Guest post by David Archibald
Baby boomers like me have enjoyed the most benign period in human history. The superpower nuclear standoff gave us fifty years of relative peace, we had cheap energy from inherent over-supply of oil, grain supply increased faster than population growth and the climate warmed due to the highest solar activity for 8,000 years. All those trends are now reversing. But it will get much worse than that. The next glaciation will wipe out many countries and nothing will stop that from happening. For example, the UK will end up looking like Lapland. As an indication of just how vicious it is going to get, consider that there are rocks on the beaches of Scotland that got blown over on ice from Norway across a frozen North Sea. As scientists, our task is to predict the onset of the next glaciation.
Onset of interglacials is driven by insolation at 65°N. That is where the landmass is that is either snow-covered all year round or not. It seems that insolation above 510 watts/sq metre will end a glacial period. For an interglacial period to end, the oceans have to lose heat content so that snows will linger through the summer and increase the Earth’s albedo. Thanks to the disposition of the continents, our current ice age might last tens of millions of years yet. From the Milankovitch data, this graph shows insolation at 65°N from 50,000 BC to 50,000 AD:
The green box has the Holocene ending at 3,000 AD – an arbitary choice. Insolation is already low enough to trigger glacial onset. For the last 8,000 years, the Earth has been cooling at 0.25°C per thousand years, so the oceans are losing heat. We just have to get to that trigger point at which snows linger through the northern summer. Solar Cycle 25 might be enough to set it off. By the end of this decade, we will be paying more attention to the Rutgers Global Snow Lab data.
From the source at: http://most-likely.blogspot.com/2012/03/milankovitch-cycles-and-glaciations.html
Model input is obliquity and precession and model output is the inverted δ¹⁸O record, with zero mean during the Pleistocene, from Lisiecki and Raymo 2004 and Huybers 2007. Lisiecki and Raymo use orbital tuning to constrain the age of the benthic records, while Huybers explicitly avoids this, consequently the two datasets are occasionally completely out of phase, but generally in good agreement, especially in the late Pleistocene.
As fitness function we take the product of the sum of squared errors (SSE) between the model and the two reference records from 2580 thousand years before present, with 1000 year timesteps.
For the longer term perspective, this is a combined crop (to make a continuous timeline) of the two fulls panel from the model prediction of the Milankovitch data.
The time period represented is from approximately 450,000 BC to 330,000 AD. The scale on the vertical axis is change in O18 content. There is a very good hind-cast match between the model and past temperature change as shown by the work of Lisiecki et al 2005 and Huybers 2007. The next glaciation is fully developed between 55,000 and 60,000 AD, with the next interglacial 20,000 years after that.
References
Huybers, P., 2007, Glacial variability over the last 2Ma: an extended depth-derived age model, continuous obliquity pacing, and the Pleistocene progression, Quaternary Science Reviews 26, 37-55.
Lisiecki, L. E., and M. E. Raymo, 2005, A Pliocene-Pleistocene stack of 57 globally distributed benthic d18O records Paleoceanography, 20, PA1003, doi:10.1029/2004PA001071.
Source Data: Download the consolidated data, including orbital parameters, insolation calculations, reference data and model output: Milankovitch.xlsx
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“As an indication of just how vicious it is going to get, consider that there are rocks on the beaches of Scotland that got blown over from Norway across a frozen North Sea.”
This statement makes the article seem like a warmist spoof. These rocks were obviously brought by the glaciers during the last Ice Age.
We shall obviously return to another Ice Age sometime over the next 10,000 years, just exactly when is something which nobody knows.
The Milankovitch Theory was given a big boost when it was shown by Gerald Roe in a published science paper be well established.The charts in the below link is quite revealing.
In defense of Milankovitch
http://earthweb.ess.washington.edu/roe/Publications/MilanDefense_GRL.pdf
I’m so glad we have Cook and Lew-boy to tell us that skeptics are never skeptical of any theory except Global Warming, otherwise I might have gotten the idea that this article was being met with some skepticism.
Here is a link to John Kehr who published a good book about the climate and what it portends in the future and I have the book in my possession and believe that it should be considered for reading because he has a good case about the CO2 conjecture being irrelevant because it promote so little warm forcing that it is not a big deal for us.
http://theinconvenientskeptic.com/the-book/
Go to bottom the page and click on Chapters 8-10 and see what the series of charts show that we are already in Climate Autumn.Charts #3-5 shows a clear cooling trend that is in step with a NEGATIVE insolation trend at 65 degrees N.
Climate Winter is not far off into the future.
Kevin-in-UK
Don’t we already have 8,000 years of data (Holocene) and much, much more? We know that the current Ice Age began about 3m years ago and glaciations have occurred approx every 100,000 years, with brief (10-14k years) interglacials in between.
I don’t pretend to be able to predict the obvious onset of the next glaciation, but under today’s ocean circulation conditions and orbital dynamics, we are 1,000+ times more likely to be in a glaciation period within 3-5,000 years than to have runaway global warming.
At my age, and my children’s ages, I doubt any of my immediate family will see either potential outcome.
Bill
I call first dibs on a Snow Tax. It is simple. If you let snow fall in your country, you pay a tax to….
Interestingly enough I was just re-reading this last night:
http://westinstenv.org/wp-content/ANURGENTSIGNALFORTHECOMINGICEAGE.pdf
Thanks for the excellent article especially the clean summary graph showing the cycle. I would love we are here indicator in the first graph.
I did struggle with this sentence: “…That is where the landmass is that is either snow-covered all year round or not….” I have always wondered why insolation is usually given at 65 North.
I guess 510 watts/m**2 refers to the daily average insolation at top of the atmosphere on the day of the summer solstice, at 65 N latitude (from Wikipedia – Insolation).
I am not falling for the warmists that pose the question “How much CO2 needs burned to stop the cooling” as it’s a red herring.
It’s akin to Spinal Tap turning their amps up to “11”
Apropos of the post, I remind myself that if I am not as skeptical about claims that support my beliefs as I am about those that oppose them, then I’m not a true skeptic; I’m merely an intellectual whore.
The data linked to by ‘warm’ et al. certainly seem to discredit the post’s thesis for the time being.
That said, Milankovitch’s theories have been triumphantly validated by Geologists.
The failure of the warmist’s initial attempts at temperature hindcasting to incorporate the established findings of Geological Science relating to the Medieval Climactic Optimum, and the Little Ice Age is a major component of my skepticism about their competance to forecast the future.
However, there seems to be a surprisingly vast array of estimates as to when we will enter the downphase of any one of his cycles. I would appreciate anybody who is more knowledgeable than I taking the time to post an explanation of those discrepancies.
“Drop Stones” from Norway would be rafted over to Scotland in sea ice after the glacial period was over, the ice breaks up, sea level rises and the thick ice collects over parts of submerged present day Scotland, melts and drops. David, remember many of your readers are going to think you mean actually blown over from Norway in a downpour of rocks.
I recall some work done on the low temperature trends in the US by region. That trend is negative. There might be a gradual increase in snow cover in mountain or higher terrain that increasingly lingers. Not that last winter in Alaska and Bering Sea ice are anything as a singular event, but in the total global picture of early winter snows and lingering spring snow cover, the extended snow cover does increase the reflection of solar radiation. Would it not that in concert with a decrease in solar output be an indication of longer winters and drier climates?
In reply to William McClenney http://wattsupwiththat.com/2012/09/16/onset-of-the-next-glaciation/#comment-1079830
I have posted your PDF link in my growing list of presentations in my White Earth forum section:
http://www.globalwarmingskeptics.info/forum-55.html
Always wanting more to add there.
Thank you for that link!
I am glad I won’t be there for the next warm peak… some future generation of warmists will “disappear” the present peak for sure and will say that it is unprecedented.
Nigel Calder suggests that a little history of glaciation science may be appropriate here:
http://calderup.wordpress.com/2010/05/14/next-ice-age/#more-782
http://calderup.wordpress.com/2010/07/10/milankovitch-back-to-1974/
And now… again…. after being banned along with solar barycentric theory,
Jupiter: The Return
confusing times
http://www.argonavis.com.br/astronomia/servlet/orbitas.svg
Very interesting and much food for long term thought. That said, I am taken back in time back to the 1970’s when all the models showed cold was bold. Then again to a later time when models showed heat was neat and CO2 was the key. We must all remember two things. This kind of long term anything based on proxies and models is great cosmology or mythology. Remember to keep a skeptical eye and Mother Nature plays with loaded dice.
Yeah, I think we are close. It looks to me as you go back into historical temperature reconstructions that each cool period for the past 3000 years has been a bit cooler than the one preceding it. The Little Ice Age was long and cold. The next Little Ice Age will be a bit less “little” and longer and cooler than the period we call the LIA. But I also note the same that Tallbloke mentions above. We are in a rather odd insolation cycle in that insolation is actually going to INCREASE a little bit from here and our orbital eccentricity is low so those are moderating factors.
But should we get things lined up just right … say a solar minimum, volcanic eruption, global patterns that result in colder than normal temperatures and that might be all that is required to overcome the hysteresis and tip us over into the “cold” stable state. That state is more stable than the “warm” stable state as we tend to stay there about 90% of the time and only briefly tip over into the “warm” state 10% of the time. I think all we need to tip the system is a summer with a greater than usual amount of summer arctic sea ice. I believe it is arctic sea ice or the lack thereof that tips us across the boundaries of those two states.
Great post! Good science fiction starts with facts and extends to the possible. The best part is that it’s all unprovable. I loved the commenters proposed solutions but don’t look forward to paying the hair dryer tax.
Reblogged this on The Next Grand Minimum and commented:
David Archibald offeres readers good advice on where we should focus our attention, on vanishing sunspots and year to year snow accumulation.
>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?
ROTFLMFA!
Anyone know the story behind that video? Is it a group of warmies thinking this actually helps their idiotic cause or yet another great parody by normal people illustrating absurdity by being absurd?
I clicked through some if their links to figure this out and still can’t get a handle on it.
Scientist in question is Milutin Milankovic
http://www.egu.eu/egs/milankovic.htm
(posted by Milivoje Vukcevic)
Scientist in question is Milutin Milankovic
http://www.egu.eu/egs/milankovic.htm
(posted by Milivoje Vukcevic)
“The onset of the next glaciation is driven by the isolation at 65N.”
Since that is wrong, every thing that follows is wrong.
http://i122.photobucket.com/albums/o252/captdallas2/climate%20stuff/internalthermaloscillations.png
The center of the Earth’s thermal mass is just south of the equator thanks to the distribution of the land masses and current orientation of the axis of rotation. 65N is a red herring, pretty much like northern hemisphere warming is an indication of the degree of CO2 induced warming.
Notice the similar dampened tropical temperature curve and the dampened solar insolation curve in the post. Most of the “climate change” discussion is irrational because the “indicators” of change have nothing to do with the assumed causes of the changes. Until you better understand the internal dynamics of this system, you can’t properly assign cause and effect.
Kinda funny actually 🙂 In thermo, follow the energy is like follow the money in politics. Happy Sunday.