A challenge for climate models

Should we bet the future of the world’s economy based on AR5 projections of future climate change?

The earth’s climate has been dominated by a series of glaciations for the last 3 million years. For the last 800,000 years  brief warm interglacial periods have coincided with maximum eccentricity of the Earth’s orbit on a 100,000 year cycle. These swings in climate are far more intense than any recent global warming – figure 1. 

Figure 1: from  Climate4you: Reconstructed global temperature over the past 420,000 years based on the Vostok ice core from the Antarctica (Petit et al. 2001). The horizontal line indicates the modern temperature. The red square to the right indicates the time interval shown in greater detail in the following figure.

Figure 1: from Climate4you: Reconstructed global temperature over the past 420,000 years based on the Vostok ice core from the Antarctica (Petit et al. 2001). The horizontal line indicates the modern temperature.

IPCC scientists remain confident that their models accurately explain global warming. We read in D.1 in the SPM : “Observational and model studies of temperature change, climate feedbacks and changes in the Earth’s energy budget together provide confidence in the magnitude of global warming in response to past and future forcing.”

So I have a simple challenge for the modelers to prove this claim. If they are so confident in their models then  they should also  be able to accurately reproduce the dynamical changes in climate that occurred during the last 100,000 year glacial cycle in response to orbital forcing. The Milankovitz cycles are known exactly,  as are past CO2 levels extracted from ice cores. Therefore it should be straightforward to run the models over the past 120,000 years and reproduce the trends observed over the last ice age period. It is in fact the ultimate hindcast.

Modern GCMs  include  “sophisticated” models of the cryosphere including ice melting and  albedo feedbacks. They also model the atmosphere/ocean circulation, water and carbon cycles and  associated feedbacks.  These same  models  then “project” future anthropogenic global warming. So exactly just how well can they also reproduce  orbital forcing of ice ages ?

Currently models  normally are run an a time interval of one day which follow  the seasonal insolation based on   current Earth’s orbital parameters. Projections for AGW are typically  run for periods  up to 100 years based on CO2 emission scenarios and other anthropogenic effects.

However modeling past climates is different. To simulate glaciations model  runs over 500,000 years including Milankovitz forcings are needed. This could probably  be done  by making a yearly run once every 1000 year interval and adjusting the orbital parameters acordingly.  I wonder if this has this ever been tried ? As far as I know the models are unable to predict the dynamics of the glacial cycle, although static runs have been made at  the  last glacial maximum (LGM) and correctly explained energy balance, but that is not the same as describing the dynamics of glaciation.

So in my opinion we should remain sceptical about future warming projections until they can  also reproduce past glacial glacial cycles. Despite this AR5 authors state essentially that without  human CO2 rises they would be able to predict the next glaciation as follows.

5.8.3 Next Glacial Inception

Since orbital forcing can be accurately calculated for the future (see Section 5.2.1), efforts can be made to predict the onset of the next glacial period. However, the glaciation threshold depends not only on insolation but also on the atmospheric CO2 concentration (Archer and Ganopolski, 2005). Models of different complexity have been used to investigate the response to orbital forcing in the future for a range of atmospheric CO2 levels. These results consistently show that a glacial inception is not expected to happen within the next approximate 50 kyr if either atmospheric CO2 concentration remains above 300 ppm or cumulative carbon emissions exceed 1000 PgC (Loutre and Berger, 2000; Archer and Ganopolski, 2005; Cochelin et al., 2006). Only if atmospheric CO2 content was below the pre-industrial level would a glaciation be possible under present orbital configuration (Loutre and Berger, 2000; Cochelin et al., 2006; Kutzbach et al., 2011; Vettoretti and Peltier, 2011; Tzedakis et al., 2012a). Simulations with climate-carbon cycle models show multi-millennial life-time of the anthropogenic CO2 in the atmosphere (see Box 6.1). Even for the lowest RCP 2.6 scenario, atmospheric CO2 concentrations will exceed 300 ppm until the year 3000. It is therefore virtually certain that orbital forcing will not trigger a glacial inception before the end of the next millennium.

So why don’t they simply explain the previous glaciation starting 100,000 years ago when there were no CO2 emissions? There are accurate data regarding the changes in insolation in magnitude and with latitude. My calculations of changes in net polar insolation are shown in figure 2.


I previously analyzed the Ice Age cycles by fitting them to a combination of the precession signal, the obliqueness signal and the elipticity signal. These results  shown  in figure 3 allow an extrapolation forward in time to predict the next ice age.

Next Ice Age due to start in 5000 years time.

Fig 3: Next Ice Age due to start in ~1000 years time.

The current glacial cycle has similar orbital parameters to the one occuring 5 glaciations ago. That interglacial warm period lasted 10,000 years or about the length of the current one. We are due for another ice age.

Detail of near term climate

Detail of near term ‘climate change’

We forget how short human history really is. Homo Sapiens evolved in the African Rift valley only 200,000 years ago during the previous glaciation. Ice ages have driven human evolution and the consequent migration out of Africa. At the last glacial maximum (LGM) most of northern Europe and North America lay under Ice glaciers. During the last glaciation the Sahara desert was grasslands and humans migrated north first to the middle east and then along the coast to Asia eventually reaching Europe, Australia and North America. Essentially humanity spread across the world during the last glaciation in a race for survival. Civilization only developed during the last 10,000 years warm inter-glacial period. Life flourishes in warm climates rather than cold climates !


Full size map (curtesy of National Geographic)

If climate models eventually succeed to hindcast past glacial cycles then I will willingly accept their ability to project anthropogenic global warming and its impact on future glacial cycles. Perhaps by then global warming will turn out to be our savior and we will need to keep CO2 levels above 400ppm just to avoid another devastating glaciation.

About Clive Best

PhD High Energy Physics Worked at CERN, Rutherford Lab, JET, JRC, OSVision
This entry was posted in Africa, AGW, Climate Change, climate science, GCM, Ice Ages, Oceans, Science and tagged , , , , . Bookmark the permalink.

20 Responses to A challenge for climate models

  1. DrOli says:

    Dear Clive

    It is fundamentally impossible to model the climate. This is not opinion, it is a fundamental property of the universe. Dynamical systems which we refer to as “fundamentally unstable phenomenon”, such as the climate, financial markets, even lava lamps … defy predictability almost as their raison d’etre. This is written into the fabric of the cosmos; it makes no difference whatsoever how many math geeks or supercomputers you throw at it.

    … incidentally, as prediction is impossible, so is climate policy, since there cannot be any (sensible) policy on anything that is not predictable, or worse, where we cannot predict the consequences of our actions (aka the Law of Unintended Consequences).

    Astonishingly, you don’t even need to know anything about non-linear dynamics or partial differential equations to prove this for yourself … you just need one word: volcanoes. I have written a four page no-equations note that demonstrates the fallacy of the IPCC models … using their own results … see here (http://www.thebajors.com/climategames.htm). It includes some appendices for those also interested in a down-to-earth explanation of the pathology in the mathematics.

    Regarding long dated back-testing: It is relatively easy for them to fudge long-dated back-tests to arrive at results that “appear convincing”. Indeed, given the long term periodicities, long-dated back-tests may actually “look” better compared to short dated ones, which are more pronounced aperiodic (and thus pretty much impossible) problems.

    However, a more compelling reason why the IPCC will likely not put too much money into long-dated back-tests is due to politics/sociology. The entire point of the IPCC “predictions” (such as they are) is not to for-tell the future, but to scare the Hell out of the voters/taxpayers. Long-dated back-tests occur on time scales that are “outside” of the human psyche. To make these “socio” fear-mongering tactics work, the time scales have to be quite short (e.g. 10-50 years) … otherwise nobody cares. The clever, albeit evil, recent innovation by the IPCC et al has been the trick to say its 100 years out, but it has momentum which must be stopped now (get it, make a ridiculously long term forecast that nobody can prove, but use a trick to imply closer urgency ).

    In any case, it is unfortunate that most people would not bother to scratch the surface on these issues, and are willing to accept rhetoric … especially when one of their other famous tricks is used … make everyone believe they are too stupid to understand, and that they must knuckle under to the “IPCC experts” … bizarrely, everybody is “way smarter” than they need to be, to prove for themselves … if took just a few minutes.

    • Clive Best says:

      Dr Oli,

      I agree that it is impossible to completely model the climate in the same way that you can’t model turbulence. The atmosphere and oceans are a massive heat engine with energy flowing through the system in partly chaotic ways. The great red spot on Jupiter seems to be a storm system lasting 1000s of years and evolving slowly. Similar long lived ocean swirls exist on Earth and no model takes any of this into account.

      All models can do is to compartmentalize problems – evaporation, carbon cycle, clouds, precipitation, Echmann forces, convection etc. and then invent a parameterization which can be coded onto a computer. These then allow the model to run and the modeller to say they model cloud formation, snow, ice melting etc. However they haven’t really done that at all. They have made a very rough approximation to reality.

      I agree with your cynical view of the sociology behind the IPCC reports and the importance of them to whole the climate/green lobby to keep the wagon rolling along. Their livelyhoods depend on it. They have some interesting bed-fellows like investment banks, landowners and energy companies who see billions of dollars of tax money up for grabs.

      For that reason they do not wish to highlight the fact that they can’t explain the dynamics of ice ages. I am sure they have tried to do this and failed. Better to stick to AGW.

      • DrOli says:

        Cheers for that. In fact one may consider any of the other many and crucial matters omitted from the IPCC style models, each of which is sufficient as a show-stopper. The list is long, but for example: water vapour, tectonics, sun cycles, etc etc. However, of particular importance is the “big picture” point I make at the end of this passage, since models do not exist in isolation but are “coupled” to their intended use/objective(s).

        One of my favourite points is that although even the IPCC admits Water Vapour (WV) is by far the most important GHG (on the order of 15 times more powerful GHG), there is essentially NO data for water vapour histories. Even the few decades of radiosonde data is disputed by the IPCC, and they insist their models must be used in place of reality.

        I wonder how the entire CC “perspective” would develop if we had WV histories going back a few million years (a la the CO2/Temp reconstructions). The “correlation/statistical modelling” approach used by some to imply “causality” of CC by CO2 is highly suspect. Amongst other things, multidimensional problems can be very easily misunderstood (or in this case, abused). A simply illustration of this type of “trap/abuse” is provided near the end of this doc (http://www.thebajors.com/Downloads/Climate%20Science%20and%20Telephone%20Polls%20v0o.pdf), which uses an easy to understand “coffee consumption/health” example to demonstrate “embedding dimension traps”. I have posted some “sister” notes to that doc here (http://www.thebajors.com/climategames.htm) for a down-to-earth explanation of mathematical modelling and pathology in the mathematics (very few equations, lots of pictures).

        In short, there are a huge number of crucial omissions from CC models. Any of which is a show-stopper. As noted many times, the (necessary) omission of volcanoes on its own spells death for climate models.

        However, and to nail this issue conclusively, of critical importance is not only the reliability of the forecast, but also the “big picture objective” of the forecast. The entire IPCC et al process aims to completely alter civilisation as we know it. That is a tall order, and forces unimaginable costs and risks. Thus, the degree of reliability/accuracy required (necessary) for a forecast to deal with that objective must be to a very high standard indeed. For example, based on the doom & gloom scenarios by the IPCC et al, the forecasts MUST have a reliability of at least +/-0.25C/100years, or thereabouts. We know with certainty that volcanoes on their own introduce on the order of 2 – 3C/100 years variability, and of course they are completely unpredictable. Thus, on that one point alone the IPCC forecast are “complete and utter nonsense”, as there is no chance whatsoever that the models can achieve any reliability anywhere near that required (indeed, their models were about 0.5C wrong on just the last 15 or so years, which scales to an error MUCH bigger than 3.5C/100 years).

        To add insult to injury, even if a reliable temperature forecast was (remotely) possible (which it is not), even then there would be NO way to deduce from temperature etc what the implications would be for man-kind/the planet. For example, the last 100 years during which the planet warmed approx 0.7 C, has witnessed the greatest increase in global/human welfare in recorded history. If that’s what the next 100 year’s of warming causes, then “bring it”.

  2. I just found a paper published back in 2002 which makes a strong case that glacial-interglacial cycles are primarily due to a ~100,000 year solar activity cycle rather than Milankovitch cycles, which suffer from the so-called 100,000 problem.


    • Clive Best says:

      Thanks. That is a very interesting paper.

      It makes me think of another possibility. The 100,000 year (and 400,000 year) cycles in the Earth’s orbital ellipticity are caused by the gravitational influence of all the planets and the sun throughout the solar system. Each planet performs a kind of slow motion dance about the ecliptic plane.

      So what effect does all this have on the sun ? The Sun’s plasma is being moved around by the net gravitational forces of all the planets as they evolve through their synchronized orbital variations. Is it any surprise then that solar activity follows the same patern ?

      No-one has yet been able to explain the 100,000 year cycle although many have tried.

  3. Euan Mearns says:

    Clive, its not every day you meet someone who says:

    My calculations of changes in net polar insolation are shown in figure 2.

    And your conclusion is rather chilling.

    Next Ice Age due to start in ~1000 years

    I’ve heard a number of different takes on this – who to believe?

    A couple of quibbles. For us geos time always passes from left to right, and high temperature is usually up. Your figure of d18O v Milankovitch would be easier to understand plotted thus. And I’m with Murray Salby on CO2 from ice cores – it is proxy CO2 not actual. This is particularly important in Vostok where it takes 1000 years to convert surface snow to ice – with much diffusion going on in firn and between firn and atmosphere in-between.

    @ Hockey – it has always bemused me how the current crop of climate analysts are happy to take 30 years measurements of our Sun and to assume that this captures all possible variability. It is naive in the extreme.

    • Clive Best says:

      Hi Euan,
      For the last million years all interglacials have lasted about 10-12,000 years. We are already 10,000 years into the current one. The last time the orbital parameters were similar to now was 400,000 years ago . That one lasted just about 12,000 years so there is no reason to suppose this would be any different. Only if CO2 really does play a pivotal role in glaciations would the big freeze be delayed. Let’s hope so !

      Yes – sorry about the negative time axis. All the data on sea bed cores has ‘years before present’ as the x-axis. That is why they get plotted against inverse time. I should really invert it.

      • Euan Mearns says:

        Clive, I’ve now read your earlier post on “Phenomenology of Ice Ages”. This is incredibly interesting stuff! I’ve learned stuff here I didn’t know about before. Starting with something happened this last 5 million years to make Earth’s climate much more sensitive to orbital cycles. My gut feel is that closing Panama Isthmus and creating the gulf stream is most likely cause, but it is also likely to be a combination of events.

        I’d note that the most recent cycle (on your figure 1 in Phenomenology) is anomalous, but going 5 cycles back the same thing happened.

        The other big new for me here is the LR04 benthic foram stack. That’s incredibly important since as you point out it’s global and its mean ocean temperature (± variance in d18O in ocean water). It presents a different picture of the Holocene to Vostok where the latter paints a picture of stable temperature for 10,000 years. LR04 shows continued warming, albeit at a slower rate from the glacial rebound. A post aimed at placing a torpedo in the Ocean Heat debate is overdue;-)

        In the last chart of your Phenomenology post you say “Next Ice age Due to Start in 5000 years” while in this one you say 1000 years. It looks like we are right on the turning point – no need to spread panic, but 1000±1000 is a tad more scary than 5000±1000. Has anything happened to cause you to update your view on this?

        • Clive Best says:

          Thanks Euan,

          The ice ages are still a mystery. They are a global phenomenon and not restricted to high latitudes. Global temperatures swings vary by up to 8C and sea level changes by 100s of meters. Yes I think that the LR04 stack is more important than Vostok as it represents global temperatures extending back 5 million years to give a complete picture of the evolution of the Earth’s climate.

          Milankovitz theory for Obliquity and Precession works reasonably well and correctly follow early glaciations until about 800,000 years ago . Since then Milankovitz fails to explain why glaciations then switched to a primary 100,000 year elipticity cycle. Something happened – a meteor impact or some other astronomic event. This is one idea I had – but I no longer think it works as there is no signal in TSI.

          Yes the current glaciation has similar orbital parameters to the one 400,000 years ago. Therefore we can expect another cooling phase to begin relatively soon. What I am really saying is that within about 1000 years a cooling phase will probably have begun. This will be a very gradual process so that 5000 years from now temperatures will have fallen a couple of degrees and glaciers will have started spreading across northern latitudes. 50,000 years later conditions will have returned to those experienced by early man during the LGM.

          One other point. I find the ocean heat content story rather strange. Basically all that we can measure is the temperature profile of the oceans. It turns out that the claim of huge heat content increases of 10^23 joules of energy in the top 700m of ocean corresponds to a temperature rise of 0.15C !

          I doubt whether the ARGO buoys in the ocean can even measure temperature changes to an accuracy of 0.1C !

          • Euan Mearns says:

            One other point. I find the ocean heat content story rather strange. Basically all that we can measure is the temperature profile of the oceans. It turns out that the claim of huge heat content increases of 10^23 joules of energy in the top 700m of ocean corresponds to a temperature rise of 0.15C !

            I doubt whether the ARGO buoys in the ocean can even measure temperature changes to an accuracy of 0.1C !

            This is what I suspected. Given that oceans are stratified vertically with respect to temperature and salinity which also show vast variance laterally and it is a dynamic system, I’d say there is zero chance that a 0.15?C rise in temperature could be measured with any confidence for the whole 700 m layer. How many ARGO buoys are out there, how long they been there and do they measure T at different depths?

            Been looking a bit at the LR04 stack. The data are reported with resolution of 1000 years. Its interesting to note that the lowest d18O (warmest temp) was 2000 years ago – Roman times! Though it is not significant compared to the analytical uncertainty. Have you any idea how many data points they have in the Holcene?

  4. A C Osborn says:

    It is also naive to believe that more CO2 causes Global Warming and is not either neutral or causes Global Cooling.
    It has certainly been proved to cool the upper atmosphere.

  5. Hi Clive and guests,

    I was wondering to get someone’s take on my insight here: I have seen the graph many times on the area of Arctic Ocean Sea Ice coverage versus the time spaced out in months. Using that graph, here is my insight. http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

    The Arctic Ocean is an ocean locked in by continents; as a consequence, it is effectively isolated from the influence of warmer ocean waters. This means that most the freezing and melting that occurs in the Arctic Ocean is due to heat exchanged between the atmosphere and the water, or because the water radiates much of its heat directly into space. If you look at the rate of freezing on the right (Sept.-March), and the rate of thawing on the left (March-Sept.), you can see that the freezing rate is obviously much more steep than the melting rate. This would imply that the atmosphere must be able to take the heat away at a faster rate and that also a significant amount of heat loss from the ocean must occur through radiation loss of heat via heat waves radiating into outer space. It seems that the anthropogenic greenhouse effect may not be as significant as is hypothesized. I am particularly interested in the orange curve that takes place on March 1st to March 3rd. That is 6 hundred thousand km^2 of ice formed in just 3 days. My goodness, heat is being taken away at an incredible rate. Where does it go? It can only go from hot to cold; since the atmosphere in the Arctic has a colder temperature than the air over the rest of the Norther Hemisphere, the heat exchange of the air is driven by convection, it will serve to cool those warmer areas and not warm them up. Another possibility is that heat could radiate into outer space; but then CO2 in the air is supposed to be inhibiting that. I hope people understand that the science explaining the current climate change model is just not accurate!

    • Clive Best says:


      During winter the Arctic receives no solar energy. Convection essentially stops as the surface temperature falls. This short-circuits the lapse rate and I think eventually the troposphere can shrink to nothing and the stratosphere touches the surface. Such an event may explain the rapid freezing of the Arctic in a few days at the beginning of March. In this case CO2 “warming “is completely irrelevant. I would go so far as to say that the greenhouse effect goes into reverse in the Arctic or Antarctic winter because the upper atmosphere is warmer than the surface. In other words CO2 keeps the surface colder than it otherwise would be. Yes enhanced CO2 increases radiation to space in this case !

      What causes the enhanced melting of Ice is higher winds bringing warmer air from lower latitudes into the arctic.

  6. Rudy says:

    I think this site has the same data that scientists are using to base their current model of Anthropogenic Climate Change; I see so many flaws in the calculations, reporting, and conclusions of this site: The first obvious one is the claim that over the past 3 decades ice loss in the arctic has been 3% per decade. That would be 9% total. So that means we still have 91% of the area of the Arctic Ocean is covered by at least 15% sea ice, (because they are using 15% coverage as their standard.) This would mean that we now have 1,305,000 km^2 less coverage of ice than we did 3 decades ago. Then they use this to calculate an average daily ice coverage data point. As far as energy and thermodynamics are concerned, it takes the same energy loss from ocean water to freeze a certain mass of ice (assuming that mass is all contained in the standard they are using, otherwise they can’t make any conclusion) and it makes little to no difference at all about the average daily ice content. What matters the most is how much energy was removed from the water and air masses in order to freeze the ocean. When they use the algorithm to make this map, they do consider a certain overall percentage of frozen water to justify white (ice) over blue (water). Ideally we want to see it all white in the average area as the red-orange outline maps out. In my estimation, if you look at the entire map, it seems to be around 3 to 5 percent less than the average over the past few decades, as indicated by the ice on either side of the red line. If the Ice normally reaches 14,500,000 km^2, then a conservative estimate of 95% of that, or 13775000 km^2 has been reached this winter. That is 725,000 km^2 less ice this year than the past several decades and they are touting this as the lowest ice formation on record in the arctic ocean. Well that record is far from their 1,305,500 Km^2 amount that is calculated out of their claim that about 3% ice loss per decade is occurring. Don’t get me wrong. I do realize that anthropogenic climate change is real; however, it seems evident that the current researchers are not at all onto the correct model. What is startling is that our government is using the EPA to shut down our energy production, and influence our resource allocation and agricultural production. That is outright scarey, the idea that science might be being being misused on purpose in order to force political and societal change on our country. https://nsidc.org/arcticseaicenews/

    • Clive Best says:

      What you are saying is that this map is “calculated” rather than measured. I had assumed this was a simple remote sensing formula. However as you say the 3% loss per decade does not agree with the comparison to the mean.

  7. Rudy says:

    I am getting my “normally” reached ice extent from the graph that appears if you select the link of the graphic showing the ice extent on March 21, 2014 contained in the red-orange line for ice extent from 1980s to 2010. This graph is the second pic in the link. It appears to me that the y axis maximum on that graph is 14,500,000 Km^2; however I know that the maximum extent is closer to 15,700,000 Km^2.

    • Clive Best says:

      In any case these curves give no cause for concern. This year and last year show a recovery in Arctic sea ice that is not incompatible with natural variation. Antarctica sea ice has increased.

  8. Rudy says:

    What they also don’t point out is that the surface of the Great Lakes froze over completely this winter. Notice in the picture that the great lakes are blue and not white. “Well” you might say, “that is because they are only considering the sea ice.” But to make an overall conclusion about Anthropogenic Climate Change, you must consider all the heat that radiates back into space, versus the amount that does not radiate back into space, due to the fact that CO2 traps this heat in and heat the Earth. The Earth had to get rid of one hell of a lot to freeze the Great Lakes, and this means that heat was not trapped, but was radiated back into space, or displaced by convection and this year’s unusual polar vortex.

    Overall, we need to instill an overall appreciation of science and scientific literacy in this country or we are all going to pay the price when non scientists start touting that the global warming issue is solved once and for all, and start instilling polices using good and necessary offices like the EPA to work against us. In similar fashion, it seems the current administration was motivated in trying to use the surgeon general’s office to come up with the justification for gun control. In this case they seem to be misusing the data, and they are not considering the deaths or injuries by other means of violence such as those caused by knives and bats and beatings. This type of lunacy seems to be the M.O. of the current administration. Still people sit back idly and watch it happen. I digress. sorry

    • Clive Best says:

      As far as changes in the earth’s albedo goes, the Great Lakes are just as important as sea ice. Yes it is wrong for them to show the lakes as blue rather than white. I expect they will argue that this is fresh water. Well in that case they should be greyed out. Note also the silence on glacial retreat across the Alps. This is beacuse there has been yet another bumper year of snow fall right across the Alps.

  9. Hello!
    Thanks for nice rewiev. All this can be explained within modified DesCartes physics. I had posted a paper “Time for climate normalization research” on Researchgate last month.
    Perhaps “Pushing the Sun out of it’s place” also can rise some interest here.
    Please do not forget, that recent sinking of bottom of Atlantic ocean interfered with that cycles.
    Good luck!

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