Glacial Inception: the climatic ‘madhouse’

clip_image026_thumb.jpgGuest essay by William McClenney

Abstract: I used to think there was only one known substitute for intelligence – stupidity. I have since realized that I left out evil (see Hitler et al). I have also come to the conclusion that the difference between confidence and arrogance is competence. Keep those thoughts in mind as we take a tour de force through the peer-reviewed literature regarding the climatic “madhouse” also known as glacial inception. It would be one thing if we were to become concerned about Anthropogenic Global Warming (AGW), say in the middle of an interglacial. It’s quite another altogether to get all worked-up over it at a probable end extreme interglacial.

Author’s Note:

As always I will be quoting liberally from the extensive literature on glacial inception which will necessarily make this quite a lengthy essay. The assumption is made that the reader has read or re-read the first 3 essays building on this subject:

http://wattsupwiththat.com/2010/12/30/the-antithesis/ where the possibility is discussed 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.

http://wattsupwiththat.com/2011/01/05/on-%E2%80%9Ctrap-speed-acc-and-the-snr/ The 2nd installment compared the speeds of projected Anthropogenic Global Warming with known climate transitions, introduced the readership to Abrupt Climate Change (ACC) and applied the simple engineering principle of Signal to Noise Ratio (SNR) to mankind’s predicted and natures actual best trap-speeds and times.

http://wattsupwiththat.com/2012/03/16/the-end-holocene-or-how-to-make-out-like-a-madoff-climate-change-insurer/ The 3rd installment was essentially an update on the previous two but with a focus on what the end of the Holocene might look like from the perspective of the ends of the most recent “extreme interglacials”.

It is recommended that these essays be (re)viewed for the vernacular, concepts, and climate framework you will need to glean the most from this further exposé.

As ever, there is also a clear need to expose the reader to the scientific method in operation: the literature.

The “science” finally fully decoupled from “policy” in 2009 (Climategate), although it may have begun as early as 1978. Readers that choose not to bone-up on the basics (the first 3 essays) and provide comments that are addressed in those prior essays, will be directed to those essays in responses. The specter of Climate Change is far and away a more dangerous prospect than anything you may have been led to believe with respect to the Anthropogenic Global Warming hypothesis.

In the final analysis, the only question that remains unanswered, with respect to climate change, is would “a caveman get this?

Introduction:

 

The profound quandaries attending the Anthropogenic Global Warming (AGW)/Climate Change hypothesis are legion. Not the least of which is:

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The possible explanation as to why we are still in an interglacial relates to the early anthropogenic hypothesis of Ruddiman (2003, 2005). According to that hypothesis, the anomalous increase of CO2 and CH4 concentrations in the atmosphere as observed in mid- to late Holocene ice-cores results from anthropogenic deforestation and rice irrigation, which started in the early Neolithic at 8000 and 5000 yr BP, respectively. Ruddiman proposes that these early human greenhouse gas emissions prevented the inception of an overdue glacial that otherwise would have already started.

conclude Muller and Pross (2007) http://folk.uib.no/abo007/share/papers/eemian_and_lgi/mueller_pross07.qsr.pdf

Ditto for Risebrobakken et al (2007, Quaternary Research 67(1): 128-135):

The climate history of the present interglacial is in many ways comparable with MIS 5.5, and the present conditions in Northern Europe do in some ways fulfill requirements for glacial inception. Even at its present minimum position the Northern Hemisphere summer insolation is, however, fundamentally different from the situation 115,000 yr ago. The insolation fall during the Holocene has been less than half of the fall during MIS 5.5. The present value is also 40 W/m2 higher than the values at 115,000 yr. Together with the high levels of greenhouse gases, this difference in insolation forcing is probably the main factor preventing glacial inception today.

 

https://bora.uib.no/bitstream/handle/1956/2088/Risebrobakken_inception.pdf?sequence=1

What makes that profound is that if CO2/GHGs/etc. really represent the gaia thermostat, and have already prevented glacial inception (Ruddiman, 2003) for perhaps thousands of years already, then by all means we should:

A. Strip said “climate security blanket” from the late Holocene atmosphere, and be quick about it. We have denied gaia her next ice age for far too long already.

B. Be thankful we stumbled onto this interglacial climate-maintenance cocktail when we did.

The last time gaia was at a ~400kyr eccentricity minimum was during MIS-11 (the Holsteinian interglacial of some authors). MIS-11 went long, lasting somewhere between 1.5 – 2 full precession cycles. MIS-19, two ~400 kyr eccentricity minima (~800 kyrs) back to the initiation of the eccentricity-paced ice age/interglacial couples of the post-MPT stage of the Pleistocene, lasted about half a precession cycle, as has the Holocene so far, and every post-MPT interglacial save MIS-11 has.

We are either going to have another “extended interglacial”, like MIS-11 did, or we won’t, like MIS-19 didn’t, given that like them we are once again at a 400kyr eccentricity minimum.

There is a particularly prickly issue that either case is stuck with:

· If the Holocene is to “go-long” like MIS-11 did, what could we possibly deploy to get us through the several thousand years of cold between the first and second MIS-11 insolation peaks (given we are at an insolation minimum now and were then)?

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MIS-11 from Lake Baikal sediments.

http://www.clim-past.net/6/31/2010/cp-6-31-2010.pdf

· If the Holocene is not supposed to “go-long”, is there something we could deploy to delay or obviate the next glacial inception? Like perhaps CO2/CH4/GHGs etc. et al?

To CO2, or not to CO2?:

That is the question. However Sirocko and Seelos, 2005, “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, make this a far more interesting question:

“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 [glacial] inception for the next 4,000 years before it then increases again.”

http://www.particle-analysis.info/LEAP_Nature__Sirocko+Seelos.pdf

Which I will restate as follows: “Can anyone think of something, anything, anything at all, that we might possibly do to span just the next 4,000 years? You know, before insolation increases again?” If not GHGs, then what, precisely?

What we have also been told, if you were listening, is that whenever we do reach the end of the present interglacial, the Holocene, we might be in for the normal, natural, “climatic ‘madhouse’” that all too often attends the ends of the post-MPT interglacials:

The lesson from the last interglacial “greenhouse” in the Bahamas is that the closing of that interval brought sea-level changes that were rapid and extreme. This has prompted the remark that between the greenhouse and the icehouse lies a climatic “madhouse”!

conclude Neuman and Hearty (1996) http://www.researchgate.net/publication/249518169_Rapid_sea-level_changes_at_the_close_of_the_last_interglacial_(substage_5e)_recorded_in_Bahamian_island_geology/file/9c96051c6e66749912.pdf

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Whereas no certified criteria have been put forth (so far) as regard glacial inceptions. What is known about the ends of the post-MPT interglacials MIS-19, MIS-11 and MIS-5e serve as our primary guides as to what climate might reasonably be anticipated to attend the next post-MPT glacial inception. At least 3 problems would seem to persist.

Without anthropogenic influence both MIS-19 and MIS-11 suffered 3 thermal excursions right at their very ends. The youngest of each was the stronger, right before each dropped into the next ice age:

MIS-19: This discussion extends the discussion presented in http://wattsupwiththat.com/2012/03/16/the-end-holocene-or-how-to-make-out-like-a-madoff-climate-change-insurer/ as related to MIS-19 which occurred somewhere within or at the Mid Pleistocene Transition, a climate evolution period between the obliquity-paced world (41 kyr glacial/interglacial cycles) to the eccentricity-paced (~100kyr glacial/interglacial cycles) world we have evolved through to the present. MIS-19 is the 8th interglacial back in the record, with MIS-1, the Holocene, being the 9th one since the MPT. Whereas MIS-19 may not satisfy everyone as an interglacial belonging to the present eccentricity-paced major climate cycles, it also occurred at a 400kyr eccentricity minimum cycle, just like MIS-11 (the Holsteinian) did and MIS-1 (the Holocene) is doing now.

http://lgge.osug.fr/IMG/fparrenin/articles/pol-EPSL2010.pdfDuring the glacial inception from MIS 19 to MIS 18, the low resolution EPICA Dome C water stable isotope record (Jouzel et al., 2007) has revealed millennial variability principally marked by the occurrence of three consecutive warm events (hereafter called Antarctic Isotope Maxima – AIM, following EPICA-community-members, 2006, and noted A, B, C on Fig. 2).

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Please note the amplitude gain at AIM-A, from the decaying interglacial baseline, exceeds that of AIM-B and C which preceded it. We have but to look at the post Holocene Climate Optimum warm spells, i.e. the MWP, Roman and Minoan (to name a few of the already named few), to see that they also peaked above the most recent grand solar maximum (may it rest in peace). How many thermal excursions will the end-Holocene have? How many has it already had?

Perhaps more importantly, how will we tell?

Seven of the last eight post-MPT interglacials have each lasted about half a precession cycle. The precession cycle itself varies between 19 and 23kyrs and we are at the 23kyr part of that cycle now, making 11,500 half. As of 2014 the Holocene is exactly 11,717 years old (based on the end of the Younger Dryas cold interval). Or pretty much about half a precession cycle.

Do Rohling et al (2010) sum it up for us?

“From that point of view, the search for a direct analogue of the Holocene should be diverted to low-eccentricity interglacials associated with a single insolation maximum. This draws attention to MIS-19 (~780 ka), for which greenhouse gas concentrations can still be derived from Antarctic ice cores (Loulergue et al., 2008), although sea-level data similar to that used here for MIS-11 and the Holocene would require new, deep (Integrated Ocean Drilling Project) drilling in the central Red Sea. Recent comparisons of CO2 and CH4 trends through MIS-19 with those of the Holocene, in the absence of sea-level constraints, have been used to suggest that the Holocene should have terminated already (Kutzbach et al., 2009), although opinions remain divided (Tzedakis, 2009).”

http://www.personal.soton.ac.uk/ejr/Rohling-papers/Rohling et al_EPSL MIS-11_revised.pdf

But the thing is that 3rd and final end MIS-19 thermal excursion was the strongest.

· MIS-11:

We have this from Desprat et al (2005):

Abstract:

The Marine Isotope Stage 11 interglacial, centered at ~400 ka, appears to be the best candidate for understanding climatic changes in the context of low insolation forcing such as that of our present interglacial. Direct correlation between terrestrial (pollen) and marine climatic indicators and ice volume proxy from deep-sea core MD01-2447 (off northwestern Iberia) shows for the first time the phase relationship between southwestern European vegetation, sea surface temperatures in the northeastern Atlantic midlatitudes and ice volume during MIS 11. A warmest 32,000 years-long period and three following warm/cold cycles occurred synchronously on land and ocean. The end of the warmest period sees the glacial inception which coincides with the replacement of warm deciduous forest by conifer (pine-fir) expansion in northwestern Iberia and, consequently, with the southward migration of the tree line in high latitudes in response to declining summer insolation. As weak insolation changes alone cannot account for ice growth, the associated vegetation changes must now be considered as a potential major feedback mechanism for glaciation initiation during MIS 11.

Marine Isotope Stage (MIS) 11, the interglacial dated at c. 400 ka, is marked by Earth’s orbital geometry being very similar to that of MIS 1 (~14 ka-present) (Loutre and Berger, 2003) and, therefore, appears to be the best candidate to predict the natural evolution of the present interglacial. The climate behavior simulated by the LLN-2D model for MIS 11 and MIS 1 shows an unusually 50,000 years long period of warmth and minimum northern hemisphere continental ice volume (Loutre and Berger, 2003). The new EPICA-DOME C record suggests that temperature remains warm for 28,000 years during MIS11 (EPICA community members, 2004). Marine data from MIS 11 have led to the traditional idea of an exceptional interglacial in the oceanic realm, the longest and warmest of the last 500 ka (Droxler and Farrell, 2000; Howard, 1997). This is challenged by several authors who claim that this interglacial was not substantially warmer than today (e.g. Bauch et al., 2000; Hodell et al., 2000). A recent review of the putative continental records of MIS 11 suggests that this interval was moister than present and temperature estimates varied from similar to the present, to warmer from place to place (Rousseau, 1999).

Earth’s particular orbital configuration during MIS-11 implies an astronomical climatic forcing greatly different than succeeding interglacial stages such as MIS 5. This different orbital forcing is traduced by a relatively weak northern summer insolation and low amplitude variations during MIS 11, contrasting with the large insolation changes and associated high maxima during MIS 5. This raises the question of the ‘‘Stage 11 Paradox’’: astronomical forcing during stage 11 is too low by itself to drive climate into interglacial conditions (Li et al., 1998) and yet the 12-11 Termination appears to be the largest of the last million years (Imbrie and Imbrie, 1980). Moreover, insolation changes cannot alone trigger the glacial initiation during MIS 11 as the summer insolation decrease is modest.

Conclusion:

New evidence from the first land–sea direct correlation of MIS 11 demonstrates the synchroneity between marine and terrestrial responses to the climate variability of MIS 11. Reassessment of continental and marine sequences from North Atlantic, Europe, Siberia as well as Antarctica reveals a similar pattern of climatic variability over MIS 11 marked by a long and warm first period followed by three warm/cold cycles. We have also demonstrated that the Holsteinian interglacial is the warmest period of MIS 11 in northern Germany. Isotopic data show that ice actually accumulated in northern high latitudes as soon as 400 ka. Further, pollen data indicate a southward migration of vegetation belts involving albedo increase and glacial inception as early as 405 ka. This ice growth is associated with a general oceanic and atmospheric cooling till 390 ka. Geological records and MoBidiC experiments contradict the 50 ka long ice-free interval simulated by the LLN-2D model which is only forced by CO2 and insolation. Models for predicting the future of our present interglacial, characterized as MIS 11 by weak insolation changes, should not underestimate the effect of declining insolation on vegetation and the associated feedback mechanisms that help foster glaciation.

http://www.researchgate.net/publication/229415952_Is_vegetation_responsible_for_glacial_inception_during_periods_of_muted_insolation_changes/file/9c96051e55e2f0f6b2.pdf

The Here and the Now:

We find ourselves something like ~6 – ~9kyrs past the “Holocene Climate Optimum.” I do not think anyone really knows how many bouts of climatic “madhouse” the end Holocene is supposed to experience, or whether or not we can detect, for the first time ever, an as yet unseen future anthropogenic climate “signal” beyond its diminutive ramp-up amplitude. Are there any credible (latitude is assumed here) estimates for how long the anthropocene will last or if it might last say longer than say ~600 years? Especially amidst up to three thermal excursions which range from 1 to almost 2 orders of magnitude larger than AGW climatic “madhouse” peaks.

So we will start with the projected anthropogenic signal from the IPCC’s Assessment Report 4 (AR4) (2007). This is Figure 10.33 from page 821 of Chapter 10:

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Note the annotation I added to point-out SRES marker series A1F1’s upper error bar which comes in at about +0.59 meters, about 2 feet, to 2099. The A1F1 SRES marker series is IPCC’s worst case scenario, or “business as usual” if we continue to do nothing about GHG etc. emissions.

How on earth (literally) are we going to detect, reliably or not, a “first-ever” anthropogenic climate “signal”, at the latest half-precession cycle old extreme interglacial, when our very best (or worst) anthropogenic future “signal” is just over an order of magnitude less than the lowest estimate of the second strong thermal pulse and sea level highstand achieved naturally at the end of the most recent interglacial? But things just might be worse than you think. If we compare apples to apples (upper error bar A1F1 of +0.59 m to the highest estimate I have seen for the end-Eemian of +52.0 m) then the end extreme interglacial “noise” grows to almost 2 orders of magnitude greater than the first-ever future maximum anthropogenic “signal” which has yet to stand-up and be recognized.

Signal processing and pattern recognition theory should inform us that detecting a signal we can’t yet describe (because CAGW is in the future, we only “model” what that might look like) from a stochastic “noise” background between 1 to almost 2 orders of magnitude greater than the “signal” is a logical absurdity. It is even more absurd if/when we have to pick which possible (of maybe 2 or 3) end-Holocene thermal excursion is supposed to be “ours”, given that the last 2 times we have been at an eccentricity minimum there were 3 dramatically stronger natural thermal excursions right at the ends of both MIS-19 and MIS-11. To date I have not seen an educated guess, other than one anthropogenic, as to how many thermal excursions the end Holocene might reasonably be expected to host.

However the real and present danger, the 800 pound gorilla(s) in the climate change room, the ones never talked about at Conference(s) of the Parties, is the climatic “madhouse”, a.k.a. the end-Holocene glacial inception, which we may still be avoiding because of our now many wayward Holocene civilizations.

One wonders if “Even a caveman would get this!” Keeping in mind, of course, that we have indeed been through glacial inception at least once (if not twice) before, as our stone-age H. sapiens selves. Way back then we couldn’t write and re-write laws, much less the laws of science, “cloudy” computer code et al, simply because apparently we could not yet write until ~10,000 or so years ago. Writing appears to be wholly a Holocene invention.

We are going to get very deep into the peer-reviewed literature on this. But there is one item that needs to be dealt with first. Without fail there will be those firmly anchored in 2003 (such as the IPCC et al etc.) when a landmark paper by Loutre and Berger (http://www.sciencedirect.com/science/article/pii/S0921818102001868 paywalled) suggested that the Holocene has another 50,000 years to run. This is based on an intermediate complexity model (LLN 2-D NH) developed at Louvain-la-Neuve. For those enamored with models.

It was soon put to rest (2005) by development of the LR04 stack of 57 globally distributed deep ocean sediment cores (a.k.a. observations):

“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 3.6 o/oo for 20 kyr, from 398-418 ka. In comparison, stages 9 and 5 remained below 3.6 o/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 effectively precludes a ‘double precession-cycle’ interglacial [e.g., Raymo, 1997] in the Holocene without human influence.”

http://large.stanford.edu/publications/coal/references/docs/Lisiecki_Raymo_2005_Pal.pdf

If you have not moved-on from Loutre and Berger’s 2003 hypothesis yet, you will find a wealth of material here with which you may do so now.

Listen, and understand. That [interglacial] terminator is out there. It can’t be bargained with. It can’t be reasoned with. It doesn’t feel pity, or remorse, or fear. And it absolutely will not stop, ever……” Kyle Reese in “The Terminator

In perhaps the single most stunning Logical Absurdity of all time, we may have proved Kyle Reese wrong. If the IPCC/AGW/CAGW (a.k.a. warmists) are correct about GHGs etc., the reason we are not already several thousands of years into the next glacial might be because of GHGs…. We may have terminated the interglacial terminator, stopping it cold in its tracks, before things went all cold (glacial, a.k.a. ice age) on us once again.

Inevitably this brings us to…………..

The “Early Anthropogenic Hypothesis” and the “Sledgehammer Argument”:

We will illustrate our case with reference to a debate currently taking place in the circle of Quaternary climate scientists. The climate history of the past few million years is characterised by repeated transitions between `cold’ (glacial) and `warm’ (interglacial) climates. The first modern men were hunting mammoth during the last glacial era. This era culminated around 20,000 years ago [3] and then declined rapidly. By 9,000 years ago climate was close to the modern one. The current interglacial, called the Holocene, should now be coming to an end, when compared to previous interglacials, yet clearly it is not. The debate is about when to expect the next glacial inception, setting aside human activities, which may well have perturbed natural cycles.

On one side, Professor Bill Ruddiman carefully inspected and compared palaeoenvironmental information about the different interglacial periods. This comparison let him to conclude that glacial inception is largely overdue [4, 5]. According to him, the Holocene was not supposed to be this long, but the natural glacial inception process was stopped by an anthropogenic perturbation that began as early as 8,000 years ago (rice plantations and land management by antique civilisations). On the other side, Professor Andre Berger and colleagues developed a mathematical model of the climate system, rated today as a `model of intermediate complexity’ [6, 7] to solve the dynamics of the atmosphere and ice sheets on a spatial grid of 19 x 5 elements, with a reasonably extensive treatment of the shortwave and longwave radiative transfers in the atmosphere. Simulations with this model led Berger and Loutre to conclude that glacial inception is not due for another 50,000 years, as long as the CO2 atmospheric concentration stays above 220 ppmv [8]. Who is right?

ask Crucifix and Rougier (2009) http://arxiv.org/pdf/0906.3625.pdf.

A year after Ruddiman first published the Early Anthropogenic Hypothesis he published an update, in which he summed up his responses to critiques of his hypothesis thusly:

“Ruddiman (2003) introduced a three-part hypothesis on early anthropogenic influences on late Holocene climate. He proposed that humans reversed a natural decrease in atmospheric CO2 values 8000 years ago by starting to clear forests for farms, that they reversed a natural methane decrease after 5000 years ago mainly by beginning to irrigate rice, and that they caused an anthropogenic warming sufficient to counter most of a natural cooling and avoided the onset of a new glaciation within the last several thousand years. Critics have correctly noted that stage 11 is a better insolation analog for the Holocene because of its comparably low eccentricity values.

 

“I recently examined (Ruddiman, in press) the part of stage 11 regarded as the closest insolation analog to the last several millennia of the Holocene and the next few millennia (Berger and Loutre, 2003). This interval occurred in the millennia between 400,000 years ago and 390,000 years ago.

 

“During this analog to modern conditions, atmospheric methane concentrations fell to just under 450 ppm and CO2 values to 250 ppm (Figure 1a and b). In both cases, the levels reached were very near to the natural Holocene levels predicted in the early anthropogenic hypothesis. As stage 11 was an entirely natural (nonanthropogenic) world in which the insolation forcing was similar to the Holocene, these observations provide strong support for the hypothesis.

 

Several lines of evidence indicate that a glaciation was underway during the part of stage 11 when insolation values were most analogous to the present. Icebergs began carrying abundant debris to Nordic Sea sediments just after 400,000 years ago, following a long interval with negligible deposition (Bauch et al., 2000). For ice rafting to have occurred in that region, new ice must have begun growing either in Scandinavia, the Barents Sea, or along the coasts of Greenland.

 

“Claussen et al. cite the EPICA interpretation that the current interglaciation must still have many millennia left to run if it is to persist as long as the one in stage 11. But the EPICA interpretation contains what I regard as a fatal flaw. EPICA aligns the beginning of the two interglaciations and compares their subsequent duration (Figure 2A), but this choice results in a total misalignment of the 65◦N summer insolation trends in the two interglaciations (Figure 2b). The correct alignment of the insolation trends (used by Berger and Loutre, 2003) matches the modern-day insolation minimum with a similar minimum 397,000 years ago (Figure 2D). This alignment of stage 1 with the end (rather than the beginning) of stage 11 leads to the conclusion that the Holocene interglacial warmth should have already ended (Figure 2C).

 

“The proposed sequence during the Holocene is as follows. Direct carbon emissions from anthropogenic (mostly agricultural) sources accounted for most of the Holocene methane anomaly and a smaller fraction (perhaps a third) of the CO2 anomaly. These direct emissions caused a climatic warming sufficient in size to cancel the appearance of small northern hemisphere ice sheets and to suppress the size of major advances of southern hemisphere sea-ice. The failure of these natural changes to develop then contributed to the remaining (and larger) part of the CO2 anomaly as a form of positive feedback to the initial ‘direct’ anthropogenic impacts.

 

Most critics of my hypothesis have neglected to respond to the single most powerful argument in its favor. In a notable exception, Crucufix et al. termed this the “sledgehammer argument”. During previous interglaciations (stages 5, 7, 9, and now also 11), when nature was in full control of climate, and when insolation trends were headed in the same direction as they are now, concentrations of CO2 and CH4 fell in every instance. Alone among the last five interglaciations, stage 1 shows a substantial greenhouse-gas rise. My challenge to the critics is this: Why did CO2 and CH4 concentrations rise in the middle and late Holocene, when they had previously always fallen? The seemingly unavoidable implication is that something about stage 1 is different—not “natural”. The most plausible answer is the onset of agriculture.

 

“The same argument works in the converse sense: any argument devised to explain the stage 1 greenhouse-gas increase as “natural” in origin has already dug itself a very deep hole. For example, Joos et al. (2004) call on terrestrial vegetation, ocean carbonate, and coral reefs as natural sources of carbon to explain the Holocene CO2 rise. Given our still-uncertain knowledge of carbon dynamics (Crucufix et al.), these alternative explanations for the late-Holocene CO2 rise can be proposed, and model simulations can be run that match a portion of the carbon-budget demands. But how will these explanations fare when tested in the past?

 

Tested against the reality of the last four interglaciations, any such explanation must fail. All of the major climatic boundary conditions during the previous interglaciations were similar to those found today: the major ice sheets had melted, sea level was high, boreal vegetation was in an interglacial state, tropical monsoon vegetation was in retreat, and insolation trends were similar (especially during stage 11). Given this pervasive similarity in the major sources of forcing, the explanations must predict (and the models must presumably simulate) similar rises in CO2 during the earlier interglaciations. In fact, for those interglaciations with stronger insolation forcing than the Holocene, the predicted CO2 increases would probably be even larger than the Holocene rise.

 

“But the CO2 and CH4 concentrations did not rise during the intervals most similar to today; they fell. It seems inevitable that these naturally based explanations must fail the test on all four previous interglaciations. Indeed, the large increases in gas concentrations these explanations should predict will make it all the more difficult to explain the large decreases actually observed.”

http://www.clas.ufl.edu/users/rrusso/gly6932/Ruddiman_05b.pdf

Muller and Pross (2007) conclude:

The possible explanation as to why we are still in an interglacial relates to the early anthropogenic hypothesis of Ruddiman (2003, 2005). According to that hypothesis, the anomalous increase of CO2 and CH4 concentrations in the atmosphere as observed in mid- to late Holocene ice-cores results from anthropogenic deforestation and rice irrigation, which started in the early Neolithic at 8000 and 5000 yr BP, respectively. Ruddiman proposes that these early human greenhouse gas emissions prevented the inception of an overdue glacial that otherwise would have already started.

Rohling et al (2010) chime in with this:

Finally, the alignment shown in Fig. 4 (which is similar to that of Ruddiman, 2005, 2007) exemplifies a completely different, more controversial (Spanhi et al., 2005; Siegenthaler et al., 2005), possibility. It has been argued that variability in the planetary energy balance during Pleistocene glacial cycles was dominated by greenhouse gas and albedo related feedback mechanisms, and that the role of insolation was limited to only triggering the feedback responses (Hansen et al., 2008). Hence, the apparently anomalous climate trends of the most recent 2.0-2.5 millennia should also be investigated in terms of changes in these feedback responses due to processes other than insolation, including controversial suggestions concerning man’s long-term impacts from deforestation and CH4 and CO2 emissions (Ruddiman, 2003, 2005, 2006, 2007; Hansen et al., 2008). There is support from modelling studies that the relatively minor early anthropogenic influences may have been sufficient to delay glacial inception (Vavrus et al., 2008; Kutzbach et al., 2009).

http://www.personal.soton.ac.uk/ejr/Rohling-papers/Rohling%20et%20al_EPSL%20MIS-11_revised.pdf

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.

 

On balance, what emerges is that projections on the natural duration of the current interglacial depend on the choice of analogue, while corroboration or refutation of the “early anthropogenic hypothesis” on the basis of comparisons with earlier interglacials remains irritatingly inconclusive.

http://www.clim-past.net/6/131/2010/cp-6-131-2010.pdf

There is less to be found regarding interglacials MIS-9 and MIS-7, which is why we will not loiter here very long, as in general the consensus would seem to be that these interglacials did not reach “extreme” classification, meaning that they may not have reached our temps or sea levels. From the research I have done, this next quotation sums up MIS-7 well with regard to sea level, the ultimate proxy of climate change:

Chappell (1974) estimated paleo-sea levels for emergent MIS 7 reefs on the rapidly rising coast of New Guinea. His calculations indicate that at least two MIS 7 sea levels were very close to present (see his Fig. 19).

 

Finally, there are a few emergent MIS 7 marine deposits on tectonically stable or very slowly uplifting coasts or islands. On tectonically stable Bermuda, Harmon et al. (1983) report ages of ~220 ka to ~200 ka for corals from the Belmont Formation, a marine deposit that occurs at elevations of 1 m – 2 m above sea level.

 

Our data from the Florida Keys, while not tightly constrained by age, indicate that sea level during MIS 7, probably ~200 ka, was close to present or perhaps a couple of meters higher. In this regard, our interpretations are in agreement with some estimates of high MIS 7 sea level from Barbados (Gallup et al., 1994; Thompson and Goldstein, 2005), at least one estimate from New Guinea (Chappell, 1974), and southern Australia (Murray-Wallace, 2002). Other studies, from coastlines with both high and low uplift rates, indicate sea level during MIS 7was significantly lower than present. Unfortunately, many MIS 7 coastal records, ours included, do not have ideal geochronology and firm conclusions about sea-level history during this interglacial must await further study.

If the global model and the estimated paleo-sea levels for south Florida are correct, then it is apparent that a significant portion of the Greenland ice sheet and possibly all of the West Antarctic ice sheet were lost during the Last Interglacial period.

 

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http://www.researchgate.net/publication/256161682_Muhs_et_al.2011QSRFloridaSeaLevels/file/50463521e3bf79d4ac.pdf

So what is the wise wise one (Homo sapiens sapiens) to do? If the efficiency (sensitivity) of CO2/GHGs as a “climate security blanket” is as high as we have been advised by the IPCC et al etc., and may have already delayed glacial inception for thousands of years, then why would anyone want to remove such a “climate sledgehammer/security blanket” from the normal, natural path of possibly millennia “overdue” glacial inception?

Did some ~97% of “us” just bump “our” heads?

The Last Glacial Inception; MIS-5e/5d:

Neuman and Hearty (1996) may have nailed it:

Rapid changes in sea level and associated destabilization of climate at the turbulent close of the last interglacial maximum appear to be recorded directly in the geomorphology, stratigraphy, and sedimentary structures of carbonate platform islands in the Bahamas. Considered together, the observations presented here suggest a rapid rise, short crest, and rapid fall of sea level at the close of 5e.

The lesson from the last interglacial “greenhouse” in the Bahamas is that the closing of that interval brought sea-level changes that were rapid and extreme. This has prompted the remark that between the greenhouse and the icehouse lies a climatic “madhouse”!

http://www.researchgate.net/publication/249518169_Rapid_sea-level_changes_at_the_close_of_the_last_interglacial_(substage_5e)_recorded_in_Bahamian_island_geology/file/9c96051c6e66749912.pdf

Sea level was 6-7 m higher than present during the last interglacial highstand 125,000-115,000 years before present (MIS 5e). Evidence from New Providence Platform, Bahamas, indicates that it was not a single rise and fall but instead oscillated a minimum of 12 m over a few thousand years.

Beach deposits that are +7.6 m above present sea level on New Providence Island represent the older peak of MIS 5e sea level. A down-stepping beach ridge indicates a subsequent sea-level position at +7.0 m. A calcrete in the subtidal deposits adjacent to the beach documents the mid-MIS 5e sea level drop. In the Exumas, a calcrete associated with this fall separates subtidal facies at -5.2 m. Sea level rises again to form the younger MIS 5e highstand; this rise is represented by a beach ridge at +5.1 m on New Providence Island and Exumas reefs up to +1.5 m above modern sea level. Parallel down-stepping beach to eolian dune transitions provide evidence for a pulsed down-stepping of sea level at the end of MIS 5e. The lowest occurrence of this transition is approximately -12 m below present sea level.

These highstand oscillations recorded in the Bahamas and elsewhere require another, yet unexplained, forcing mechanism of much shorter duration than Milankovitch frequencies but also document rapid climate changes during warm interglacial periods.

opine Kelly et al (2012) (paywalled here: https://gsa.confex.com/gsa/2012AM/finalprogram/abstract_212012.htm

Six years (2006) earlier, we had this from Landais et al http://www.climate.unibe.ch/~born/share/papers/eemian_and_lgi/landais_masson-delmotte06.cd.pdf:

From this, we can establish a tentative comparison of the ice core records on the GT4 timescale with the two marine records over the glacial inception. This comparison suggests that the cold phase GS 26 (before the DO 25 warm phase) manifested itself in the northern Atlantic region as well as in the mid-latitude surface ocean (up to the Iberian margin, MD 95-2042) as a slight cooling (less than one-fourth of a typical rapid cooling during the last glacial). No clear IRD signal is recorded, except the one found by Chapman and Shackleton (1999), which seems to occur during the warm phase of DO 25 (Shackleton et al. 2002), suggesting that GS 26 was not driven by an iceberg discharge (Fig. 1). Summarizing, the sequence for the glacial inception and the beginning of the glacial period is the following:

The polar temperature decreases in both the North and the South. The slow growth of ice sheets seems to be in phase with or slightly lags the polar temperature decrease, as described by Cortijo et al. (1994, 1999). This ice sheet growth was probably driven by the summer temperature decrease at polar latitudes (Oerlemans 2001) as a consequence of the decreased northern insolation. The obliquity decrease acts as a positive feedback for the ice sheet growth because of the associated increase in low- and high-latitude insolation gradients that enhances the transport of water masses (Fig. 4; Ruddiman and McIntyre 1979; Khodri et al. 2001).

The first rapid event (succession of GS 26 and DO 25) is recorded in the northern hemisphere but has no Antarctic counterpart. It is triggered while the CO2 level and ice sheet size are still intermediate between interglacial and full glacial values.

Finally, our proposed sequence of events associated with the glacial inception (simultaneous cooling in north and south and moderate increase in continental ice volume, followed by the CO2 decrease) contrasts with the somewhat different situation during glacial terminations. By comparing the Byrd (Antarctica) and GISP2 records, the Greenland warming during the last termination started slowly 2 k years or less before the initiation of the Antarctic warming (Alley et al. 2002). Then, the Greenland main warming (Bølling-Allerød) occurred only 6 kyears after the beginning of Antarctic warming. Moreover, the analysis of the properties recorded in the Vostok and EPICA Dome C Antarctic cores indicates that during terminations: (1) the temperature at high southern latitude increases only a few hundred years before CO2 (Monnin et al. 2001; Caillon et al. 2003b), (2) the dynamics of the warming was very different between North and South and (3) the northern ice sheet deglaciation occurred several thousand years after the southern warming (Pepin et al. 2001).

In addition, we propose a relative dating of the Greenland glacial inception with respect to East Antarctic temperature, atmospheric CO2 evolution and global ice sheet growth. According to this dating, the glacial inception involved synchronous cooling at both poles during the initial slow growth of the northern hemisphere ice sheets. Rapid climatic variability in the North Atlantic initiated with DO 25, which seems to be associated with a small temperature change and has no Antarctic counterpart. It occurred before ice sheets reached their glacial maximum extent and while atmospheric CO2 was still relatively elevated. After that event, atmospheric CO2 dropped to glacial levels and NorthGRIP DO 24 and 23 depict characteristics of classical DO (up to +16C for DO 24, i.e. comparable to the DO 19 at the same site; IRD signal; Antarctic counterpart).

Finally, the rapid climatic variability during the warm and cold phases of DO 23 and 24 suggests that the THC encountered frequent shifts between ‘‘off’’ and ‘‘on’’ modes. The first rapid event, DO 25, which occurred during the initial ice sheet build-up, suggests a key role for the atmospheric hydrological cycle in climate dynamics. The water cycle influence has already been proved to favour the glacial inception. We show here that it could additionally create a rapid climatic variability when the influence of ice sheets discharge is reduced.

Hodgson et al (2006), in looking at coastal east Antarctica lake-sediment records, shed this light:

MIS-5e ended abruptly with a rapid transition to glacial conditions, the lake was covered by a layer of firnified snow and ice, and phototrophic biological activity ceased for a period of c. 90,000 years.

Much is known about palaeoenvironments in the northern hemisphere during the MIS5e interglacial. Records show periods of temperatures warmer than today leading to a northward expansion of Mediterranean vegetation in southern Europe and northward expansion of the fauna with animals such as the hippopotamus becoming widespread as far north as Southern England (Williams et al., 1998). With the increased temperatures, the global ice volume declined and far-field coral reefs record eustatic sea levels approximately 5–6m higher than today (Lambeck and Chappell, 2001).

In the Antarctic, palaeoenvironmental records of MIS5e are more limited.

Our results suggest that MIS5e was not a stable period as there are two distinct periods of elevated organic and carbonate carbon deposition (Fig. 2b). We speculate that these were short-lived warm periods. Two warm periods (130.7–130 and 125.7–118.2 kyr BP) have also been detected in Austrian alpine stalagmites (Holzka¨mper et al., 2004). Until there is an appropriate technology for dating MIS5e in these lake sediments we cannot establish if there is a common forcing behind these warm events. The transition from interglacial into glacial conditions was rapid and is represented in its entirety between 26 and 23 cm. This suggests that the end of MIS5e was a relatively sudden event and not a gradual transition to colder conditions. Alkenone sea surface temperature data from the Southern Ocean record this sharp cooling at around 120 kyr BP (Ikehara et al., 1997), marine cores from the Atlantic suggest that it occurred over a period of less than 400 yr, and possibly much shorter (Adkins et al., 1997), and in Greenland the transition took as little as 70 yr (Anklin et al., 1993).

The transition into glacial conditions was a relatively sudden event. This is supported by marine and ice core records.

http://www.researchgate.net/publication/222333370_Interglacial_environments_of_coastal_east_Antarctica_comparison_of_MIS_1_(Holocene)_and_MIS_5e_(Last_Interglacial)_lake-sediment_records/file/9c960525ff43b0ac6b.pdf

Necessarily, at a minimum, this obliges us to consider:

1. “Thirty-five new, high-precision, uranium-series ages of fossil corals from the Key Largo Limestone indicate that sea level was significantly above present for at least 9000 years during the Last Interglacial period, and possibly longer.

 

Older fossil reefs at three localities in the Florida Keys have ages of w200 ka and probably correlate to MIS 7. These reefs imply sea level near or slightly above present during the penultimate interglacial period. Elevation measurements of both the Key Largo Limestone and the Miami Limestone indicate that local (relative) sea level was at least 6.6 m, and possibly as much as 8.3 m higher than present during the Last Interglacial period.

 

The East Antarctic ice sheet (EAIS) can contribute a potential sea level rise of ~52m (Lythe et al., 2001),

 

“Our elevation measurements from south Florida imply an RSL significantly above present during the LIG. From reefs in the Q5 unit of the Key Largo Limestone on Key Largo, we estimate an RSL of ~6.6 m above present and from Windley Key, ~8.3 m above present, assuming a ~3-m water depth for corals. The Miami Limestone elevations, at least in the Miami area, imply an RSL of 8.1-8.6 m above present during the LIG, assuming an ooid-shoal depth of ~1-m.

 

“Although it could in principle contribute as much as ~52 m of global sea-level equivalent (Lythe et al., 2001), the EAIS is thought to be relatively stable (Huybrechts and de Wolde, 1999). Using estimates of ice-volume made by Bamber et al. (2001), Greenland could in principle contribute as much as ~7.3 m of global sea-level equivalent. The potential sealevel contribution of the GIS ice sheet in the LIG is constrained by cores from central Greenland that show there is LIG ice, as old as ~123 ka, near the base (North Greenland Ice Core Project Members, 2004). Thus, the LIG contribution of the GIS to global sea level must be something less than 7.3 m.”

 

http://www.researchgate.net/publication/256161682_Muhs_et_al.2011QSRFloridaSeaLevels/file/50463521e3bf79d4ac.pdf

2. Which can be a bit awkward to explain with respect to Lysa et al (2001):

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3. “The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5C warmer than today.

 

Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time.

 

This high resolution NGRIP record reveals a slow decline in temperatures from the warm Eemian isotopic values to cooler, intermediate values over 7,000 yr from 122 to 115 kyr BP. The end of the last interglacial thus does not appear to have started with an abrupt climate change, but with a long and gradual deterioration of climate. Before full glacial values are reached, however, the record does reveal an abrupt cooling, with a first d18O decrease at about 119 kyr BP, followed by relatively stable depleted d18O levels, which we name here the Greenland stadial 26. The stadial is followed by an abrupt increase at,115 kyr BP, the onset ofDO25 ( reference 37, Fig. 4). NGRIP is the first ice core climate record to so clearly resolve these rapid and large fluctuations in climate right at the beginning of the full glacial period.

http://epic.awi.de/10226/1/Nor2004a.pdf

4. “Using this record we determine the duration (17.70 ± 0.20 ka) and age of onset (127.20 ± 1.60 ka B.P.) of the last interglacial, as reflected by terrestrial ecosystems. This record also reveals that the transitions at the beginning and end of the interglacial spanned only ~100 and 150 years, respectively. Comparison with records of other earthsystem components reveals complex leads and lags. During the penultimate deglaciation phase relationships are similar to those during the most recent deglaciation, peaks in Antarctic warming and atmospheric methane both leading Northern Hemisphere terrestrial warming. It is notable, however, that there is no evidence at Monticchio of a Younger Dryas-like oscillation during the penultimate deglaciation. Warming into the first major interstadial event after the last interglacial is characterized by markedly different phase relationships to those of the deglaciations, warming at Monticchio coinciding with Antarctic warming and leading the atmospheric methane increase. Diachroneity is seen at the end of the interglacial; several global proxies indicate progressive cooling after ~115 ka B.P., whereas the main terrestrial response in the Mediterranean region is abrupt and occurs at 109.50 ± 1.40 ka B.P.

 

Finally, the very abrupt end of the LI, that occurred within no more than 0.15 ka (Fig. 3b), but that lagged by ~6.3 ka the onset of long-term decreases in SST, Vostok dD and CH4 and increase in global ice volume, once again indicates a nonlinear response and suggests important threshold processes.”

http://www.pnas.org/content/104/2/450.full?origin=publication_detail

5. Between 115 and 110 ka, the substantial ice accumulation in northern high latitudes (MIS 5e/5d transition) was synchronous with successive drops, C26 and C25, in northeastern Atlantic SST. In northwestern Iberia Abies-Pinus trees developed at the expense of Quercus-Carpinus forest. A tundra-like environment occupied northern Germany, marking the end of the interglacial in northwestern Europe at 115 ka, and boreal forest likely colonised northeastern France. The first displacement of the vegetation belts at 121 ka was enhanced at 115 ka indicating an amplification of the vegetation and climate gradients in northeastern Atlantic and European borderlands probably related with the well-developed ice caps at that time.

http://folk.uib.no/abo007/share/papers/eemian_and_lgi/sanchez-goni_loutre05.epsl.pdf

6. “Using this record we determine the duration (17.70 ± 0.20 ka) and age of onset (127.20 ± 1.60 ka B.P.) of the last interglacial, as reflected by terrestrial ecosystems. This record also reveals that the transitions at the beginning and end of the interglacial spanned only ~100 and 150 years, respectively.

 

Finally, the very abrupt end of the LI, that occurred within no more than 0.15 ka (Fig. 3b), but that lagged by ~6.3 ka the onset of long-term decreases in SST, Vostok dD and CH4 and increase in global ice volume, once again indicates a nonlinear response and suggests important threshold processes.”

http://www.pnas.org/content/104/2/450.full?origin=publication_detail

7. “Until a few decades ago it was generally thought that large-scale global and regional climate changes occurred gradually over a timescale of many centuries or millennia, scarcely perceptible during a human lifetime. The tendency of climate to change relatively suddenly has been one of the most surprising outcomes of the study of earth history, specifically that of the last 150,000 years (e.g., Taylor et al., 1993). Some and possibly most large climate changes (involving, for example, a regional change in mean annual temperature of several degrees celsius) occurred at most on a timescale of a few centuries, sometimes decades, and perhaps even just a few years.

 

“The beginning of crop agriculture in the middle east corresponds very closely in time with a sudden warming event marking the beginning of the Holocene (Wright, 1993). The burial in ice of the prehistoric mummified corpse of the famous ‘Iceman’ (e.g., Bahn and Everett, 1993) at the upper edge of an alpine glacier coincided with the initiation of a cold period (‘Neoglaciation’) after the Holocene climate optimum (Baroni and Orombelli, 1996).”

ftp://meteor.geol.iastate.edu/data/2005/stuff/adamsetal99.pdf

8. With polar temperatures 3–5C warmer than today, the last interglacial stage (~125 kyr ago) serves as a partial analogue for 1–2C global warming scenarios.

We find a 95% probability that global sea level peaked at least 6.6m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0m but is unlikely (33% probability) to have exceeded 9.4 m. When global sea level was close to its current level (~10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6m kyr-1 but is unlikely to have exceeded 9.2m kyr-1. Our analysis extends previous last interglacial sea level studies by integrating literature observations within a probabilistic framework that accounts for the physics of sea level change.

The results of our analysis support the common hypothesis that LIG GSL was above the current value, but contrary to previous estimates, we conclude that peak GSL was very likely to have exceeded 6.6m and was likely to have been above 8.0 m, though it is unlikely to have exceeded 9.4 m. The LIG was only slightly warmer than present, with polar temperatures similar to those expected under a low-end 2C warming scenario. Nonetheless, it appears to have been associated with substantially smaller ice sheets than exist at present. Achieving GSL in excess of 6.6m higher than present is likely to have required major melting of both the Greenland and the West Antarctic ice sheets, an inference supported by our finding that both Northern and Southern hemisphere ice volumes are very likely to have shrunk by at least 2.5 m.e.s.l. relative to today. Incorporating a large database of palaeoclimatic constraints thus highlights the vulnerability of ice sheets to even relatively low levels of sustained global warming.

http://geoweb3.princeton.edu/people/simons/PDF/Nature-2009.pdf

9. Sea level was 6-7 m higher than present during the last interglacial highstand 125,000-115,000 years before present (MIS 5e). Evidence from New Providence Platform, Bahamas, indicates that it was not a single rise and fall but instead oscillated a minimum of 12 m over a few thousand years.

Beach deposits that are +7.6 m above present sea level on New Providence Island represent the older peak of MIS 5e sea level. A down-stepping beach ridge indicates a subsequent sea-level position at +7.0 m. A calcrete in the subtidal deposits adjacent to the beach documents the mid-MIS 5e sea level drop. In the Exumas, a calcrete associated with this fall separates subtidal facies at -5.2 m. Sea level rises again to form the younger MIS 5e highstand; this rise is represented by a beach ridge at +5.1 m on New Providence Island and Exumas reefs up to +1.5 m above modern sea level. Parallel down-stepping beach to eolian dune transitions provide evidence for a pulsed down-stepping of sea level at the end of MIS 5e. The lowest occurrence of this transition is approximately -12 m below present sea level.

These highstand oscillations recorded in the Bahamas and elsewhere require another, yet unexplained, forcing mechanism of much shorter duration than Milankovitch frequencies but also document rapid climate changes during warm interglacial periods.

https://gsa.confex.com/gsa/2012AM/finalprogram/abstract_212012.htm

10. The results from these subsets were fairly consistent. Across all subsets, the median projection peaked between 6.4 and 8.7 m. With the exception of the subset containing only erosional features, the 95% probability exceedance value ranged from 5.7 to 7.0 m, the 67% probability value ranged from 7.3 to 8.7 m, and the 33% probability value ranged from 8.4 to 10.5 m. (The values for the subset containing only erosional features were slightly lower and more broadly spread, with 95%, 67% and 33% values of 20.3 m, 3.9 m and 6.8 m, respectively.

Our results suggest that during the interval of the LIG when sea level was above -10 m, the rate of sea level rise, averaged over 1 kyr, was very likely to have reached values of at least about 5.6 m kyr-1 but was unlikely to have exceeded 9.2 m kyr-1. Our data do not permit us to resolve confidently rates of sea level change over shorter periods of time.

The results from the LIG suggest that, given a sufficient forcing, the present ice sheets could sustain a rate of GSL rise of about 56–92 cm per century for several centuries, with these rates potentially spiking to higher values for shorter periods.

The results of our analysis support the common hypothesis that LIG GSL was above the current value, but contrary to previous estimates, we conclude that peak GSL was very likely to have exceeded 6.6m and was likely to have been above 8.0 m, though it is unlikely to have exceeded 9.4 m.

 

“The LIG was only slightly warmer than present, with polar temperatures similar to those expected under a low-end, 2C warming scenario. Nonetheless, it appears to have been associated with substantially smaller ice sheets than exist at present. Achieving GSL in excess of 6.6m higher than present is likely to have required major melting of both the Greenland and the West Antarctic ice sheets, an inference supported by our finding that both Northern and Southern hemisphere ice volumes are very likely to have shrunk by at least 2.5me.s.l. relative to today. Incorporating a large database of palaeoclimatic constraints thus highlights the vulnerability of ice sheets to even relatively low levels of sustained global warming.

http://www.researchgate.net/publication/40693968_Probabilistic_assessment_of_sea_level_during_the_last_interglacial_stage/file/e0b4951753e120f4c7.pdf

11. Marine and continental records from the Northern Hemisphere have shown that the last glacial period was characterized by rapid climatic variability (e.g. Bond et al. 1993; Genty et al. 2003). The GRIP and GISP2 ice cores (Dansgaard et al. 1984, 1993; Grootes et al. 1993) depict a continuous and high-resolution record of such climatic variability associated with large temperature changes over Greenland (up to 16°C within ~100 years; Lang et al. 1999).”

The rapid temperature increase associated with the DO 25 marks the onset of the rapid climatic variability in the North Atlantic. Before this event, the NorthGRIP d18Oice and Vostok dD profiles first show a common cooling during 10 kyears. The phasing, however, cannot be firmly established because of the ±2,500 years uncertainty in the relative timescales.

Using that temperature reconstruction, the Antarctic cooling is slightly delayed and suggests that the main Antarctic temperature decrease occurred only 2–3 k years after the main Greenland temperature decrease (Fig. 4), which still lies within our uncertainty range.

http://www.climate.unibe.ch/~born/share/papers/eemian_and_lgi/landais_masson-delmotte06.cd.pdf

12. “Last interglacial ended approximately 115 thousand years ago, when the Norwegian warm current was substantially reduced and the dominant near-meridional circulation in Europe turned into near-zonal. Sites in southwestern Europe continued to experience temperate climate. Build-up of the Early Glacial ice was accompanied by the warming of equatorial ocean. Some features of the seasonal and geographic distribution of recent temperature and precipitation anomalies indicate that the cause of the ongoing global warming has a significant natural component.”

http://geolines.gli.cas.cz/fileadmin/volumes/volume11/G11-009.pdf

13. And then there’s Bausch and Erlenkeuser’s (2008) “”critical” climatic evaluation of last interglacial (MIS 5e)”:

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http://journals.co-action.net/index.php/polar/article/download/6172/6851

In summing-up this section we cannot help but find ourselves in awe of Mother Nature’s most recent glacial inceptions, and in contempt of “our” anemic predicted/projected/purportedly unprecedented effects on climate. If the best/worst that H. sapiens sapiens can possibly do, in at least the ~2 centuries past the current half-precession cycle (a.k.a. the Industrial) age, was to:

· bolster the delay of glacial inception, which should have begun millennia ago, or

· inject a lot of sequestered carbon into the late Holocene atmosphere/ecosphere because “Frankly my dear, [the climate] could not give a dam

then AGW has either already delivered an extended interglacial, or it soon will. Interestingly, the AGW/CAGW hypothesis does not address the possibility that it might not…….

The question nobody wants to ask WAS asked by Wallace S. Broecker in 1998:

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Glacial Inception – The Clues:

At least as far back as 1978 researchers were pondering glacial inception:

“The role of oceanic circulation appears to be a major one. During the inception and growth phases, it seems essential that there be warm ocean surfaces to provide the moisture (Barry 1966) and the “heat of glaciation” [released during condensation (88%) and freezing (12%)], which balances the energy budget over the ice sheets (Adam 1975). The ocean-core records indicate that, indeed, ice-sheet growth around 115,000 BP and 75,000 BP coincided with warm oceans (W. Ruddiman, personal communication 1977).” Andrews and Barry, 1978, http://adsabs.harvard.edu/full/1978AREPS…6..205A

Writing in GeoLines (2000, v. 11, p. 9-11) http://geolines.gli.cas.cz/fileadmin/volumes/volume11/G11-009.pdf), George Kukla of Lamont Doherty Earth Observatory of Columbia University, lays out some detail for us:

There were four interglacials in the last half million years and ours is the fifth one. Past interglacials invariably ended with the increase of solar energy income to low latitudes in boreal spring, compensated by decrease to high latitudes in autumn. The change was caused by orbital shift. A qualitatively similar shift is taking place now (Kukla et al., 1992).

The question is whether the current interglacial will:

1) -last into foreseeable future, maintained by increasing levels of greenhouse gases,

2) -end suddenly with a catastrophic breakdown of thermohaline circulation, or

3) -gradually turn into a colder world following the orbitally driven blueprint of past interglacials, only in part modified by the artificial increase of greenhouse effect.

Thus it is not only impossible, but highly probable that the early stage of the last glacial was marked by warming of low latitude oceans.

Conclusion

Summarizing, the last interglacial ended at the MIS 5e/5d boundary some 115 or 116 ka ago.

Several features of the last interglacial/glacial transition resemble the recent temperature and precipitation trends.

 

“They are:

 

1) Preferential warming of the low latitudes.

2) Increasing meridional temperature gradient.

3) Increasing precipitation in cold season in the high northern latitudes (which supposedly also accompanied the ice build-up in MIS 5d).

4) Cooling of the northern North Atlantic with simultaneous warming of the equatorial one.

 

“While some of the above features may be due to the increase of man-made greenhouse gases, they may also indicate that the natural redistribution of shortwave radiation is already affecting the ongoing climate change (Kukla et al., 1992). However no increase of ice volume, nor a decrease of mean sea level have yet been observed.

http://geolines.gli.cas.cz/fileadmin/volumes/volume11/G11-009.pdf

By 2004 we have this from Muller and Kukla:

During most of the Eemian interglacial (ca. 126–115 ka), the North Atlantic Current extended far north into the Nordic Seas and European environments were comparable to those of the Holocene. However, ca. 115 ka an SST drop in the Nordic Seas marked a southward displacement of the North Atlantic Current. This hydrographic shift was associated with substantial cooling in northern Europe and drier conditions in the Mediterranean region. The polar timberline retreated southward from 69N in northernmost Scandinavia to 52N in central Europe, and thermophilous deciduous trees became extinct north of the 48th parallel. Woodlands persisted in southern Europe for another 5 k.y. well into marine isotope substage 5d. These conditions indicate steep vegetation and climate gradients at the inception of the last glacial.

Shifts in terrestrial ecosystems are reconstructed from pollen records as the vegetation response to climate changes is pronounced and relatively fast.

Between 123 and 116 ka, the northern limit of woods dominated by thermophilous trees was at 60N in southern Sweden (Robertsson, 2000), and the polar timberline was at 69N between the sites Kijarvet and Leveaniemi (Robertsson, 1991) in northernmost Scandinavia (Fig. 2A). This configuration of Atlantic circulation and European vegetation resembles the present-day situation (Fig. 2A).

The marine records show decreased SSTs in the Nordic Seas ca. 115 ka. However, surface waters remained warm for at least another 5 k.y. in the subpolar North Atlantic southwest of the Iceland-Scotland Ridge. This contrast marks a strong increase of the meridional SST gradient during this interval. We conclude that the North Atlantic Current had ceased to penetrate into the Nordic Seas. The event, labeled C26, occurred at the transition from marine isotope stage (MIS) 5e to 5d. Data from a core on the Bermuda rise, located at the mixing zone of North and South Atlantic deep water, show a pronounced decline of the North Atlantic deep-water component at the MIS 5e to 5d transition within a period of 200 yr (Lehman et al., 2002).

At sites in southern Europe (e.g., Les Echets, Tenaghi Philippon) we see a reduction of thermophilous trees after C26 owing to insufficient moisture rather than lack of summer warmth (Tzedakis, 2003).

It has been hypothesized that the disappearance of tree populations in northern Europe ca. 115 ka may have been caused by orbital changes that reduced insolation in the growing season (Tzedakis, 2003). Such insolation changes are, however, very slow. Most likely the continuously decreasing high-latitude radiation in concert with expanding ice cover, associated albedo feedback, and increased freshwater input into the Nordic seas forced the system to cross a critical threshold. Such a shift would have triggered the abrupt displacement of the North Atlantic Current with its associated impact on terrestrial environments in Europe.

http://www.climate.unibe.ch/~born/share/papers/eemian_and_lgi/mueller_kukla04.geo.pdf

Risebrobakken, Dokken and Jansen (2005, American Geophysical Union, Geophysical Monograph Series 158) contribute this:

Variable climatic and oceanographic conditions characterized the last interglacial at high northern latitudes, probably related to changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC). The magnitudes of these changes are comparable to the Holocene variability, and were thus significantly subdued compared to glacial climate changes. A thermal optimum occurred during the early part of the interglacial, followed by a period of reduced Atlantic inflow to the northernmost Nordic Seas. Subsequently, a new period with increased strength of the AMOC occurred. Significant amounts of Ice-Rafted Debris (IRD) were deposited in the northernmost Nordic Seas before any major change of the global ice volume. This implies an early onset of local ice sheet growth, probably the result of enhanced inflow of Atlantic water to the northernmost Nordic Seas contemporary with a Northern Hemisphere summer insolation minimum. Contrasting sea–land conditions provided large moisture fluxes towards land, giving rise to rapid, early glacial growth.

 

The onset of a new glaciation following the last interglacial has been considered as a response to a continuous decrease of Northern Hemisphere summer solar insolation, leading to colder atmospheric and surface ocean conditions in the Arctic region, decreasing evaporation, and expansion of sea ice and snow fields and associated feedbacks. Consequently, the surface water in the Nordic Seas was freshened and the production of Norwegian Sea Deep Water may have decreased as a response to these changes [e.g. Imbrie et al., 1992; Khodri et al., 2001]. In accordance with this, Cortijo et al. [1994] reason that cooling of the Norwegian Sea and the North Atlantic preceded growth of the continental ice sheet. Atmospheric general circulation model studies indicate that the initiation of permanent snow cover and the growth of ice sheets is favored by colder sea-surface conditions [Yoshimori et al., 2002]. However, warm interglacial conditions and strong convection prevailed through the inception phase in the subpolar North Atlantic [Duplessy and Shackleton, 1985; Ruddiman and McIntyre, 1979; Ruddiman et al., 1980]. It has been argued that the moisture necessary to obtain the rapid ice accumulation of the Laurentide and Scandinavian ice sheets was provided by increased storminess resulting from the contrast between these warm water masses and the colder land and ice-covered regions, as the temperature gradient between polar and subpolar areas increased. Several recent papers also argue in favor of an intensified Atlantic Meridional Overturning Circulation (AMOC) during the glacial inception phase, stressing the importance of direct influence of AMOC on the high northern latitude climate during glacial growth [McManus et al., 2002; Otterå and Drange, 2004 (in press); Wang and Mysak, 2002]. The majority of studies that focus on the penultimate glacial inception, however, are based on reconstructions of subpolar areas. Thus, it is of great importance to document the glacial inception history as recorded in the polar region, where feedbacks related to an early change in ice albedo might be important.

 

In the present situation, strengthened NwAC is characterized by a restricted lateral extent of warm Atlantic water, as compared to a more widespread but shallower extent at times of a reduced NwAC [Blindheim et al., 2000]. Changes in the strength of the NwAC are primarily the result of changing strength of the westerlies. Our results indicate an intensified AMOC from 117 ka BP. Warm water conditions together with an increased content of the Arctic front indicator G. quinqueloba are recorded in MD99-2304, while MD99-2303 was probably bathed by Arctic water. These conditions with a strong AMOC occur at the same time as the summer insolation at 65°N approached its minimum (Figure 6).

 

The enhanced warming characterizing the end of the warm phase of MIS 5.5 at MD99-2304 culminated in a marked cooling, registered by a rapid fall of the relative content of subpolar foraminifers and increased planktonic δ18O values (Figures 5 and 6a). Immediately after this warm phase, the first major IRD input is recorded in the Fram Strait (Figures 4b,c and 5). This first IRD input coincides with the first MIS 5 global change in ice volume, as indicated by benthic δ18O from NEAP18K (Figure 4a-c) [Chapman and Shackleton, 1999], and with the dated onset of global fall in sea level [Stirling et al., 1998], according to our time scale used in this paper. Thus, glaciers at Spitsbergen grew large enough to reach the coastline and calve before any major global ice sheet growth was observed. The combination of low insolation and strengthened influx of warm water probably favored this rapid growth of the Svalbard–Barents Sea Ice Sheet (SBIS). An increased thermal contrast between sea and land at high latitudes will produce large moisture fluxes towards land [Wang and Mysak, 2002], and a steady source of moisture is needed to provide major glacial growth [Hebbeln et al., 1994; Nesje and Dahl, 2003].

 

We suggest that warm open water conditions at times of reduced summer insolation initiated the growth of ice on land through the inception phase, while the further development of grounding of ice at the epicontinental Barents and Kara Sea was dependent on the global sea level as well. The possible effect of a strong AMOC late in MIS 5.5 and its potential influence on the initial glacial growth at high northern latitudes was noted by McManus et al. [2002].

 

The importance of the different mechanisms probably changed through time, depending on the present boundary conditions of the climate system. However, the widespread distribution of these cold spell events (C19–C25 [Chapman and Shackleton, 1999; McManus et al., 1994]) along the axis of the Gulf Stream and its subsequent warm northward-flowing currents accentuates the importance of the ocean dynamics and its influence on the climate system. From the results from core MD99-2304, it appears that at times even slight changes in the water mass configuration may destabilize a marine-based ice sheet. Hall et al. [1998] showed that a vigorous behavior of the AMOC did characterize at least the glacial inception phase and the period into MIS 5.4. At the periods with major calving of the Northern Hemisphere ice sheets, large amounts of freshwater were introduced to the main areas of deep-water formation, both in the Nordic Seas and in the Labrador Sea. Increased freshwater flux to these sensitive areas most probably perturbed the deep-water formation and weakened the AMOC [e.g. Clark et al., 2002; Ganopolski and Rahmstorf, 2001; Manabe and Stouffer, 1997]. A reorganization of the deep-water circulation related to the North Atlantic IRD events has been documented [Chapman and Shackleton, 1999; Hall et al., 1998; and Lehman et al., 2002], supporting the interpretation of a weakened AMOC as a response of the increased freshwater influx. The regional impact of a weakened AMOC will be large. Generally colder conditions will be induced in the Nordic Seas, the North Atlantic, and surrounding areas [Manabe and Stouffer, 1997]. Such coolings are documented by several paleoclimatic studies, e.g. the regionally distributed IRD events are associated with cold atmospheric temperatures at Greenland [Bender et al., 1994] and cold sea-surface conditions in both the subpolar North Atlantic [McManus et al., 1994] and the subtropical North Atlantic [Lehman et al., 2002] (Figure 8a-d).

 

In general, the MIS 5.5 climate seems to have been relatively unstable due to variable AMOC. Nevertheless, the amplitude of this variability was much smaller than glacial climate changes. Glaciers at Spitsbergen grew large enough to initiate major calving before any large global changes in ice volume occurred. This early glacial inception was initiated by the strong sea–land temperature gradient resulting from the contemporary warm sea-surface and summer insolation minimum. This maintained significant moisture fluxes toward land, concomitant with reduced summer melting, which resulted in rapid glacier growth. We also propose that similar conditions were important for the initiation of glacier growth in high Northern Russia, related to an intensified deflection of Atlantic water into the Barents Sea when the AMOC is strengthened.

http://www.agu.org/books/gm/v158/158GM20/158GM20.pdf

By 2009 we have this:

We investigated deep water changes in the Southern Ocean during the last glacial inception, in relationship to surface hydrology and global climatology, to better understand the mechanisms of the establishment of a glacial ocean circulation. Changes in benthic foraminiferal d13C from three high-resolution cores are compared and indicate decoupled intermediate and deep water changes in the Southern Ocean. From the comparison with records from the North Atlantic, South Atlantic, and the Southern Ocean, we show that the early southern deep water d13C drop observed at the MIS 5.5–5.4 transition occurred before any significant reduction of North Atlantic Deep Water ventilation. We propose that this drop is linked to the northward expansion of poorly ventilated Antarctic Bottom Water (AABW) mass in the Southern Ocean. Associated with an early cooling in the high southern latitudes, the westerly winds and surface oceanic fronts would migrate equatorward, thus weakening the upwelling of Circumpolar Deep Waters. Reduced heat brought to Antarctic surface waters would enhance sea ice formation during winters and the deep convection of cold and poorly ventilated AABW.

Different mechanisms have been proposed, associated with a rapid switch from Northern Component Waters to Southern Component Waters at mid depths in the South Atlantic [Molyneux et al., 2007], or emphasizing the key role of the subtropical front as amplifier and vehicle for the transfer of climatic change to the Southern Ocean [Cortese et al., 2007]. But published data are insufficient to give the necessary integrated view of the Southern Ocean circulation changes and associated mechanisms during the last glacial inception.

Therefore, North Atlantic Deep Waters ventilation did not change significantly before the beginning of the glacial period (MIS 4).

This indicates that, during the entire stage 5, a well-ventilated NADW was reaching the South Atlantic, at least above 3000 m, and entering the Southern Ocean, before mixing with Pacific/Indian deep waters.

These d13C shifts have been interpreted as an increased influence of poorly ventilated AABW in the deep North Atlantic and shoaling of NADW.

This suggests a progressive northward expansion of the boundary of a poorly ventilated water mass, with low d13C values (likely equivalent to AABW), from the southern sites to the northern sites. Moreover, the northern sites, which show higher d13C values than in the southern cores throughout MIS 5 and 4 (Figure 7b), appear closer to the zone of transition (strong d13C gradient) between poorly ventilated AABW and better ventilated CDW.

This suggests an equatorward shift of the oceanic surface fronts [Howard and Prell, 1992; Labeyrie et al., 1996]. The subantarctic front may have experienced a more pronounced northward shift than the subtropical front. Or it could have shifted in between the northern and southern cores locations, thus inducing a steeper meridional SST gradient.

This indicates that the equatorward shift of oceanic surface fronts and the associated climate changes may have induced the progressive northward expansion of poorly ventilated AABW in the deep Southern Ocean.

The oceanic circulation of the last Interglacial period (MIS 5.5) (Figure 8a) was similar to the modern one [Duplessy et al., 2007; Duplessy and Shackleton, 1985; Evans et al., 2007]. We suggest that the early cooling observed in the high southern latitudes cores during MIS 5.5 (Figures 5a and 5b) induced an equatorward shift of the westerlies and associated oceanic fronts (Antarctic divergence, polar and subantarctic fronts) [Toggweiler et al., 2006].

Such link is suggested by several indicators: glacial simulations with an atmospheric model (equatorward shift of the westerlies of 7° for a 3K cooling) [Williams and Bryan, 2006], paleoclimatic reconstructions (e.g., shift of the westerlies from ~50°S presently to ~41°S during glacial times in South America [Moreno et al., 1999]), and by modern observations (a poleward shift of the westerlies is observed over the last 40 years) [Hurrell and van Loon, 1994; Shindell and Schmidt, 2004].

A comparison over the last glacial inception of three cores representing different Southern Ocean water masses suggests a decoupling between intermediate and deep water changes in the Southern Ocean.

We also show that these Southern Ocean deep water changes lag the cooling observed in subantarctic surface waters. We propose a succession of ocean-atmosphere feedbacks, in reaction to the early cooling observed in the high southern latitudes. Surface cooling at the MIS 5.5–5.4 transition would be associated with an equatorward shift of oceanic surface fronts and the westerlies, which moved away from the Antarctic divergence. The upwelling of Circumpolar Deep Waters would be reduced [Toggweiler et al., 2006]. Both decreased heat brought to circumpolar surface waters and cooling in the high southern latitudes would enhance winter sea ice formation [Hellmer, 2004]. This would increase the related brine release and enhance deep convection of cold and poorly ventilated AABW.

http://www.climate.unibe.ch/~born/share/papers/eemian_and_lgi/govin_michel09.pao.pdf

Crucifix (2011) offer this for consideration:

The Pleistocene record suggests that modern insolation is not much above that needed for glacial inception. However, the complexity of the climate response to the complex astronomical forcing implies that further theoretical elaborations are needed to transform this statement into a reliable prediction about the slow evolution of climate like: `greenhouse gas should have declined during the Holocene, leading to glacial inception’. In particular, there is no perfect insolation analogue to the Holocene in the past and, would there be one, it cannot be guaranteed that climate would behave exactly the same way as during that hypothetical analogue. We mentioned several reasons for this. One is the possibility that small disturbances may, at strategic times, delay glacial events by several thousands of years. Locating such ‘high-sensitivity’ times is an attractive challenge. If the Holocene was such a time, any small disturbance, including the pre-industrial anthropogenic activity, may have durably inflected the course of climate.

http://arxiv.org/pdf/1112.3235.pdf?origin=publication_detail

Capron et al (2012), writing in “A global picture of the first abrupt climatic event occurring during the last glacial inception”, Geophysical Research Letters, VOL. 39, L15703, doi:10.1029/2012GL052656, expand our understanding:

The transition between the Last Interglacial (hereafter Marine Isotopic Stage 5.5, ~129–116 thousand years before present (ka)) into the first stage of the last glacial period (MIS 5.4, 116–105 ka) is the only glacial inception recorded in Greenlandic ice cores [NorthGRIP Community Members, 2004].

Still, high-resolution data do not show the precise North Atlantic sequence of events over the last glacial inception and how this is linked to climatic and environmental changes in the lower latitudes. Here we employ the NorthGRIP record to report a detailed picture of the onset of the rapid climatic variability in Greenland and in the lower latitudes based on new high-resolution (centennial to sub-decadal) profiles of a wide range of parameters measured on both ice and air trapped in ice (Figure 2 and Table 1).

We first present new high-resolution d18Oice measurements covering the glacial inception between 108 and 123 ka (Figure 2 and Table 1). Two abrupt increases of d18Oice are objectively identified in this time interval and quantified using the RAMPFIT software [Mudelsee, 2000]. This weighted least-squares method estimates the level of the d18Oice for stadial and interstadial conditions, a linear trend between the change points, and a measure of the uncertainty of these estimated change points based on a set of 400 bootstrap simulations for each abrupt event. The onset of GIS 25 is characterized by a d18Oice increase of 1.12 ± 0.05 ‰ and the end of GIS 25 is punctuated by a second abrupt d18Oice increase of 1.51 ± 0.04‰. This sub-event is referred later as GIS 25 s. These magnitudes are significantly reduced in comparison to subsequent GIS onsets (Figure 1).

 

Our new high resolution d15N profile reveals an increase of 0.044‰ at GIS 25 onset. Using the firn densification model from Goujon et al. [2003], the best fit between measured and modelled d15N is obtained for a warming of 3 ± 2.5C. The warming at the onset of GIS 25 occurs in 180 years and is three to up to five times smaller than for the subsequent abrupt events [e.g., Landais et al., 2006]. We also show that GIS 25 is then terminated by a previously undocumented short warm event, GIS 25 s, lasting 300 ± 90 years with a amplitude of 5 ± 2.5C (Figure 2).

 

In contrast, no clear CH4 signal is associated with the d15N peak marking DO 25. Indeed, a 47 ± 11 ppbv CH4 increase is concurrent to GIS 25 onset, an amplitude also encountered during two other CH4 peaks identified during GS 26 and GIS 25 when no significant Greenland temperature change is registered. This contrasts with the CH4 shifts between 80 to 200 ppbv that are associated with the glacial DO events [Chappellaz et al., 1993] (Figure 2). Such a small CH4 increase could result from the fact that the temperature rise at the onset of GIS 25 is also significantly smaller than the one observed for the subsequent rapid events as the temperature sensitivity of the CH4 change at the onset of GIS 25 is in the observed range of later rapid events. But the fact that there are other CH4 signals of similar strength without a corresponding temperature shift points to an additional temperature-independent driver of CH4 changes during glacial inception. The reduced CH4 change at the onset of GIS 25 compared to later rapid events indicates that neither boreal nor tropical CH4 sources significantly responded to this abrupt warming.

 

This result suggests that there is not a simple coupling between high-latitude temperature and ITCZ shifts during abrupt climatic events that holds for all time periods.

http://nora.nerc.ac.uk/19708/1/2012GL052656.pdf

One such region is the Mediterranean, located at the transition between the dry Hadley cell atmospheric circulation north of the Inter-Tropical Convergence Zone, and the turbulent moisture-bearing westerly flow of the higher latitudes.”

http://www.researchgate.net/publication/27713817_Laminated_sediments_as_archives_of_short_timescale_climate_change_and_palaeoceanography_of_the_Mediterranean/file/60b7d523b25f15617b.pdf

By early 2014 there was this from (Liu et al, “Impact of declining Arctic sea ice on winter snowfall”, Proceedings of the National Academy of Sciences, (www.pnas.org/cgi/doi/10.1073/pnas.1114910109 ):

While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and east Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic oscillation.

 

Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased heavy snowfall in Europe during early winter and the northeastern and midwestern United States during winter. We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters.

 

During the past few winters, North America, Europe, and east Asia have experienced anomalously cold conditions, along with record snowfalls (1–3). Anomalously heavy snowfall wrought havoc in large parts of the United States and northwestern Europe for the winters of 2009–2010 and 2010–2011. A series of snowstorms hit central and southern China for the winter of 2007–2008.

 

As shown in Fig. S1, significantly above-normal winter snow cover has been present in large parts of the northern United States, northwestern and central Europe, and northern and central China for the four winters since the record low Arctic sea ice during 2007. However, no clear persistent out-of-phase NAO/AO-snow cover and in-phase El Niño-snow cover relationship are evident in the observations for the past four winters (Fig. S2). Diminishing Arctic sea ice and its potential climatic impacts have received increasing attention (10–12); i.e., many studies have demonstrated that regional loss of Arctic sea ice can have hemispheric consequences in atmospheric circulation (13–19). Recent studies show that cold conditions and increased snow cover over Siberia in autumn are correlated with reduced September sea ice cover in the Pacific sector of the Arctic (20, 21). Furthermore, Fig. S2 does support a persistent out-of-phase sea ice-snow cover relationship for the past four winters. Here we extend previous studies by combining observational data analyses and numerical experiments, demonstrating how anomalously large snowfall in large parts of the Northern Hemisphere continents in recent winters are linked to diminishing Arctic sea ice.

 

When highly reflective sea ice is replaced by open water during the ice melting period, there is a substantial solar heat input directly into the ocean, increasing the heat stored in the upper ocean.

 

Warming of the upper ocean retards the recovery of sea ice during the fall freeze-up. As a result, the ice coverage in late autumn and early winter for the past few years is significantly below the mean of 1979–2000, exceeding two standard deviation of ice variability (Fig. S3).

 

A decrease of autumn Arctic sea ice of 1 million km2 corresponds to a significantly above-normal winter snow cover (>3-12%) in large parts of the northern United States, northwestern and central Europe, and northern and central China (Fig. 1B).

 

One important contributor to the anomalously large snowfall in recent winters is changes in atmospheric circulation linked to diminishing Arctic sea ice. The regression map between sea ice area and sea level pressure (SLP) reveals that following anomalously low ice coverage in autumn, the winter SLP is substantially higher over the Arctic Ocean, the northern Atlantic, and much of high-latitude continents, which is compensated by lower SLP in midlatitudes (Fig. 2A). This pattern shows some resemblance to the negative phase of the winter AO (Fig. 2B). However, some significant differences are noticed. First, the pattern linked to the reduction of autumn sea ice shows broader meridional meanders in midlatitudes rather than the zonal symmetry associated with the winter AO pattern (Fig. 2 A vs. B). A recent study also noted that recent loss of summer sea ice in the Arctic is directly connected to a shift to a more meridional atmospheric circulation pattern in the following autumn and suggested that increased modification of atmospheric circulation pattern would be anticipated with continuing loss of summer sea ice to less than 20% of its climatology over the next decades (26). Second, the pattern linked to the reduction of autumn sea ice shows clearly different interannual variability relative to the classical winter AO pattern; i.e., the detrended autumn Arctic sea ice and winter AO indices have weak correlation (0.28), only accounting for approximately 8% of the shared variance. Thus, the atmospheric circulation change linked to the reduction of sea ice is different from the classical AO.

 

This suggests a shift to a more meridional anomalous wind pattern in winter congruent with the reduction of the autumn Arctic sea ice. Weak westerly winds tend to enhance broader meanders that are likely to form blocking circulations. Fig. 3A shows that associated with the reduction of autumn sea ice, there is an increased incidence of blockings during winter over much of northern high-latitude continents, with the most pronounced increase in eastern Europe, central Siberia, southern Alaska, and the northwestern United States (20–60% greater than climatology). These blocking patterns favor more frequent incursions of cold air masses from the Arctic into mid- and low-latitude of northern continents. As shown in Fig. 3B, there is an increased frequency of cold events over much of northern continents, with the most pronounced increase in the eastern and Midwestern United States, northwestern Europe, between mid-east and central Asia, and central and south China (20–60% greater than climatology). This leads to cold conditions over much of northern continents; i.e., temperature anomalies extending southeastward from northwestern Canada to the southeastern United States, and eastward/southeastward from northwestern Europe to central China can be 2–3 °C below-normal in association with 1 million km2 decrease of the autumn Arctic sea ice (Fig. 2C).

 

Another potential contributor to anomalously large snowfall in recent winters is changes in atmospheric water vapor content over northern high latitudes. The rapid retreat of sea ice in summer and slow recovery of sea ice in autumn, particularly after 2007, greatly enhances moisture flux from the ocean to the atmosphere. This increases the humidity of Arctic air masses remarkably during ice growth period. Following anomalously low ice coverage in autumn, the regions with the most pronounced increase of specific humidity (integrated from surface to 700 hPa) during late autumn and early winter are found in northern/eastern Europe, far eastern Siberia, and western Alaska (Fig. 3C).

 

The increase of humidity in autumn provides an additional local moisture source to Europe, in addition to circulation change induced moisture transport from midlatitudes through shifting the storm track southward and increasing storminess over the Mediterranean (Fig. 2A).

 

This further indicates that the moisture source in Europe (northeastern North America) might be primarily locally driven in late autumn and early winter (winter) and switches from locally driven to moisture transport from lower latitudes in early winter (late winter).

 

The results of this study add to an increasing body of both observational and modeling evidence that indicates diminishing Arctic sea ice plays a critical role in driving recent cold and snowy winters over large parts of North America, Europe, and east Asia. The relationships documented here illustrate that the rapid loss of sea ice in summer and delayed recovery of sea ice in autumn modulates not only winter mean statistics (i.e., snow cover and temperature) but also the frequency of occurrence of weather events (i.e., cold air outbreaks). While natural chaotic variability remains a component of midlatitude atmospheric variability, recent loss of Arctic sea ice, with its signature on midlatitude atmospheric circulation, may load the dice in favor of snowier conditions in large parts of northern midlatitudes.

 

If the decline of Arctic sea ice continues as anticipated by climate modeling results (31, 32), we speculate that episodes of the aforementioned circulation change will become more frequent, along with more persistent snowstorms over northern continents during winter.

http://www.lasg.ac.cn/UpLoadFiles/File/papers/2012/2012-pnas.jiping.liu.pdf

The pieces of the glacial inception puzzle thus begin to congeal:

· In contrast to the slow waltz of climate into glacial inception some proselytize, the ends of the interglacials appear to occur quite suddenly. The range being something on the order of 70-200 years. Which means that glacial inception, which should have already happened according to some, could actually occur during the 21st century.

· Kukla (2000) provide:

- Preferential warming of the low latitudes.

- Increasing meridional temperature gradient.

- Increasing precipitation in cold season in the high northern latitudes (which supposedly also accompanied the ice build-up in MIS 5d).

- Cooling of the northern North Atlantic with simultaneous warming of the equatorial one.

I would like to crowdsource Kukla’s 2000 indicators to those who can demonstrate expertise in addressing them.

· Risebrobakken et al (2005) provide these pieces: “However, warm interglacial conditions and strong convection prevailed through the inception phase in the subpolar North Atlantic [Duplessy and Shackleton, 1985; Ruddiman and McIntyre, 1979; Ruddiman et al., 1980].”

 

“Several recent papers also argue in favor of an intensified Atlantic Meridional Overturning Circulation (AMOC) during the glacial inception phase, stressing the importance of direct influence of AMOC on the high northern latitude climate during glacial growth [McManus et al., 2002; Otterå and Drange, 2004 (in press); Wang and Mysak, 2002]

 

“During the inception and growth phases, it seems essential that there be warm ocean surfaces to provide the moisture (Barry 1966)” Andrews and Barry, 1978.

 

“These conditions with a strong AMOC occur at the same time as the summer insolation at 65°N approached its minimum”

 

The combination of low insolation and strengthened influx of warm water probably favored this rapid growth of the Svalbard–Barents Sea Ice Sheet (SBIS). An increased thermal contrast between sea and land at high latitudes will produce large moisture fluxes towards land [Wang and Mysak, 2002], and a steady source of moisture is needed to provide major glacial growth [Hebbeln et al., 1994; Nesje and Dahl, 2003].

 

“We suggest that warm open water conditions at times of reduced summer insolation initiated the growth of ice on land through the inception phase” “This early glacial inception was initiated by the strong sea–land temperature gradient resulting from the contemporary warm sea-surface and summer insolation minimum. This maintained significant moisture fluxes toward land, concomitant with reduced summer melting, which resulted in rapid glacier growth Risebrobakken et al (2005).

 

“We suggest that the early cooling observed in the high southern latitudes cores during MIS 5.5 (Figures 5a and 5b) induced an equatorward shift of the westerlies and associated oceanic fronts (Antarctic divergence, polar and subantarctic fronts) [Toggweiler et al., 2006].

 

….paleoclimatic reconstructions (e.g., shift of the westerlies from ~50°S presently to ~41°S during glacial times in South America [Moreno et al., 1999]), and by modern observations (a poleward shift of the westerlies is observed over the last 40 years) [Hurrell and van Loon, 1994; Shindell and Schmidt, 2004].

In one sense I offer this compilation as a sort of extension to Liu et al (2014) http://www.lasg.ac.cn/UpLoadFiles/File/papers/2012/2012-pnas.jiping.liu.pdf , whom came very close, I think, to “getting it”. Liu et al (2014) provide an almost blow by blow account of many of the things now thought to characterize glacial inceptions. It seems as if they almost took the last step, as we have done here, in looking at what it all might very well mean.

The arctic warms, melts, causes a delay in re-freezing, which allows that much more moisture evaporation to feed into such things as blocking highs, resulting in severe winter storms laden with more moisture to provide thick blankets of snow in the northern continental latitudes. The further south and longer the heavy snows persist, like the past few winters, the orbital weakened/weakening incoming solar radiation (insolation) is reflected, not absorbed. Obviously it is far more complex than that, but that very well might be the gist of the matter.

Scholarly thoughts on these matters are solicited.

Reflections:

We initiated this discussion with a musing about intelligence, stupidity and evil. This essay provides but a small snapshot of the probably surprising number of researchers that have put a surprising amount of thought into “when we live” vis-à-vis the climatic “madhouse” that is glacial inception, which might be imminent. There are so many logical absurdities here that it is difficult to know just where to begin. Not necessarily in any particular order I will attempt to some up as many as I can remember:

· For over two decades now the IPCC and academia have studied anthropogenic global warming. I have yet to see where they consider the climatic “madhouse” known as glacial inception and whether or not we could be anywhere close to such, with the possible exception of Loutre and Berger (2003). Instead we have focused very hard on AGW, which could cause climate to quickly, catastrophically, and perhaps unrecoverably reach the absolute reference standard of climate, sea level, to somewhere from just shy of 1% to just over 10% of what gaia did anyway at the end of the last interglacial. The logical absurdity here should be obvious. The largest climate problem of all is actually the smallest one we think we can now can identify: AGW (see every issuance from the IPCC). That is patently absurd.

· Then there is the problem of recognizing the AGW “signal” from the natural background “noise” which can contain at least 2-3 thermal pulses from 1 to almost 2 orders of magnitude higher at the ends of the post-MPT interglacials. What will our “signal” look like? What will our “signal” looked like submerged in 1 to say 2 orders of magnitude stronger noise, noise that can contain so far up to 3 such peaks? By what method does anyone propose to isolate such an obviously weak signal from the obviously much larger “noise” envelope? Whereas this may not qualify as patently absurd (I am certainly open to signal processing experts chiming in here), it seems only a hair shy to me at this point.

· In what may just be the largest logical absurdity of the entire CO2/GHGs/etc. debate/non-debate/discussion is if the IPCC et al ad infinitum are correct about CO2/GHGs/etc. then Ruddiman (2003) might also be correct. In which case we have already cheated glacial inception for perhaps thousands of years already, and now “we”, supposedly ~97%, want to take it out?

Let me make sure I get this straight, because this cannot be had both ways. If the “early anthropogenic hypothesis” is correct, and the CO2/GHGs/etc./AGW hypothesis is correct, then removing said “climate security blanket” from the late Holocene atmosphere would favor glacial inception then, right? So glacial inception is to be preferred?

Did ~97% of “us” just bump “our” heads?

Necessarily, if the CO2/GHGs/etc./AGW hypothesis is not correct, what will removing CO2/GHGs/etc. accomplish with respect to climate change? To be considered responsive (serious et al etc.), comments must take the mass of research sampled here into consideration in replies.

· Even on things which actually have happened the science is not that particularly well-settled, which makes consideration of the science being settled on things which have not yet happened a bit unsettling. Another patent logical absurdity.

· The IPCC estimate of the forcing which is estimated to accompany a doubling of atmospheric CO2 concentration is something like 3.7 watts per square meter, if memory serves me correctly. Suffice it to say it is somewhere between 3 and 4 W/m2. Again, if memory serves, this may be related to the top of the troposphere, precisely where in relation to the poles this might be I must rely upon others to provide.

It may not matter much.

Returning to the quote from Lisiecki and Raymo (2005) above, we have this:

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.”

Glacial inception during MIS-11, with sea level running for thousands of years about +21.0M amsl, occurred with an arctic circle (65 degrees North) insolation some 15 W/m2 above their reported present Holocene minimum of 474 W/m2.

If there is a logical absurdity here, and I would appreciate well-considered feedback on this point, then the AGW signal of between +3 to +4 W/m2 at 65N (top of the troposphere compared to ground at 65N) would get us to only 11 W/m2 below the insolation value where glacial inception occurred during the longest known post-MPT interglacial. I could very easily be wrong on this one, but it seems to me that whatever and at what level our AGW “signal” is calculated to be at 65N it would need to at least exceed the insolation value during the MIS-11 to MIS-10 glacial inception.

If not, this is nothing but a silly-buggers game isn’t it?

The intellectual (intelligence vs. stupidity) spectrum here is easy to sort out. One was either aware of these much larger late Holocene climate discussions, or one was not. This goes to the argument that the difference between confidence and arrogance is competence. You are either aware of them now (if you made it this far at least you have been exposed), or you might not ever be. The difference being that ignorance can be cured, but dumb(?), that’s forever……..

Finally, would what remains be evil? (Which can apply to the entire spectrum between intelligence and the lack thereof) As demonstrated herein, the peer-reviewed literature is robust with respect to investigating possible/probable end-Holocene climate scenarios of “biblical” proportions with respect to the worst case AGW hypothesis and the most recent end extreme interglacial climate “track records”. If you were aware of the vast literature (which the lengths exposed here are but an abbreviated taste) addressing the ~1 to ~2 orders of magnitude larger glacial inception “gorillas” with us here in the now half-precession old Holocene climate change room, and the climatic “madhouse” that such represents, and failed not only to inform us of this possibility/probability, but further failed to critically analyze/publish on it/IPCC-it, how might this not be considered evil?

At the possible/probable end of the most recent extreme interglacial, our most advanced hominid/technological state ever, would this not comprise the simplest of intelligence tests?

 

Reverberations:

“Half the work done in the world is to make things appear what they are not.”

E.R. Beadle.

If you torture the data enough, nature will always confess

Ronald Coase.

“Two things are infinite: the universe and human stupidity; and I’m not sure about the universe.”

Albert Einstein

“One who deceives will always find those who allow themselves to be deceived.”

Niccolo Machiavelli

A belief is not merely an idea the mind possesses; it is an idea that possesses the mind.

Robert Bolton

97% of everyone have experienced AGW gases. The rest await the privilege…..

 

Meanwhile enjoy the interglacial. While it lasts……………..

All the best,

William

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100 thoughts on “Glacial Inception: the climatic ‘madhouse’

  1. Tour de Force usually means ‘with great skill or excellence’. As written, the author makes it seem like he is boasting about himself, which I’m sure was not his intention.

  2. The “abstract” is not one. This could use a real summary of the main points and conclusions right up front that encourages me to read this mile long piece.

  3. “I used to think there was only one known substitute for intelligence – stupidity. I have since realized that left out evil (see Hitler et al).”
    ————
    Evil is a substitute for intelligence? Does that mean that morality is too?

    Also, it seems to me that evil does not preclude intelligence. Lotsa evil-cum-intelligent people throughout history.

    “I have also come to the conclusion that the difference between confidence and arrogance is competence. ”
    ————
    I have know people who are both competent and arrogant. Competence does not automatically confer humility.

  4. Tzedakis, et al, 2012, is valuable for its estimate of an end to the Holocene in 1500 years, based upon analogy with MIS 19, but marred by its assumption that CO2 concentration matters. Their paper argues that glacial inception cannot occur at current “high” levels of CO2:

    http://www.nature.com/ngeo/journal/v5/n2/full/ngeo1358.html

    Determining the natural length of the current interglacial

    P. C. Tzedakis, J. E. T. Channell, D. A. Hodell, H. F. Kleiven & L. C. Skinner

    Nature Geoscience 5, 138–141 (2012) doi:10.1038/ngeo1358

    Published online 09 January 2012

    “No glacial inception is projected to occur at the current atmospheric CO2 concentrations of 390 ppmv (ref. 1). Indeed, model experiments suggest that in the current orbital configuration—which is characterized by a weak minimum in summer insolation—glacial inception would require CO2 concentrations below preindustrial levels of 280 ppmv (refs 2, 3, 4). However, the precise CO2 threshold4, 5, 6 as well as the timing of the hypothetical next glaciation7 remain unclear. Past interglacials can be used to draw analogies with the present, provided their duration is known. Here we propose that the minimum age of a glacial inception is constrained by the onset of bipolar-seesaw climate variability, which requires ice-sheets large enough to produce iceberg discharges that disrupt the ocean circulation. We identify the bipolar seesaw in ice-core and North Atlantic marine records by the appearance of a distinct phasing of interhemispheric climate and hydrographic changes and ice-rafted debris. The glacial inception during Marine Isotope sub-Stage 19c, a close analogue for the present interglacial, occurred near the summer insolation minimum, suggesting that the interglacial was not prolonged by subdued radiative forcing7. Assuming that ice growth mainly responds to insolation and CO2 forcing, this analogy suggests that the end of the current interglacial would occur within the next 1500 years, if atmospheric CO2 concentrations did not exceed 240±5 ppmv.”

    If, as some researchers think, MIS 11 is a better orbital match for the Holocene, then our current interglacial will last a lot longer. If you draw a simple trend line down, extrapolated from the lower highs & lower lows of up & down temperature since the Minoan Warm Period or earlier Holocene Optimum, you do indeed get down to glacial levels within at most a few thousand years. But against that forecast are present & future orbital parameters akin to those of long-lasting MIS 11. However, both that interglacial & the Eemian (MIS 5) were also warmer at their peaks than the Holocene.

    Ruddiman has not gained a lot of support because, among other reasons (such as the relative unimportance of CO2 & CH4), the Eemian lasted longer than the Holocene (although not as long as MIS 11 interglacial). The two shorter interglacials between MISs 19 & 11 might tend to support his hypothesis that human activity has already delayed glacial onset, but orbital parameters offer a better solution.

    As I’ve commented here before, no one can say whether the Holocene will end in 1000 or 10,000 years (or more), since there is evidence for both propositions. Comparing to the Eemian, which lasted about 5000 years longer than the Holocene has so far, a lower figure might be supported, since that interglacial’s peak was hotter than ours. Scandinavia was an island, hippos swam in the Thames at the site of London & the southern dome of the Greenland ice sheet partially melted. It probably disappeared almost entirely during MIS 11 & appears definitely to have done so during MIS 19:

    http://news.nationalgeographic.com/news/2007/07/070705-oldest-dna.html

    The end of the Holocene is overdue only if arbitrarily compared with the two unusual interglacials (MIS 7, c. 200 Ka, & MIS 9, c. 300 Ka) before the Eemian (c. 100 Ka) & after MIS 11 (c. 400 Ka), which is a better orbital fit to ours, as also is MIS 19 (c. 800 Ka). Experts disagree as to which of the ~400K year cycle interglacials more closely agrees with orbital mechanics of the coming millennia.

  5. Error: In the Ruddiman paragraph above, I meant the short interglacials between MIS 11 & MIS 5 (the Eemian), ie MIS 7 & 9. Sorry.

  6. I could not contain a bit of a chuckle, since I just read the abstract to Lovejoy 2014 (“Scaling fluctuation analysis and statistical hypothesis testing of anthropogenic warming”) right before I read this. This excerpt from above:

    “How on earth (literally) are we going to detect, reliably or not, a “first-ever” anthropogenic climate “signal”, at the latest half-precession cycle old extreme interglacial, when our very best (or worst) anthropogenic future “signal” is just over an order of magnitude less than the lowest estimate of the second strong thermal pulse and sea level highstand achieved naturally at the end of the most recent interglacial?”

    is a bit different from this excerpt from Lovejoy’s abstract:

    “We statistically formulate the hypothesis of warming through natural variability by using centennial scale probabilities of natural fluctuations estimated using scaling, fluctuation analysis on multiproxy data. We take into account two nonclassical statistical features—long range statistical dependencies and “fat tailed” probability distributions (both of which greatly amplify the probability of extremes). Even in the most unfavourable cases, we may reject the natural variability hypothesis at confidence levels >99 %.

  7. I am still of the opinion that there is no one single cause of glacial inception. First, the environment of relatively low NH insolation must occur but I don’t believe that is the cause in and of itself. I believe that is what creates the environment for a bistable system (with hysteresis) to flip to the other mode. I believe it takes some other trigger or possibly even a combination of events to cause that to cross the threshold and flip the system to the other (cold) stable state.

    Yes, we might be in the correct insolation zone. In fact, the system might have already “flipped” in the 13th century but we have experienced a brief period of increased solar activity that has moderated it. But we have still not fully “recovered” to where we were in the 12th century. Areas of Scandinavia that were being actively farmed are still too cold for farming and areas of the Alps that were being mined prior to the 13th century are still iced in. We might have been lucky and experienced an ephemeral warming.

    Assuming Svensmark is correct in his hypothesis about cosmic rays and their impact on cloud formation and the impact of clouds on global albedo and that impact on climate, solar variability might be the thing that triggers the system to flip states. Or maybe you need a combination of a large volcanic eruption coincident with a weak solar magnetic cycle while we are at low insolation. Earth has thousands of years to patiently wait for the proper conditions to be met. She is in no particular hurry and enjoying the ride through time. Now that we are in a weaker phase of solar activity, I believe it is likely we will see some cooling. There is evidence this has already started in the European Alps:

    http://notrickszone.com/2014/05/27/warming-scientists-humiliated-strong-cooling-seizes-european-alps-considerably-colder-winters-since-198889/

    Another place to watch would be the Athabasca glacial field. If we were to be in a longer term solar activity doldrums where we have simply experienced several decades of a burst of activity and if that activity is quieting again, we could well be ripe for the system to change. Once it DOES change and enough of the surface is covered with snow/ice, it makes it exceedingly difficult to recover in summer. It isn’t until insolation recovers again and is able to melt back enough ice (possibly thawing the ice in the Arctic Ocean in summer) that we quickly “flip” back out into the (shorter) stable warm mode for a while. Will the Sun’s activity turn out to be a brief Dalton type minimum or will it be a longer Maunder sort? I don’t think anyone knows with any certainty. But I do believe that grand minima occurring before about 4,000 years ago happened during a period where insolation was high enough that they didn’t cause any drastic cooling. But I also believe we are now at a stage were they are going to have a much higher impact on climate now than they did then. Add a massive volcanic eruption to the mix (VEI 7) coincident with a solar minimum and all bets are off. The Tambora eruption happened during the Dalton Minimum and we see the result in the summer if 1816 in the Northeastern US. We don’t really know much about the weather in the rest of the northern half of the US because those areas were not settled densely. But that was followed by strengthening solar cycles (1915 was in Cycle 6 with an average sunspot number peak of 48.7 (May 1816)) but that was followed by increasing solar activity in cycle 7 (71.5) and cycle 8 (146.9). Had Tambora erupted 20 years earlier, the result might have been much different if we were able to accumulate more snow cover during the weak solar cycles to increase the net albedo enough that the increase in solar activity in subsequent cycles and reduction in cloud cover would find no net reduction in overall albedo due to the snow/ice. But even during glacial periods we will have warming to near modern temperatures for a few hundred years (stadials) though they aren’t enough to “flip” the system to the warm stable state.

    It’s coming. The environment is favorable for a switch, now we just are waiting for the right trigger to come along — and maybe it did in the 13th century and we are now experiencing only a brief respite.

  8. But the clouds got in the way…..
    Thanks for all the research. It underscores where we are in geologic circumstance, at the end of the Holocene. What I don’t see is how anyone would know how cloudy the sky has been relatively speaking. On the other hand the LIA should tell us we are not far from the end of the Holocene.

  9. Gary says:
    May 29, 2014 at 11:59 am

    lsvalgaard says:
    May 29, 2014 at 12:49 pm

    I too would welcome a brief summary of the points the author hopes to make & support by his citations.

  10. Thank you for all your work. It was most interesting. I would hazard a guess that if sudden stratospheric warming continues unabated and the jet stream keeps meandering south, it won’t take much to push us into an ice age. All it takes are a few really cold summers and one summer during which the ice and snow do not melt.

  11. A lot of interesting geology that is somewhat outside the argument, unfortunately. There is no dispute that a >2C rise may stabilize out in some way “beneficial” for the planet as a whole, or in some way that will actually sterilize the planet. The point is that established large numbers of humans will not adapt quickly enough or calmly enough to avoid huge social disruption and loss of life. Furthermore, the point of CAGW terror is that the “natural” world is already so stressed that many species will no be able to shift location in greater enough numbers fast enough to avoid extinction. Too many people, too damaged a world to handle a >2C shift in 86 years.

    The fact that nature did worse by going into a glacial period with a low (<280 ppm) CO2 concentration is not relevant for those who want to stabilize our atmosphere's CO2 at 350 ppm. If 280 kept us out of a glacial period, 350 sure will.

    The fact that nature may up and screw us any ol' time is also irrelevant for those who want to control/limit our CO2 emissions. "We" can do something about our CO2 emissions. We can't do anything about what glacial-level natural variations can do (in the absence of natural conditions).

    All this work does, however, show that "unprecedented" by the warmists is a lie, that the world did very well, thank you, under fast warming to high temperature levels, and that the science is definitely not settled, and the outcome of more CO2 for the short time frame definitely not certain. But we are not in a "natural" situation any more and humans AS ORGANIZED are pushing the limits of nature's resilience (with respect to man's needs).

    Overall, I like the geology, but these are strawmen raised for the skeptics.

  12. “We statistically formulate the hypothesis of warming through natural variability by using centennial scale probabilities of natural fluctuations estimated using scaling, fluctuation analysis on multiproxy data. We take into account two nonclassical statistical features—long range statistical dependencies and “fat tailed” probability distributions (both of which greatly amplify the probability of extremes). Even in the most unfavourable cases, we may reject the natural variability hypothesis at confidence levels >99 %.”

    I thought the funniest part of Lovejoy 2014 was this:

    The measurement error was crucial to the thesis of the Lovejoy paper, yet the reviewers allowed him to get away with saying it was only 0.03 Cº when the oldest of the global datasets, and the one favored by the IPCC, actually publishes, every monthy, combined uncertainties that are ten times larger.

    I think .1 degrees is still Gavin’s official position on GISS, even though his cadre of government workers at Minitruth NASA have changed virtually all the official temperatures in the record by more than that since he said that. We have always been warmer than Eastasia!

  13. Very interesting, but perhaps overstated? eg, “the reason we are not already several thousands of years into the next glacial might be because of GHGs “. Man-made GHGs have only been around in any significant quantity for 150 years at most, probably a lot less. So they have not been responsible for the avoidance of “several thousand years” of glacial. The article goes on to suggest that the onset of agriculture was responsible. OK, it’s possible, but colour me sceptical.

    What is encouraging about the article is that it understands and works with the non-linear nature of climate, as illustrated by the “climatic “madhouse”“, the many statements along the lines of “The tendency of climate to change relatively suddenly has been one of the most surprising outcomes of the study of earth history” and the investigations of such changes.

    A request : Please can a simple-language (but properly referenced) version of this article, without the pejoratives (“stupidity”, “evil”, etc), be prepared. The article is far too long and complex to be presented as food for thought to AGWers, as per lsvalgaards’ “elevator test“.

    [Also, the statement “The largest climate problem of all is actually the smallest one we think we can now can identify: AGW (see every issuance from the IPCC). That is patently absurd.” is I think ambiguous and needs tidying up.]

  14. A million years of eccentricity fluctuations before & after AD 1850:

    Correlation with interglacials (from article on possible role of the moon):

  15. Mike Jonas says:
    May 29, 2014 at 1:53 pm

    Besides CO2, Ruddiman specifically blames rice paddies & livestock for methane. Others have looked to deforestation. But I like you am skeptical.

    http://en.wikipedia.org/wiki/Plows,_Plagues_and_Petroleum

    Even Gavin has his doubts.

    IMO the Holocene’s duration so far is adequately explained by orbital mechanics & solar variations. But the timing of its end remain in doubt.

  16. This brings up the one thing that stands out to me WRT the ice core temperature vs. CO2 plots. That is why does re-glaciation. or at least the thermal drop into re-glaciation, occur when CO2 is at its highest concentrations? Happens every time.

  17. You seem to be a victim of the belief that “high levels of greenhouse gases” have something to do with our climate. They are actually historic lows when compared to Jurassic, Permisan, or Cambrian. It is simply nonsensical to say that “…. if CO2/GHGs/etc. really represent the gaia thermostat, and have already prevented glacial inception (Ruddiman, 2003) for perhaps thousands of years already, then by all means we should ….Strip said “climate security blanket” from the late Holocene atmosphere, and be quick about it. We have denied gaia her next ice age for far too long already.”
    The unsaid portion is that greenhouse warming can be stopped by emission controls and we must speed it up because it is an emergency. (By the way, capitalize Gaia). Nothing could be further from the truth.No one has experimentally observed the enhanced greenhouse effect in nature. This includes Hansen who claimed to have observed it in 1988. What he claimed to have was a 100 year warming that could not be anything but greenhouse warming. He was wrong. He used ground-stations-only data to extend his warming below 1910 where more complete temperature records show cooling. He also included a non-greenhouse warming from 1910 to to 1940 as part of his 100 year warming. Take off everything below 1940 from his curve and you are left with a remnant consisting of 25 years of cooling and 23 years of warming. No way can this prove the existence of the greenhouse effect but he has gotten away with it for 26 years now. What they use as “proof” of the greenhouse effect nowadays is the Arrhenius greenhouse theory. Problem with that one is that it does not work with the current lack of warming. If a theory predicts warming from addition of carbon dioxide to the atmosphere and if for 17 years there is no warming you know that this theory is invalid and must be discarded. The only greenhouse theory that does explains the lack of warming today is the Miskolczi greenhouse theory. That is because it is capable of handling the more general case of greenhouse effect when several greenhouse gases simultaneously absorb in the IR. In such a case the gases present will jointly form an optimal absorption window they control. For the earth atmosphere the gases that matter are carbon dioxide and water vapor. The optical thickness of their joint absorption window is 1.87, calculated by Miskolczi from first principles. If you now add carbon dioxide to the atmosphere it will start to absorb just as Arrhenius says. But as soon as this happens water vapor will start to diminish, rain out, and the original optical thickness is restored. This is exactly why there has been no warming for the last 17 years, despite constantly increasing atmospheric carbon dioxide. This has also happened earlier, the last time in the eighties and nineties before the appearance of the super El Nino of 1998. A historic example comes from weather balloon database of NOAA that goes back to 1948. Miskolczi used it to study absorption of IR by the atmosphere over time. And discovered that absorption had been constant for 61 years while carbon dioxide at the same time increased by 21.6 percent. This is an exact parallel to what is happening today. So what are the consequences for us? For one thing, sensitivity becomes zero because doubling of carbon dioxide does not warm the atmosphere. For another thing, any warming imputed to the enhanced greenhouse effect simply does not exist. If any part of your theory depends upon it the theory is simply wrong. And last, but not least, is the fact that anthropogenic greenhouse effect simply does not exist. AGW is nothing more than a pseudo-scientific fantasy.

  18. Arno Arrak says:
    May 29, 2014 at 2:16 pm

    Only in the Late Carboniferous (Pennsylvanian) & Early Permian glaciation was CO2 as low as during the Neogene (Miocene, Pliocene, Pleistocene & Holocene).

  19. It is a real travesty that the author goes to the trouble to write this essay, but chooses to use absolutely horrible and virtually unreadable graphic illustrations, all due to the use of the of (low-quality) jpeg image format. Why bother postig the images at all if they are unreadable? Please learn to use PNG format for images that are not continuous-tone. jpeg format is designed for photographs are works nicely for such. The use of jpeg format for line drawings seems to be a particular problem with WUWT, for whatever reason.

  20. You’ve overlooked that CO2 makes oceans boil and ice ages impossible.

    (Actually you might not have done. To be fair, I only skimmed it looking for the well reasoned summary points about the science. Will there be some at some point?)

    (P.S. Me being an idiot aside, thanks for the hard work that’s clearly gone into this…)

  21. So, look at Antarctica.

    Now, conventionally, glacier inception focus only on the northern hemisphere because, well, because all of the scientists and people who fund scientists are up there. But, also, even at the darkest of the glacier advances, the southern edge of the furthest south glaciers in north America were a little south of Chicago. Call the edge of the glaciers at 41-42 north latitude. European glaciers were even further north – with a few mountain top exceptions down near Africa.

    In the southern hemisphere, a line at 42 south latitude includes only a little bit a Chile and small part of Argentina! Nothing in Africa, Australia, nothing anywhere else at all. Antarctica of course was covered in ice then, and is covered in ice now.

    So. Today. The edge of the Antarctic sea ice received more solar radiation than does the arctic 7 months of the year. The Arctic? only 5 months of the year, and those five months are during the LOWEST part of the annual solar cycle: the earth is hit by up to 103 LESS watts/m^2 when the arctic is exposed than when the Antarctic ice is exposed to 24 hour of sunlight!

    In March, when both are hit by the same intensity of solar radiation (at nearly the nominal average value of 1361 watts/m^2) both get the same insolation.

    But in September, when they again are hit by the same levels of radiation, the Antarctic sea ice is at its maximum at latitude 59 south, and the Arctic sea ice is at its minimum at 79- 80 north latitude. ( 82 north if the minimum is 3 Mkm^2 if we get that low a sea ice extents.) Any “excess” antarctic sea ice down south – and we have steadily INCREASING antarctic sea ice for 30 years now – in September is hit with five times MORE solar insolation per second than does a square meter of “missing” or melted arctic sea up north!

  22. RGB has previously pointed out the glaciation that took place at the end of the Ordovician and the beginning of the Silurian periods when co2 was 7,000 ppm and dropped to just above 4,000 ppm for the whole of the glaciation.

    This would seem to rule out the idea that any amount of co2 can play any role at all in extending an interstitial.

    I think the most likely rate of descent into the next glaciation (which probably started several thousand years ago) can be obtained by drawing a curve or staight line through the peaks or troughs of the Minoan, Roman, Medieval warm periods or some mean of those troughs and peaks.

  23. Yes, a long paper where ones needs a couple of days to digest. Why? because there seemed to be no sections or chapters and has been mentioned, it also seems to lack the abstract and conclusion, although they seem to be present.

    Having said that,

    lsvalgaard says:
    May 29, 2014 at 12:49 pm

    The piece fails the ‘elevator test’. What is the bottom line? [you have 10 seconds to explain it]

    Can be summarized into Three possibilities. One there is going to be Global Warming. Two, there is going to be Global Ice Age, or Three Global whether is static. It does not matter which occurs, (in a sense it does matter, but superfluous to the bottom line).

    The main thing that is of paramount importance is the long term survival of mankind and the common factor that is going to be needed in all three scenarios is the supply of energy.

    If we have energy, then man will adapt accordingly, hopefully.

    Regards
    ClimateHeretic

  24. William McClenney said,

    In one sense I offer this compilation as a sort of extension to Liu et al (2014) http://www.lasg.ac.cn/UpLoadFiles/File/papers/2012/2012-pnas.jiping.liu.pdf , whom came very close, I think, to “getting it”. Liu et al (2014) provide an almost blow by blow account of many of the things now thought to characterize glacial inceptions. It seems as if they almost took the last step, as we have done here, in looking at what it all might very well mean.

    The arctic warms, melts, causes a delay in re-freezing, which allows that much more moisture evaporation to feed into such things as blocking highs, resulting in severe winter storms laden with more moisture to provide thick blankets of snow in the northern continental latitudes. The further south and longer the heavy snows persist, like the past few winters, the orbital weakened/weakening incoming solar radiation (insolation) is reflected, not absorbed. Obviously it is far more complex than that, but that very well might be the gist of the matter.

    Scholarly thoughts on these matters are solicited.

    - – - – - – - – - – -

    William McClenne,

    That was a mega-post. Thanks.

    My impression is that you offered the above quote as a tentative finding to your very extensive survey of the literature pertaining to the end Holocene climate variability leading to inception of the next glacial period. I think you maybe wanted commenters to critique the tentative finding. If I am wrong about what you wanted, then I apologize.

    You clearly stressed one point often throughout your post in your bolding of quotes from the literature. That point of yours is indicated by the following words in many of the bolded parts of the quotes from the literature wrt the rate of climate change in the end Holocene and glacial inception period: ‘less than two decades’, ’sharp threshold’, ‘climatic madhouse’, ‘three [inplied to be rapidly occurring] warm/cold cycles’, ‘ended abruptly with a rapid transition’, ‘was rapid’, ‘relatively sudden event’, ‘as little as’, ‘relatively sudden event’, ‘rapid and large fluctuations’, ‘transition […]~100 and 150 years’, ‘the very abrupt end […] < 0.15 ka’, ‘only ~100 and 150 years’, ‘very abrupt end’, ‘change relatively suddenly’, ‘even just a few years’, ‘rapid climatic variability’, ‘terminate suddenly’, ‘end suddenly’, ‘triggered the abrupt displacement’, ‘rise to rapid’, ‘subsequent abrupt events’, ‘to later rapid events’, ‘this abrupt’, ‘during abrupt climatic’, etc, etc.

    Is this repeated emphasis on very short time scales to the climate variability at Holocene end and at glacial inception the balanced view from the geo-sciences? Is urgency clear? We’ve seen what CAGW has wrought with its attempt at urgency, so I am not yet supportive of any sense of urgency in the case of your bolded quotes from literature on the end of the current interglacial and beginning of the glacial.

    This comment is long already. Any other points I will make in additional comments.

    John

  25. Anthony,

    When did you become a book publisher?

    [REPLY: No idea what you are talking about -A]

    Theoretically, something that could make CO2 sound like an important solution to an important problem, maybe Tom Steyer and his ilk would buy it. Why not, they bought CAGW. We need a graph, something that goes along flat for a while and then turns suddenly DOWN…

  26. Thanks, William McClenney, for the sustained documenting and explanations.
    Yes, the warm climate will have to end and a cool climate return.
    How soon?
    I missed the article’s answer somehow, unless it is that it has already started.
    To me, his means that there should be no more global warming sustained for more than a few tears in a row, until Earth goes into the “climatic “madhouse” that is glacial inception, which might be imminent.”, then we get really colder fast.

  27. Maybe it’s just me, but when Godwin’s law is proven in the second sentence……
    ……..I only scrolled through the rest, looking for the conclusion.
    All I got was a bunch of quotes.

    Stupid is a strong word, use it sparingly.

  28. u.k.(us) says:
    May 29, 2014 at 5:13 pm

    “Maybe it’s just me…”

    I think I know what you mean. Thanks to your comment about Godwin’s Law, I’ve just learnt a new phrase from wikipedia: “Reductio ad Hitlerum
    :)

  29. Gah!
    My brain hurts, Brian. Lots of wriggly lines. Lots of hard words. Lots of sciencey stuff.

    But no answer to the key question.

    Are we doomed from fire or ice?

  30. I get the absorption spectrum argument for CO2′s alleged warming effect. Meantime:

    1) CO2 has risen steadily over the last 20 years, while atmospheric temperatures have flatlined for the last 17.8 years;

    2) 430 mya, CO2 was 11/eleven times higher than at present, but Earth was in a deep ice age, while 65 mya, CO2 was barely twice today’s levels but Earth was too warm for permanent, year-round ice even at the poles — i.e., overall there is ZERO correlation between CO2 levels and paleoclimatic temperatures (except when CO2 -lags- the temperature change);

    3) on Venus, when pressure effects are backed out, temperatures are no warmer than they “should” be just from being closer to the Sun — despite 96% CO2 atmosphere. You might like to argue albedo — if so, the albedo must be exactly right to offset the “warming” effect of CO2 at an altitude of 49 km; but, of course, since Venus is covered by cloud, not a roof, the albedo effect must lessen with increasing altitude (like coming up out of clouds in a plane, hm?), and yet at higher altitudes, Venus’ temperature is slightly LESS than it “should” be due to proximity alone. So you’ll have to explain why -less- albedo causes -more- (CO2-countering) cooling.

    Correlation does not equal causation. However, -absence- of correlation most certainly means absence of causation.

    Occam’s Razor: the thesis “CO2 does not warm atmospheric temperature” has a lot less ‘splainin’ to do, Lucy, than does “CO2 causes (even a little) warming”.

    Honestly, CO2 is going to “shade” the Earth from incoming IR exactly, molecule for molecule, as it “traps” outgoing IR. And any CO2 molecule even slightly above the surface of the Earth has a slightly greater probability of reradiating IR towards space — simple geometry’ll give you that.

  31. Sorry folks, had to have some rack time. The length of this piece was driven by what is clearly a large body of research conducted by many on the many different, often fairly specific, aspects of glacial inception and the lengths of previous interglacials, but not many compilations attempting to draw a lot of these perspectives together. One goal of the piece was to take a stab at doing that. Another goal was to take a look at the AGW hypothesis from the perspective of pretzel logic; if CO2/GHGs/etc. are really all that crash-hot an insulator, why would anyone in their right mind actually want to remove them at such a point in time as a half-precession cycle old interglacial. Personally, I don’t think that the AGW hypothesis holds much, if any, water. But the Catch 22 here is that if one does believe in the AGW meme then you find yourself between a rock and a hard place very quickly. Nothing sums that up better than the early anthropogenic hypothesis of William Ruddiman. Playing the devil’s advocate here, if one concedes CO2/GHGs are as crash-hot as we have been told, and has already deterred glacial inception, then wouldn’t scaling their atmospheric concentrations back risk glacial inception? And especially so at a half-precession cycle old interglacial like this one? That’s quite the Catch 22, wouldn’t you agree?

    How many Canadians and northern Eurasians are comfortable taking that risk? And that is just one of the Logical Absurdities incumbent to the AGW meme.

    I am glad Crosspatch opened the ball on the lengths of the interglacials, I was hoping someone would do that. You see there is a lot of research looking at various proxies which come up with different lengths of virtually all of the post-MPT interglacials. Why is this important? It’s another Catch 22. Even on things which actually have happened, the science is not that particularly well settled, making consideration of the science being settled on something which hasn’t happened yet rather unsettling.

    John Whitman, you are correct. I indeed wanted, and so stated, to stimulate some crowdsourcing, particularly in oceanography and how this ties to climate evolution. Again, another point of this piece is to acquaint the readership with the vast literature on this subject while also pointing out just how anemic the prognostications of AGW appear when compared and contrasted with (a) what nature did all by herself, frequently and recently and (b) particularly in the setting of a glacial inception, which there is good reason to suspect could be imminent. When viewed in the light of signal to noise ratio, the worst case attributable to CAGW would be basically impossible to detect, and especially so in the climatic “madhouse” of a glacial inception.

    Will respond to other comments shortly.

  32. Paleo shows two attractors, glaciation and de-glaciation. My metaphor is that the moth of the Holocene is winging its way closer and closer to the flame of the glaciated attractor. AnthroCO2 can only shield the moth from the flame, and only temporarily. William’s piece here is a detailed examination of the flapping of the wings.

    I also like William’s rock and hard place metaphor. My formulation is that the higher the climate sensitivity to CO2, the faster we would be now naturally cooling, without, of course, man’s feeble warming efforts.
    ============

  33. lsvalgaard says:
    May 29, 2014 at 12:49 pm

    “The piece fails the ‘elevator test’. What is the bottom line? [you have 10 seconds to explain it]”

    Sorry Leif, a large compilation of direct quotes does not lend itself well to the elevator test, nor did I have any such intention. The only conclusion is that a conclusion probably isn’t possible given that all pieces of the puzzle would seem to be in motion during glacial inceptions.

    One simple conclusion does stand out, however. And that is that glacial inceptions appear to be rather sudden events, not necessarily as long drawn out as some may have believed.

  34. Arno Arrak says:
    May 29, 2014 at 2:16 pm

    “You seem to be a victim of the belief that “high levels of greenhouse gases” have something to do with our climate.”

    Actually Arno I am not enamored of the AGW meme at all. But I often find that adopting the opposing point of view, for the purpose of discussion, can lead to some fascinating outcomes. Here, for the purposes of discussion, I have accepted the AGW meme and ridden it down the rabbit hole by merely considering when we live. We find that if the AGW meme is correct, removing it from the late Holocene atmosphere might actually be the wrong thing to do. If AGW etc. et al have already prevented glacial inception, perhaps for a few millenia, then wouldn’t removing such an effective climate security blanket leave us at risk of glacial inception? Wouldn’t it be wiser to stuff as much climate security blanket up there, while we still can?

    Tables turned, nicely and neatly. Always be careful what you wish for.

  35. J Martin on May 29, 2014 at 3:15 pm

    RGB has previously pointed out the glaciation that took place at the end of the Ordovician and the beginning of the Silurian periods when co2 was 7,000 ppm and dropped to just above 4,000 ppm for the whole of the glaciation.

    This would seem to rule out the idea that any amount of co2 can play any role at all in extending an interstitial.

    The “Cryogenian” (Sturtian, Minoan) glaciations 600-800 million years ago which approached snowball-earth status are even more problematic, occuring during CO2 concentrations of tens of thousands of ppm CO2. Not to mention the earlier Huronian glaciation 2 billion odd years ago, during which the atmosphere was about half CO2.

  36. Why only human? What about volcanic eruptions? Is he suggesting CO2 and carbon are off setting another glacial period? Gee, he is hopeful isn’t he?

  37. I think I have mentioned it before but quite honestly the way these people are reacting to suspected global warming and it causes, makes me believe they know the truth. The earth is cooling and possibly moving towards another Mini Ice Age or full glacial period. But for the realistic scenario, it will be the Gulf Stream, if that is diverted or slows, it will effect the weather in the Northern Hemisphere. Some university suggested if this happened they place huge fans under the sea to keep the Gulf Stream circulating. Well we have heard of bird choppers, what about whale choppers. They would have to generate a huge force. LOL

  38. Thanks William for bringing this fascinating (and very scary) research to light. The IPeCaC has never paid attention to geology or other facets of the real world. Its little dweebs are peering at computer screens, running models and doing “real, incontestable science”. Makes me want to puke.

    To lsvalgaard says:
    May 29, 2014 at 12:49 pm: The elevator quote: “We’re goddamned lucky to be alive, because compared to the well-known interglacial periods of the past, we should be back to Cro-Magnon days, wearing skins and hunting mammoths in the front of the massive continental glaciers. Maybe – just maybe – anthropogenic CO2 and other GHG are staving off that outcome. Just in case, buy some long johns.” ;) Yes, geologists can be brief.

  39. In this most interesting of topics, this piece needs some organization and telescoping. A lot of this stuff could be put in appendices. In a world gone mad with global warming this good news type of topic (possible prevention of the worst of the next glacial), should be done like you hammer a nail – a few taps followed by some quick hits and a final blow to set the nail flush in its place. I’ve had to skim it only.

  40. Anthony, and William McClenney,

    The “book” comment referred to the length of the post, far too long for the many busy people on here to digest. The gist seems to be, the current era closely resembles the beginning of several recent ice ages. Since this was the gist of “Climate Science” in the 1970′s, a successful re-run of this meme would save millions of lives, help us to quit burning food, prevent the price of a kWH from rising through the roof, put an end to the destruction of scenic vista’s caused by wind turbines, and let people drive nice big comfortable cars again.

    Once again, a convincing graph that shows that CO2 is the only thing keeping the ICE away could be a good thing for all of us. I am not convinced that CO2 really has much to do with it, as the rate of increase in the atmosphere seems pretty steady despite humankind adding 6X more per year than we did in the 50′s, and temperatures are steady, clearly no correlations whatsoever.

    A graph, a graph, our country for a graph!

  41. “Why did CO2 and CH4 concentrations rise in the middle and late Holocene, when they had previously always fallen?”

    Because it was not the end of the interglacial? Methane? Dude, you think our cows were farting that much more than the native steppe herds?

    Human CO2 is 5% of the annual carbon cycle and .25% of the accumulated greenhouse gasses by volume. Hard to imagine that effort slowing the inception of an ice age. If there is a solenoid or tipping point in the program it is at the end of a glacial and start of an interglacial. We warm out of a glacial fast, and enter grudgingly.

  42. Regarding politics and the media, it is remarkable that there is no debate or even mention of the issue of glacial inception, aside from absurd films like “Day after tomorrow” which even genuflect to AGW with infantile cracks in Antarctica. Perhaps a glacial discussion would “muddy the water” for the CAGW meme which the elites have agreed needs to take center stage to frighten the population into compliance with a green de-industrialization agenda.

    William’s frustration with this strange silence is understandable, its not really rocket science to look at the recent interglacials since the mid-Pleistocene revolution and draw quite obvious conclusions about their timing in regard to Milankovich cycles and their duration particularly in regard to the precession cycle. (This paper by Maslin and Ridgewell points to a more dominant timing effect of precession, an interesting discussion in glacial-interglacial timing in general as well as a reminder that, over the long term, glaciation is deepening with interglacials becoming less frequent – there is no guarantee in fact that the current one is not the last for a very long time.)

    http://andy.seao2.info/pubs/manuscript_maslin_and_ridgwell.pdf

    So if human society was rational, or even partly rational, then the fact that we are half a precession cycle into the current Holocene interglacial, and that the skewed dome-shaped temperature curve of the Holocene (maximum at 8000 years ago) further suggests that an imminent glacial inception, while not inevitable, is at least a possibility worth serious attention – all this would be expected to provoke a public debate similar to that which exists for meteor strikes, global warming etc. But nothing. Silence. It is however an informative silence, a silence that tells us important things about human society. What it tells us was best articulated by Jeremiah: “The human heart is deceitful above all things and desperately sick. Who can understand it?”

  43. I love WUWT, it’s my most-visited website. I enjoy almost every post. Glacial inception is an important and interesting subject and it is regrettable that this post is so large. It’s far too much even for me to read and I expect that few visitors are willing to devote up to an hour to work their way properly through such an enormous quantity of material even though is it surely of the highest quality and represents a great deal of hard work.
    In the end I found myself scrolling down through it and just picking out the bold bits. The post should summarise the material as an abstract and link to a PDF with the full “paper”, then everyone from casual visitor to hardened enthusiast would be properly catered for.

  44. :-) yeah its long, but its good.
    if I had progeny or expected to be round for many more decades
    I’d be looking to buy inland further, in climate thats a bit too warm right now,
    to give me n mine a better chance of making it.
    as neither is the case, I will simply make sure I have warmer clothes and look for short season crops.:-)

  45. On Cosmos, Neil DG-T suggested the glacial cycle is all about orbital harmonics. He further stated that running such assumptions forward leads to at least 10,000 year before the next glacial inception. I’ve not heard it before, and it sounds crack to me. However, I intend to look into it. Does anyone know anything about what Neil was talking about? Again, it is what I would normally chalk up to quackery. However, hearing Neil say it makes me reluctant to dismiss it, but Neil has said some pretty lame things on Cosmos. This one is easily lame as well.

  46. J Martin says: (May 29, 2014 at 3:15 pm) “RGB has previously pointed out the glaciation that took place at the end of the Ordovician and the beginning of the Silurian periods when co2 was 7,000 ppm and dropped to just above 4,000 ppm for the whole of the glaciation.“. SkS claims that the sun was much weaker then, and that this explains the apparent discrepancy. Does anyone know what TSI was back then, and has anyone done the calculations to see if the TSI then was low enough to offset the 10-times higher CO2 levels (assuming IPCC estimate of climate sensitivity ~=3 is correct).

  47. The abrupt end and beginning of interglacials does mean we may well have delayed the onset of the next glacial period. But not for long. While there is a ton of stuff to mull over between the 4 articles, the one point seems to be that a little warming is nothing compared to the next glaciation that will occur. As far as a detriment to man and the rest of nature. And the reality that there is nothing man can do about it at this time.

  48. I have the facts on this one:
    “the glaciation that took place at the end of the Ordovician and the beginning of the Silurian periods when co2 was 7,000 ppm and dropped to just above 4,000 ppm for the whole of the glaciation.“
    SkS knows for a fact that the sun was much, much, much weaker then. With high quality satellite records going back ~2 billion years, they provide a foolproof explaination of the obvious difference.

    The IPCC knows for a fact that the climate sensitivity is exactly 3, +/-4. The satellite records show that the TSI back then was about 1 watt / M^2. The sun basically looked like a nighlight in the sky at high noon.

    In all seriousness, this essay by William McClenney is just a humor piece I think. It contains just enough “facts” and information from which you can pontificate and draw any conclusion you desire. I would prefer a list of facts, followed by modest range of probabilities. It seems he is flip-flopping between CAGW advocate and pro-science mindsets. Just my humble opinion.

  49. I don’t automatically accept it, but if true, terminating (or postponing) the earth’s glacial cycle would be mankind’s most important accomplishment so far. We need to keep it up, tho, for another 4k yrs at least.

    Go 1000 ppm CO2!

  50. For those complaining, the thing about long & complex issues is, they’re long & complex.

  51. lsvalgaard says:
    May 29, 2014 at 12:49 pm
    “The piece fails the ‘elevator test’. What is the bottom line? [you have 10 seconds to explain it]”

    Mc Clenney does not sound like a Russian name but this reads like a Russian novel. I will wait for the movie version.

  52. Mike Jonas says:
    May 30, 2014 at 5:16 am
    J Martin says: (May 29, 2014 at 3:15 pm) “RGB has previously pointed out the glaciation that took place at the end of the Ordovician and the beginning of the Silurian periods when co2 was 7,000 ppm and dropped to just above 4,000 ppm for the whole of the glaciation.“.

    This would seem to rule out the idea that any amount of co2 can play any role at all in extending an interstitial.

    phlogiston says:
    May 29, 2014 at 7:09 pm
    J Martin on May 29, 2014 at 3:15 pm

    The “Cryogenian” (Sturtian, Minoan) glaciations 600-800 million years ago which approached snowball-earth status are even more problematic, occuring during CO2 concentrations of tens of thousands of ppm CO2. Not to mention the earlier Huronian glaciation 2 billion odd years ago, during which the atmosphere was about half CO2.

    Mike Jonas says:
    May 30, 2014 at 5:16 am
    SkS claims that the sun was much weaker then, and that this explains the apparent discrepancy. Does anyone know what TSI was back then, and has anyone done the calculations to see if the TSI then was low enough to offset the 10-times higher CO2 levels (assuming IPCC estimate of climate sensitivity ~=3 is correct).

    The dim sun is a pathetic fig leaf for warmists to use to hide the fact of prior ice ages with sky-high CO2. If the sun was 20% weaker 4 billion years ago then in the Saharan-Andean ice age during the Ordovician, ~400 mYa, the difference from today is only one tenth of this, i.e. 2%. Their argument would make sense if the world was in permanent ice age back in the Archaean, Proterozoic and part of the Phanerozoic. But why in the deep past did the world go in and out of ice ages with no correlation with CO2? Why did temperature and CO2 levels sometimes move in opposite directions for tens or hundreds of millions of years? The notion against all palaeo evidence that CO2 drives temperatures is imbecilic crap and anyone who is honest knows it.

  53. Summary: Chicago should already be covered by 1,000 feet of ice. Be thankful for CO2, and burn baby burn.

  54. This is a well written essay, with compelling analysis and much factual corroboration.
    I would respectfully point out that adding the bit at the beginning about ‘evil’ and ‘Hitler’ does not add to the work and actually detracts from it. Giving climate obsessed people excuses to ignore thoughtful work by crying “Godwin’s law!” does not advance the skeptical case.

  55. The author may say that Loutre and Berger (2003) was put to rest quickly, but over at Wikipedia it forms the backbone of predictions of the course of present interglacial–this particular topic being under the editorial control of Wm. Connelly.

  56. phlogiston says:
    May 30, 2014 at 10:14 am

    While concurring with your points, it appears that over at least the Phanerozoic, solar brightness has gained about one percent per 110 million years, so the sun was probably four percent weaker during the Ordovician glaciation, c. 440 Ma. Still not enough to compensate for CO2 levels on the order of ten times higher than now.

  57. If the global model and the estimated paleo-sea levels for south Florida are correct, then it is apparent that a significant portion of the Greenland ice sheet and possibly all of the West Antarctic ice sheet were lost during the Last Interglacial period.

    But in Greenland -
    “GRIP Drilling Effort – In the first drilling season in 1990, the drill reached a depth of 770m where the ice is 3840 years old. In 1991, the drilling continued into 40,000 year old ice at a depth of 2521m, and on 12 August 1992, the drill hit bedrock at 3029m below the surface, where the ice is 200,000 years old or more.

    http://www.ncdc.noaa.gov/paleo/icecore/greenland/summit/document/

    And Antarctica – its 850 ka

    http://en.wikipedia.org/wiki/File:EPICA_delta_D_plot.svg

    Don’t see a lot of flat no data years in these plots, so the snow / ice has been accumulating. All that frozen water above sea level means our current sea level will be lower until it does melt.

  58. milodonharlani – Thanks for “probably four percent weaker during the Ordovician glaciation“. Is there any reasonably hard proxy data, or is this educated guess the best available?
    At the IPCC’s 3.7Wm-2 per doubled CO2, 4000 ppm CO2 would deliver log2(4000/400)*3.7*(1-0.04) = 11.8Wm-2 more than today’s 400ppm. At 7000ppm, it would deliver 14.7Wm-2 more.
    At around 1100Wm-2 at Earth’s surface today, a 4% weaker sun would deliver about 1100*0.04 = 44Wm-2 less.
    The difference between 44Wm-2 and 14.7Wm-2 is equivalent to about 8 doublings of CO2. So, under the CO2 conjecture, the whole Ordovician should have been a glacial. Correct?

  59. SkS claims that the sun was much weaker then

    Yes, they would but we are not talking about brightness per se. The radiative emissions would probably have been sufficient to swamp any co² molecules in the atmosphere (I’m waiting for Leif) to simulate today’s co² effect.

  60. Mike Jonas says:
    May 30, 2014 at 1:17 pm

    That GCM sensitivity guess doesn’t work for previous geological periods is just one of many problems with the models.

    The sun is a main-sequence star, the past luminosity of which is given for t ≤ t0 by the
    expression below, where L0 is its current luminosity & t0 is its present age:

    L(t) = [1 + (1-t/t0)2/5]^-1 * L0.

    It works out to about one percent per 110 million years & gives rise to the supposed dim early sun paradox, since by this formula 4.55 billion years ago the sun should have been only 41% as bright as now. Maybe Dr. Svalgaard can help me out.

  61. Stephen Richards says:
    May 30, 2014 at 1:29 pm

    The sun was only about 4% weaker then, not enough to compensate for so much more CO2. The lame excuse I’ve seen was that CO2 has only been sampled at intervals of ten million years for the Ordovician & Silurian, so concentration might have had a sharp excursion, a downturn, then rebound which proxies don’t pick up, due to too low a time resolution. That “might” is all they have. Pure conjecture without any physical basis as evidence.

  62. “http://wattsupwiththat.com/2010/12/30/the-antithesis/ where the possibility is discussed 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.

    Good work and worthy of consideration of all its points.

    However, the article still seems to accept that GHGs are doing waht the warmists assert that they are doing – and ARE GOING TO DO what the alrmists say the GHGs are doing. Yet right in that post the author says this:

    An astute reader might have gleaned that even on things which have happened, the science is not that particularly well settled. Which makes consideration of the science being settled on things which have not yet happened dubious at best.

    and this:

    So, in juxtaposition to the hypothesis of future global climate disruption from CO2, a scientist might well consider an antithesis or two in order to maintain ones objectivity.

    So, with a consensus that can’t even its observations and assessments of the past right, let us consider a real antithesis.

    The REAL consensus today is much bigger than simply CAGW. CAGW is an offshoot of the Gradualist-Uniformitarian doctrine (let’s shorten it to GUD), which says, essentially that not only are the processes of the present slow and gradual and sedate, but they project this sedateness into the past – to well before the advent of Man.

    GUD asserts essentially that erosion ans slow earth science processes are the only processes working now, and that for the last many millions of years those is all that could possibly have happened. It asserts basically that the Earth is a closed system with an all-but-constant input of energy from the Sun. Although it admits that there are other things in the Solar System than the planets, the OTHER things – the comets and asteroids – are insignificant and have never played any part in the Life of Planet Earth in the Time of Man.

    CAGW is simply one small part of that GUD, one that insists that the only things that can be allowed to be considered as parts of the natural history of the planet Earth are GUD elements – slow and gradual processes of the continents, the oceans and the atmosphere. Slow subduction of tectonic plates, slow Milankovitch cycles, slow erosion, slow melting or growing of ice sheets, slow internal and external processes.

    So, the TRUE antithesis needs to be one which is opposed to this assertion of slowness, always slowness.

    In the GISP2 ice cores there are evidences of WILD swings in the O18 levels in Greenland. See http://en.wikipedia.org/wiki/File:Ice-core-isotope.png These caused temperature swings during just the last ice age of about 14C. These lead us to the Dansgaard-Oeschger Events (D-O) of the Pleistocene, and also to the more recent Bond Events, both temperature excursions that came on a time scale of 1470-1500 years. There are 12 recognized Bond Events, with the last one timed to the Little Ice Age and the first one timed to the Younger Dryas.

    Now we are getting to my point – an additional antithesis. There is, as many here have been fortunate to have noticed (because Anthony has posted on it a few times), such a thing as the Younger Dryas Impact Hypothesis (YDIH), (see Firestone et al 2007) which posits that at the moment of the onset of the Younger Dryas (12.8 kya) a cosmic object came out of the sky and smacked planet Earth. It is posited that this impact CAUSED the Younger Dryas, and that in the process exterminated the mammoths and all megafauna in North America. The supposed great mammoth killers, Clovis Man, met his demise at this time, too, it seems. So, we had three things that happened all at the same time – a new ice age began, the megafauna (mammoths, etc.) died of, and so did Clovis Man. No beautifully made Clovis points have been found after the moment of the onset of the Younger Dryas. The hypothesis is new, and it covers a lot of ground, so much of the evidence is still being worked on. And contrary to the yelling and screaming of some skeptics – who are doing little more than simply writing Op-Eds and kibitzing – the evidence keeps coming in and refining the YDIH concept.

    So, the OTHER antithesis hypothesis is that GUD – Gradualism and Uniformitarianism – does not always rule. The wild swings of the past have been numerous. The YDIH so far only addresses ONE of the wild temperature excursions, but the Bond Events and the D-O Events show that there were MANY such extreme fluctuations.

    One of the “flaws” pointed out in the YDIH is that it does not explain OTHER extreme fluctuations. It is WAAAAY early in the game to be able to directly address that particular criticism. The researchers on the YDIH are presently simply trying to establish that THAT one happened for certain. One step at a time.

    But I can conjecture that if one Bond Event ties in with the Younger Dryas, and if the Younger Dryas is tied in with an impact, perhaps the OTHER Bond Events also were impacts. (Yes, the 1500-year regularity of them is probably a problem, but one whose resolution is for later in the game.) And if the Bond Events are tied in with the D-O Events, does that also tie the D-O Events in with the YDIH? Could there POSSIBLY have been so many impacts during the Pleistocene and into the Holocene?

    What this presents us with is the concept that ALL of the fluctuations in the GISP2 O18 record, plus ALL the Bond Events were impacts. YES, right now it seems a bit crazy.

    But if the YDIH turns out to be true, then GUD no longer is 100% true. And if not 100%, then can we say NOW how many times some non-Gradualist event occurred?

    But the point here is that THIS is perhaps the 2nd of the antitheses to CAGW. It is so much assumed that so much in the natural history of Earth was so constant. I would remind you all, though, that that idea of constancy only goes back about 150 years. Prior to that time the same evidence that is today seen as ice age evidence was seen as evidence of huge catastrophic floods.

    I will only say in passing and in conclusion that 71% of the Earth is ocean, and that means that the odds of ocean impacts is about 5:2. Ocean impacts are projected to deliver mega-tsunamis, tsunamis far, far larger than the Japan or Sumatran tsunamis.

    The resultant climate effects? It is too early to really know…

    Impacts are anything but Gradualist or Uniformitarianism.

  63. A general statement here. I did warn right near the start that this was going to be long. There were 3 reasons for that (1) there is a stunning amount of research worth documenting (providing links to, (2) those that pooh-pooh the possibility of glacial inception deserve to be confronted with that fact, and (3) in my research on this I found no real compilation to point to, so this is it. There will be no 140 character version.

    There is also a subtext message here. Denial. Phlogiston got it. Here we are arguing about a possible 2-5C rise in global temps because of CO2 when that is exactly what has happened during glacial inception a minimum of 3 times, 2 of those occurred at the ends of eccentricity minimum end interglacials.

    Unfortunately the original Word version (I don’t savvy Wordmess) did contain more structure but this did not translate through very well. The “chapters” are denoted with bolded and underlined headings. Sorry those do not appear very obvious.

    Some appear to have taken the ploy of adopting the opposing point of view for the purposes of discussion to mean that I support AGW. I do not. The purpose of doing that was to confront those that do with the logical absurdity of even thinking of removing CO2 from the late Holocene atmosphere if (a) it may already have prevented glacial inception and (b) if they are right about CO2, removing it might very well precipitate glacial inception.

    The very real possibility of glacial inception at a half-precession old interglacial makes a mockery of the AGW case.

    I do not believe either case. What I do believe is that we are and will be at insolation values close to those where glacial inceptions did occur during at least MIS-11 and MIS-5e. What I felt was important was to communicate, in the authors words, the thinking on this fascinating subject and what they suggest are some of the tell-tale signs. I do not possess the expertise in oceanography or climatology to render judgement on those issues, so I did not. But I felt that they should be put together by someone in one place for the first time.

    For those worried about the graphics, just click through the links and download the papers yourself. I will see what I can do about getting Anthony some hi-res png’s if I have the software to do this. They will only be as high-res as those in the original papers.

    kevin kilty says:
    May 30, 2014 at 11:06 am

    Your point is well taken and is exactly the point I was trying to make. First it was a model run published 11 years ago. Observational data put it to rest just 2 years later. Personally I am tired of having it thrown in my face in virtually every discussion involving the possible/probable end Holocene, that is why I took it on first.

    Your point involving William Connelly is one of the better ones illustrating the difference between intelligence, stupidity and evil. I don’t think William Connelly is stupid, but his track record makes a strong supporting case for the difference between intelligence and evil. As does MatheMANNics.

    Jonathan Berber says:
    May 30, 2014 at 3:32 am

    If you have a place in mind, let me know and I’ll see if I can get it there.

    beng says:
    May 30, 2014 at 7:39 am

    You, like some others, get it. You win the prize!

    Eric Sincere says:
    May 30, 2014 at 6:24 am

    “I would prefer a list of facts, followed by modest range of probabilities.”

    Clearly you did not get it. Many have complained that all it is is a list of facts, and they are partially correct. That was partially the intention. Unfortunately there probably are no modest ranges of possibilities. What we have learned, to our chagrin, is that glacial inceptions actually occur quite quickly. If the lowest end reported estimate is possible, we could have glacial inception before the end of the 21st century.

    gymnosperm says:
    May 29, 2014 at 9:41 pm

    “We warm out of a glacial fast, and enter grudgingly.”

    Really excellent point! That is exactly what I thought in the 1970′s. Enjoy your stay there!

  64. “Really excellent point! That is exactly what I thought in the 1970′s. Enjoy your stay there!”
    I won’t burden this thread with another link but the ice cores did not exist in the 70′s and the sea cores had only just begun. Check out the modern slopes some time and get back to me.

    Your quotes contain contradictions, advocating once a failure of the gulf stream, and again an intensification of the AMOC. As you say, you can’t have it both ways.

    You seem to love Milankovitch as much as the forams do, yet Prokopenko figure 7 clearly shows that neither the June nor the September nor the Ides of March precession insolation can explain the Younger Dryas.

  65. gymnosperm says:
    May 30, 2014 at 9:07 pm

    Getting back to you.

    “ice cores did not exist in the 70′s”:
    Maybe you missed “In the summer of 1961, Chet Langway and the engineers took
    their new thermal drilling system back to northern Greenland and set up shop in the relative luxury of a curious experimental instal- lation near Thule Air Force Base. Camp Century, the “City Under the Ice,” was a secret Cold War installation that the Army had begun developing in 1959………”About all that survives of Camp Century today is the name it gave to the ice core completed that last summer and the scientific history it made.” You can obtain a copy here: http://www.nap.edu/catalog.php?record_id=10750

    “Slopes”?
    Sorry, I’m not following you.

    “Your quotes contain contradictions”:
    It may not always be apparent to laymen, which is why it was clearly stated in the Authors Note “As ever, there is also a clear need to expose the reader to the scientific method in operation: the literature.” It was also clearly stated that “Even on things which actually have happened the science is not that particularly well-settled, which makes consideration of the science being settled on things which have not yet happened a bit unsettling.” Welcome to how science is done.

    “You seem to love Milankovitch as much as the forams do”:
    This might just be a case of bad grammar. Whereas I said things like “eccentricity-paced ice age/interglacial couples” and “obliquity-paced world (41 kyr glacial/interglacial cycles) to the eccentricity-paced (~100kyr glacial/interglacial cycles) world”, I assumed this would not be taken in reverse, such as “ice age/interglacial couples paced eccentricity” etc. When a thing has been “paced” it has “lead (another runner in a race) in order to establish a competitive speed.” https://www.google.com/search?hl=en&as_q=paced+definition&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&tbs=&as_filetype=&as_rights= Sorry you didn’t realize that. Now “love” and Milankovitch” are interesting points inasmuch as I never actually used either word. Could you be more specific?

    You realize, of course, that the first rule of getting out of a hole is to stop digging, right?

  66. You can forget about that ”52 m a s l” last interglacial sea level. It is near Archangelsk, in an area that was glaciated both during the last and second-to-last ice-ages. It only shows that the area hasn’t risen to the same level during the two interglacials (the high Eemian sea-level is probably due to the much larger ice-cover during MIS 6).
    Generally speaking sites within glaciated areas, or within the fore-bulge outside the ice-caps cannot be used to determine absolute sea-levels during interglacial (this includes e. g. the Bahamas), though the can be used to determine relative changes, e. g. the two peaks during MIS 5 (the Eemian).
    The same applies to tectonically unstable areas, such as e. g. Hawaii and most of the Mediterranean.
    To show the size of this problem i might add that the highest last interglacial shoreline I am aware of is at 991 m. a. s. l. (in South Island, New Zealand) and the lowest at 360 m below (NW coast of Hawaii island).

    Only measurements on tectonically stable coasts, and preferably at sites where the last interglacial shoreline is horizontal over a long distance can give an idea of the “true” sea-level during earlier interglacials. I deliberately say “true” because the sea-level isn’t really the same all over the World, it varies by several meters due to thermal and gravitational effect. It did that during earlier interglacials too, but not in the same way as during the present one.

    There isn’t a really lot of places that actually fulfil the requirements above, but the ones that do suggest that the maximum sea-level during the last interglacial was 2-5 meters higher than at present.

    The levels during earlier interglacials are even more uncertain. MIS 7 sea-levels were almost certainly lower than today, MIS 9 probably about the same as today, and MIS 11 probably slightly higher than at present. But MIS11 levels were definitely nothing like the 15-25 meters often claimed, this is easily seen in a few places where the land has been rising for a long time (e.g. the Huon Peninsula on New Guinea and the Coorong coastal plain in Australia) and the interglacial coastlines form a “staircase”. If the MIS11 sea-level was really that hig, the MIS11 “step” in the staircase would be much higher than the next older and younger. It isn’t.

  67. RACookPE1978 says:

    “Nothing in Africa, Australia, nothing anywhere else at all. Antarctica of course was covered in ice then, and is covered in ice now.”

    Actually there were quite large ice-caps on the south islamd of New Zealand and Tasmania and sizeable montane glaciers in the Kosciusko range of Australia. Most subantarctic islands such as South Georgia, Kerguelen and Campbell were very extensively glaciated too.
    Glaciation in Africa was indeed quite minor and only consisted of enlarged glaciers on the high equatorial mountains and niche glaciers in the Drakensberg mountains of Lesotho.

  68. William McClenney :

    For your information Bermuda is in the forebulge zone of the Laurentide ice cap and consequently not a suitable site to determine absolute interglacial sea-levels. The problem is exacerbated by the exceptional length of MIS11 which means that isostatic equilibration had time to proceed much further than it has today.

    You seem to think that the Lyså et al. 2001 paper somehow contradicts my post which strongly suggests that you either hasn’t read it or (more likely) hasn’t understood it. Lyså et al report the current levels of the various deposits they describe, but they don’t bother to point out that these were not the same at the time of deposition because this is so glaringly obvious. Have a look at Fig 10 in the paper for example.

    I am unable to comment on the 350.me.uk link since the account has apparently been suspended.

    Please, try to keep up.

  69. William McClenney:

    If you are really interested in last interglacial sea levels I strongly recommend Pedoja, K. et al. 2011. Relative sea-level fall since the last interglacial stage: Are coasts uplifting worldwide? Earth Science Review 108(1-2):1-15, and particularly the worldwide compilation of MIS 5e shoreline levels in the Supplementary Information. It is by no means comprehensive, but it is by far the best available.

  70. I am still waiting for the “community organizers” who advocate that human activity is causing meaningful changes to the climate to show what the average climate is, and whether our present climate is below or above this average. But alas, there appears to be no appetite for this key metric.

    This should not come as a surprise especially when it is recalled that the vast majority of demands, suggestions and recommendations that accompany what passes for climate science all rapidly converge on statism, collectivism and the destruction of personal liberal and the resulting suppression of prosperity. This madness is not science, it is a form of gaia worship. It is a shame that so many otherwise brilliant and supposedly secular people are so duped by the oldest religion in human experience.

  71. The more you bicker, the easier it is for me to keep up with both of you. Well, I’m sucking air in the exhaust, at least.
    ===========

  72. 1. Narrow your topic! Less is more!
    2. Standard research article format! Please! Goes something like this:

    Abstract
    Introduction
    Literature Review
    Problem
    Methods
    Results
    Discussion
    Conclusion
    Limitations
    Further Research

  73. I’m sure that even Neanderthals took some preliminary ice cores but the business did not begin in earnest until the 80′s. If you examine the results of this work in even the most cursory way you will observe that temperature, CO2, CH4, Deuterium, etc. climb rapidly and smoothly out of a glacial but zig zag slowly and fitfully into one. Duh.

    Your effort is based on two assumptions. The first is that human CO2 has more than a lunch money effect on climate, and the second is that our current climate is a madhouse.

    The first is very debatable and the second is simply not true. Welcome to the scientific method.

  74. Thank you William for this considerable effort. Perhaps because geology is my field, I did not find it too long. Yes it did take a while, yes it could be improved with organization , but very inclusive. It is an angle I have used in discussion in the past. It is interesting to see the reaction of “believers” when I thank them for bringing the CO2 issue forward knowing the natural resistance to reducing their “carbon footprint” will work counter to their wishes. Personally I believe that Co2 causes some warming, but that nearly all it’s effects are in the first 50, perhaps 100 ppm’s , and any further increase will cause cooling. This POV is supported by much of your post. Thanks again for bringing this forward once again.

  75. tty says:
    May 31, 2014 at 4:32 am

    I tend to prefer http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow045009.pdf,

    “The geomorphology and morphostratigraphy of numerous worldwide sites reveal the relative movements of sea level during the peak of the Last Interglaciation (Marine Isotope Stage (MIS) 5e, assumed average duration between 13072 and 11972 ka). Because sea level was higher than present, deposits are emergent, exposed, and widespread on many stable coastlines. Correlation with MIS 5e is facilitated by similar morphostratigraphic relationships, a low degree of diagenesis, uranium–thorium (U/Th) ages, and a global set of amino-acid racemization (AAR) data. This study integrates information from a large number of sites from tectonically stable areas including Bermuda, Bahamas, and Western Australia, and some that have experienced minor uplift (2.5 m/100 ka), including selected sites from the Mediterranean and Hawaii.”

    And so once again we find ourselves with dueling quotes which feeds into “Even on things which actually have happened the science is not that particularly well-settled, which makes consideration of the science being settled on things which have not yet happened a bit unsettling.”

  76. gymnosperm says:
    May 31, 2014 at 9:49 am

    “Your effort is based on two assumptions. The first is that human CO2 has more than a lunch money effect on climate, and the second is that our current climate is a madhouse.

    “The first is very debatable and the second is simply not true. Welcome to the scientific method.”

    In reading this, I was reminded of one of my favorite lines from Back to the Future, when George McFly says to Lorraine “You are my density”

    The first “is simply not true.” It is not my assumption that “CO2 has more than a lunch money effect on climate”, it is the assumption made in the AGW hypothesis, which I use against itself.

    The second assumption you seem to think I have made “is that our current climate is a madhouse”. Again, this “is simply not true.” I did not and do not make that assumption. The point I am trying to illuminate for you is “This has prompted the remark that between the greenhouse and the icehouse lies a climatic “madhouse”, which was stated by Neuman and Hearty (1996) http://www.researchgate.net/publication/249518169_Rapid_sea-level_changes_at_the_close_of_the_last_interglacial_(substage_5e)_recorded_in_Bahamian_island_geology/file/9c96051c6e66749912.pdf

    “As ever, there is also a clear need to expose the reader to the scientific method in operation: the literature.”

    “In the final analysis, the only question that remains unanswered, with respect to climate change, is would “a caveman get this?””

    Thanks for confirming both of those for us.

  77. ffohnad says:
    May 31, 2014 at 11:49 am

    Gymnosperm is directed to your thoughtful comment.

    Thanks.

  78. Hmmmmm.
    “We don’t have a clue” seems a fair summary of the state of the science.
    We re learning more – but we still don’t know a shedload . . . .
    I have read that “The science is settled” – I am unconvinced. Apologies.

    Auto

  79. ““In the final analysis, the only question that remains unanswered, with respect to climate change, is would “a caveman get this?””

    I am not the only caveman who did not get this, but now that you have explained your position in a reasonably literate fashion, I must still disagree on a couple points. The difference between a stadial and an interstadial (if I may revert to the 70′s) is not the difference between an icehouse and a greenhouse. The icehouse is the madhouse.

    http://wp.me/a1uHC3-iH

    The last greenhouse in the Eocene far earlier and only hinted above was, well, sane. We live in a manic phase of the icehouse (routinely referred to as the hollowscene, a figment of the anthroposcene).

    There may well be fibrillations at the transition points between glacial and interglacial stages. Perhaps due to my lack of diligence and poor upbringing I did not notice any of these in the Baikal record. What we have is the DO events which seem to involve hemispheric oscillation.

    Would it be too much to suggest that the madhouse is bipolar disorder?

    Cheers,

  80. gymnosperm says:
    May 31, 2014 at 9:37 pm

    There may well be fibrillations at the transition points between glacial and interglacial stages. Perhaps due to my lack of diligence and poor upbringing I did not notice any of these in the Baikal record. What we have is the DO events which seem to involve hemispheric oscillation.

    Would it be too much to suggest that the madhouse is bipolar disorder?

    I agree with you that William’s article should have included a discussion of bipolar seesawing since this appears to be a feature of both the start and end of interglacials.

    Here is a (tactfully de-carbonized) abstract by Tzedakis on the bipolar seesaw as an indicator of glacial inception:

    Determining the natural length of the current interglacial

    P. C. Tzedakis, J. E. T. Channell, D. A. Hodell, H. F. Kleiven & L. C. Skinner

    Nature Geoscience 5, 138–141 (2012) doi:10.1038/ngeo1358
    Received 23 May 2011 Accepted 28 November 2011 Published online 09 January 2012 Corrected online 10 January 2012

    The timing of the hypothetical next glaciation remains unclear. Past interglacials can be used to draw analogies with the present, provided their duration is known. Here we propose that the minimum age of a glacial inception is constrained by the onset of bipolar-seesaw climate variability, which requires ice-sheets large enough to produce iceberg discharges that disrupt the ocean circulation. We identify the bipolar seesaw in ice-core and North Atlantic marine records by the appearance of a distinct phasing of interhemispheric climate and hydrographic changes and ice-rafted debris. The glacial inception during Marine Isotope sub-Stage 19c, a close analogue for the present interglacial, occurred near the summer insolation minimum, suggesting that the interglacial was not prolonged by subdued radiative forcing. Assuming that ice growth mainly responds to insolation forcing, this analogy suggests that the end of the current interglacial would occur within the next 1500 years.

    While Tzedakis states that the seesaw appears 3000 years after glacial inception, his reference for the seesaw is when it reaches an extreme amplitude resulting in ocean scale ice rafting events detectable as phased raft-deposits. It is possible that this could be the late phase of a bipolar seesaw that grows in amplitude for many years before reaching this huge scale. Thus it is possible that the current signs of Arctic-Antarctic reciprocity could represent the beginnings of the seesaw which will grow with time, ending in ocean scale ice rafting and catastrophic drop to glacial conditions.

    Having said that, gymnosperm’s point is also true that climate temperature variability is more acute during cold and cooling periods than in interglacials, including the DO events. (Glacial periods are both cooling and cold since there is a steady deepening of glaciation over the 90,000 odd year glacial intervals. In fact as discussed by Maslin and Ridgeway interglacials are triggered at the deepest points of glaciation where some positive feedback is triggered, maybe the weight of ice causing volcanic activity, maybe something else.)

    http://andy.seao2.info/pubs/manuscript_maslin_and_ridgwell.pdf

    Such is this glacial instability that you get these “micro-interglacials” in the middle of glacial periods where temperatures jump all the way to interglacial, but hang there only for less than a century before dropping right back down to full on glacial. That is madhouse climate.

  81. Gymnosperm,

    Warms my heart to see you got it. And that’s a twofer! “Manic phase of the hollowscene”, I like it! Yes, since the MPT we have only been in the warm phase of earth’s climate about 10-15% of the time. “Bipolar disorder” may be more accurate than you think. Although I cannot locate it right now, and also apparently failed to include it in the “clues” section, I do remember one author, or authors, mentioned that the restarting of the bipolar seesaw is one of the clues to the beginning of glacial inception. I will try to find it and post it here before Anthony closes comments. Not a bad description actually.

    I will be out of town most of this week, so it may be next weekend before I correct this oversight.

    Adios.

  82. William McClenney on June 2, 2014 at 5:52 am

    William – please look at the post just before your one and you will find the reference by Tzedakis you are looking for (bipolar seesaw and glacial inception).

  83. Phlogiston,

    You are indeed correct. Apparently I failed to copy that paper into the folder on glacial inception, but that is indeed where I saw this.

    Thanks :-)

  84. Thanks for combining all this reference material. I have made a PDF for use on my e-reader.

    As for the images, I agree that JPG is not the best and wish WUWT would recommend that guest posters use PNG or GIF whenever possible.

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