Guest post by David Middleton, featured image borrowed from Meadow Heights PTA.
Global warming caused by fossil fuel emissions is blamed by scientists for intensifying storms, raising sea levels and prolonging droughts. Now there’s growing evidence of a positive effect: we may have delayed the next ice age by 100,000 years or more.
The conditions necessary for the onset of a new ice age were narrowly missed at the beginning of the Industrial Revolution in the 1800s, researchers at the Potsdam Institute for Climate Impact Research near Berlin wrote Wednesday in the journal Nature. Since then, rising emissions of heat-trapping CO2 from burning oil, coal and gas have made the spread of the world’s ice sheets even less likely, they said.
“This study further confirms what we’ve suspected for some time, that the carbon dioxide humans have added to the atmosphere will alter the climate of the planet for tens to hundreds of thousands of years, and has canceled the next ice age,” said Andrew Watson, a professor of Earth sciences at the University of Exeter in southwest England who wasn’t involved in the research. “Humans now effectively control the climate of the planet.”
[…]
“However, our study also shows that relatively moderate additional anthropogenic CO2-emissions from burning oil, coal and gas are already sufficient to postpone the next ice age for another 50,000 years,” which would mean the next one probably won’t start for 100,000 years, he said.
“The bottom line is that we are basically skipping a whole glacial cycle, which is unprecedented.”
[…]
Words fail me. I won’t even bother to point out that we are living in an Ice Age which began back in the Oligocene…
Nor will I bother to point out that the current atmospheric concentration of carbon dioxide doesn’t even break out of the Cenozoic noise level…
By “ice age,” the author probably means “glacial stage”… The climate is barely warmer than the coldest period of the current interglacial stage…
The subject of the Bloomberg article is Ganopolski et al., 2016…
Abstract…
The past rapid growth of Northern Hemisphere continental ice sheets, which terminated warm and stable climate periods, is generally attributed to reduced summer insolation in boreal latitudes1, 2, 3. Yet such summer insolation is near to its minimum at present4, and there are no signs of a new ice age5. This challenges our understanding of the mechanisms driving glacial cycles and our ability to predict the next glacial inception6. Here we propose a critical functional relationship between boreal summer insolation and global carbon dioxide (CO2) concentration, which explains the beginning of the past eight glacial cycles and might anticipate future periods of glacial inception. Using an ensemble of simulations generated by an Earth system model of intermediate complexity constrained by palaeoclimatic data, we suggest that glacial inception was narrowly missed before the beginning of the Industrial Revolution. The missed inception can be accounted for by the combined effect of relatively high late-Holocene CO2 concentrations and the low orbital eccentricity of the Earth7. Additionally, our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1,000 to 1,500 gigatonnes of carbon will postpone the next glacial inception by at least 100,000 years8, 9. Our simulations demonstrate that under natural conditions alone the Earth system would be expected to remain in the present delicately balanced interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time.
They basically developed a model relating insolation to atmospheric CO2. If I am reading it correctly, they are asserting that insolation drives changes in atmospheric CO2 which then drives the glacial-interglacial stages.
Then they go on to say “that under natural conditions alone the Earth system would be expected to remain in the present delicately balanced interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time.”
So, it’s actually “worse than we thought”… Earth is naturally delicately balanced between a Late Pleistocene glacial stage and the Paleocene-Eocene Thermal Maximum. So, no matter what we do, George Carlin was right…
Is Brandon Gates paid by the word?
Do you ask because you do this on salary?
“Humans now effectively control the climate of the planet”
I did not bother reading past that sentence
These guys were trained in science?
In 50 years time how will lecturers describe this era? For weeks I have been trying to describe it in a nutshell. I am gobsmacked. When passion and warped agenda drives pragmatic thought and conclusion anything can result
The medieval inquisitions were no more shameful. We have all the tools to know so much better yet the same ignorance and lack of common sense prevails
Complete nonsense. Here are the facts.
a. The extension of the Holocene interglacial is due to orbital eccentricity being low. This prevents a precessional Great Winter after the interglacial Great Summer, so there is no great fall in insolation forcing. Instead the interglacial relies much more on obliquity, which is at a maximum at present, and the obliquity maximum lasts for 20 kys. And sontheninterglacial can extend – helped by Willis Eschenbach et al’s cloud thermostat system. The last time these events coincided was 400 kyr ago, and the interglacial was equally long – and that long interglacial had nothing to do with man’s emissions.
b. The reason there will be no ice age for another 100 kyr, is that eccentricity will remain low for the next 100 kyr, and so there is not going to be a precessional Great Winter for all that time. An ice age is initiated by a Great Winter, and is then continued by the growth of ice sheets and their high albedo. And it gets to a stage where even a subsequent Great Summer cannot melt the ice sheets, because their albedo is too high.
c. If man is beginning to effect the climate, it is more to do with industrial soot on the ice sheets (and possibly farming dust, when the fields are bare all winter). It is dust-ice albedo that controls the feedback of ice ages and interglacials, not CO2. So this proposal is wrong at all levels.
See Clive Best’s review of the dust albedo theory, as he sums it up quite succinctly:
http://clivebest.com/blog/?p=7024
Ralph
What amuses me is the assumption that deferring a new ice age is a BAD thing.
The good folks at the Guardian seem to have forgotten that during the last ice age most of Britain was covered in ice sheets upwards of a mile thick and the rump in the southeast was a polar desert rather like Northern Alaska or Siberia.
In North America the ice sheets covered virtually all of Canada and the Northern USA as far south as the Ohio river. Manhattan was buried under ice a mile thick. Glaciation also affected much of California and Oregon while much of the mid west was a desert/
Deserts around the world expanded enormously as dry conditions prevailed and sea levels dropped none of the modern sea going cultures would survive.
This would apparently be a Good Thing in Guardian Land.
To the eco-radicals, any change that is caused by man is bad.
So delaying an ice age is by definition bad, even if life on this planet would benefit by such a change.
The following comment in The Independent by Odin2 is well-written.
http://www.independent.com/news/2016/jan/11/phony-climate-claims/#comment-2454473297
Both of the satellite data sets (RSS & UAH v6) show that there has been no global warming in the past 18+ years despite increasing CO2 emissions during this period equal to 1/3 of the rise in CO2 since pre-industrial times. If CO2 emissions were a direct and significant cause of global warming, we would have experienced global warming during the 18+ year pause. We did not.
The satellite data (funded/maintained by the US government) is the most comprehensive and most accurate temperature data the US government has. RSS and UAH satellite data are crosschecked against each other and against balloon data sets and show remarkable consistency. RSS is maintained and operated by scientists who are Believers. The surface data is sporadic which requires substantial extrapolation (guesswork) to fill in the gaps, is less comprehensive, and is subject to the urban heat island effect and tampering. Even the surface temperature data shows only slight global warming during the last 18+ years which is substantially below the temperature projections of the IPCC’s climate models. A recent study shows that even the unperturbed NOAA surface stations have overstated US temperature data by as much as 50%. “Unperturbed” stations are stations that “have not been moved, had equipment changes, or changes in time of observations, and thus require no “adjustments” to their temperature record to account for these problems.”
There is no empirical evidence showing that humans (primarily CO2 emissions) are the primary cause of global warming since the start of the industrial age (AGW). In fact, studies show that temperatures change as much as 800-1000 years before CO2 changes. The effect cannot come before the cause. It is more likely that increasing ocean temperatures cause outgassing of CO2 from the oceans into the atmosphere so the Believers have it backwards. In any event, we all know that correlation does not prove causation.
The hypothesis that humans cause global warming (AGW) is not supported by empirical evidence and relies heavily on computer climate models which overemphasize CO2’s role in climate change and de-emphasize the role of clouds, solar cycles, ocean cycles, volcanoes, cosmic rays, changes in the earth’s orbit, and other natural causes of climate change. These computers have been notoriously wrong almost all of the time (when compared to real world data) and have been compared to a sports team that played the entire season without winning a game. Computers that model an imaginary planet and are programmed with guesses of a few of the many variables affecting climate are not data or empirical evidence. Ninety-five percent of the climate models relied upon by the IPCC failed to predict the 18 year and eight month pause and their projections of future temperatures during this period substantially exceeded the observed temperatures.
The outside atmospheric levels of CO2 are currently around 400 ppm. During the last ice age CO2 levels fell to 180 ppm and plants started to shut down. If CO2 levels had reached 150 ppm or lower, plants would have started to die off and all plant and animal life on the planet could have died. Green houses regularly keep CO2 concentrations at 1000-1200 ppm because the plants grow better. In the past, CO2 levels have been at several thousand parts per million and plants and animals thrived. US submarines try to keep CO2 levels below 8,000 ppm. Federal OSHA standards set CO2 maximums at 5,000 ppm. When you exhale, your breath contains more than 40,000 ppm CO2. The most predominant greenhouse gas is water vapor. In fact, 95% of the greenhouse effect is caused by water vapor.
We are much closer to being CO2 deprived than we are being threatened by too much atmospheric CO2. Plants thrive on more CO2- that is a good thing. CO2 is not a pollutant. It is a weak greenhouse gas that is colorless and odorless which comprises only .04% of the atmosphere (naturally occurring CO2 + CO2 emissions). CO2 emissions are only 3-4% of the total CO2 in the atmosphere. So, CO2 emissions make up only .0012 to 0.0016 % of the atmosphere. That is why blaming global warming on CO2 emissions is like having ‘the flea wag the dog’.
Climate change is natural and has been occurring since the formation of the planet. The 18 year and 8 month pause just proves that the skeptics were right all along-natural causes of climate change are more powerful than the insubstantial effects that human generated CO2 has on the world’s climate.
AGW is about power, politics and greed. Every time the facts change, the Believers move the goal posts . They have at least 66 excuses for the 18+ year pause in global warming and the failure of the computer climate models to predict it. The Believers blame any unusual (but normal) climate event on global warming with no scientific proof. This is often done with a scary picture or one that pulls on the heart strings, and the text of the article will say “could be caused”, “is consistent with”, or “may be caused by” global warming. This is code for we have no scientific evidence but we want to scare you so we can tax CO2 and promote our political agenda and profit from the AGW industry (which we must perpetuate at all costs).
The earth is estimated to be 4.5 billion years old and the climate has been changing most of this time. The relevant questions are how much global warming is caused by human activities (primarily CO2 emissions) and are the effects good or bad? The the lack of empirical evidence supporting AGW leads to the conclusion that any warming effect that CO2 emissions may have on climate is insubstantial and that the effects of global warming are largely beneficial. Increased CO2 levels are greening the planet. Even the West African Sahel is greening.
CO2 lags temperature at all measured time scales.
A few more thoughts below: Climate heresy now, but conventional wisdom in 10-20 years.
Regards, Allan 🙂
http://wattsupwiththat.com/2015/06/13/presentation-of-evidence-suggesting-temperature-drives-atmospheric-co2-more-than-co2-drives-temperature/
Observations and Conclusions:
1. Temperature, among other factors, drives atmospheric CO2 much more than CO2 drives temperature. The rate of change dCO2/dt is closely correlated with temperature and thus atmospheric CO2 LAGS temperature by ~9 months in the modern data record
2. CO2 also lags temperature by ~~800 years in the ice core record, on a longer time scale.
3. Atmospheric CO2 lags temperature at all measured time scales.
4. CO2 is the feedstock for carbon-based life on Earth, and Earth’s atmosphere and oceans are clearly CO2-deficient. CO2 abatement and sequestration schemes are nonsense.
5. Based on the evidence, Earth’s climate is insensitive to increased atmospheric CO2 – there is no global warming crisis.
6. Recent global warming was natural and irregularly cyclical – the next climate phase following the ~20 year pause will probably be global cooling, starting by ~2020 or sooner.
7. Adaptation is clearly the best approach to deal with the moderate global warming and cooling experienced in recent centuries.
8. Cool and cold weather kills many more people than warm or hot weather, even in warm climates. There are about 100,000 Excess Winter Deaths every year in the USA and about 10,000 in Canada.
9. Green energy schemes have needlessly driven up energy costs, reduced electrical grid reliability and contributed to increased winter mortality, which especially targets the elderly and the poor.
10. Cheap, abundant, reliable energy is the lifeblood of modern society. When politicians fool with energy systems, real people suffer and die. That is the tragic legacy of false global warming alarmism.
Allan MacRae, Calgary, June 12, 2015
http://wattsupwiththat.com/2015/12/15/voxs-david-roberts-consilience-or-just-plain-silliness/comment-page-1/#comment-2098864
This is the dCO2/dt vs. temperature relationship I was referring to above. See my 2008 paper at:
http://icecap.us/index.php/go/joes-blog/carbon_dioxide_in_not_the_primary_cause_of_global_warming_the_future_can_no/
or this plot:
http://www.woodfortrees.org/plot/esrl-co2/from:1979/mean:12/derivative/plot/uah/from:1959/scale:0.22/offset:0.14
There are several observations about this striking dCO2/dt vs. temperature relationship:
1. The dCO2/dt vs. temperature correlation is remarkably strong for a natural global phenomenon.
2. The integral (of dCO2/dt) is atmospheric CO2, and it LAGS temperature by about 9 months in the modern data record. CO2 also LAGS temperature by about 800 years in the ice core record. Thus CO2 LAGS temperature at all measured time scales. Thus the global warming hypothesis assumes that the future is causing the past. Thus the CAGW hypothesis fails.
3. This close dCO2/dt vs temperature relationship indicates that temperature drives CO2 much more than CO2 drives temperature.
4. The dCO2/dt vs. temperature correlation is the only detailed signal I have found in the data – there is NO evidence that CO2 LEADS temperature or that increasing atmospheric CO2 significantly increases global temperature.
5. Furthermore, global temperature declined from ~1940-1975, increased from ~1975-2000, and has stayed flat (or cooled slightly) since ~2000, all while atmospheric CO2 increased; so the correlation of temperature to increasing atmospheric CO2 has been NEGATIVE, Positive, and Near-Zero. I suggest Near-Zero is the correct estimate of the sensitivity (ECS) of global temperature to increasing atmospheric CO2. There is and never had been a manmade global warming crisis – there is no credible evidence to support this failed hypothesis.
6. With few exceptions including some on this blog, nobody (especially the global warming alarmists) wants to acknowledge the LAG of CO2 after temperature – apparently this LAG of CO2 after temperature contradicts deeply-held beliefs about global warming dogma.
7. While basic physics may suggest that CO2 is a greenhouse gas, the overwhelming observational evidence indicates that the impact of increasing CO2 on global temperature is so small as to be insignificant.
8. In summary, observational evidence strongly indicates that the manmade global warming crisis does not exist.
9. Finally, atmospheric CO2 is not alarmingly high; in fact, it is dangerously low for the survival of terrestrial carbon-based life on Earth. Plants evolved with about 2000ppm CO2 in the atmosphere, or about 5 times current CO2 concentrations.
10. In one of the next global Ice Ages, atmospheric CO2 will approach about 150ppm, a concentration at which terrestrial photosynthesis will slow and cease – and that will be the extinction event for all terrestrial life on this planet.
11. More atmospheric CO2 is highly beneficial to all carbon-based life on Earth. Therefore, CO2 abatement and sequestrations schemes are nonsense.
12. As a devoted fan of carbon-based life on this planet, I feel the duty to advocate on our behalf. I should point out that I am not prejudiced against other life forms. They might be very nice, but I do not know any of them well enough to form an opinion. 🙂
Regards to all, Merry Christmas, Happy Holidays!
– Allan
You’re welcome Third World.
Yawwwwwn.
*Chuckle* — How exactly does he know that ‘skipping’ an ice age is ‘unprecedented’?
PIK…..end of interest.
They built a formula which more-or-less makes an assumption about CO2 sensitivity and then how the Milankovitch cycles vary and they construct a tipping point regime.
“The critical summer insolation at 65° N can be described as S = α ln([CO2]/280) + β, where α = −77 W m−2 and β = 466 W m−2 and [CO2] is the concentration of CO2 in parts per million.”
the −77 W m−2 ln(CO2/280) is just a variant of the CO2 sensitivity; and,
+ 466 W m−2 is just a variant of how summer solar insolation varies at 65N.
http://nature.com/articles/doi:10.1038/nature16494
I’ve said before that the tipping point is really when the summer solar insolation at 75N falls below 440 W m -2 which is the point where the Sun doesn’t have enough strength to melt the snow.
But the formula does NOT work once CO2 is over 280 ppm. I mean really. Any CO2 level over 280 ppm would cause an ice age using this formula.
= -77 * ln(400/280) + 466 = 438 W m -2
= -77 * ln(240/280) + 466 = 478 W m-2 (this is what they say was their tipping point – except when CO2 goes over 280 ppm, the formula goes the other way and starts producing lower solar insolation numbers – it only works when CO2 is below 280 ppm).
Climate scientists are bad at basic math.
“we may have delayed the next ice age by 100,000 years or more”.
In short – no we did not.
It will come and it will be catastrophic.
And not like the “Globul Worming” catastrophy. For real.
However, when the ice age is over in about 100,000 years, CO2 induced warming will take off with a vengeance.
With the track record of AGW hypester predictions, we should now become seriously concerned about an abrupt change to rapid glaciation.
This report loses it with the false assertion about storms becoming worse.
The current interglacial is ending. Nothing can stop it.
http://www.scottcreighton.co.uk/images/Spiral-Precession/Glacial_eras.jpg
It’s time for whites to abandon Europe and N America and build a new empire in warmer lands:
*Whites congregate in Oz and build an aqueduct from New Guinea supplying 300 million people
*They then conquer islands and peninsulas throughout the world with nice climates
*The Arabian Peninsula is taken to get back our oil and checkmate Islam
http://i.imgur.com/IwbuVZJ.png
Stick it in your bottom numbnuts!
Numlock
Yes I also remember playing the board game Risk in my youth – whoever got Australia usually went on to win the game.
It’s easily defendable and a good springboard for conquest. At least if the rules are simple.
But… but… but… won’t this make the polar bears unhappy?
So, according to the “study” we can expect the Holocene to turn out to be a 120,000 year inter-glacial. Hmmm, the average length of inter-glacials for the past million years was about 12,000 years. What a powerful master control knob of climate that CO2 is. Too bad it couldn’t make the world warmer for the past 18 years even though it has been steadily increasing in our atmosphere. Darn those natural factors that get in the way of this master control knob of climate.
FJ
Putting it in those terms makes it clear that it is nonsense. Stepping back and getting the bigger picture is always useful. What is the bigger picture of our current glaciation? Starting 3 million years ago, shallow glacial cycles 40 kyrs long then the MPR then deeper cycles 100 kyrs long. The pattern is clear – deepening glaciation.
In this context talk of effectively the abrupt end of glaciation is shortsighted and wrong. No – the next transition somewhere up ahead is not the end of glaciation but the end of interglacials and permanent, possibly global “snowball earth” glaciation.
The earth is doing now what it does every 150 million years as we orbit the galaxy with that period: entering a deep glaciation. Probably all such periods start with a transition phase of oscillation between glaciation-interglacials.
Good times!
And for our next stunt we shall stop the tides from rising.
An excerpt from a page on the film “Revenant” starring Leonardo Di Caprio:
Some of the filming occurred near Calgary, where unpredictable chinook winds have produced spring-like conditions in the dead of winter for as long as weather has been recorded. Evidently unaware of these chinooks, DiCaprio attributed a sudden thaw to the unprecedented effects of global warming, much to the the amusement of locals and Canadian media.
http://www.imdb.com/title/tt1663202/trivia?ref_=tt_trv_trv
Some of the filming for the film “The Revenant” occurred near Calgary, where unpredictable chinook winds have produced spring-like conditions in the dead of winter for as long as weather has been recorded. Evidently unaware of these chinooks, DiCaprio attributed a sudden thaw to the unprecedented effects of global warming, much to the the amusement of locals and Canadian media.
http://www.imdb.com/title/tt1663202/trivia?ref_=tt_trv_trv
What are you saying?
As a good gullible, Leo is prepping for a career as a Climatologist?
You have to admit, in that instant he portraits the Alarmed Ones Idiocy perfectly.
And here I thought he could not act.
Look back at the start of the last ice age. By 114,000 years ago, the Eemian interglacial is over and the planet is already half-way into the extreme cold of an ice age, temperatures have dropped by -2.5C globally already. Solar insolation is reaching its deepest downturn part of the Milankovitch (the rose shaded area). This is basically as deep as the solar insolation gets at 65N. Only twice in the last 1,000,000 years was it slightly lower than this.
ie, 114,000 years ago, the ice age has fully started and it is on. Albedo has already increased from 29.8% to 32.0%. The glaciers are already moving south. Sea level has already fallen by 50 metres.
CO2, on the other hand, is still at 275 ppm ???? No trigger here. It does not fall to the magic 240 ppm until 5,000 years later.
http://theinconvenientskeptic.com/wp-content/uploads/2012/01/Chap_6-Illustration_45.png
Because global temperatures are albedo driven. And also driven into an interglacial by a similar albedo process. The ice needs to be covered in dust, before an interglacial can be initiated.And it taked some 60 kyrs of cooling, before the dust can be created.
R
Exactly what I was going to post Bill, and look how fast Greenland dropped:
http://s8.postimg.org/5oikhqhad/New_Neem_Temps_vs_NGRIP_Antarctica.png
Interesting. The present interglacial hasn’t declined as much as the previous, as we’re already at/near the precessional min for 65N insolation. Granted, temps from the Holocene Optimum have declined a bit, but not as much. Would you attribute that difference to the current low cyclicity of the present 65N insolation minimum?
Brandon Gates
January 13, 2016 at 8:39 pm
“… according to them, net longwave at the surface is a 63 W/m^2 loss on average, whereas evapotranspiration accounts for a 80 W/m^2 loss from the surface.”
Fig.1 of Trenberth, Fassulo and Kiehl is wrong. Only the net transport of heat from surface to space is important: Thermals 17, evotranspiration 80, and radiation 356-333 = 23 W/m^2. The radiative transport from surface to atmosphere actually is a mixed transport because thermalization in the atmosphere is involved. Pure radiative transport is the transport via the atmospheric window 40/239 = 0.17.
Paul Berberich,
In the strictest sense that it’s a globally-averaged estimate based on uncertain observation, I agree with you. In the sense that temperature experienced at the surface is a function of net fluxes at the surface, I do not agree with you.
If we’re trying to figure out net energy gain/(loss) from the entire system, it’s 341 incoming solar – 102 reflected solar – 239 outgoing longwave at TOA, which is zero. Since that diagram shows 0.9 W/m^2 at the surface, there should be a positive value at TOA. It’s annoying that there isn’t; I suspect that this is what happens when one draws figures using whole numbers where tenths are significant.
If we’re trying to figure out what’s going on in the troposphere:
Were it not for rounding error again, that could explain UAH and RSS TLT ….
Anyway, the main point is that for any given layer in that diagram, the values should just about net zero for an “equilibrium” or “steady state” climate, and they just about do.
No dispute there, however the cartoon would get pretty cluttered if they’d attempted to represent any more layers of atmosphere. My minor gripe about rounding errors aside, I think the way they drew it is just fine.
Brandon Gates,
“In the sense that temperature experienced at the surface is a function of net fluxes at the surface, I do not agree with you.”
My point of view: on the average the heat flux from surface to space is a constant. At the surface it is mainly due to convection and evaporation. The radiative transport steadily increases with height, and the others decrease. It is difficult to calculate the contributions of the different channels because they are interconnected. For instance, evaporation needs convection as everybody knows. When the radiative transport in the atmosphere decreases due to increasing CO2 concentrations, the other transport channels do not remain constant. In this respect, I think that the Figure of Trenberth et al.. is misleading.
I remember this clearly from The Great Global Warming Swindle. They had footage from a late 60s early 70s interview where they asked some “expert” what we could do about the obviously coming Ice Age (ha ha), and the response was “we could increase our CO2 output, and delay the onset for a while”.
just three words to answer this claim:
Laughing Out Loud
like if we as humans could do that
It is good to see that someone else has glommed onto this issue. It isn’t that I have any illusions about the efficacy of CO2 as a GHG, The fascinating aspect of this is how thoroughly the issue of “when we live” when integrated with the alarmist view of CO2 utterly eviscerates the argument about what to do about CO2.
See:
http://wattsupwiththat.com/2012/03/16/the-end-holocene-or-how-to-make-out-like-a-madoff-climate-change-insurer/
for my now 4 year old take on this subject.
You see, if alarmists are absolutely right about the insulating properties of CO2, then the one absolute thing you would not even deign to consider is removing said climate security blanket from the late Holocene atmosphere. You might just get the tipping point you fret about, but of the opposite sign to the one expected.
You see, it’s like this. As of 2016, the Holocene is 11,719 years old (+/-99 years). So what?
(https://www.researchgate.net/profile/Anders_Svensson3/publication/251435280_A_new_Greenland_ice_core_chronology_for_the_last_glacial_termination/links/0a85e53c7c1255ff78000000.pdf)
Well, since the Mid Pleistocene Transition, some ~800,000 or so years ago, there has been only 1 interglacial that lasted beyond about half a precession cycle. The precession cycle varies between 19kyrs and 23kyrs, and we are at the 23kyr part right now, making 11,500 half.
So we have a 1 in 8 chance of the Holocene going long like MIS-11 did and MIS-19 did not. Those being the other 2 post-MPT interglacials that have also occurred at an eccentricity minima, which we are also at once again.
But once again we are assaulted with models and models. Having written tons of geophysical and hydrogeological modeling codes since the late 1970’s, I do not have a particularly favorable view of models, particularly GCMs. Look at any of the spaghetti plots of model runs versus the satellite data (the surface data is a horrid mess, thanks to Anthony et al’s efforts). But I take particular exception of Berger and Loutre’s 2-dimensional, medium complexity late 1990’s runs of CLIMBR2 and the prediction of “An exceptionally ling interglacial ahead?” This was roundly and soundly eviscerated with actual data from 57 globally distributed deep ocean sediment cores published in a landmark paper (meaning oft-quoted and cited) published in 2005 by Lisiecki and Raymo. The operative quote being:
“Recent research has focused on MIS 11 as a possible analog for the present interglacial [e.g., Loutre and Berger, 2003; EPICA community members, 2004] because both occur during times of low eccentricity. The LR04 age model establishes that MIS 11 spans two precession cycles, with 18O values below 3.6o/oo for 20 kyr, from 398-418 ka. In comparison, stages 9 and 5 remained below 3.6o/oo for 13 and 12 kyr, respectively, and the Holocene interglacial has lasted 11 kyr so far. In the LR04 age model, the average LSR of 29 sites is the same from 398-418 ka as from 250-650 ka; consequently, stage 11 is unlikely to be artificially stretched. However, the June 21 insolation minimum at 65N during MIS 11 is only 489 W/m2, much less pronounced than the present minimum of 474 W/m2. In addition, current insolation values are not predicted to return to the high values of late MIS 11 for another 65 kyr. We propose that this effectively precludes a ‘double precession-cycle’ interglacial [e.g., Raymo, 1997] in the Holocene without human influence.”
http://courses.washington.edu/proxies/Lisiecki_Raymo-d18O_Stack-Pa05.pdf
The failure to recognize this suggests only a surficial treatment of this subject by the authors of this new paper. Having said that I do applaud the fact that at least somebody, other than me it often seems, gets this issue.
In 1998, Wallace Broecker, arguably the father of modern paleoclimatology, published a paper intended to stimulate discussion of the issue of interglacial length. In it he posed 3 eminently reasonable questions:
(1) Were previous intervals of peak interglaciation terminated by abrupt global coolings?
(2) How close are we to the end of the present interval of peak interglaciation?
(3) Will the ongoing buildup of greenhouse gases alter the natural sequence of events?
Answers:
1. Yes, intervals of peak interglaciation were indeed terminated by abrupt coolings.
2. As it turns out, we are either due or overdue for glacial inception right now.
3. But it is his 3rd question that exposes the Achille’s Heel of the AGW argument.
Details for Question 1:
“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
“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
“For example, Lunt et al. [2008] suggest that the growth of Northern Hemisphere ice sheets can be triggered if atmospheric CO2 levels fall below a threshold of 400 ppmv. Thus, this value could have important implications for the timing of the next glacial inception.”
http://www.soest.hawaii.edu/oceanography/faculty/zeebe_files/Publications/UchikawaZeebe08.pdf
I have already covered Question 2 above, operative number being 11,719.
But we certainly got a very good discussion going related to Broecker’s 3rd question in the form of Ruddiman’s 2003 Early Anthropogenic Hypothesis, the most concise description of which is to be found in Mueller and Pross’ 2007 conclusions:
“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.”
http://folk.uib.no/abo007/share/papers/eemian_and_lgi/mueller_pross07.qsr.pdf
If you want to get right into the meat of it, may I suggest Tzedakis’ 2010 thorough analysis of MIS-1/MIS-11/MIS-19 and the Early Anthropogenic Hypothesis:
http://www.clim-past.net/6/131/2010/cp-6-131-2010.pdf
So you see, it isn’t so much if the warmista’s are wrong about the efficacy of CO2 as a GHG, the far more intriguing question is “What if they are right?” Because if the climateers are right about CO2, then they could not possibly be more wrong about what to do about it here at the now 11,719 year old Holocene.
Meanwhile, enjoy this precious little interglacial, while it lasts……..