ages to CO2, rather than orbital cycles

International study raises questions about cause of global ice ages

From Dartmouth College

Moraines, or rocks and soil deposited by glaciers during the Last Glacial Maximum, are spread across the landscape near Mt. Cook, New Zealand’s tallest mountain, and Lake Pukaki. Credit Aaron Putnam

HANOVER, N.H. – A new international study casts doubt on the leading theory of what causes ice ages around the world — changes in the way the Earth orbits the sun.

The researchers found that glacier movement in the Southern Hemisphere is influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit, which are thought to drive the advance and retreat of ice sheets in the Northern Hemisphere.

The findings appear in the journal Geology. A PDF is available on request.

The study raises questions about the Milankovitch theory of climate, which says the expansion and contraction of Northern Hemisphere continental ice sheets are influenced by cyclic fluctuations in solar radiation intensity due to wobbles in the Earth’s orbit; those orbital fluctuations should have an opposite effect on Southern Hemisphere glaciers.

“Records of past climatic changes are the only reason scientists are able to predict how the world will change in the future due to warming. The more we understand about the cause of large climatic changes and how the cooling or warming signals travel around the world, the better we can predict and adapt to future changes,” says lead author Alice Doughty, a glacial geologist at Dartmouth College who studies New Zealand mountain glaciers to understand what causes large-scale global climatic change such as ice ages. “Our results point to the importance of feedbacks — a reaction within the climate system that can amplify the initial climate change, such as cool temperatures leading to larger ice sheets, which reflect more sunlight, which cools the planet further. The more we know about the magnitude and rates of these changes and the better we can explain these connections, the more robust climate models can be in predicting future change.”

The researchers used detailed mapping and beryllium-10 surface exposure dating of ice-age moraines – or rocks deposited when glaciers move — in New Zealand’s Southern Alps, where the glaciers were much bigger in the past. The dating method measures beryllium-10, a nuclide produced in rocks when they are struck by cosmic rays. The researchers identified at least seven episodes of maximum glacier expansion during the last ice age, and they also dated the ages of four sequential moraine ridges. The results showed that New Zealand glaciers were large at the same time that large ice sheets covered Scandinavia and Canada during the last ice age about 20,000 years ago. This makes sense in that the whole world was cold at the same time, but the Milankovitch theory should have opposite effects for the Northern and Southern Hemispheres, and thus cannot explain the synchronous advance of glaciers around the globe. Previous studies have shown that Chilean glaciers in the southern Andes also have been large at the same time as Northern Hemisphere ice sheets.

The ages of the four New Zealand ridges – about 35,500; 27,170; 20,270; and 18,290 years old — instead align with times of cooler sea surface temperatures off the coast of New Zealand based on offshore marine sediment cores. The timing of the Northern Hemisphere’s ice ages and large ice sheets is still paced by how Earth orbits the Sun, but how the cooling and warming signals are transferred around the world has not been fully explained, although ocean currents (flow direction, speed and temperature) play a significant role.


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March 20, 2015 10:40 am

surely these rampant warmists must get weary of trying to jam their square pegs in round holes?

Reply to  cnxtim
March 20, 2015 12:25 pm

Try this experiment. Tell one of you respected professional colleagues that people with qualifications are needed for a psychological experiment. The experiment consists of pounding a square peg into a round hole. Progress reports will have to be generated. Papers will have to be written. Tell them the pay will be $500.00 per hour, or an amount that will impress.
You will be disappointed at the results.

steven strittmatter
March 20, 2015 10:44 am

Do they address the ~800 yr. lag in CO2?

Reply to  steven strittmatter
March 20, 2015 10:56 am

its predicted by AGW theory. In fact the lag was predicted before it was discovered.
Addressing evidence tat shows your theory is correct would be funny.

Tim of Roseville
Reply to  Steven Mosher
March 20, 2015 1:59 pm

You truly are blinded by ideology. How can CO2 be the the cause of temp change when it lags the change in temp. Your position is illogical, and the lag was not predicted by the AGW hypothesis.

Reply to  Steven Mosher
March 20, 2015 2:10 pm

AGW theory predicts everything. Which means that it predicts nothing.

Reply to  Steven Mosher
March 20, 2015 2:10 pm

It wasn’t anthropogenic when the lag was occurring. That CO2 came out of the warming oceans.

richard verney
Reply to  Steven Mosher
March 20, 2015 5:12 pm

Please gicve reference citings to papers published before the ice core samples were analysed that predicted that there would be a substantial (circa 800 year0 lag between atmospheric concemntrations of CO2 and temperature changes.
I would like to see evidence of your assertion that AGW theory predicted this.
If AGW theory does predict that there will be such a lag, then it surely suggests that present day warming is not due to anthropogenic emissions of CO2 since the late 19th century, and the effect of those emissions is something to be felt in the future circa 2650 onwards.

Michael Wassil
Reply to  Steven Mosher
March 20, 2015 5:51 pm

Steven Mosher March 20, 2015 at 10:56 am

So AGW says today’s CO2 concentration is caused by temperature increases during the Medieval Warm Period. Correct? That’s news to me! So why exactly did Mann et al think it so important to get rid of the MWP? And the LIA? And why does the IPCC use 1950 as the start of AGW? Just curious. Something doesn’t compute.

Victor Ramirez
Reply to  Steven Mosher
March 20, 2015 8:57 pm

I think Steven omitted a (/sarc) tag people. No need to get knickers knotted.

Reply to  Steven Mosher
March 20, 2015 10:19 pm

Predicted? Not so much. Assume you refer to Lorius et al.
“changes in the CO2 and CH4 content have played a significant part in the glacial-interglacial climate changes by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcing – See more at:
Ah, of course, they amplify the weak orbital forcings in retrospect. Kind of like copying in advance.
Further gems:
“For example, whether temperature changes lead or lag changes in CO2 or CH4 is not relevant to the study of fast feedbacks”
Budofcourrrse! The feedback was so fast it got there ahead of time.
Pretty much like the fast feedback we have seen the last eighteen years.

Reply to  Steven Mosher
March 21, 2015 3:31 am

No it wasn’t predicted by “AGW theory.” It was “predicted” by the Second Law of Thermodynamics and the fact that solubility is positively correlated with the temperature of a liquid.
It was explained away as not being inconsistent with the AGW hypothesis. And it resulted in the logically fallacious corollaries that the lag didn’t prevent the CO2 from contributing to the warming and the assumption that the additional CO2 forcing was required because they couldn’t ascribe enough forcing to the Milankovitch cycles.

Reply to  steven strittmatter
March 20, 2015 11:09 am

the effects of CO2 travel back in time, two birds killed with one paper!

jim hogg
Reply to  Joe
March 22, 2015 2:58 am

Applause . . applause . . Thanks for that . . put a smile on my sceptical face this dull morning . .

Reply to  steven strittmatter
March 20, 2015 11:23 am

Sure. Sea ice is an early version of the precog (fr. Minority Report). The ice gets high on minute fluctuatuons in CO2 and gets visions into the future. It’s actually much better at predicting climate than todays climate scientist.

March 20, 2015 10:46 am

pdf costs $25 per day to look at.
Also, at the beginning they had to say that CO2 has an effect but it doesn’t seem to be mentioned anywhere else. Gotta mention it to increase the grant allocation.

Reply to  Oldseadog
March 20, 2015 11:32 am

I get the feeling that mentioning CO2 is a requisite within the editing process. If the authors object, no publication.

Reply to  Oldseadog
March 20, 2015 11:38 am

Proper obeisance the God Co2 is required before publishing.

Reply to  Alx
March 21, 2015 5:49 am

I remember reading a physics book from the old Soviet days. In the introduction, the poor author had to weave in something about “dialectical materialism” and “the class struggle of the proletariat”.
The current CO2 mantra is not all that different, except these days it’s done in order to get published and get more grant money; in the old Soviet Union they did it to avoid the Gulag.

Michael 2
March 20, 2015 10:47 am

It’s complex. The science isn’t quite settled. Send money.

March 20, 2015 10:49 am

They have NO data to support their claims. I should have said the data if anything runs counter to their claims.

Stevan Reddish
Reply to  Salvatore Del Prete
March 20, 2015 11:09 am

Actually, every study into causes and timing of ice ages struggles with the contradictory data.

Reply to  Stevan Reddish
March 20, 2015 5:50 pm

But Stevan – IF you select your data carefully, close your eyes tightly, wish VERY HARD and click your heels together three times you can always find what you seek.

Leo Smith
Reply to  Stevan Reddish
March 21, 2015 2:23 am

AGW never struggles with contradictory data, just like every other religion: ‘Inshallah’

Reply to  Stevan Reddish
March 21, 2015 3:36 am

It makes one think that Earth’s climatic reactions to subtle changes in insolation might just be more complicated than can be explained with computer simulatons.

Reply to  David Middleton
March 21, 2015 9:23 am

@ David Middleton

… might just be more complicated than can be explained with computer simulatons.

If it cannot be explained by computer simulations it cannot be explained .
My central interest in all of this ( beyond crushing Hansen’s Venus “runaway” absurdity ) is in fostering a succinct , well factored , quantitative model of the planet starting from the basics — which is understanding the temperature of a radiantly heated naked ball . That is the only way these 4th and 5th decimal point global variations can be quantitatively understood .
I would agree that this is impossible in traditional mass market computing languages which end up being literally a million lines of inscrutable code .
But , as a Canadian friend , Randy MacDonald says ,

In APL , If you can think it , it’s done .

Good APL is generally more succinct and more general that traditional textbook notation and will execute efficiently on any scale computers . The only way these issues will be understood is with such powerful executable notations where adding some parameter over entire maps of the sphere may require just the addition of a single brief expression .

Another Ian
Reply to  Salvatore Del Prete
March 20, 2015 4:04 pm

Comment at

Jason Calley says:
March 20, 2015 at 6:56 pm
The science is settled!!
(It is only the data that we are still busy falsifying…)”

March 20, 2015 10:51 am

People are still looking for a “magic bullet” to explain climate, which is a vastly complex and interconnected system that to date has shown to be “bulletproof.
In their Abstract, the authors state that “…the behavior of southern mid-latitude glaciers was not tied to local summer insolation intensity. Instead, glacier extent … was aligned with Southern Ocean surface temperature and with atmospheric carbon dioxide.”
Of course “aligned” euphemises correlation and implied causation (here’s that magic bullet again!), and I’ll have to wait to get beyond the paywall to find out how CO2 gets into the firing chamber.
This science is nowhere near dull!!!

Reply to  tomwys1
March 20, 2015 12:18 pm

If only Einstein knew about CO2, and he would have figured out his Unified Field Theorem. Everything goes back to CO2. I bet the constant pi, if one was to figure the final 3 digits, would discover that it ends in CO2.

Reply to  JP
March 20, 2015 3:37 pm

I understand the (Sarc/)

Reply to  JP
March 20, 2015 3:41 pm

I’ve seen arguments that the Planck thermal radiation function is an artifact of the black carbon spectrum .

Reply to  JP
March 20, 2015 6:10 pm

Right, now I get it. Einstein was wrong E≠MC2 actually CO2=Mc2.

Frederik Michiels
Reply to  JP
March 24, 2015 3:52 pm

E=CO2 would be Einstein’s new finding

March 20, 2015 10:57 am

So, basically another argument from ignorance, to wit, if the climate isn’t changing in the way we thought it was, then the only alternative is the only other way we can think of.
Recent research has revealed that hemispheric symmetry is subject to homeostatic albedo response. I would suspect that is the most likely solution to the puzzle.

Data Soong
Reply to  Bart
March 20, 2015 11:13 am

Great point, Bart, about the homeostatic albedo response. I hadn’t heard of that before, so thanks for the link with the explanation! Another thought: if the northern hemisphere is receiving significantly less solar radiation than the southern hemisphere, the ice sheets would be expected to expand in the northern hemisphere and shrink (at least to begin with) in the southern hemisphere. However, the northern hemisphere has A LOT more land mass than the southern hemisphere: land mass that is much more easily covered with thick ice (which has a higher albedo than thin ice.) So, the net cooling of the northern hemisphere might easily overwhelm the increased solar irradiance on the southern hemisphere.

Sturgis Hooper
Reply to  Data Soong
March 20, 2015 11:27 am

Besides the fact that there will be sea and land ice at 65 to 75 degrees S even with a little more sunshine, there is also the fact that not all Milankovitch Cycles produce the bihemispheric differential. Axial tilt obviously does, but eccentricity doesn’t. And it is that orbital parameter which appears now to be most important, as indicated by the switch from 40,000 year-long glacial cycles to 100,000 years, ie the eccentricity signal.

Reply to  Data Soong
March 20, 2015 8:51 pm

What affect will lower sea levels have on Antarctic sea ice conditions in the long term? The sea ice may not melt as far back in the southern summer. Circulation flows would likely be altered in the ACC, and also at least through the southern oceans. Perhaps, the intense antarctic cold ends up spreading out to hold greater influence closer to lower latitudes. Plus, lower sea levels will mean additional land mass in the SH. Who can say what the affects would be on the global balance.

Reply to  Bart
March 20, 2015 3:52 pm

Great point, Bart, about the argument from ignorance.

March 20, 2015 10:57 am

If they are correct then even the CO2 rising and falling is natural variation.

Matt Skaggs
March 20, 2015 10:57 am

The last sentence in the abstract does indeed invoke CO2, although it is not otherwise mentioned there. Is there someone in the WUWT community who can get past the paywall and summarize how the glacial advances correlate to CO2? I am guessing it is just wiggle-matching.

Gentle Tramp
Reply to  Matt Skaggs
March 20, 2015 11:59 am

Exactly – where is the connection?

Reply to  Gentle Tramp
March 20, 2015 1:11 pm

“where is the connection?”
In their minds, on the grant application and now in the minds of the CO2-is-evil people.

March 20, 2015 10:59 am

“Here we address a long-standing puzzle of ice-age climate called the “fly in the ointment of the Milankovitch theory.”
pretty simple: The Milankovitch theory had a problem. problem fixed. Note the theory has note been rejected for years despite the “fly in the ointment”, note that nobody screamed “falisified”. Nope, there was a “fly in the ointment”. Now dead fly.

Michael Wassil
Reply to  Steven Mosher
March 20, 2015 6:00 pm

I don’t see how this fixes anything. The insulation of Antarctica, closing of the Panama Isthmus and their respective affects on ocean circulation seem much more relevant than Puff, the magic sky dragon.

Dr. Strangelove
Reply to  Michael Wassil
March 21, 2015 4:39 am

440 million years ago, CO2 was over 4,000 ppm and the world was in an ice age. Popper would say you only need one contradicting observation to falsify a theory.

Reply to  Michael Wassil
March 21, 2015 5:08 am

An inconvenient truth… one of many.

Reply to  Steven Mosher
March 20, 2015 8:44 pm

Still no explanation, just off the cuff (being polite) comments.

Reply to  Steven Mosher
March 21, 2015 3:48 am

It only kills the “fly” if CO2 forcing yields about 4.5°C of warming, inclusive of feedbacks, and other unknown factors, like cloud albedo effects, are insignificant.
If the ECS is consistent with instrumental observations (0.5-2.5°C), it doesn’t kill the fly.

Reply to  David Middleton
March 21, 2015 6:53 am

David Middleton
March 21, 2015 at 3:48 am
Without M. cycles in Climatology,,,,,,,, is like back to the black board, where at that point your ECS makes not even sense, regardless of what value you try to consider for it.
Agw will be put on ice probably for ever..:-)

Catherine Ronconi
Reply to  Steven Mosher
March 21, 2015 5:22 am

The fly was never there. A non-existent problem solved!
1. The effects of insolation changes differ between the hemispheres. The SH getting more while the NH gets less doesn’t make the SH melt while the NH gains ice.
2. Not all Milankovitch Cycles affect the hemispheres differently.
CO2 concentration changes are an effect, not a cause of temperature changes, although they might offer a slight feedback effect.

March 20, 2015 11:00 am

This makes sense in that the whole world was cold at the same time, but the Milankovitch theory should have opposite effects for the Northern and Southern Hemispheres, and thus cannot explain the synchronous advance of glaciers around the globe.
The point is the SH. and N.H. are not created equally when it comes to their response to Milankovitch Cycles.
The S.H. is set up as in such a way that it does not really matter if summer time insolation increases or decreases because the area of land that is entrenched in snow/ice is going to remain the same regardless of summer time insolation changes , in contrast to the N.H. where a difference in summer time insolation can cause a significant difference in the land area covered by snow/ice, thus effecting the albedo of the entire planet.
S.H. albedo remaining steady while N.H. albedo increasing due to favorable Milankovich Cycles.
In other words it is the N.H. which is subject to changes due to Milankovitch Cycles /albedo changes which influences the entire globe while the S.H is not subject to those changes nearly as much due to geographical considerations.

Data Soong
Reply to  Salvatore Del Prete
March 20, 2015 11:16 am

I just realized that this same idea that I pointed out in a reply above is exactly what you mentioned here mere minutes before me. It’s good to know that I am not alone with my hypothesis. 🙂

Reply to  Data Soong
March 21, 2015 12:23 am

The Northern Hemisphere has a land/sea ratio of 1:1.5 approx. The Southern Hemisphere has 1:4. The oceans control the SH.
The Milankovic Cycles footprint is too widespread and deeply impressed in the geological record to be dismissed. Besides, precessional wobble of the planet’s axis of rotation is not the only MC, there are all the orbital variations as well. At present, the MC have brought things together in a very benign assembly with the planet’s orbit very close to circular, with an eccentricity of the about 0.0167 which means the orbit is nearly circular. the Earth’s orbit is nearly circular.
The eccentricity varies from about 0.0034 (even more circular than now) to almost 0.058 over hundreds of thousands of years as a result of gravitational interactions among the planets.

Steve from Rockwood
Reply to  Salvatore Del Prete
March 20, 2015 11:45 am

And elevation differences probably as well.

Reply to  Steve from Rockwood
March 20, 2015 9:06 pm

…and the “continental drip theory” – where the continental land masses drip down from the north pole – so that there is more land mass in high latitudes of the northern hemisphere, whereas in the southern hemisphere the preponderance of continental land mass is at the equator – excepting Antarctica itself.

Reply to  Salvatore Del Prete
March 20, 2015 1:52 pm

“This makes sense in that the whole world was cold at the same time, but the Milankovitch theory should have opposite effects for the Northern and Southern Hemispheres, and thus cannot explain the synchronous advance of glaciers around the globe. ”
Is where they have gone idiotically wrong. You, Salvatore, and Data Soong, have got it right.
“They” have made the typical “noob” idiot mistake of simplification and leap to conclusion. Had they actually read about the Milankovitch cycle hypothesis they would have enough clue to know they were being idiotic.
The “thumbnail” is that first Milankovitch thought something similar, but found the data conflicted. Then he tried another approach that also failed as it was “exactly backwards”. Then he had the “Ah Ha!” moment and got it right. It is all neatly described in a history of his work that I’ll recommend below. But first:
The basic cause of the asymmetry is the land. The South Pole is all land all the time surrounded by water. The North Pole is all water all the time surrounded by land. Due to this, the South Pole is ALWAYS frozen. Always. Full stop. No melting. Done deal. (Anyone talking about the South Pole “melting” is full of it. No other option applies.) Only the North Pole can melt.
And melt it does, but ONLY when things are just EXACTLY right. We are, fundamentally, an Ice Age Planet that pops out of it just for a tiny little while and only when things are just right to melt the north pole ice. Anyone who is all worked up that the North Pole is melting is like the dog trying to sink his teeth into a car tire doing 30 MPH. If he gets what he wants he will be seriously injured and absolutely mortified. WHEN the North Pole freezes over next and stays frozen we are headed head first into that long night of deep freeze frozen ice age “pronto” with no recourse. Again: Period, full stop.
What Milankovitch figured out was that when ALL the parameters of the Earth Orbit line up just so, we barely cross the threshold for North Pole melting and poke our little frozen noses out for just a little while. Then when any of them gets far enough away from that magic alignment, it’s all ice ice baby all the time again. We are presently on the cusp of that W/m^2 rate and can be stable in either frozen or melted states depending on albedo of snow on the ground…
One other point, the key bit is NOT distance from the sun. In fact, we melt when furthest from the sun. Solar energy is not diminished worth note by distance, BUT when the Earth is at it furthest from the sun, it takes longer to make the season change happen. So when it is summer at furthest from the sun we have a few more days of summer. It is that few more days, not the simple W/m^2, that melt things and let the interglacial happen.
So, when summer in the Northern Hemisphere happens with the Earth furthest from the sun, and the tilt is maximized so polar heat is maximized, and the orbital eccentricity is maximum so we get the most added days of N.H. summer, then, and only then, can ONE pole melt, that being the N.H. pole, and allow an interglacial. At all other configurations we freeze.
(Sidebar per the 41K / 100K year problem: IMHO it is pretty easy to explain. In the past we were warmer. We could melt the north pole on lesser changes, like the 41 ky changes alone. Now we are, overall, much colder. It takes ALL the parameters being neatly aligned and that only happens on the 100 Kish year cycle. Really about 120 ky including the interglacial part… Look at the temp record and you can still see spikes up at the 41 ky cycle points, just not enough to melt the North Pole…)
FWIW, if you would understand the actual Milankovitch theory (which is unlike what most folks think it is and post about and complain about and…) there is a very nice small and readable book that explains it all nicely. It is the story of the history of Milankovitch and his work with paper and pen while in a German prison, only incidentally going into the theory and how it works, via relating what he tried and failed and tried again until he got it right. That book is highly recommended:
“Ice Age: The Theory That Came In From The Cold!” by John and Mary Gribbin.
Please, buy it and read it. It’s a wonderful tale and full of useful information for the small size and only 105 pages. You will never look at Milankovitch the same way again once you know about his life and how carefully he worked all this out. Spending, literally, years in a prison cell with plenty of time to think and nothing but pen and paper to do the work. (The Germans in that WW were not fond of his nationality…) At the end you will understand just how interglacials form, and why they are the key bit, not “why ice ages happen”… we are default ice…
If the warmistas had a clue about this they would be actively praying for “global warming”. In no more than 2000 years and potentially as short as 300 years you can kiss Canada good-by as the ice returns. New York City goes too, but a bit later as the ice takes a while to build up… And there is absolutely nothing we can do to stop it.
Now, back at this “paper”…
As they have already got it entirely wrong by saying that the hemispheres ought to be counter cyclical to each other (and completely do not have a clue that Milankovitch took that approach, found it wrong – provably – and discarded it) and are clueless about what Milankovitch actually SAID causes interglacials, the rest of their work is disposed of in the same trash barrel. If you can’t even check your references and read your citations, the rest is going to be garbage…

Reply to  E.M.Smith
March 20, 2015 2:27 pm

Like your description

We are, fundamentally, an Ice Age Planet that pops out of it just for a tiny little while and only when things are just right to melt the north pole ice.

But please don’t think this contradicts what I stated as being the fundamental most accurately known data . What you are saying is that it’s the very non-linear interaction between the asymmetry of the hemispheres and 3% change in our distance over ( peri- ; ap- ) -helion cycle , and the 273.15K tipping point which dominate effect .
The gray body temperature in our orbit is only about 3.1 degrees above that freezing point at aphelion so the fact that the planet is livable at all is a close call .

Reply to  E.M.Smith
March 20, 2015 2:34 pm

Milankovitch Book is ordered, thank you.
“Ice Age: The Theory That Came In From The Cold!” by John and Mary Gribbin.

Reply to  E.M.Smith
March 20, 2015 2:42 pm

We have only been an ice planet since the Oligocene, when Antarctica was separated from the other Gondwanan continents by deep oceanic channels. Then, as a reult of the closure of the Inter-American Seaway about three million years ago, the NH joined the SH in being icy.
Ice Houses occur at about 150 million year intervals, but the extent of ice depends upon the configuration of the continents. The Mesozoic Ice House interval didn’t produce major ice sheets, but the two during the Paleozoic Era did (the first with CO2 levels in the thousands of ppm). Before that, under a weaker sun, the Precambrian Ice Houses led to Snowball or Slushball Earth episodes.
Nir Shaviv, et al, have argued that Ice Houses result from earth’s passage through spiral arms of the galaxy.

Reply to  E.M.Smith
March 20, 2015 4:57 pm

E.M.Smith March 20, 2015 at 1:52 pm
Tx, great summary.

Reply to  E.M.Smith
March 20, 2015 11:10 pm

A very good overview.
What the mid-Pleistocene revolution (change from approximate 41 kyr to 100 kyr interglacial spacing) is indeed that in the long term glaciation is deepening and it is getting harder to pop out of glacial to interglacial.
We may just be in a transition phase going into deep global glaciation, as the earth does every 150 million years or so. Snowball earth could lie ahead.

Reply to  E.M.Smith
March 21, 2015 1:04 am

The norm for planet Earth is not an ice age. It has had over a 1.5 billion years of no ice. We are in an ice age at present, and have been in the Quaternary Ice Age for about the last 2.4 MY. The Ice Age alternates between stadials (cold periods or glaciations) and interstadials (momentary warm periods.)
At first, the stadials, or glaciations, lasted about 41,000 years but the later ones (including the last one) have lasted 100,000 years. Lifetime of the interstadials has been anything from about 10,000 years to the current one’s 12,000+ years. Another glaciation may not be far away.
For the cause of Ice Ages, we have to look to the Solar System’s orbit about the centre of the galaxy. Each time a spiral arm is crossed, there appears to have been an Ice Age. See Dr. Nir Shaviv’s research published on his website.

Reply to  E.M.Smith
March 21, 2015 8:00 am

Thanks EM & others.
And then there’s Roe’s analysis correlating rate-of-ice-growth/decline w/the Milankovitch cycles quite closely. So there’s little doubt MCs are the underlying cause. Of course, regional positive feedbacks (prb’ly a combination of albedo, ice-sheet dynamics and N Atlantic circulation changes) are present amplifying the MCs.
The less Arctic ice/snow there is, the more buffer we have from the next glacial temperature plunge.

Samuel C Cogar
Reply to  E.M.Smith
March 21, 2015 2:40 pm

E.M.Smith, …. great explanation, …. i thoroughly enjoyed reading it …. and learned a few new things in the process.

Reply to  E.M.Smith
March 21, 2015 3:44 pm

Ouch, no Kindle edition!

Gentle Tramp
Reply to  E.M.Smith
March 21, 2015 6:08 pm

@E.M. Smith
Thanks for your interesting opinion, but your following quote is rather wrong.
QUOTE: “Spending, literally, years in a prison cell with plenty of time to think and nothing but pen and paper to do the work. (The Germans in that WW were not fond of his nationality…)”
In reality he spent only a short time in a real prison cell but was then allowed to work for 4 years freely and with all normal comforts in the very well equipped library of Budapest University until the end of WW 1. This was in fact a really ideal place for his work, where he was treated with all respect and dignity. (BTW: It were not Germans but Austrian who did detain him as an enemy state citizen during WW1. This was a quite common practice of all belligerent nations in the world wars and German citizens living in France, UK, Australia, Canada (and later in the US) had to endure the same treatment as well, but the most of them under less comfortable conditions.)
In WW2 he was not bothered by the Germans at all. On the contrary, in Wikipedia one can read for instance:
“After the successful occupation of Serbia on 15 May 1941, two German officers and geology students came to Milanković in his house and brought greetings from Professor Wolfgang Soergel of Freiburg. Milanković gave them the only complete printed copy of the “Canon” to send to Soergel, to make certain that his work would be preserved. Milanković did not take part in the work of the university during the occupation, and after the war he was reinstated as professor.
The “Canon” was issued by the Royal Serbian Academy, 626 pages in quarto, and was printed in German as “Kanon der Erdbestrahlung und seine Anwendung auf das Eiszeitenproblem”. The titles of the six parts of the book are:
– The planets’ motion around the Sun and their mutual perturbations
– The rotation of the Earth
– Secular wanderings of the rotational poles of the Earth
– The Earth’s insolation and its secular changes
– The connection between insolation and the temperature of the Earth and its atmosphere. The mathematical climate of the Earth
– The ice age, its mechanism, structure and chronology.
During the German occupation of Serbia from 1941 to 1944, Milanković withdrew from public life and decided to write a “history of his life and work” going beyond scientific matters, including his personal life and the love of his father who died in his youth. His autobiography would be published after the war, entitled “Recollection, Experiences and Vision” in Belgrade in 1952″
For more information of his life and work see here:ć

Reply to  E.M.Smith
March 21, 2015 6:17 pm

EM Smith, thanks for a very insightful explanation re. Milankovitch’s work, and also for recommending the Gribbins’ book. I read about ten books of John Gribbin’s books between 20 or 30 years ago on astronomy and cosmology-related subjects and I enjoyed them all. But I didn’t know John and Mary had written on Milankovich. So now I’m looking forward to reading that.
As for the “switch” from 41K to 100K cycles, just as you say, the first assumption must be that the earth has gotten colder so now takes more than maximum inclination to accomplish the melt. But why has it gotten colder? Is there a cosmic connection? Or could the root cause be that the annual pulse of Antarctic meltwater that has been going on for 20 million years or more has been steadily making the deep oceans colder, and thereby indirectly cooling the surface from below?

March 20, 2015 11:00 am

Evaporation from the ocean surface is how the ocean and atmosphere cool at the surface.

March 20, 2015 11:01 am

This whole CO2 meme will set back several scientific disciplines by a generation as the CAGW crowd sucks up finite funding and leads everyone on a wild goose chase.

Reply to  Tucker
March 20, 2015 3:43 pm

Somewhere Comrade Lysenko is smiling….

Reply to  Tucker
March 20, 2015 3:46 pm

Wrong tense .

March 20, 2015 11:07 am

So the oceans cool, which lowers atmospheric co2, and warm, raising atmoshpheric co2
But it is the co2, not the warming and cooling oceans which control the temperature??

Reply to  phodges
March 20, 2015 11:31 am

Correct, according to The Church of CO2, the flea controls the elephant.

Reply to  phodges
March 20, 2015 12:39 pm

It seems to me that we are at the stage where portraits of the CO2 molecule are being spotted in wall stains, etc.

Paul Coppin
Reply to  otsar
March 21, 2015 5:29 am

It was there, this morning, brazenly staring back at me from the top cake in my stack of pancakes. I did the only responsible thing I could think of, I sequestered it.

Reply to  otsar
March 21, 2015 3:58 pm

The proper term for it is “carbon pollution”.
I wonder if these people worry about getting too much chlorine in their diet from eating salted potato chips?

March 20, 2015 11:08 am
Here is data showing temperature records which shows they are full of it.

March 20, 2015 11:26 am

It is the season of the N.H. that dictates the average global temperature for the globe not the S.H.
Same principal for Milankovitch Cycles . My post at 11:00am, Mar 20 look at.

March 20, 2015 11:29 am

ALL ‘science studies’ today that have anything remotely to do with ‘climate change’ is pegged on the CO2 stuff. All of it. This is how they get their funding. Even the stupidest, most unattached object of study has to be tied into ‘CO2 is going to kill us/it’.

March 20, 2015 11:36 am

They have got to be kidding me. Seriously? So all that 22 and 40 and 100 ky stuff visible across the entire Pliestocene, that’s all just chaotic oscillation in some sort of complex oceanic CO_2 reservoir system? Pure chance that the periods are coincident with orbital stuff?
I want some of what they’re smoking.

Reply to  rgbatduke
March 20, 2015 11:45 am

“I want some of what they’re smoking.”
Yeah, but do they have to light it with our paper money?

Reply to  rh
March 20, 2015 5:28 pm

Thank you for admitting that there is no substance that you can smoke that will lower your IQ by 60 points.
If you believe that is what I said, I can only conclude that you have a reading comprehension problem. It is unknown to me if the problem is of natural occurrence, or the consequence of IQ lowering by artificial means.

Reply to  rh
March 20, 2015 5:52 pm

That’s OK …..just blame it on what YOU are smoking.
Well I don’t smoke anything, hence the root cause is more likely naturally occurring deficiencies in mental acuity.

Reply to  rgbatduke
March 20, 2015 5:07 pm

I want some of what they’re smoking.
Well I am confused. You want something that demonstrably lowers IQ by 60+ points?

Reply to  davidmhoffer
March 20, 2015 5:18 pm

Mike Borgelt March 20, 2015 at 5:11 pm
Citation for your claim of lowering IQ please.

You have, apparently, missed the point of the comment. Since what they’re smoking is completely hypothetical, the effect is implied by the quality of their work. Since no specific substance was identified, only that the hypothetical substance was the root cause of the poor quality work, the request for a cite is unreasonable. If you believe otherwise, I can only wonder if you are suffering the deleterious effects of smoking the precise same hypothetical substance.

Reply to  davidmhoffer
March 20, 2015 6:01 pm

You are assuming their IQ were above 60 to begin with.

Reply to  davidmhoffer
March 20, 2015 9:19 pm

One can always go from sixty to zero by smoking hemlock.

Reply to  davidmhoffer
March 21, 2015 4:06 pm

“You have, apparently, missed the point of the comment. Since what they’re smoking is completely hypothetical, the effect is implied by the quality of their work. Since no specific substance was identified, only that the hypothetical substance was the root cause of the poor quality work, the request for a cite is unreasonable. If you believe otherwise, I can only wonder if you are suffering the deleterious effects of smoking the precise same hypothetical substance.”
Thank you all for proving my friends are wrong when they label ME the single most argumentative person on the planet.

Reply to  rgbatduke
March 21, 2015 7:13 am

March 20, 2015 at 11:36 am
Very wrong rgb.
That will mean that the 22, 40 and 100ky stuff, where probably you missed the 60ky stuff in between, can be explaining that the climatic cycles are of 20ky length, so every 100ky glacial period will be seen as a summery of 5 full climatic cycles (periods),,,,, as the climatic signal of Alaska suggests..:-)
Is not chaotic at all.::-),,,,,,,or perhaps only to those who try to deny even the contemplation of this as probable.
The coincidence of anthropogenic CO2 emissions with the global warming that is failing to turn in an AGW is a much more head scratching coincidence than the one you mention.

March 20, 2015 11:39 am

OMG, how stupid can they get – when global temperatures are running about 5-6 degrees C, like they did 20,000 years ago, you bet that glaciers will be growing in locations like Chile and New Zealand.

March 20, 2015 11:41 am

That evidence for cold periods within the last glacial period is some good data to have. Now we just need to extend the solar activity record back that far. Usoskin 2007 produced/examined an 11,500 year proxy record from GCR in ice cores. Shaviv produced a much longer 500 million year record from his meteorite study, but with very low resolution. Is there any ice-core GCR study or stalagmite GCR study or other type of cosmogenic isotope study extends the higher resolution solar proxy record back 20,000 or more years?
Ok, here we go, a 2002 paper studying GCR in marine sediments: “Variations in solar magnetic activity during the last 200 000 years: is there a Sun–climate connection?”
Excerpt: “The marine δ18O record and solar modulation are strongly correlated at the 100 ka timescale. It is proposed that variations in solar activity control the 100 ka glacial–interglacial cycles.”
And from 2004: “Evidence for a link between the flux of galactic cosmic rays and Earth’s climate during the past 200,000 years,”
which includes a graph of several 200,000 year proxy records:
Would be nice to see the evidence for a possible solar explanation for this new cold-period data considered alongside the possible CO2 explanation.
Anybody know of any more recent higher-resolution solar proxy studies for the last glacial period?

March 20, 2015 11:43 am

How do they explain all the ice ages that occurred after the CO2 levels were in the thousands of parts per million? Shouldn’t the earth have burst into flames after it reached the “tipping point?”

Reply to  rh
March 21, 2015 4:14 pm

That was different, because we did not add that CO2.
It only causes a problem when it is “unnatural” human added carbon pollution.
Honestly though, all one needs to know is that CO2 always lags warming.
Cooling starts while CO2 is rising, and warming starts while CO2 is falling.
Over and over again. It could not be more clear.
CAGW is pure BS, as is the hypothesis written about in this article.
BTW, thanks to all the sane people who comment here.

March 20, 2015 11:46 am
Next I will send average global temp. for July to show N.H. dictates this.

March 20, 2015 11:48 am
This ties in with the points I was making in my post at 11:26 am and 11:00am mar 20

March 20, 2015 11:50 am

The CAGW hypothesis suffers from the logical fallacy of post hoc ergo propter hoc…
The reason CO2 levels fall during glaciation periods is that cooling oceans absorb more CO2, and during warm Interglacials, warming oceans release more CO2 due to a process called outgassing..
Ice core analysis shows that when global cooling cycles first start, CO2 levels are still rising, and when global warming cycles first start, CO2 levels are still falling…. Eventually the CO2 levels follow the warming/cooling trends, but that’s in response to ocean temps…
Milankovitch cycles involving Earth’s orbital eccentricity, axial tilt and precession, combined with solar flux still best explain the long and medium term climate cycles.
CO2 levels merely FOLLOW Milankovitch cycles, and certainly are NOT the climate control knob, which Warmunists desperately try to claim…

March 20, 2015 11:53 am

They only go back 41kyrs — not even half a full glacial/interglacial cycle. The paper is paywalled so it’s hard to know exactly what they did. Projects CLIMAP and SPECMAP used much better dated sediment cores worldwide to establish the theory than beryllium in moraines. And it was recognized way back in the 1980s that continental ice certainly modified the purely orbital-based cycles. It will take a lot more to disprove the Milankovich explanation.

March 20, 2015 12:02 pm

Well let’s see…extended ice coverage in the northern Hemisphere = more sunlight reflected = less heat absorbed by planet = cooler oceans & atmosphere = buildup of ice on poles, mountain tops worldwide = advancing glaciers in both hemispheres. My theory would be that the Milankovitch cycles that are able to warm the northern hemisphere aren’t able to do the same in the southern hemisphere as effectively due to the lack of ocean over the southern pole. A good indicator of this would be to determine the speed at which the ice advances over the northern hemisphere versus the speed it advances over the southern hemisphere. It should be somewhat slower in the southern hemisphere.

Bruce Cobb
March 20, 2015 12:05 pm

Funny how if you study the tail of a dog the dog moves in relation to the tail, ergo, the tail wags the dog. QED.

Mark from the Midwest
March 20, 2015 12:09 pm

Dartmouth, home of the Maple Tree Study, (see WUWT Feb 26). They seem to be willing to do any kind of schlock study to try and be relevant to the AGW crowd.

March 20, 2015 12:10 pm

As discussed in our website, prolonged, intense episodes of effusive basaltic volcanism end ice ages by depleting ozone due to erupted chlorine and bromine (as HCl and HBr), resulting in increased high-energy UV-B irradiance, which causes global warming, whereas prolonged, intense episodes of explosive andesitic volcanism plunge Earth into ice ages by loading the stratosphere with dust and sulfate aerosols, thus increasing albedo (andesitic eruptions also produce HCl and HBr, but their warming effect is overwhelmed by the cooling effect of dust and aerosols). Both styles of volcanism are the result of tectonic plate motion (basaltic at divergent plate margins, andesitic at convergent margins). The synchronous tracking of glacial-interglacial cycles by Milankovitch rhythms in both hemispheres is more likely due to the latter’s gravitational effects on plate motion, which are global in scope, than to its effects on insolation, which are hemisphere-dependent.

March 20, 2015 12:13 pm

A long winded method of establishing claims that CO2 causes the Antarctic ice expansion?
Perhaps this theory belongs with the excuses for the pause in temperatures.

March 20, 2015 12:14 pm

CO2. Is there anything it cannot do?

Mark from the Midwest
Reply to  JP
March 20, 2015 3:27 pm

Yes, there are some things it cannot do, but we have good remedies with large quantities of fried fish and a massive amount of cold beer

Reply to  Mark from the Midwest
March 20, 2015 3:38 pm

Both of which are 90%( CO2+H2O – O2 ) + a bit of other stuff and more H2O

Michael Wassil
Reply to  JP
March 20, 2015 6:06 pm

JP March 20, 2015 at 12:14 pm
CO2. Is there anything it cannot do?

Nope. It’s puff the magic dragon.

Reply to  JP
March 20, 2015 9:23 pm

I’t didn’t cook my breakfast, wash my clothes, or shovel the snow off my walk.

Reply to  eyesonu
March 21, 2015 4:20 pm

That is because you lack the funding necessary to show the link between CO2 and cooked breakfasts, washed clothing, and shoveled walkways.

Joel O’Bryan
Reply to  eyesonu
March 21, 2015 8:57 pm

All you need to do is get on CO2 AGW grant gravy train and with a $250K/yr senior professor PI salary, you can pay someone else to do those things. It’s simple, it uses someone;s money to make those little life annoyances go away. That’s how the Limousine Liberals do it.

March 20, 2015 12:19 pm

How do papers like this get published, mostly with other peoples money?
Imagine that the US government thought glacier cycles were caused by a giant comet that comes close to earth every 100K years. Particles from the comet’s tail get caught in earths gravitational field for thousands of years, blocking the sun. The particles slowly fall to earth, and just when the planet starts to warm up, here it comes again. Then imagine that government issued several Billion dollars worth of grants to prove it. How many peer-reviewed papers would be produced saying that it could, may, might, possibly, be true?

William Astley
March 20, 2015 12:22 pm

If the warmist’s objective was to solve a scientific problem rather than to their push CO2 propaganda, then would have considered the logical implications of all of the paleo climatic data and the current temperature data.
Cyclic warming and cooling both poles requires a mechanism that is capable of simultaneously warming and cooling both poles. There is no mechanism to cyclically increase and decrease atmospheric CO2. CO2 does not cyclically increase and decrease when there is Dansgaard-Oeschger warming and cooling both poles. Variation in atmospheric CO2 is not the cause of the Dansgaard-Oeschger warming and cooling and is not the cause of the glacial/interglacial cycle.
There is cyclic warming and cooling in the paleoclimatic record (both poles cyclically warm and cool with the same periodicity 1500 years and 400 years) that correlate with high solar magnetic cycle activity were all followed by a cooling phase when the solar magnetic cycle moves into a like maunder minimum.
P.S. The solar magnetic cycle is moving rapidly into a Maunder like minimum which explains why there is suddenly record sea ice in the Antarctic and the start of high latitude cooling in the Northern hemisphere.

“Does the current global warming signal reflect a natural cycle”
…We found 342 natural warming events (NWEs) corresponding to this definition, distributed over the past 250,000 years …. …. The 342 NWEs contained in the Vostok ice core record are divided into low-rate warming events (LRWEs; < 0.74oC/century) and high rate warming events (HRWEs; ≥ 0.74oC /century) (Figure). … ….The current global warming signal is therefore the slowest and among the smallest in comparison with all HRWEs in the Vostok record, although the current warming signal could in the coming decades yet reach the level of past HRWEs for some parameters. The figure shows the most recent 16 HRWEs in the Vostok ice core data during the Holocene, interspersed with a number of LRWEs. …. ….We were delighted to see the paper published in Nature magazine online (August 22, 2012 issue) reporting past climate warming events in the Antarctic similar in amplitude and warming rate to the present global warming signal. The paper, entitled "Recent Antarctic Peninsula warming relative to Holocene climate and ice – shelf history" and authored by Robert Mulvaney and colleagues of the British Antarctic Survey ( Nature, 2012,doi:10.1038/nature11391), reports two recent natural warming cycles, one around 1500 AD and another around 400 AD, measured from isotope (deuterium) concentrations in ice cores bored adjacent to recent breaks in the ice shelf in northeast Antarctica. ….
Furthermore there is a peculiar polar temperature anomaly which provides an additional logical pillar to support the assertion that solar cycle modulation of planetary clouds is the cause of the cyclic warming and cooling.
When both polar regions warm, the Antarctic ice sheet cools slightly. When both polar regions cool, the Antarctic ice sheet warms slightly. This phenomena is confusingly called the polar see-saw (which implies that entire polar region is affected when it is only the Antarctic ice sheet which is out of syn) as the Greenland ice sheet warms when the Antarctic ice cools and vice verse.
The cause of the Antarctic ice cyclic temperature anomaly, is as explained by Svensmark in this paper, that the albedo of the Antarctic ice sheet is higher than low level clouds and the Antarctic ice is isolated by the Antarctic polar vortex. Therefore an increase in low level clouds in the high latitude regions of the Southern hemisphere causes the Southern sea to cool and the Antarctic ice sheet to warm slightly.
A reduction in high latitude Southern hemisphere cloud cover, post 2012 is the explanation for the record Antarctic sea.

The Antarctic climate anomaly and galactic cosmic rays
Borehole temperatures in the ice sheets spanning the past 6000 years show Antarctica repeatedly warming when Greenland cooled, and vice versa (Fig. 1) [13, 14]. North-south oscillations of greater amplitude associated with Dansgaard-Oeschger events are evident in oxygenisotope data from the Wurm-Wisconsin glaciation[15]. The phenomenon has been called the polar see-saw[15, 16], but that implies a north-south symmetry that is absent. Greenland is better coupled to global temperatures than Antarctica is, and the fulcrum of the temperature swings is near the Antarctic Circle. A more apt term for the effect is the Antarctic climate anomaly.
Timing of abrupt climate change: A precise clock by Stefan Rahmstorf

Many paleoclimatic data reveal a approx. 1,500 year cyclicity of unknown origin. A crucial question is how stable and regular this cycle is. An analysis of the GISP2 ice core record from Greenland reveals that abrupt climate events appear to be paced by a 1,470-year cycle with a period that is probably stable to within a few percent; with 95% confidence the period is maintained to better than 12% over at least 23 cycles. This highly precise clock points to an origin outside the Earth system; oscillatory modes within the Earth system can be expected to be far more irregular in period.

Reply to  William Astley
March 21, 2015 4:27 pm

Very worrisome.
I suspect that by the time the truth becomes obvious to everyone, the skeptics will have little cause or inclination to gloat, as we will all be in a very bad situation, with crops failing and famines ensuing.
Unlike the warmistas, I hope very much to be wrong, and will be happy if the Grand Solar Minimum and associated cooling turns out not to occur.
But that sunspot trend chart looks an awful lot like real science, and reeks of having not been made up to suit a political agenda.

March 20, 2015 12:22 pm

This paper has 10 authors, with surely many 100’s hours put into this by each author. How can so many people be so ignorant, or so fooled, into wasting their careers?
“The researchers found that glacier movement in the Southern Hemisphere is influenced primarily by sea surface temperature and atmospheric carbon dioxide rather than changes in the Earth’s orbit..”
But we can still be happy for them. It seems good enough to have their CO2 religion work (at random times) only in the Southern Hemisphere.

March 20, 2015 12:38 pm

Orbital mechanics since Kepler have been known more precisely than any other factor determining our insolation and thus temperature . Holding spectral map constant , our temperature varies as the square root of our distance from the Sun . More surely than the flushing of a toilet , this is settled physics . None of this “no such thing as settled … ” crap .
Orbital factors should simply be calculated and subtracted from the data . Then the unexplained variance is left in the residuals .
That’s one reason I found so interesting . It analyses the largest cycle of all ( next to the diurnal ) , the 0.8% +- variation our equilibrium temperature from peri- to ap- -helion . That variation in energy must be accounted for and the fact that some is in subharmonics makes me want to understand PID math better .
I don’t understand why satellite thermal engineers are not more involved in these debates . There’s an awful lot of relevant settled quantitative understanding and algorithms in that field .

Stephen Richards
March 20, 2015 12:39 pm

How on earth did they seperate the efect of CO² from that of the oceans and milankovic?

March 20, 2015 12:44 pm

“…glacier movement in the Southern Hemisphere is influenced primarily by sea surface temperature …”
well, that’s kind of a given, isn’t it?

March 20, 2015 12:48 pm

And let’s ignore the position of the continents while we are at it… We wouldn’t have a big mountain of ice at the south pole if there wasn’t a land mass down there to catch all that frozen water. A quick trip to the Scotese website will reveal a landmass at the poles is not essential for an iceage, but it sure helps if the Milankovitch cycles are favouring cold times!

Reply to  travelblips
March 21, 2015 2:32 am

Generally, there is always glacier when there is land at one of the poles.
They do have to be above sea level however, and when a 3 or 4 km glacier builds up and lasts for a million years, the landmass tends to get depressed, often below sea level. The ocean floods in and the glaciers break-up. This appears to be common enough, so there can be periods of time when a continent is at one of the poles but remains unglaciated most of the time because it is below sea level.
Land masses can also be configured so that mid-latitude ocean Gyres flow along the western side of the continent(s) and keep it warm enough to stop full glaciation. It is still frigid especially in the six months of darkness but the snow can melt in the summer.

Catherine Ronconi
Reply to  Bill Illis
March 21, 2015 4:10 am

Ordovician/Silurian Ice Age, onset c. 443 Ma: lots of land at the South Pole. Map is from before the onset of glaciation. Look at Silurian map (from after the glaciation) to see how the continents were drifting.
Carboniferous/Permian Ice Age, c. 300 Ma: lots of land near the South Pole.
Jurassic/Cretaceous Ice House, c. 168 Ma: Colder than before and after during the warm Mesozoic Era, but not enough land at either pole for ice sheets to form, hence no “Ice Age”, but there were montane glaciers. During the preceding age of the Middle Jurassic Epoch, sea temperature fluctuated, so hard to date onset of Ice House conditions. Evolution of proto-feathers may have been in response to colder conditions.
Cenozoic Ice Age, c. 38 Ma: Antarctica over the South Pole and separated from South America and Australia by deep ocean channels. Ice sheets on that continent in the Oligocene Epoch, waxing and waning during the Miocene and Pliocene, then joined by NH ice sheets in the Pleistocene, after closure of the Inter-American Seaway.

Bill Illis
Reply to  Bill Illis
March 22, 2015 5:38 am

Here’s the perfect explanation for the Ordovician and Carboniferous ice ages (noting the two situations I mentioned above which can stop the glaciers).
You can think of it as Gondwana starting upside down in the South Pacific and migrating across the South Pole, taking 150 million years. It eventually broke up and Africa then ended up rightside up at the equator. Antarctica briefly moved north off the south Pole but then drifted back to end up right on top of it.
Gondwana lasted from 570 Mya to 200 Mya (having also been part of Pangea from 290 Mya to 200 Mya). Before that, they also were part of the super-continent Pannotia which was at the south Pole from 650 Mya to 600 Mya which resulted in the last Snowball Earth episode (basically all the continents were locked together over the South Pole and temperatures on top of the 5 km high glaciers reached -100C).
The high resolution temperature estimates put the peak of Ordovician ice age at -7.5C, 443.4 million years ago which is the exact peak of the extinctions timeline. The ice age started at 458 Mya and ended by 415 Mya.
The Carboniferous ice age stared about 360 Mya and ended about 290 Mya, although there were brief interludes in this ice age.
So something kept Gondwana relatively ice free from 415 Mya to 360 Mya. The best guess would be that all the land near the pole was pushed down below sea level by all that glacier and when it eventually rebounded back above sea level, the glaciers rapidly returned and the land was pushed down again. (we know north Africa went below sea level not long after the Ordovician ice age started but there isn’t much data for the non-glaciated interval).
Note how many times I mentioned land at the South Pole and resulting ice ages.

March 20, 2015 2:20 pm

Alice is in climate wonderland.
The Milankovich theory (scary east-European sounding name so it must be wrong – Gaad bless America!) states that since the MPR interglacials are spaced by about 100,000 years corresponding to the eccentricity cycle.
So they study the glacial dynamics of four New Zealand ridges – about 35,500; 27,170; 20,270; and 18,290 years old.
This is all within less than quarter of a SINGLE ONE glaciation – the most recent Wisconsin glaciation.
Can someone tell me how this is supposed to test a theory about glacial-interglacial spacing with a 100,000 year interval?
Does dear little Alice even understand what the Milankovitch theory is?
One year ago she probably didn’t even know what an ice age is, before getting drafted from political science to “climate science”.

Catherine Ronconi
Reply to  phlogiston
March 20, 2015 3:17 pm

Perhaps they’re studying the shorter term Milankovitch Cycles, those not derived from eccentricity, but obliquity, precession, etc.

March 20, 2015 3:12 pm

Steven Mosher is standing on his head and so all the evidence, for him, points to the verification of CAGW by any event.

Reply to  ntesdorf
March 20, 2015 6:02 pm


Reply to  ntesdorf
March 20, 2015 6:54 pm

sorry I dont agree that climate change will be catastrophic. you fail

Reply to  Steven Mosher
March 21, 2015 4:44 am

Must be the BAGW then Beneficial Anthropogenic Global Warming
or perhaps the
DMAGW; Doesn’t Matter Anthropogenic Global Warming
Regardless, what is debatable is the “Anthropogenic” and “degree and duration of Global Warming” parts of AGW, leaving only the it is either Beneficial, Catastrophic or Doesn’t Matter parts.
Which sounds about right

David A
Reply to  Steven Mosher
March 21, 2015 6:18 am

Steve M, do you actively criticize the disparate world wide attempts at CO2 mitigation and tax? If so where have you done this?

March 20, 2015 3:30 pm

ls it known if the ice sheets expanded over North America before the same thing happened in Europe during the last ice age.?
Because if that was the case, than l can understand how that would have helped to expand the ice sheets across Europe later on.

Pedantic old Fart
March 20, 2015 4:04 pm

Is anybody going to question how a combination of orbital eccentricity, axial wobble and precession could cause one pole of the earth to be cooled and the other pole warmed simultaneously? The “opposite effect. Does this require the earth to be stopped in its orbit for 100,000 years? How can they possibly make such a claim?

Michael 2
Reply to  Pedantic old Fart
March 20, 2015 5:35 pm

Pedantic old Fart “Is anybody going to question how a combination of orbital eccentricity, axial wobble and precession could cause one pole of the earth to be cooled and the other pole warmed simultaneously?”
No, not yet anyway. Past performance is not an indicator of future performance.

Sturgis Hooper
Reply to  Pedantic old Fart
March 21, 2015 6:47 am

Orbital eccentricity affects the whole planet equally. No need for stoppage.
Axial tilt and precession do lead to different insolation in the two hemispheres, but that doesn’t matter. In the present configuration of the continents, the effect of lower insolation at high latitudes in the NH is much greater than the effect of of greater insolation at high SH latitudes, where there is going to be ice no matter possible range in variation.
During the Ordovician and Carboniferous Ice Ages, the reverse was true. The preponderance of land was in the SH rather than the NH.

March 20, 2015 4:35 pm

This research might exclude Milankovitch cycles as main driver of the glacial->interglacial transition, but does not exclude them as a primer.
It’s actually not necessary to study New Zealand glaciers to come to the same conclusion, it is apparent from temperature proxies that show that by the time when the interglacial actually starts, the Milankovitch cycle is already back at its minimum. There’s something else driving the change of the climate. But again, “if we don’t see any other reason it must be CO2” is a bad argument here.
My opinion is that it is sea temperature/albedo cycle actually. During glaciation, Earth’s albedo is high thanks to all the surface/sea ice but the atmosphere is dry. All it takes is some thawing to reduce albedo and start the transition to interglacial. Once it’s warm and Earth’s albedo is low, the sea water gradually warms up and drives atmospheric humidity along. When the humidity is high enough, clouds increase albedo again and the Earth starts descent towards another glaciation. As soon as there is enough surface ice and sea water cools down sufficiently, atmosphere dries out again and is primed for another transition to interglacial.

March 20, 2015 4:43 pm

Astrology can also be really complicated and take years to study all the associated BS.

Reply to  wickedwenchfan
March 20, 2015 5:36 pm

If you think climate and astrology are difficult, then just have a crack at alienology.
It could be the new science to replace climatology if the climate research grants dry up.
Then we will in our lifetime have seen Y2K, CAGW and then aliens.

Reply to  toorightmate
March 20, 2015 7:04 pm


Then we will in our lifetime have seen Y2K, CAGW and then aliens.

Undocumented not-yet-arrived immigrants.

March 20, 2015 5:49 pm

CAGW forecasting is like driving a car using the rear view mirrors.

Reply to  Max Photon
March 20, 2015 9:38 pm

I did that once after hitting a deer (dark night) and the air bags deployed. One head light, van absolutely full of smoke, but fortunately heavy traffic so I could steer by the drivers side rear view mirror (driving by the other drivers headlights behind me only to tell from the lines in the road in the mirror if I was still in the road) for over a quarter of a mile.
Air bags create a load of smoke. EPA regulation?

Reply to  eyesonu
March 20, 2015 9:42 pm

Forgot to add: 60 mph, smashed glasses, bruised arms and chest.
[Good, quick thinking. Glad you survived with no further injuries to yourself, your passengers, or your fellow drivers.
Was the deer OK? .mod]

March 20, 2015 6:24 pm

It might be nice if Mosh provided some proof for the stuff he posts. But that would be too much to ask of him.

Reply to  Tom Trevor
March 20, 2015 6:48 pm

read the paper.

March 20, 2015 6:27 pm

So what if the research discussed in the head article gave an obligatory nod to CO2. Thousands of other research papers do the same. It happens without the authors even being aware of what they are doing. What is notable is that the timing of the glacial events that have been identified in this study ties in nicely with a number of other modern studies on glaciation in the Southern Alps (South Island, New Zealand). Interestingly it also ties in with the timing of several cold events identified in the various Antarctic ice cores. These cold events occur at times when there are modest warming events in the Northern Hemisphere. So the work probably confirms something that has been suspected for nearly 20 years. This is a see-saw relationship between Northern and Southern Hemisphere climatic events. The see-saw operates at a sub-Milankovitch scale (i.e. on the scale of Bond and DO events). The work indicates that the climate at 40 to 45 deg south of the equator (South Island, NZ) has direct linkages to events in Antarctica. So Southern Hemisphere climate is not a simple slave to that in the Northern Hemisphere, which is what had been thought until relatively recently.
There is discussion above about Antarctic ice volume. Please note that the extent of the Antarctic ice shelves and the grounding of the ice is dependent on sea level. As sea level rises and falls due to Northern Hemisphere ice sheets accumulating and then melting, the Antarctic ice shelves couple or decouple from bedrock. This changes the way the Antarctic ice is braced and lets ice either accumulate on land or flow to sea faster. So in some ways there is direct coupling between the Hemispheres and in other ways there is not.

masInt branch 4 C3I in is
March 20, 2015 6:35 pm

Cosmogenic radionucleotide dating such as beryllium-10 can be used to date exposed surfaces perhaps to 30 million years BP with a half-life of 1.387 million years. Milankovitch cycles (from Wikipedia), “The major component of these variations occurs on a period of 413,000 years (eccentricity variation of ±0.012). A number of other terms vary between components 95,000 and 125,000 years (with a beat period 400,000 years), and loosely combine into a 100,000-year cycle.”
The critical data from this study comes from “The ages of the four New Zealand ridges – about 35,500; 27,170; 20,270; and 18,290 years old”.
These “critical data” have nothing to do with Milankovitch cycles!
About 2 decades ago I found myself with a group of Geologists as we were examining an exposure of a diamicton with apparent drop-stones (i.e. a marine ice sheet of a Precambrian Glaciation, more than one) in the footwall of the Wasatch Fault adjacent to the campus of the Brigham Young University.
About a year ago I, as a reviewer, recommended rejection of a paper based on its Abstract.
I am sure that the “collections department representative” of the magazine Geology ‘tip-toed the light fantastic’ waving the Cheque above his head for all to see down the street to the bank that holds the accounts receivable of the magazine Geology.
Science is not served with papers like this.

March 20, 2015 9:16 pm

They are right about Milankovitch, wrong about CO2. Sure there is a Milankovitch forcing layer, just look at OCO-2 to see why plankton just love him, but his only cycle that produces a net insolation variation at planetary scale is eccentricity. Eccentricity has periods of 100k and 400k years. Neither period is evident in the first half of the Pleistocene. At the mid P transition an unsatisfying 100kyr period emerges, but the 400kyr signal is absent from the entire Pleistocene. Many, including Richard Muller, have suggested the apparent 100kyr signal in the late P is built up.
We might hazard a WAG about how many pertinent forcing layers Milankovitch must share his mojo with. There is probably some BS statistical regression for this. OR, we could quit dithering with epicycles and just admit we don’t know Jack.

March 20, 2015 9:34 pm

I thought the surges and ebbings of ice age glaciations in the past few million years had a linkage to atmospheric CO2 – with CO2 lagging, due to being a positive feedback rather than a root cause. Warmings caused the oceans to outgas CO2, and coolings caused the oceans to remove CO2 from the atmosphere.
Nowadays, the amount of CO2/carbon in the sum of the atmosphere, hydrosphere and biosphere is not constant but increasing, due to modern transfer of carbon from the lithosphere to the sum of the atmosphere, hydrosphere and biosphere. The oceans are removing CO2 from the atmosphere despite the warming, because anthropogenic CO2 is being dumped into the atmosphere, causing the atmosphere to be excessively CO2-rich compared to the oceans even considering warming causing reduced solubility of CO2 in water.
Solubility of a gas in a liquid is a ratio of gas concentration above the liquid to concentration of the gas in the liquid, which means a higher concentration of gas over the liquid means the liquid has to have more of the dissolved gas to be in equilibrium with the gas over the liquid. The good news here is that while adding CO2 to the atmosphere from lithospheric carbon warms the world, the hydrosphere can absorb some of this added CO2 despite warming reducing the solubility of CO2 in water, due to the nature of solubility of a gas in a liquid.

March 20, 2015 10:01 pm

A Milankovitch cycle does not always have to have planetary/global effect on insolation in order to have an effect on global temperature. If the northern and southern hemispheres have unequal climate sensitivity to a change in year-round insolation, or unequal climate sensitivity to a change in north/south balance of insolation (year-round or seasonal), then a Milankovitch cycle that does not affect global insolation may, or sometimes may, cause an effect.
The northern and southern hemispheres are very different. The Arctic is an ocean almost surrounded by land. The Antarctic is a continent surrounded by ocean. Regional feedbacks to the various Milankovitch cycles are not the same in these two areas.
Something that has been seen to complicate this is that the surges and ebbings of the ice age glaciations in the past ~1.2 million years largely followed the ~100,00 year eccentricity one of the Milankovitch cycles, and for almost two million years before, this largely followed one of the others.
Also changing in the past few million years, is when the modern several million years of ice age (caused by Antarctica’s contental drift taking it to the South Pole) lowered the global ocean level in recent millions of years, so that the Isthmus of Panama got in the way of connecting the Atlantic and Pacific oceans, in terms of heat transfer by ocean current.

March 20, 2015 11:01 pm

What the Climate State are doing to science is the same as what the Islamic State are doing to archaeology in Syria and Iraq.

William Astley
March 21, 2015 2:17 am

There is a misunderstanding by the general public, concerning the facts of what has happened in the paleo climate record, as to how large the past abrupt changes were, and how abrupt the past climate changes were, and that the very abrupt, very rapid changes are cyclical. The general public believe there has been one ice age, not 22 glacial/interglacial cycles where the cooling has become larger and faster.
Each and every interglacial period has started abruptly and ended abruptly 8000 to 12,000 years, later. The abrupt changes to the planetary temperature (Younger Dryas type changes where the high latitude regions cool by 8C with 75% of the cooling occurring in less than decade.) where in the order of the same magnitude as the Younger Dryas change.
Abrupt, rapid change climate is a real, imminent in your face problem, not a theoretical will happen in a 1000 years problem. If this assertion is correct, we need to move this discussion on.
The orbital position of the earth does affect planetary temperature. The mechanism is not however insolation changes from the sun.
Planetary temperature in the paleo record changes abruptly, not gradually changing. Insolation changes due to planetary orbital changes gradually not abruptly. Insolation changes due to orbital changes are opposite for the two hemisphere. Milvankovich’s insolation theory is an urban legend. (See this link for more than a half dozen paradoxes.) There is something fundamental incorrect with the approach to solve one of the most important scientific problems ever faced by humanity when an urban legend is still discussed decades after it is known it is an urban legend and cannot possibly cause what is observed. It is ironic, surreal, that we are discussing the increase atmospheric CO2 is not a problem, the problem.
The problem is that urban legends incorrectly, irrationally fill the theoretical void. Pure scientists have no idea how to solve holistic problems that involve multiple fields where there are multiple fundamental errors in the basic theories. (i.e. In the case of this problem the sun and other stars are different than assumed which explains what has happened in the past to the geomagnetic field and to the climate, and explains what is currently happening to the sun, and what will happen to the climate/geomagnetic/earth.)
The abrupt changes to planetary temperature are caused by abrupt changes to the geomagnetic field intensity and orientation. In the last 15 years, the geomagnetic field specialists have found the geomagnetic field changes cyclically and abruptly and that planetary temperatures correlate with the abrupt geomagnetic field changes.
The sun is causing the abrupt changes in the geomagnetic field and the orbital position when the sun changes abruptly modulates (amplifies or inhibits the solar change) the sun’s change on the geomagnetic field.
It is a physical fact that the geomagnetic field intensity is now for unexplained reasons dropping in intensity at 5%/decade and has dropped by roughly 8%. That is an extraordinarily fast drop. That is a drop faster than theoretical possible for core based changes. Changes in the earth’s core did not cause what is observed.…than-expected/

Earth’s magnetic field, which protects the planet from huge blasts of deadly solar radiation, has been weakening over the past six months, according to data collected by a European Space Agency (ESA) satellite array called Swarm. While changes in magnetic field strength are part of this normal flipping cycle, data from Swarm have shown the field is starting to weaken faster than in the past. Previously, researchers estimated the field was weakening about 5 percent per century, but the new data revealed the field is actually weakening at 5 percent per decade, or 10 times faster than thought. As such, rather than the full flip occurring in about 2,000 years, as was predicted, the new data suggest it could happen sooner. Floberghagen hopes that more data from Swarm will shed light on why the field is weakening faster now.

Is the geodynamo process intrinsically unstable?
Recent palaeomagnetic studies suggest that excursions of the geomagnetic field, during which the intensity drops suddenly by a factor of 5 to 10 and the local direction changes dramatically, are more common than previously expected. The `normal’ state of the geomagnetic field, dominated by an axial dipole, seems to be interrupted every 30 to 100 kyr; it may not therefore be as stable as we thought.

What Caused Recent Acceleration of the North Magnetic Pole Drift?
The north magnetic pole (NMP) is the point at the Earth’s surface where the geomagnetic field is directed vertically downward. It drifts in time as a result of core convection, which sustains the Earth’s main magnetic field through the geodynamo process.
During the 1990s the NMP drift speed suddenly increased from 15 kilometers per year at the start of the decade to 55 kilometers per year by the decade’s end. This acceleration was all the more surprising given that the NMP drift speed had remained less than 15 kilometers per year over the previous 150 years of observation.
Why did NMP drift accelerate in the 1990s? Answering this question may require revising a long-held assumption about processes in the core at the origin of fluctuations in the intensity and direction of the Earth’s magnetic field on decadal to secular time scales, and hints at the existence of a hidden plume rising within the core under the Arctic.(William: The cause of what is observed is not a massive Arctic region plum of magma that starts for unexplained reasons in the 1990’s. As noted above the satellite analysis has shown that drop in the geomagnetic field is now 5%/decade which is ten times faster than a core based change in the geomagnetic field.)

Are there connections between the Earth’s magnetic
field and climate? Vincent Courtillot, Yves Gallet, Jean-Louis Le Mouël,
Frédéric Fluteau, Agnès Genevey
We review evidence for correlations which could suggest such (causal or non-causal) connections at various time scales (recent secular variation approx 10–100 yr, historical and archeomagnetic change appox. 100–5000 yr, and excursions and reversals approx. 10^3–10^6 yr), and attempt to suggest mechanisms. Evidence for correlations, which invoke Milankovic forcing in the core, either directly or through changes in ice distribution and moments of inertia of the Earth, is still tenuous. Correlation between decadal changes in amplitude of geomagnetic variations of external origin, solar irradiance and global temperature is stronger. It suggests that solar irradiance could have been a major forcing function of climate until the mid-1980s, when “anomalous” warming becomes apparent. The most intriguing feature may be the recently proposed archeomagnetic jerks, i.e. fairly abrupt (approx. 100 yr long) geomagnetic field variations found at irregular intervals over the past few millennia, using the archeological record from Europe to the Middle East. These seem to correlate with significant climatic events in the eastern North Atlantic region. A proposed mechanism involves variations in the geometry of the geomagnetic field (f.i. tilt of the dipole to lower latitudes), resulting in enhanced cosmic-ray induced nucleation of clouds. No forcing factor, be it changes in CO2 concentration in the atmosphere or changes in cosmic ray flux modulated by solar activity and geomagnetism, or possibly other factors, can at present be neglected or shown to be the overwhelming single driver of climate change in past centuries. Intensive data acquisition is required to further probe indications that the Earth’s and Sun’s magnetic fields may have significant bearing on climate change at certain time scales.

Reply to  William Astley
March 21, 2015 12:20 pm

William Astley
March 21, 2015 at 2:17 am
From most of what you say, the only conclusion I get is:
Nothing in this Earth of ours has changed or varied lately more than the Magnetic field and the CO2 emissions.
Nice correlation there…!
Seems these two both in the same road lately!

Reply to  William Astley
March 23, 2015 5:42 am

I noticed your mention of warming in the 1980s. Work I’m now engaged on points to late 1987 as the point at which a sudden change in European/Russian temperatures changed by + 0.5 to + 1C. The traditional linear fit to climate around this period, say 1960 to the present, can be readily shown to be a poor model. Just split the data at about Sept 1987 and do two linear fits. Quick and easy and enlightening.

March 21, 2015 2:23 am

It was generally understood that the ice age cycles are governed by NH Milankovitch Cycles. The NH has land that is succeptible to Milankovitch downturns while the SH does not.
When it gets 5C colder in the NH, the SH does not escape that. The atmosphere is a well-mixed gas after all and there is no barrier at the equator to stop the oceans either.

William Astley
Reply to  Bill Illis
March 21, 2015 8:07 am

Milankovitch’s theory is an urban legend. The glacial/interglacial cycle is not caused by changes in summer insolation at 65N. There is no theory which provides a forcing mechanism as to what causes the glacial/interglacial cycle, the Dansgaard-Oeschger cycle, and the Heinrich events is better than the insolation urban legend.
In reality, in the physical world, there is a forcing function. The sun changes abruptly in a manner which we have never seen before which abruptly changes the geomagnetic field, which explains why the planet abruptly cooled during the Younger Dryas abrupt cooling event for 1200 years. The sun returns to its normal cycle, the geomagnetic field takes 1200 years to integrate the abrupt charge change. The orbital position when the Younger Dryas abrupt change occurred was to amplify the geomagnetic field when the integration was finished. The geomagnetic field intensity increases by a factor of three to four during the interglacial periods.
Come on man.
The following are some of the paradoxes that support the assertion that Milankovitch’s theory is an urban legend, summer insolation changes at 65N does not cause the glacial/interglacial cycle.
1) How does one explain the observation that the glacial/interglacial cycles started with a cycle periodicity of 41,000 years in duration and then 1.6 millions ago the cycle time changed to a cycle of 100,000 years (90,000 years glacial and 10,000 years interglacial.)
2) Orbital eccentricity is the weakest of the orbital cycle modulation on insolation. Why does it dominate for the last 1.6 million years?
4) There is evidence in the paleo climate data of cyclic abrupt climate change. (Heinrich events, such as the 12,900 years BP Younger Dryas abrupt cooling event.) Insolation does not change abruptly and hence cannot cause what the observed cyclic abrupt climate changes.
5) The glacial and interglacial periods end abruptly. The paleo record supports the assertion that the mysterious cyclic abrupt climate forcing function terminates both the glacial and interglacial period.
6) The cycle abrupt climate change cools both the Southern Hemisphere and the Northern hemisphere synchronously. This does not make sense at the Southern Hemisphere has maximum insolation in the summer when the Northern Hemisphere has minimum insolation in the summer.
7) There is the 100,000-year paradox which is the fact that eccentricity variations have a significantly smaller impact on solar forcing than precession or obliquity and hence might be expected to produce the weakest effects. The greatest observed response is at the 100,000-year timescale, while the theoretical forcing is smaller at this scale, in regard to the ice ages. …
8) There is the 400,000-year problem which is that the eccentricity variations have a strong 400,000-year cycle. That cycle is only clearly present in climate records older than the last million years. If the 100ka variations are having such a strong effect, the 400ka variations might also be expected to be apparent. This is also known as the stage 11 problem, after the interglacial in marine isotopic stage 11 that would be unexpected, if the 400,000-year cycle has an impact on climate. ….
9) There is the stage 5 problem which refers to the timing of the penultimate interglacial (in marine isotopic stage 5) that appears to have begun ten thousand years in advance of the solar forcing hypothesized to have caused it (this is also called the causality paradox).
10 ) There is the paradox that effect exceeds cause. 420,000 years of ice core data from Vostok, Antarctica research station. The effects of these variations are primarily believed to be due to variations in the intensity of solar radiation upon various parts of the globe. Observations show climate behavior is much more intense than the calculated variations. Various internal characteristics of climate systems are believed to be sensitive to the insolation changes, causing amplification (positive feedback) and damping responses (negative feedback).
11) There is the unsplit peak problem. The unsplit peak problem refers to the fact that eccentricity has cleanly resolved variations at both the 95 and 125ka periods. A sufficiently long, well-dated record of climate change should be able to resolve both frequencies,[15] but some researchers interpret climate records of the last million years as showing only a single spectral peak at 100ka periodicity. It is debatable whether the quality of existing data ought to be sufficient to resolve both frequencies over the last million years.
6) The transition problem
Variations of Cycle Times, curves determined from ocean sediments
The transition problem refers to the switch in the frequency of climate variations 1 million years ago. From 1–3 million years, climate had a dominant mode matching the 41ka cycle in obliquity. After 1 million years ago, this switched to a 100ka variation matching eccentricity, for which no reason has been established.
7) There is the paradox that there is no Identifying dominant factor. Milankovitch believed that decreased summer insolation in northern high latitudes was the dominant factor leading to glaciation, which led him to (incorrectly) deduce an approximate 41ka period for ice ages.[16] Subsequent research has shown that the 100ka eccentricity cycle is more important, resulting in 100,000-year ice age cycles of the Quaternary glaciation over the last million years.
The extreme AGW paradigm pushers have anchored the climate change discussion on a warming world.

Sudden climate transitions during the Quaternary
The time span of the past few million years has been punctuated by many rapid climate transitions, most of them on time scales of centuries to decades or even less. The most detailed information is available for the Younger Dryas-to-Holocene stepwise change around 11,500 years ago, which seems to have occurred over a few decades. The speed of this change is probably representative of similar but less well-studied climate transitions during the last few hundred thousand years. These include sudden cold events (Heinrich events/stadials), warm events (Interstadials) and the beginning and ending of long warm phases, such as the Eemian interglacial. Detailed analysis of terrestrial and marine records of climate change will, however, be necessary before we can say confidently on what timescale these events occurred; they almost certainly did not take longer than a few centuries.
Various mechanisms, involving changes in ocean circulation, changes in atmospheric concentrations of greenhouse gases or haze particles, and changes in snow and ice cover, have been invoked to explain these sudden regional and global transitions. We do not know whether such changes could occur in the near future as a result of human effects on climate. Phenomena such as the Younger Dryas and Heinrich events might only occur in a ‘glacial’ world with much larger ice sheets and more extensive sea ice cover. However, a major sudden cold event did probably occur under global climate conditions similar to those of the present, during the Eemian interglacial, around 122,000 years ago. Less intensive, but significant rapid climate changes also occurred during the present (Holocene) interglacial, with cold and dry phases occurring on a 1500-year cycle, and with climate transitions on a decade-to-century timescale. In the past few centuries, smaller transitions (such as the ending of the Little Ice Age at about 1650 AD) probably occurred over only a few decades at most. All the evidence indicates that most long-term climate change occurs in sudden jumps rather than incremental changes.
The 41 kyr world: Milankovitch’s other unsolved mystery

March 21, 2015 2:33 am

Coming later to this AGW debate than ,probably , most other contributors , some of the data discussed still has the excitement of novelty . One such plot is the well known Vostok plot ( and I appreciate there are many subsequent ice dome studies) .
I do not dispute the claims made that, whatever the trigger or primer for the sharp rises in ice temperature , the acceleration is enhanced by CO2 emission from the oceans , but this raises some questions in my mind:
Why does the temperature max out at about 2C above “benchmark” in each of the 4 main cycles ? Is it because the CO2 emission has slowed sufficiently for underlying cooling effects to re – establish?
Why is the prevailing temperature for much of the Quaternary period far below present global temperatures?
Is the ice core temperature representative of global temperatures ?
I saw somewhere a version of the Vostok plot that had dust levels added . These appeared to peak just prior to the onset of warming of the 4 main cycles . Any connection? Where did the dust come from , presumably amenable to geochemical analysis , and was it the trigger for warming?

Reply to  mikewaite
March 21, 2015 8:30 am

The feedback driving abrupt change between glacial and interglacial (both ways) is driven largely by albedo, there is no evidence for and no need for any role of CO2 other than as a passive marker of temperature.
Consider this fact: there exists an albedo feedback threshold latitude (AFTL) at some high latitude. Below this latitude, ice cover cools it’s environment due to albedo. Above this latitude insolation is so weak that cooling by evaporation and radiation into a cold atmosphere is more significant than reflection/albedo. In short, South of the AFTL sea ice cools, North of it sea ice warms. By contrast open water north of the AFTL cools the climate.
Big changes between glaciation-interglacials are driven by albedo feedback which operates both ways when a large amount of ice is below the AFTL. But once the ice retreats to above the AFTL albedo feedback stops. CO2 is an irrelevance in this process.

Reply to  Phlogiston
March 21, 2015 9:36 am

Thank you for the response Phlogiston .The question of the effect of albedo seems to be coming up more frequently here. Perhaps IPCC will give it more attention (won’t hold my breadth).
Whatever the future conclusions on the ice cores it is , to me, remarkable that the scientists involved can extract so much from a cylinder of ice, and the results themselves still seem amazing.

Ed Zuiderwijk
March 21, 2015 3:11 am

From the abstract:
“but the Milankovitch theory should have opposite effects for the Northern and Southern Hemispheres, ….”
This is a misconception. The total insolation is decreased during an iceage. The average goes down. The Southern hemisphere may go up somewhat with respect to that average, the temperature still decreases.

Bill Illis
March 21, 2015 4:48 am

Moraine peaks at 41,760, 35,500; 27,170; 20,270; and 18,290 years ago.
And they are SO different than the Greenland’s temperatures that CO2 must be responsible (rather than the build-ups and drawdowns of NH ice-sheets and the resulting global Earth Albedo changes).
Hi-res Greenland and Antarctic temps and CO2 over the last 50,000 years.

Reply to  Bill Illis
March 21, 2015 6:02 am

If the ECS is 3°C, shouldn’t the Greenland ice cap’s average surface temperature be about 1.3° C warmer than it was during the Medieval Warm Period?

Sturgis Hooper
Reply to  David Middleton
March 21, 2015 6:11 am

Wait until Gavin has time for more adjustments. It will be.

Bill Illis
Reply to  David Middleton
March 21, 2015 6:36 am

Technically Greenland’s temperature was 25C lower when CO2 fell to 180 ppm so it has a 5 times polar amplification factor.
Now that is probably more because of the Greenland d18O isotope to temperature formula which is based on borehole temperatures is way off reality and it was really only 10C colder, not 25C colder. The borehole models really screwed up Greenland’s temperatures and set-back the science by decades.
So your GISP2 numbers are probably only half as variable as Kobashi 2010 has it.
In the above chart, I was converting Antarctica and Greenland to a global temperature equivalent just to avoid the big artificial variability which is built into Greenland’s ice age temperature estimates..

Reply to  David Middleton
March 21, 2015 7:27 am

My point was that the Greenland ice cap doesn’t appear to be any warmer now than it was during the MWP.
So, either the rise in CO2 from 280-400 ppmv yielded no measurable warming, Greenland should be about 1.3-6.5°C colder than the MWP or CO2 was a lot higher during the MWP than indicated by Antarctic ice cores.

March 21, 2015 5:00 am

I don’t have access beyond the paywall, but it seems to me they’re making the case for internal ocean variability being the biggest “control knob”.

March 21, 2015 6:24 am

regarding glaciers many of the earth`s glaciers in the Alps, Asia, New Zealand and Patagonia retreated nearly half a century before the industrial revolution and man`s CO2 emissions. So if there was a CO2 connection it is not due to humans.

March 21, 2015 7:10 am

Amazing! lead author Alice Doughty, a glacial geologist at Dartmouth College who studies New Zealand mountain glaciers to understand what causes large-scale global climatic change such as ice ages. From the study of alpine glaciation to global climate in a nutshell. Next they will be claiming they now understand global beach formation from their sad box research. I wonder how mush tax funding supported this agenda driven rampage at the expense of Science. SHAMEFUL is what it is.

Evan Jones
March 21, 2015 9:02 am

From what I dope out, the paper is saying the the Milliecycles still rule, but there is a more complex feedback mechanism involved in the retreat of the ice sheet.
It does not appear to be saying CO2 drives the ice ages, but that it feeds back the warming of the cycles. But we already knew that: CO2 outgassing “shortly” follows the interglacial onset, and has a knock-on effect, contributing ~1C to the interglacial acme and slowing the descent into the following ice age.
The paper merely seems to be hypothesizing the mechanics in greater detail. Interesting, but not a groundbreaker, so far as I can tell.

March 21, 2015 9:39 am

“…a reaction within the climate system that can amplify the initial climate change, such as cool temperatures leading to larger ice sheets, which reflect more sunlight, which cools the planet further.”
This describes a positive feedback loop, how does the earth ever warm up after getting locked into it? This would apply to a positive feedback loop for temperature increasing as well like a home thermostat telling the heater to give more heat as the house get hotter. For a system to stay stable in need a negative feedback to keep from running away in one direction.

March 21, 2015 10:34 am

Rrom the article;
“The results showed that New Zealand glaciers were large at the same time that large ice sheets covered Scandinavia and Canada during the last ice age about 20,000 years ago. This makes sense in that the whole world was cold at the same time, but the Milankovitch theory should have opposite effects for the Northern and Southern Hemispheres, and thus cannot explain the synchronous advance of glaciers around the globe. Previous studies have shown that Chilean glaciers in the southern Andes also have been large at the same time as Northern Hemisphere ice sheets.”
So the MC are confirmed by this study to cause IA’s – and not refuted as some above have said.
Also why should the MC “have opposite effects for the Northern and Southern Hemispheres”?
With TSI yes – but the SH is mostly water which will store the heat overwhelmingly as the NH cools and the feed-backs there due land-mass lower albedo will dominate, and the atmosphere cool over the entire planet.
Currently the MC is at a point where TSI is strongest in the SH summer (~8%) and NH winter. It needs to be the other way around to warm the planet overall. Now it seems also that SH glaciers are sensitive to sea temps (evaporation/deposition of snow (LH) + sensible heat). The ocean current cycle must be much delayed vs the MC cycle, and bear in mind the cold melt water pouring into the ocean and sinking over millenia too.

Paul Coppin
March 21, 2015 12:09 pm

March 21, 2015 at 7:13 am
March 20, 2015 at 11:36 am
Very wrong rgb.

[[popcorn] Ok…[/popcorn]

Reply to  Paul Coppin
March 21, 2015 12:38 pm

Verry sorry, but can’t really tell what exactly your reply means.
Mods any help there with the translation?!?

Paul Coppin
March 21, 2015 2:09 pm

Means calling out rgb as just “wrong”, is likely to be entertaining, not that he can’t be…. Rolling out the popcorn and waiting to see if there’s gonna be a show… 🙂

Reply to  Paul Coppin
March 21, 2015 4:11 pm

Ah, ok, I see.
Thanks for the clarification/////and good luck with the popcorns. 🙂

March 21, 2015 2:52 pm

This post emphasizes something that has been known for some time from Greenland and Antarctic ice core data. When orbital cycles decrease insolation in the northern hemisphere (NH), they increase insolation in the SH. Yet glacial cycles in both NH and SH occur at about the same time and correlate with low insolation in the NH. So orbital cycles per se are not the direct cause of SH glaciation. Neither can increased NH ice albedo be the sole cause (although it is contributory), because this ice cannot cool the globe by some 4-6 deg-C, as suggested by proxy data.
Somehow the SH is depleted in solar heat during glaciation. Some may be stored in deep oceans, but I suspect increased SH cloud cover and higher albedo play a significant role.

March 21, 2015 8:10 pm

If greenhouse gases played a part in ice age climate change then H2O would have had to be the primary culprit. The climate has had to have sufficient negative feedbacks to make it stable enough for life to have evolved. AGW theory is dependent on the idea that, because H2O is a greenhouse gas, H2O provides a positive feedback to changes in CO2 so as to amplify how CO2 affects climate. But the theory ignores the fact that H2O is also a major coolant in the Earth’s atmosphere moving heat energy from the Earth’s surface of where clouds from via the heat of vaporization. They also ignore clouds and what must happen in the upper atmosphere. I would expect that if changes in CO2 affected climate then such changes would change the temperature lapse rate in the troposphere but it does not. There is no real evidence that CO2 has any effect on climate.

David Blake
March 22, 2015 6:43 am

Afternoon all.
As many have said the orbital cycle theory of ice ages just doesn’t make sense.
1) As the paper, and NOAA, acknowledge the cycles and glaciation can be antiphase: NOAA: “during the most recent ice age occurred at about the time the region was experiencing a peak in local sunshine.” See (e.g) the last cycle in the below image, it’s the wrong way round.
2) The change in forcing is too small, so they must invoke a high sensitivity to CO2.
3) Why does the temperature only respond stringly to the fifth cycle? Whats wrong with the photons of the other peak? And why a rapid change on the fifth, when the orbital forcings are gradual?
To my mind a much better, simpler, and more elegant mechanism for ice ages comes from the Arctic flicking between ice free and ice covered states.
Phase 1) When the Arctic is frozen over the ocean beneath it is prevented from losing heat to space. Warm currents from the equatorial Atlantic arrive, but in effect the ice “insulates” the sea from radiating (and evaporating and conducting) to space, so more energy builds up than would normally be the case in an ice-free state.
And it builds up.
And builds up. Slowly heating the oceans over hundreds, thousands, of years.
We are talking about 14 billion m^2 of sea area that would (in an ice free state) be radiating/convecting/evaporating tens of W/m^2 to space. But it’s not as ice cover is preventing that. (Note open sea can obviously absorb solar also, but at the high N lattitudes there isn’t much direct solar especially in winter)
Eventually there’s enough heat in the system to start melting the ice again, leading to…
Phase 2) Only when the ice cap has lost sufficient area can the process shift to the opposite phase. As the Atlantic can now lose heat via the now Ice free (or mostly ice free) Arctic the energy in the system starts to fall.
And fall. And fall.
Note that the Arctic is also evaporating water vapour, but there’s limited solar for it to act as a positive feedback there. So we now have cold temperatures + moisture –> snow, snow, snow, snow, snow, and the ice builds up, and up and up, and it’s deja vu all over again as we move back to phase 1.
The M-cycles may be the final “push” that melts that last bit of Arctic ice sending the system into phase 2. That explains why it’s only the peak cycles that do so. The change in their own energy is not sufficient on it’s own.

March 22, 2015 7:08 pm

An attempt to link past ice ages to CO2, rather than orbital cycles, is equivalent to a drowning man clutching at straws. The catastrophic man-made global warming mantra is now so broken, these climate change charlatans will resort to anything to keep their mantra flame burning. It’s shameful! It’s embarrassing! It’s disgraceful! It’s unscientific!

March 23, 2015 6:48 am

In our country there is a saying, when something is wrong and says: “Where is the much-midwife midwife, children are suffering from hernia” .This can be applied to “toil” theory of the causes of climate change. It is really so far all hernial, if we consider so claims, evidence and predictions, of which there are no real nor the results or certificates.
Milankovic was on his way to find out the true causes and gave the receipts of the theory related to the long-term laws of motion of our planet and its behavior under the influence of the greatest causes of all the phenomena in our solar system, and that is the sun. Science has no sense to realize that all changes to the planets and the sun, the consequences of mutual influence on each other. This what some scientists, who are on the right track evidence of true causes of climate change, related to the appearance of the sun, these are only indicators of something much more subtle and more powerful what causes these changes, and we do not want to analyze. The simplest is to blame CO2, because it can not prove or disprove any of its properties that can cause these changes. Place the probe into the ground to the depth of several tens of meters and measuring the magnetic field of the earth and temperature and find their mutual relationship and will be more clearly which direction and who act on these changes. I claim that four influential planets, their positions around the sun, forming cycles of about 11.2 years, which determines the behavior of sunspot. These spots do not cause climate change but are pointers of some bigger and stronger changes in the planets. It is pictured as when someone gets redness and increased body temperature. This is an indication that something big going on in the organism, and the organism to which there are sunspots are planet and only sun, only we still do not have “competent doctor” who knows when it causes. I’m trying to publish this, but everyone wants and they are used to pay for them to learn something new. While this relationship does not change, can not be defined not true causes of climate change.

johann wundersamer
March 23, 2015 11:16 am

‘the more robust
climate models can be in
predicting future change.’
never forget:
It’s about the future of our climate models.
stay tuned.

March 23, 2015 6:40 pm

I am always bemused when workers suggest that the post-MPT terminations, and subsequent interglacials, were spurred by GHGs. Think that through for a moment. At each glacial maximum, when populations of just about everything are down, some mysterious, rhythmic (paced by eccentricity) burst of CO2 appears from somewhere and terminates the glacial and rockets us into an interglacial. OK, such a burst of CO2 that can cause sea levels to jump ~400 feet would seem to require the majority of our attention. How on earth (literally) do we deal with that? Instead of focusing on the “big thing”, we are instead focused on something which according to AR4, Figure 10.33, series marker A1F1, and the upper error bar at that, might yield a +0.6 meter rise in sea level by 2099. Anybody else realize that we are focused on the smallest possible aspect of GHG inspired sea level rise?
But wait, if you call in the next 10 minutes, we will double the cognitive dissonance with this stunning bit of mental chicanery. Assume, for the purposes of discussion, that CO2 is responsible for glacial terminations. Humor me (and yourself). OK, and now you want to remove it from the 11,718 year old (uh, that’s half a precession cycle you know) late Holocene atmosphere. Riiiiggghhhtttt!!!! What? You want to remove the only prognosticated speedbump to glacial inception? I mean, er, ah, 7 of the last 8 interglacials have each lasted about half a precession cycle.
They never see that one coming………..

March 24, 2015 5:10 pm

You would be surprised to learn that some would be farmers standing for election in NSW believe that CO2 levels are rising and contributing to global warming. That Australian soils were caused by glaciers grinding down rocks (no glaciers in Australia possibly one in Tasmania) but the tree lines were lower and rain forests less abundant. Hadn’t they heard of igneous, sedimentary and metamorphic rocks. Basalt and granite are igneous. That land clearance rules was ruining farmers? Well land clearance and die back of certain gum trees has been blamed on soil erosion and degradation. They want clean energy to stop climate change. Ah, they get paid $15k per year to put up a wind turbine on their land. I told one aspiring member of this class, to bloody look up at the sky, see what angle the sun was, and the type of clouds in the sky and watch when deciduous trees turn color. It’s a shame but behind their silly and corrupted views that there is $$$’s.

Reply to  bushbunny
March 24, 2015 7:53 pm


I told one aspiring member of this class, to bloody look up at the sky, see what angle the sun was, and the type of clouds in the sky and watch when deciduous trees turn color.

Alice Springs is right at -23.5 latitude right? That is, the middle of OZ is crossed by the southern tropic of Capricorn, and so half of Australia is in the tropics, and the other half is between the tropics and the southern equniox zone, right?

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