Onset of the Next Glaciation

Bill Yarber says:
September 16, 2012 at 7:39 am
I agree – we can expect to come out of the current interglacial in the relatively near future – unless of course we have managed to reach the warmists runaway tipping point beforehand (/sarc!). But of course, this presumes the causal cyclical variation and periodicity continues as per expectation!
I still find it curious that excessive warming is declared after a few decades of slightly rising temps, in the same way as the so called ‘cooling’ was alarmingly declared in the 70’s – however, both deductions, when viewed on an appropriate scale, look more like insignificant ‘farts’ within the natural temperature variability range!! To then have the audacity to link some allegedly observed ‘little’ temperature rise to a trace gas (that has been at much much higher levels in the past), and extrapolate out to ‘catastrophe’ is really beyond any level of believability…..to a geologist anyway!

meemoe_uk says:
September 16, 2012 at 9:23 am
“the sun has nothing to do with it [Jupiter has]. ”
OK Leif, I wasn’t expecting that from u. So how does Jupiter control Earth’s slide into ice ages?
Glaciations are caused by changes in the Earth’s orbit and axial tilt. Gravitational perturbations from [mostly] Jupiter slowly changes those parameters with well-known cycles [known several million years past and in future]. This is how. And has, of course, nothing to do with solar activity.

Stones rolling across from Norway?
I don’t get the mode of traction.
Though I try and I try and I try and I try.
davidq wrote:

Perhaps we need to widen and deepen the Panama canal. Didn’t the current onset of glaciation start occurring after the Atlantic and Pacific was cut off?
20 Miles wide, 300 feet deep. doable?

Perhaps, but the greenies would hate it. It has been proposed to open up a sea-level canal by “nuclear excavation”.
Atlantic-Pacific InterOceanic Canal
http://archive.org/stream/interoceaniccana00unit/interoceaniccana00unit_djvu.txt
See also Operation Chariot
http://en.wikipedia.org/wiki/Operation_Chariot_(1958)
But I’m not sure of the need. It is just one glacial period we would want to avert not all of them. And there are probably other ways. Soot suits the bill.

Leif Svalgaard says on September 16, 2012 at 12:07 am:
“- – —- –.
Luckily, the slide into a glaciation is long and slow, tens of thousands of years, and, of course, the sun has nothing to do with it [Jupiter has].”
= = = = = = = = =
Are you quite sure that Jupiter is working quite independently and on it’s own? –
Is it not likely that there are possible Solar Cycles (SC) which we, at the moment, know didly sqat about” that influences things like planetary orbits and in fact everything else in the solar system?
Come to think of it; why do sunrays still shine through orifices in stonewalls etc. (Stonehenge is one example – and there are many others) the same way as they did when they were first built in ancient times if the axial tilt of the Earth fluctuates back and forth between 22 and 24.5 degrees every 41000 years – and the globe also does a “Gyroscopic wobble” or a complete circle around it’s axis every 23000 years – which should mean that since it is, presently, mid-summer in the Northern Hemisphere in June when that hemisphere tilts towards the Sun – 11500 years (half a wobble) ago it would have been mid winter in June. – Any evidence for that in ice cores etc.?

Thankfully, by the time the next “ice age” starts to seriously affect our ability to feed the population of the planet, food production won’t be dependent on climate.
http://www.plantlab.nl/4.0/index.php/social-contribution/
http://www.omegagarden.com/
Assuming, of course, we have not stifled electricity production to the point where these kinds of solutions are impossible.

aksam@op.pl
sept 16 3;01am
party pooper

But perhaps the most interesting thing is the high year to year variability. Given the large albedo difference between snow and bare ground, it looks to me like natural variability plays a significant role in the start of the glacial phase.
I agree. The Earth is clearly a system with a large “heat capacity” that exhibits considerable hysteresis and sufficient nonlinearity in the form of e.g. albedo and other feedbacks to sustain at least bistable behavior in the current glacial era. Bistable systems can, for certain values of the primary drivers (in the case of the Earth, at the very least net insolation but sadly there are many, many more and they themselves are highly nonlinear and possibly coupled and fed back independent of albedo or insolation per se) have two locally stable dynamic equilibrium states. The way the ice ages and interglacial eras should properly be viewed is on a timescale granularity of at least a thousand years if not longer, where long slow macroscopic (externally caused) changes in insolation associated with orbital resonances, precession, and possibly other unknown factors in the solar system or even the galaxy— not the Earth per se — create a cycle something like this: (starting arbitrarily with the Earth in a stable cold phase, since that is the most likely state in a glacial era):
* Macroscopic changes push the Earth from the single dynamically stable state it is in into a state which is truly bistable, where the sustained cold is due to local stability from feedbacks like albedo and possibly global circulation patterns and the presumably relatively low temperature/heat content of the oceans. CO_2 may or may not play an important role in this feedback — I rather think it does, but it is almost certainly not the dominant factor as it appears to follow rather than lead (also, see Ordovician/Silurian transition!).
* Macroscopic changes CAN — and at least sometimes, probably do — literally force the Earth out of glaciation by moving the climate system across the local stability boundary by force majeure, no fluctuations necessary. In this case the transition from stable cold to stable warm is directly driven and relatively rapid.
* At other times the macroscopic changes may simply alter things so that fluctuations gradually carry the climate from one state to the other through a random walk in a basically neutral environment. One expects a very different “spectrum” of fluctuations in the two cases — in the latter case one might see rapid warming followed by rapid cooling followed by rapid warming before (perhaps) stabilizing in one state or the other (usually in response to an ongoing but slow change towards full stability in the final state).
One way or another, then, we might well end up in the warmer interglacial phase of the glacial era, and initially it is quite likely that this warm phase is truly stable so that decadal or century scale noise (macroscopic or “microscopic”, the latter associated with phenomena or feedbacks in the Earth’s climate system itself) literally cannot cause transition back to a true cold phase. The end of the Wisconsin followed by the Younger Dryas fluctuation followed by the Holocene proper is a classic example of this sort of process — macroscopic drivers that first enabled, then mandated a warm phase transition out of the ice age to the point where even a global microscopic fluctuation like the YD could not stop the progression towards stable warmth.
* The macroscopic drivers continue to evolve, however, and they gradually return the Earth into first the truly bistable regime — where if we were glaciated we would remain glaciated but since we are warm we remain warm — and then to a point where fluctuations be damned, a driven transition to a stable cold phase occurs. Again the spectrum of the global temperature during the cold phase transitions would be expected to be quite different in the case where the macroscopic drivers quickly and directly force the transition compared to one where the changes are slow enough that fluctuations drive the process.
A glance at the thermal record of the Holocene suggests that the Earth is currently out in the bistable regime as far as macroscopic drivers are concerned. The paper above does nothing more than confirm this for at least one or two explicit models for those drivers. It also suggests that there could be time scales of decades to centuries before those drivers force the inexorable motion towards cold phase once again, but it quite literally cannot address the issue of fluctuation-driven transitions in the meantime because it does not provide much in the way of a MICROSCOPIC stability analysis or for that matter an analysis of macroscopic parameters with considerable variability outside of the model as well.
One of the most interesting of these is that of solar state. The Sun is apparently a rather variable star, with not only its regular 11/22 year Hale cycle variability but with considerable modulation of that variability on much longer and (as far as I know) not particularly well-understood timescales, timescales against which the entire period of observation with modern instrumentation are utterly insignificant. However, there are many other unknowns to consider — the progression of the Sun (and hence Earth) through an interstellar medium of variable density, “black swan” events that we simply haven’t been around looking with modern instrumentation long enough to observe (major CMEs such as the 1859 event or even one an order of magnitude longer and stronger), divergences between even the observable proxies of solar state (e.g. sunspots) and ones that would have been invisible e.g. solar magnetic state until very recently.
However, there is also noise due to volcanism — one good sized Tambora can ruin (or at least alter) global climate for years if not decades, global decadal circulation fluctuations, fluctuations in the “oceanic conveyor belt” (that may or may not have been responsible for the Younger Dryas), fluctuations in GHG levels outside of volcanism, and yeah, long term persistent changes due to human activity.
For example, one can consider
http://en.wikipedia.org/wiki/Desertification
Deserts are a prime example of a MICROSCOPIC bistable climate system that share many properties with the bistability described above. Plants tend to both cool the local climate and bind moisture. If there are enough plants growing on a major geographical tract of land with marginal rainfall (marginal to put it into the bistable regime) the plants cool and bind moisture sufficiently that positive feedback maintains the growing plants and the regime is locally stable in a non-desert state. However, once you introduce goats… they create the Sahara. Perhaps not singlehandedly, perhaps not all of it, but there is substantial evidence that the introduction of goats and farming culture caused the collapse of a fragile non-desert state in North Africa leading to the desertification of much of it, a process that continues measurably today as an exploding human population continues to push land at its boundaries across the stability boundary in between the desert/non-desert states.
This sort of anthropogenic climate change has been occurring for thousands of years, and has occurred at a vastly accelerated rate in the 20-21st centuries as modern medicine and relative affluence have caused populations to increase in already strained local ecosystems. It absolutely has an effect on “global warming” — indeed century scale desertification of a substantial fraction of marginal land is precisely the sort of microscopic fluctuation that might be expected to have potential global effects due to feedbacks known and unknown within the global climate system. Curiously, it isn’t AFAIK invoked as even a partial explanation of late 20th century warming, although one would think that the shift of as much as 10% of the Earth’s land surface area in the strict direction of desertification of previously wild and vegetation covered lands over that same time frame might have an important effect quite outside of CO_2 levels (and indeed, has an important effect ON CO_2 levels as well).
The last “interesting” piece of evidence is that the Little Ice Age, occurring in apparent coincidence with the Maunder Minimum, was the coldest period in the entire Holocene post the Younger Dryas fluctuation, and occurred as global temperatures had been gradually decreasing from the Holocene optimum for thousands of years. This large temperature excursion in response to what may have been a relatively minor variation in a primary driver (the Sun) strongly suggests that the Earth is either entering or is already solidly into the bistable regime where sufficiently sustained fluctuations can drive it nonlinearly towards the cold stable state, quite possibly drive it “rapidly” in that direction (where rapidly is still century long timescales — the LIA was simply not long enough and didn’t get enough e.g. albedo feedback going to affect a full transition).
Some climate scientists I communicate with think it likely that the increased CO_2 levels have already shifted the Earth into a state where at the very least fluctuation-induced transitions are no longer possible — the Earth is no longer bistable (if it was in the first place, which of course we do not know). The CAGW prediction, of course, is that the Earth is at least tristable and that we may have shifted it or be shifting it all the way back to an even warmer phase that hasn’t been observed for some 50 million years of geologic time (and that intuitively seems a bit unlikely to occur in an ice age, interglacial or not). I have some doubts of this, largely because of the Ordovician/Silurian transition, wherein the Earth entered an ice age, relatively rapidly, in spite of having seventeen times the atmospheric CO_2 content that it does now when it began, and in spite of sustaining it at ten times the current concentration for the entire period the ice age lasted.
This one event suggests that macroscopic (or microscopic?) drivers exist that at least can trump massively greater CO_2 concentrations than we currently have and force an ice age straight into the teeth of only greenhouse warming. Since we are already in a relatively brief interglacial of an ice age, at the probable end of that interglacial on the timescale of a few thousand years either way (likely already in bistable/unstable to the cold transition) the plausibility of a third-phase “catastrophe” seems significantly reduced. However, our ignorance is great. For all practical purposes, we have at most 33 to 50 years of “reliable” data on global climate based on modern instrumentation and knowledge, and sadly much of even that data has been corrupted by things like nuclear war and the extensive testing of nuclear bombs post World War II confounding efforts to normalize radioactive proxy scales and at the very least reducing the reliability of our knowledge of prior solar state based on strictly visible light observational records (e.g. sunspots).
Lief an others appear to be conducting a truly heroic effort to rescue the situation, but in statistical modeling I like to tell clients the simple truth that you cannot squeeze blood from a turnip or make reliable inferences with inadequate or corrupted data. It’s not magic, it is information theory, and true information degradation cannot be restored or interpolated by statistics-fu.
This same process is at work throughout climate science. The thermometric record — what should be the single most reliable measure of the state of the global climate across at least the century or two of reliable thermometric instrumentation at least approximately distributed around the globe — is manifestly profoundly corrupted by confounding phenomena from the UHI effect and desertification to systematic method errors in the way temperatures were sampled (on what is quite frankly a completely inadequate fraction of the Earth’s surface throughout most of that period). Once again the issue is simple information theory. One cannot restore the missing or corrupted information without making assumptions, and if one then uses the restored information as if it were data to arrive at new conclusions, those conclusions are inevitably contaminated by the assumptions made to the extent that they have no real predictive power.
It has been said by very reasonable scientists that it will take at least a century of observation with modern instrumentation to be able to get a firm (predictive) grip on the climate. It will take us a good chunk of that to just get a good handle on the Sun, decades more of observation to come to properly understand the ocean, decades more to live through at least a few permutations of global decadal oscillations. Even over the last 30 years, however, there has been a truly substantial divergence between the off-the-cuff prediction of Hansen and at least some CAGW enthusiasts, a divergence that is gradually restoring a measure of sanity to the scientific discussion.
Unfortunately, much of the political discussion remains extreme, both because “catastrophe sells” whether the product being sold is a politician seeking votes or a news medium seeking readers or watchers. Saying “there isn’t anything particularly interesting happening to the global climate, however variable the local weather is and always has been” just isn’t the sort of thing to attract votes or public attention. Even scientists are hardly immune to the lure of the extreme — the extreme makes it easier to get grants, attracts more fame and notoriety to published papers, solidifies prospects for tenure and life success. Who reads a paper that says “I performed a statistical analysis of a hypothesized increase in the violence and frequency in major tropical storms and found that they were if anything less violent and less frequent”? Even scientists might give a secret little sigh — the extreme is so much more appealing, making the temptation to discover extremity in boring, quotidian data far too great.
Nowhere is this temptation more clearly visible in climate science than in the infamous extrapolations of “Sea Level Rise” (SLR). SLR has been recorded — and extremely reliably recorded, compared even to the temperature — for at least a century, and there is an overlap on a multidecadal timescale with satellite observations to further validate the fixed sea gauge-based results from all over the world. The data clearly show a nearly constant rate of SLR of 2-3 mm/year over nearly the entire period.
Almost all of this rise is due to thermal expansion of the ocean water, not ice melt. The ocean itself is, in fact, one very, very large thermometer! The thermal expansion is directly related to the increase of the enthalpy content of the ocean water as the Earth has re-warmed from the LIA and Dalton coldward fluctuations (whatever their proximate macroscopic/microscopic causes). It suggests a smoothly averaged steadily increasing global temperature that is utterly divorced from CO_2 as a proximate cause. It is also highly extrapolable. At 3 mm/year, a full century of continuation is a solid 30 cm of SLR, period. There is no statistically significant acceleration visible in the entire record, and the linear trend significantly predates the era where anthropogenic CO_2 might have contributed to it:
http://en.wikipedia.org/wiki/File:Trends_in_global_average_absolute_sea_level,_1870-2008_%28US_EPA%29.png
Yet state governments such as that of NC are being urged to plan for and spend money like water subject to the assumption of well over one meter of SLR over less than 90 years! The public is being warned of dramatic surges, flooding real estate, doom and destruction! Science papers, with carefully cherrypicked end points, seek to scry some sort of disaster from some small section of the 140 year long record, even though a glance suffices to reveal that global sea level has risen almost exactly nine inches over the last 140 years.
Surely there is enough time to discern any such intense and dramatic acceleration in SLR rate and act on a decadal time scale, in plenty of time to avert any real or imagined disaster. But the actual 140 year record is not interesting enough, and does not sell newspapers or air time on the television. It does not attract the votes of either eco-nuts or mere ordinary citizens who have a perfectly normal concern about their environment (or oceanfront real estate). It does not make anyone’s research career to report that SLR is behaving the way it was when Teddy Roosevelt was riding over San Juan Hill, back when the sun never set on the British Empire, and most importantly, back when the global population of humans was roughly one seventh what it is today, and almost entirely non-industrialized by modern standards, with no cars or airplanes and only a few countries and continents even linked by rail.
Nature has plenty of room for disasters. We could at any moment be hit by a gamma ray burst that sterilizes the entire planetary surface. An asteroid could fall and produce a real climate change catastrophe. A pandemic could start that wipes out six out of seven living people in five years. Yellowstone could erupt as a supervolcano, provoking environmental changes that wipe out half of the human race and a million species over a few years. And yes, we could still have a nuclear or nuclear/biological war that decimates the human race and alters the planet in profound ways. Several of these — the pandemic, in particular — are far more plausible than the CAGW scenario. Others are plausible (but unlikely) and if they happen there is damn-all we can do about them.
It is a shame that people spend — or rather waste — quite so much time and energy and money on the prospects of unlikely disasters, so much more so when there are so many far more constructive uses to which all three could be put to the betterment of both the human race and for that matter the environment.
Replanting the deserts, for example
rgb

Matthew W 6:17:
“They won’t lose any ground, it’ll just be piled higher!!”
Now that’s the difference between me and you educated blokes – I wouldn’t have thought of that 🙂

ExWarmist says:
September 16, 2012 at 5:25 am.
Note that humans were bottle-necked down to approx 3000 individuals in the last glaciation and almost died out.
Interesting.Got a link for that ,please.
And as for glaciation,no need to panic.We Canucks get it every year,but glorious AGW fights it off for us. :):)
And of course,any scientist worth more than a plugged nickel knows warm is good,cold is bad.

george e. smith says:
September 16, 2012 at 11:28 am
So Dr Svalgaard, before I read your reference (which I will),
Please do before commented too much
it occurs to me, that Dr Archibald’s assertion (that 65N insolation drives interglacial onsets),
This is not Archibald’s assertion, but that of Milankovitch, Koeppen, and Wegner back in the 1940s. And most of Archibald’s article is borderline wrong. E.g. if you look at his first Figure it should be evident that temperatures the next 30,000 years are heading up, not down.

Leif said, “no, you are wrong” I don’t think so or I wouldn’t have said it 🙂
Frankly, 45S to 65S would be the latitudes to watch most closely for glaciation. It wouldn’t take much of a reduction in solar forcing to increase the Antarctic sea ice which would reduce the efficiency of the circumpolar current. From there, all hell would break loss at both poles, but the tropical oceans would remain rather stable.
http://i122.photobucket.com/albums/o252/captdallas2/climate%20stuff/SouthernoceansSSTwithtanganyiuka.png
Working up from the southern oceans the Nielsen et al. southern oceans reconstruction with the Tierney et al. tropics (lake tanganyika surface temperature) shows a different picture of the thermal oscillations in the oceans.
http://redneckphysics.blogspot.com/2012/09/the-best-place-to-start-is-at-beginning.html
If you want a chuckle, I am looking at how longer term self organizing criticality can make “perfect” proxies of past climate rather easy to misinterpret. Since 40,000 years ago there were grass lands in northern Siberia, I am inclined to believe all glaciations were not created equally. The solar cycles provide a push, but need some help.