Guest post by William F. McClenney
This post is essentially an update to The Antithesis and On “Trap Speed”, the ACC and the SNR.
The entire non-debate on anthropogenic climate effects has always struck me “as two fleas arguing over who owns the dog they are riding on” (Crocodile Dundee). One of the required paradigms of AGW is patently ignoring “when we live” (ignorance of signal to noise ratio, or SNR).
We live today possibly near the end of the most recent interglacial, the Holocene, or the 11,715 years since we melted our way out of the last glacial, the Wisconsin Ice Age, the interglacial in which all of human civilization has occurred. Five of the last six interglacials have each lasted about half a precession cycle. The precession cycle itself varies between 19,000 and 23,000 years and we are close to the 23kyr point now, making 11,715 years about half……..which is why this discussion has relevance.
So when will the Holocene end?
Even if you are not presently afraid of
But first a look at the often painful, difficult advance of Science.
Who was Alfred Lohar Wegener?
“He was the object of a kind of loathing that is only rarely seen in science.
“It wasn’t long before the established authorities closed ranks against Wegener’s concept as if they were stamping out a plague. He never understood the depth of resistance to his thinking. Continental drift was received not merely as a mistaken idea but as an evil that jeopardized the credibility of geology as a science and the professional reputation of anyone who espoused it. Wegener was denied professorships at German universities, but eventually he found himself at the University of Graz in Austria. Ironically, though, in 1928, he was asked to lead a German expedition to Greenland.”
–John D. Cox, “Climate Crash: Abrupt Climate Change and What it Means for Our Future”, ISBN: 0-309-54565-X, Joseph Henry Press (an imprint of the National Academies Press), 2005
The expedition got underway in 1930. In November,1930, Ernst Sorge, of Wegener’s Greenland meteorological expedition, discovered for the first time the records of paleoclimate preserved in the ice.
“It would be some years before researchers would fully appreciate the value of Ernst Sorge’s cold and lonely work in the winter of 1930 when he sawed and chipped and shoveled a shaft 54 feet down into the Greenland ice. Glaciologists at the time thought of the ice sheets almost exclusively as geological features whose movement across the landscape chronicled the slow waltz of a changing climate.”
Wegener died that winter of 1930. His Continental Drift theory of 1912 would not be proven until the 1960’s, revolutionizing geology as the Theory of Plate Tectonics. It would be 30 years beyond that (the 1990s) before the scientific contributions of Ernst Sorge were fully recognized as another revolutionary concept: Abrupt Climate Change.
When Do We Live?
Concern about abrupt climate change is especially inversely healthy today, as the Holocene is but the latest of the post Mid Pleistocene Transition (MPT) Extreme Interglacials, a thing almost nobody knows. An Extreme Interglacial can be variously described as a technical aspect of Ice Rafted Debris (IRD) in the ocean stratigraphic record, or more frequently as an interglacial that has achieved at least our sea level or our isotopic temps (<3.6 o/oo dO18). There is also a bit of controversy as to just which of the post MPT interglacials qualify. For the purposes of this essay we will define them as Marine Isotope Stages (MIS) 11, 5e (the Eemian) and 1 (the Holocene), with provisional inclusion of MIS-19, for reasons we will delve into.
Figure 1 Post-MPT interglacials with an expansion of part of the last glacial period and the Holocene. (Note: MIS-19 is unlabeled at the far left – click to enlarge)
As one may glean from Figure 1, something seems to have happened to the 100kyr amplitude about 400kyrs ago, the climate ride got a tad wilder from then to present. The speculation is long and worth researching yourself, however it is not exactly the subject of this piece.
As discussed in The Antithesis, we could very well be at the end of the most recent extreme interglacial. Although it is quite likely this thought will strike many as trivial, for some inexplicable reason it seems reasonable to wonder what the ends of the other extreme interglacials might have been like.
If AGW/CAGW causes you qualms, queasiness or abject terror/irrational rage, then you would be wise to take the exit ramp here.
Because there is, and has been, a long-running debate in the paleoclimatology literature that I suspect few of you have ever heard of, and it kicked off at the same time as the AGW hypothesis (or theory for post-normal scientists).
Wallace Broecker, arguably one of the fathers of modern paleoclimatology provides the best of the earliest quotes as regards this debate:
The next year (1999), in a paper posted on the Cambridge Conference Network (CCNet) by famous astronomer Fred Hoyle (originator of the now disfavored Steady State Theory Hypothesis), it was stated:
“This is why the past million years has been essentially a continuing ice-age, broken occasionally by short-lived interglacials. It is also why those who have engaged in lurid talk over an enhanced greenhouse effect raising the Earth’s temperature by a degree or two should be seen as both demented and dangerous. The problem for the present swollen human species is of a drift back into an ice-age, not away from an ice-age.”
Bringing it up to the present, we have this:
Public release date: 8-Jan-2012
Contact: Jim Channell
352-392-3658
University of Florida
Global warming caused by greenhouse gases delays natural patterns of glaciation, researchers say
GAINESVILLE, Fla. — published online Jan. 8 in Nature Geoscience.
“The Earth’s current warm period that began about 11,000 years ago should give way to another ice age within about 1,500 years, according to accepted astronomical models. However, current levels of carbon dioxide are trapping too much heat in the atmosphere to allow the Earth to cool as it has in its prehistoric past in response to changes in Earth’s orbital pattern.”
Which is more or less where Broecker was coming from in 1998 and where we ended up in “The Antithesis”. A hypothesis that we might extend the present interglacial by the timely venting of a “climate security blanket”, if you will. Also known as the Industrial Age.
Just to recap a bit of that, Loutre and Berger (Loutre M. F. and Berger A.: Marine Isotope Stage 11 as an analogue for the present interglacial, Global Planet Change, 36, 209–217, 2003) predicted, from a computer model, that the current interglacial, the Holocene, might very well last another 50,000 years, particularly if CO2 were factored in. This would make the Holocene the longest lived interglacial since the onset of the Northern Hemisphere Glaciations some 2.8 million years ago (some say over the last 5MY).
Of course, this was a model, for those enamored with models. It was soon put to rest by Lisiecki and Raymo (A Pliocene-Pleistocene stack of 57 globally distributed benthic D18O records, Paleoceanography, Vol. 20, PA1003, doi:10.1029/2004PA001071, 2005) which was quoted in “The Antithesis”, and will be again later in this discussion.
So this does indeed bear some serious scrutiny. We will begin with the Cenozoic and work our way to better and better resolutions. I again apologize for the presentation of some of these graphics. I whipped some of them together from professional papers for a slide show some years back, but, unfortunately, failed to take the time to properly reference them.
Figure 2. The Cenozoic
There are a great many things to be pondered in Figure 2. Why have we been roughly cooling off since the PETM? Is the increase in climate variability about the mean since the dinosaurs to present indicative of (a) poorer proxies or less data with time? or (b) truly indicative of a gradually more variable climate? Would comparisons of climate at the PETM be valid for a post Panama Seaway closed world? And those are just a few.
Figure 3. Expanding out the last 5 million years of climate (the LR04 Age Model)
In Figure 3 we expand out the past 5 million years of climate change developed from those 57 deep ocean drilling program cores of Lisiecki and Raymo (2005). We see the beginning of the 41kyr obliquity paced million years of glacial/interglacial oscillation about 2.8mya and we see the initiation of the eccentricity paced 100kyr pairings at about 0.8-1mya. We see again the onset of the extreme interglaciations at about 400kyrs.
Figure 4. Expanding out post MPT time. (Note the different time scales on the lower merged image at about 140kyrs)
In Figure 4, we zoom-in yet more on the post-MPT time beginning with MIS-19. In this depiction we see that MIS-19 did not appear to achieve temperatures of the true extreme interglacials, but it does have a lot more to offer. Orbitaly, it could be our closest interglacial analog in the climate record, although this is a matter of some debate in the literature.
The End Extreme Interglacials
MIS-19
Which brings us to the point of this essay, what were the end extreme interglacials like? Although MIS-19 may not satisfy everyone as being an extreme interglacial, it did occur at an eccentricity minimum just like MIS-11 was and MIS-1 presently is. So in terms of trying to comprehend what might be the end extreme interglacial natural climate noise it has “standing”.
Figure 5. Multi-proxy view of post-MPT time.
So what was the end of MIS-19 like?
Figure 6. Three Consecutive Warm Events at Glacial Inception During MIS-19
Well, MIS-19 appears to have had at least 3 abrupt warming events during glacial inception. Had the genus Homo gone all-civilized on us during MIS-19, we would all have had one heck of a time settling our AGW damage claims with our climate-change insurers, especially with the final one being of the highest dD amplitude. If any insurance types are here, I just gave you the proverbial “silver bullet” for rejecting AGW related climate damage claims. So collect your premiums with the appropriate conceit of a proper Wall Streeter, unless, of course, you also issue coverage for natural climate changes or “Acts of God”.
K. Pol et al. (2010) also attempt various astronomic and MIS-1 fittings to see how ours “stacks up” (Figure 6). Could we also be in range of such events?
MIS-11
Which brings us to MIS-11, the Holsteinian interglacial. Remember I said that 5 of the last 6 interglacials all lasted about half of a precessional cycle? Well that 6th one was MIS-11.
Figure 7. New MIS-11 as Corrected for Isotopic Fractionation (K.Pol et al, 2011)
MIS-11 has long been shown to consist of at least two insolation peaks, a fairly sharp one soon after glacial termination, and a long, fairly broad one after an interval of cooling. But if you take the time to closely inspect all of the figures presented here, you will likely note that they are not all the same everywhere and in every study. It’s called science. The estimated length of MIS-11 seems to vary from 20-33kyrs, depending upon which study you are reading.
At the risk of repetition from “The Antithesis”, Lisiecki and Raymo (2005) state:
“Recent research has focused on MIS 11 as a possible analog for the present interglacial [e.g., Loutre and Berger, 2003; EPICA community members, 2004] because both occur during times of low eccentricity. The LR04 age model establishes that MIS 11 spans two precession cycles, with 18O values below 3.6o/oo for 20 kyr, from 398-418 ka. In comparison, stages 9 and 5 remained below 3.6o/oo for 13 and 12 kyr, respectively, and the Holocene interglacial has lasted 11 kyr so far. In the LR04 age model, the average LSR of 29 sites is the same from 398-418 ka as from 250-650 ka; consequently, stage 11 is unlikely to be artificially stretched. However, the June 21 insolation minimum at 65N during MIS 11 is only 489 W/m2, much less pronounced than the present minimum of 474 W/m2. In addition, current insolation values are not predicted to return to the high values of late MIS 11 for another 65 kyr. We propose that this effectivelyprecludes a ‘double precession-cycle’ interglacial [e.g., Raymo, 1997] in the Holocene without human influence.”
Chronis Tzedakis, in an exhaustive look at the MIS-1/MIS-11/MIS-19 conundrum (Tzedakis, 2010, The MIS 11 – MIS 1 analogy, southern European vegetation, atmospheric methane and the “early anthropogenic hypothesis”, Climate of the Past, vol. 6, pp 131-144, European Geosciences Union) considers the matter thusly:
“While the astronomical analogy between MIS 1 and MIS11 has been incorporated in mainstream literature, there is a distinct difference between the two intervals: the Holocene contains one insolation peak so far, while the MIS 11 interval of full interglacial conditions (Substage 11c of the marine isotopic stratigraphy) extends over two insolation peaks. Thus an interesting situation has arisen with regard to the precise alignment of the two intervals.”
“The two schemes lead to very different conclusions about the length of the current interglacial, in the absence of anthropogenic forcing, …
“… the precessional alignment would suggest that the Holocene is nearing its end, “while the obliquity alignment would suggest it has another 12,000 years to run its course.
“In this view, the two Terminations are incommensurate and MIS-1 is analogous only to the second part of MIS-11c.”
Figure 8. Tzedakis’ 2010 Alignments of the EDC3 core for the Holocene and MIS-11
Figure 9. Another recent view of the Twin-Peak Nature of MIS-11
Figure 10. MIS-11 from Lake Baikal sediments.
Multiple views of MIS-11 clearly indicate a Twin-Peak configuration, though, as one might well expect, varies from one place to the next. K, Pol et al (2011) and Tzedakis (2010) both tend to show an elongated and higher amplitude late peak for MIS-11a whereas Voelker et al (2009) and Prokopenko et al (Clim. Past, 6, 31–48, 2010, www.clim-past.net/6/31/2010/) show a broader, more symmetrical pair of peaks.
Apparently, the second one was a real doosie:
As we leave the double insolation-peak MIS-11, with it’s possible +21.3m amsl highstand and 20-33kyr length, I am again struck by the magnitude of both the natural noise and the difficulty one will have winning an argument with a clued-in climate change insurer over a whopping IPCC AR4 worst case +0.59m amsl fizzle, with or without it’s consensus accolades.
MIS-5e
Which brings us to the most recent interglacial, the Eemian, or MIS-5e. As it occurred midway between the last eccentricity maximum and our present minimum it is not considered to be a good orbital analog. However it seems to have also been quite the extreme little interglacial.
I will again be using some citations quoted in “The Antithesis” to “insure” against the risk that some of the “insured” won’t get it.
Hearty and Neumann (Quaternary Science Reviews 20 [2001] 1881–1895) abstracting their work in the Bahamas state:
“The geology of the Last Interglaciation (sensu stricto, marine isotope substage MIS 5e) in the Bahamas records the nature of sea level and climate change. After a period of quasi-stability for most of the interglaciation, during which reefs grew to +2.5 m, sea level rose rapidly at the end of the period, incising notches in older limestone. After brief stillstands at +6 and perhaps +8.5 m, sea level fell with apparent speed to the MIS 5d lowstand and much cooler climatic conditions. It was during this regression from the MIS 5e highstand that the North Atlantic suffered an oceanographic ‘‘reorganization’’ about 11873 ka ago. During this same interval, massive dune-building greatly enlarged the Bahama Islands. Giant waves reshaped exposed lowlands into chevron-shaped beach ridges, ran up on older coastal ridges, and also broke off and threw megaboulders onto and over 20 m-high cliffs. The oolitic rocks recording these features yield concordant whole-rock amino acid ratios across the archipelago. Whether or not the Last Interglaciation serves as an appropriate analog for our ‘‘greenhouse’’ world, it nonetheless reveals the intricate details of climatic transitions between warm interglaciations and near glacial conditions.”
Savvy insurers take note to make appropriate use of the “Acts of God” clauses.
Boettger, et al (Quaternary International 207 [2009] 137–144) abstract it:
“In terrestrial records from Central and Eastern Europe the end of the Last Interglacial seems to be characterized by evident climatic and environmental instabilities recorded by geochemical and vegetation indicators. The transition (MIS 5e/5d) from the Last Interglacial (Eemian, Mikulino) to the Early Last Glacial (Early Weichselian, Early Valdai) is marked by at least two warming events as observed in geochemical data on the lake sediment profiles of Central (Gro¨bern, Neumark–Nord, Klinge) and of Eastern Europe (Ples). Results of palynological studies of all these sequences indicate simultaneously a strong increase of environmental oscillations during the very end of the Last Interglacial and the beginning of the Last Glaciation. This paper discusses possible correlations of these events between regions in Central and Eastern Europe. The pronounced climate and environment instability during the interglacial/glacial transition could be consistent with the assumption that it is about a natural phenomenon, characteristic for transitional stages. Taking into consideration that currently observed ‘‘human-induced’’ global warming coincides with the natural trend to cooling, the study of such transitional stages is important for understanding the underlying processes of the climate changes.”
Figure 11. Hearty et al (2007) End Eemian highstand(s)
Figure 12. Hearty et al (2007) modern MIS-1 notch and MIS-5e notches in the Bahamas and Barbados
Figure 13. MIS-5e Sea Levels Compiled from Around the World (modified after Hearty et al, 2007, red estimates added)
In Figures 10-13, we see the End Eemian in quite remarkable detail. This is predominantly due to its relatively young age compared to any other interglacial. One needs but to consider the effects of the average 400 foot sea level swings in and out of each of them, some going higher than others, to grasp how each of them tend to erase the evidence from the others. For instance, paleoclimatologists that are adept at deep sea diving might be able to uncover evidences of say MIS-7 and MIS-9 sea level highstands because they are presently below sea level. I wouldn’t take out to much insurance on that though.
And look at the range of estimates, +6m to +45m amsl, and often detecting the highstands at the very end of the Eemian.
In discussing the Late Eemian Aridity Pulse (LEAP) at the end-Eemian, Sirocko et al (A late Eemian aridity pulse in central Europe during the last glacial inception, nature, vol. 436, 11 August 2005, doi:10.1038/nature03905, pp 833-836) opine:
“Investigating the processes that led to the end of the last interglacial period is relevant for understanding how our ongoing interglacial will end, which has been a matter of much debate…..”
“The onset of the LEAP occurred within less than two decades, demonstrating the existence of a sharp threshold, which must be near 416 Wm2, which is the 65oN July insolation for 118 kyr BP (ref. 9). This value is only slightly below today’s value of 428 Wm2. Insolation will remain at this level slightly above the inception for the next 4,000 years before it then increases again.”
Now that is some bombshell! We may only have about the next 4,000 years, a little less than half the time since we “Homos” learned how to write, where climate sensitivity will be alarmingly close to glacial inception.
“The Antithesis” provides documentation of CO2 effects during the latter half of the last glacial, so I will refer you to that essay for the succulent details. Suffice it to say that what this may boil down to is strip the appropriate amount of “climate security blanket” out of the late Holocene atmosphere as fast as is humanly possible (perhaps tipping us into the next ice age), or keep a decently healthy dose of it up there for at least the next 4,000 years.
So there you have it, all tipping points now in play.
THE END HOLOCENE
So we now have quite the conundrum. Will we do a typical eccentricity minima sea-level “Cha-Cha” at our very end? It would appear to be the norm, and may not be restricted just to eccentricity minima end extreme interglacials given the “competition” from MIS-5e, which occurred neither at an eccentricity minima or maxima.
And they do appear to be rather extreme, don’t they? So do not be too shy about investing in savvy climate change policy writing insurers. If they read this, they will probably never have to pay out a claim. Pay attention Big Oil etc., you could have a field day on Kivalina and other Public Trust Doctrine style litigation just by “stocking-up” on what has “gone down” climate-wise, without even having to be exposed to the heathen devil gas itself.
From I what I have been able to glean, this seems to boil down to three competing hypotheses:
- Anthropogenic Global Warming/Catastrophic AGW. World will continue to warm, perhaps catastrophically, as a result of GHG emissions.
IPCC AR4 worst case estimate for sea level by 2100 is +0.59 meters amsl. End Eemian achieved, at least, 10 times this (if we use +6 meters amsl), almost an order of magnitude more if we use the +45m estimate. End Holsteinian achieved 36 times this predicted excursion (using 21.3 meters amsl), covering the low and high ends of natural, end extreme interglacial, climate noise.
The Signal to Noise Ratio (SNR) range for AGW predictions to 2100 come in at a range of 0.1 to 0.03 compared to “normal” end extreme interglacial climate noise. Worst case projections are therefore woefully not anomalous (at best 10% of natural noise), with the projected AGW/CAGW signal scoring a measly 3-10% of normal end extreme interglacial climate noise levels.
Such a signal will be difficult to distinguish.
- Holocene Interglacial (Loutre and Berger, 2003) will “go-long” (perhaps another 50,000 years), outlasting every previous interglacial in the past 5 million years.
“With the end of MIS 11 full interglacial conditions and the start of ice accumulation estimated to have occurred at 395 kyr BP (de Abreu et al., 2005; Ruddiman 2005a, 2007), the precessional alignment would suggest that the Holocene is nearing its end, while the obliquity alignment would suggest it has another 12 000 years to run its course.” (Tzedakis, 2010)
“In essence, this alignment represents a synchronization of the obliquity signal instead of precession, which according to Masson-Delmotte et al. (2006) may be more appropriate, because of the role of obliquity changes in triggering deglaciation especially during intervals of weak precessional variations, as is the case for MIS 11 and 1.” (Tzedakis, 2010)
- Holocene is a tad over half-a precession cycle old now. If a precession match, it might be “winding-up” to “wind-down”, like all previous end extreme interglacials.
The possibility consequently exists that at perhaps precisely the right moment near the end-Holocene, the latest iteration of the genus Homo unwittingly stumbled on the correct atmospheric GHG recipe to perhaps ease or delay the transition into the next glacial.
We may have actually already “engineered” a “climate security blanket” capable of dealing with:
“The onset of the LEAP occurred within less than two decades, demonstrating the existence of a sharp threshold, which must be near 416 Wm2, which is the 65oN July insolation for 118 kyr BP (ref. 9). This value is only slightly below today’s value of 428 Wm2. Insolation will remain at this level slightly above the glacial inception for the next 4,000 years before it then increases again.”
Apologies for quoting Sirocko et al (2005) twice in rapid succession.
Which rather handily devolves to,
Have a wonderful end extreme interglacial!
William F. McClenney
Rats,
I just put a down payment on some Saskatchewan farmland.
Thanks William, these are the posts w/alot of “meat”. You’ve obviously put quite a bit of work into this. I especially like real historical evidence to munch on and absorb.
The sea-level highstands at the end of the interglacials are interesting. The temp proxies don’t show unusually high temps, but the sea-levels suggest that there should have been — how else do they rise so high so quickly? Maybe ice-sheet instabilities in Greenland/Antarctica caused some ice disintegration, flooding the polar oceans? That might explain the sudden highstand & the subsequent rapid cooling.
I will aggregate some first responses here. Sorry folks, WordPress impresses me as the elite of post-normal word processor/publishing systems, so since there are no easily accessible tools all responses will be as basic as WordPress enabled possible.
Mark Smith: It’s the study of the earth which also includes rocks.
Caz: It is sort of a convention. I remember reading a paper some while back on re-establishing some aspects of this, and I do not remember the name of the body which issues these conventions.
Maurizio: From the same Broecker 1998 paper cited above we also have this (which I forgot to include in the essay):
“It is frequently suggested that the warming expected from the buildup of man-made greenhouse gases might be a blessing in that it will counter the natural cooling expected if Earth climate continues to track Milankovitch’s insolation cycles. But, if the Earth’s climate is destined to undergo an abrupt rather than a gradual cooling, then the likelihood of a compensation by the ongoing greenhouse warming is indeed small.”
I tend to agree with you.
Alan: If you like that typo, see if you can find the one in Figure 13’s caption! Given that I sent this to Anthony after hours of frustration with WordPress and the recently installed, instantly AWOL Greasemonkey Comment Ninja, I am not sure if I personally can change either of them.
[Reply: Fixed 3007 to 2007. -ModE (who uses Linux / Unix so likes command line interfaces 😉]
trbixler: You got it! You too Kelvin.
P.S. If anyone has a non-pretzel logic solution to using WordPress efficiently, I am all ears. At the moment I think of it just like the old command-line UNIX of old where “When a mathematician sits down to solve a math problem with a pencil, which should he be more concerned with? The math problem? Or the pencil?”
Nowhere in that intricate record is there any indication that CO2 was “forcing”, yet now it will be? That’s paw-waving, I think.
Edit (one of many):
“
NutBut if you take the time”OTOH, maybe …
😉
Continental Drift is NOT the same as Plate Tectonics. They are based on many of the same observations but invoke entirely different mechanisms for movement of the Earth’s crust.
vukcevic says:
March 16, 2012 at 6:13 am
I have looked in some detail at the Arctic-North Atlantic barrier (Greenland Scotland ridge) and concluded that, despite the Milankovic effect on the insolation, conditions do not exist any longer for another Ice Age.
http://www.vukcevic.talktalk.net/NA3R.htm
===================================================
Are Greenland and Scotland, and the ridge between them new in the last 12,000 years? How have things changed?
I believe it was Glen Beck who published information on the people who shill the chicken-little climate change hype but also own ocean-front property which would be underwater if the AGW claims about sea-level rise were true.
Would Al Gore really by that condo in San Francisco if he thought it would be worthless in a few years?
More Soylent Green! says:
And I hadn’t realized that man suddenly appeared on the scene just a few decades ago.
vukcevic says:
March 16, 2012 at 6:13 am
I have looked in some detail at the Arctic-North Atlantic barrier (Greenland Scotland ridge) and concluded that, despite the Milankovic effect on the insolation, conditions do not exist any longer for another Ice Age.
My understading is the Earth is in an ice age…we are just in the warm part (inter-glacial)
is, I love your brief synopsis of the earth’s recent (geologically speaking) climate history. I also like the way you used Wegener. This was a man who took a lot of grief because he disputed the “settled” science. The current crop of “climate” scientists (I use the word “scientist” loosely when describing them) should take note when they throw the phrase “the science is settled” around. It’s been my impression when reading their output though, that they really have very little knowledge of past research and theories pertaining to their fields. It appears they only look at past work that agrees with their viewpoint.
On a lighter note, I’ll do my best to save civilization as we know it by using the grill every chance I get to produce CO2 and particulate carbon. At least that’s the excuse I’ll use to my wife and friends.
HenryP says: ” there were enormous amounts of plants and greenery available for them to eat from. That is where our reserves of coal and oil actually came from”.
I had heard that the coal deposits came about when plants invented lignin and there was a delay before the fungi invented a way to eat it.
Is this urban legend? I am quite prepared to believe it is. Help unclutter my brain.
A few more un-enhanced responses:
Brian H: You are correct. This question was settled by 2003, 2 years before Gore’s propaganda video. I would point you to Sole, Turiel and Llebot (Physics Letters A (366 [2007] 184–189) for a fascinating discussion on the D-O events and CO2’s efficacy as a GHG. Sorry, the advanced absent commenting tools of WordPress disallow me from posting a proper link.
Steve M: The issue of what is an ice age and what is a glacial gets blurred throughout the literature. Many workers define an ice age as the 100myr climate cyclicity, which may be proper. However this is not always adhered to in the vast majority of the literature.
EDS Anthony – maybe im misunderstanding something but –
“We live today possibly near the end of the most recent interglacial, the Holocene, or the 11,715 years since we melted our way out of the last glacial…”
“or the” ? Im thinking the the is superfluous.
David A says:
……………..
No it is not new. The island of Surtsey is less than 50 year old.
Thanks for this wonderful post!
And:
HenryP says:
March 16, 2012 at 5:20 am
“Remember that the only way that dinosaurs and other gigantic animals could have existed on earth (many millions of years ago) was because there were enormous amounts of plants and greenery available for them to eat from. That is where our reserves of coal and oil actually came from. We know from the records that in those days CO2 was many times higher then what it is now. So to now put a limit on CO2 in the air is as stupid as to ask for a limit on H2O.”
Agreed. Maybe it’s time to call for really significant CO2 emissions. The precautionary principle. Stop the coolers! (new name for “warmists”)
I guess you’ll be spending this summer in re-education camp, then. See if you can get into one of the ones where you get food.
Very,very interesting and well done !!
William F. McClenney,
Your article is well done. It provides a necessary context to counter the hysteria induced by the IPCC centric CAGWism that is publicly failing to masquerade as unbiased and balanced open science.
QUESTION: In your researches did you run across interesting competing theories to the Milankovic theory for cause of the ice age cycles of glacial/interglacial periods?
John
So we need icecap formation to cause climate to go into another mode.
The reminds me of something I read about early snowfall in siberia and early onset of winter.
DirkH;
There’s a lovely brain-busting version of that analysis of dino environments here:
http://dinosaurtheory.com/index.html
Long story short: the pterosaurs flew lightly thru and the dinos were buoyed by an atmosphere 2/3 the density of water, about 370 bar! Long necks didn’t need multiple hearts to get blood to the head, bone strength was adequate to support brachiosaurs etc. on dry land, not just eternally wading, and the wedge-body shape of the predators was for powering thru the heavy air.
Delightful icono-smashing stuff.
John Whitman: Yes indeed, there are quite a few papers that question the attribution of the Milankovitch cycles. It would probably take me a few days to dig some of them up from my “cybrary” (which at this moment contains 7,530 papers and other files divided into 259 folders and subfolders). So suffice it to say that eccentricity is thought to be the weakest of the 3 (or 4) orbital forcings, yet is seems to pace the most dramatic recent climate of the extreme interglacials. Go figure. A lot of workers indeed have……
Personally I wouldn’t put to much faith in those late-MIS 5e and Late-MIS 11 extreme highstands. There is no evidence of them anywhere in the World except on Bermuda and in the Caribbean.
For example there is no trace of them in southern Australia (Coorong coastal plain) which has probably the best preserved interglacial sealevel record in the World.
Note that Bermuda and the Caribbean are both very much affected by hurricanes and that there is good evidence that arctic-tropic temperature gradients become extremely steep at the end of interglacials.
tty: Uh, did you actually take a look at Figure 13 as regards MIS-5e? MIS-11 is another matter as it is MIS-1, NIS-5e, MIS-9 and MIS-7 interglacials back. Been a little bit of geologic action over the past 400kyrs, tectonics, erosion etc. so MIS-11 is a little more of a crap shoot given that a lot of evidence for it has been erased or displaced. What seems clear is that MIS-11 is the longest and possibly the warmest of the post-MPT interglaciations. One wonders if more heat for something like 2-3 times the age of the Holocene might have melted just a little bit more icecaps. Or would you be more inclined to agree that more warming causes cooling?
I had noticed this about a year ago. I remember thinking at the time that insolation would possibly not drop to the point where we tip into glaciation and some global warming hucksters would attempt to spin that extended interglacial as somehow caused by man and use that to justify their supercalifragilistic global warming hyperbole. It will, in my opinion, all depend on summer ice extent in the Arctic Ocean as I rather firmly believe that is what flips the state of the system. Too much summer ice cover in the Arctic Ocean and the system “flips” cold. Once it flips to that state, it takes much greater insolation to flip it back. We will be very close. A major volcanic eruption might be enough to tip the balance to the cold state. Once we get to a point where we have substantial summer ice in the Arctic, I believe we’re done for 80K years or so.
William McClenney says:
March 16, 2012 at 8:27 am
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William McClenney,
Hey, thanks for the comment about the existence of many papers critical of Milankovitch cycle theory. One or two references would be helpful. But please no extra effort on your part is expected . . . . you have already done much with your wonderful article here.
On another thought. To dampen any potential of sense of urgency and hysteria about the potential ‘End of the Holocene’ we should consider the approximate rate of change of the temperature drop from the peak at the end of the previous interglacial about 140k years ago. The end of that interglacial had (from its peak temperature) a drop in temperature (based on figs 1 & 4 shown in McClenney’s post) on the rough order of ~1C/~+1000yrs. I confirmed that estimate from figs 1 & 4 by seeing what Prof Murry L. Salby shows in his very recent new textbook ‘Physics of the Atmosphere and Climate’ (January 2012, Cambridge University Press). Salby has a graph in Chapter 1 a graph from Petit et al. (1999) that shows ‘Reconstructions of atmospheric temperatures, carbon dioxide and methane as function of time before present, inferred from ice core drilled at Vostok Antarctica’; the timescale being a period of 450Kyr before present. That Petit et al. (1999) figure is very similar to figs 1 & 4 of this post by McClenney.
John