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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The next glaciation will wipe out many countries and nothing will stop that from happening.
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].
“there are rocks on the beaches of Scotland that got blown over from Norway across a frozen North Sea. As scientists, our task is to predict the onset of the next glaciation.”
But the first task is to stop making things up.
A good paper on Milankovitch’s theory: http://www.leif.org/EOS/2006GL027817-Milankovitch.pdf
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?
With all our revulsion regarding models, it is difficult to say “OK, but this one refutes global warming”. Well, it might, but is it not still a model? And this ice age is how far into the future? No point in being alarmist at all, because the effects of continental glaciation are well known! It’s like running a big scraper across the world. Nothing will stop it.
The Climate alarmists, on the other hand, need to raise alarm to curry support for what is largely a speculative circumstance. They need to invent a bogeyman, and invent a solution, which, like kinetic energy, compounds at the square of its velocity! They can’t define the problem, so how on earth can they propose a solution?
This article has spooked me. In fact, I’ve just put on my hawthorn reg grundies.. Can we do anything to avert returning to an ice age?
This post so apes the CAGW meme that I can’t help wondering if it was not written with tongue firmly in cheek Very much, “Back to the Seventies”.
Hmm, I don’t think I’ll sell my wool shares just yet .
This effort turns everything everyone has been told for the last thirty odd years, completely upside down. It puts paid to the increase in warming as those old studies have continually demonstrated, which will not happen and also introduces the fact that the Sun, remember the Sun, will have the last say after all. Meanwhile we pass the popcorn as the lunacy of the CAGW hysterics wanders on it’s already disturbing path. But this time, it’s all downhill.
Or, the 65N insolation may not drop low enough to cause glacial onset this time round and the Holocene may continue for another 50k years.
Nobody knows.
More likely those rocks were embedded in icebergs calved from Norwegian glaciers that got blown across the North Sea. BTW, they are called Drop Stones.
“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”
I agree,
But… Where are the evidences that it is happenning ?
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=6
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=7
OMG, Mann got his hockey stick up side down!
Thanks
JK
Just have to ask this:
Given the recent discussion about geo-engineering to combat the alleged AGW (parasol gases and the like):
How much human-generated CO2 would be required to counteract an ice age? If we have 1000 years to pump CO2 into the atmosphere, is it possible to maintain the interglacial indefinitely?
(This, of course, assumes that humanity won’t do itself in, in some other way, in the intervening thousand years.)
Please would somebody tell the Australian prime minister J Gillard what’s around the corner she is hell bent on destroying us with the carbon tax
I guess i won’t be around to notice. Good news then. No more need to worry about our grandchildren’s earth and how we leave it. Bummer for the ecofanatics though.
Obviously, as a geologist, I find this easy to read – but for those who may find it difficult to comprehend, the net result is we don’t have to worry for a good few centuries yet!
In passing, I’m not keen on the use of the term ‘trigger’ for a glacial event – it implies a ‘non-reversible’ and ‘fixed’ point, kind of like the tipping point scenario that the warmista like to use for earths mean temp (which all geologists know is false!). Lots of factors have to come together, and remain together, for some considerable time for glacial onset to fully take hold (IMHO).
What I mean is that a glacial period could be presented/considered by ‘coolists’ to be initiated by the onset of several cold winters, but this would be a false premise – in the same way as ‘runaway’ thermal heating didn’t occur as per the ‘warmists’ arguments in the 90’s! Obviously. no one ‘knows’ for sure, but I can’t imagine the next glacial period being able to be defined without at least a few centuries of data?
An interesting piece, but to be fair, I think the timescale inferences have been perhaps lost to the general non-geological folk…just saying…
Here is a link to the Rutgers snow extent graphs.
http://climate.rutgers.edu/snowcover/chart_seasonal.php?ui_set=namgnld&ui_season=2
Note the increasing winter snow extent trend, particularly from around 2007. Also the steep decline in spring snow extent.
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.
So, how long have we got before we are all screwed?
BRRRRRR!!
Maybe it is time to have central heating installed (at last)
Re Kev-in-Uk says: September 16, 2012 at 1:33 am
Obviously as a concerned citizen, I think governments should be applying the precautionary principle and ACT NOW! Together, we can prevent glaciation. We can fight glaciation and the causes of glaciation. The developed western economies obviously have the most to lose, so I suggest a mere 1% of GDP is transferred to building the Atomic Hairdryer fleet. With suitable funding, we can blow that pesky ice back to the holocene optimum, all for a modest management fee.
Andy;
What have you been using up till now, campfires in a recess in the wall?
“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.”
Are you sure? Sorry, but this looks a bit like model based scare mongering to me.
Remember when the cemetery plot salesman is justifying their exorbitant prices by promising perpetual care, that “perpetual” will end once an advancing glacier covers over the graveyard, and your “eternal resting place” gets scraped and ground away to non-existence. Get the “dust to dust” over early and take the cremation.
Although if anyone here feels up to the marketing challenge, there are many abandoned mines available that are suitable for conversion to thousands of glacier-proof burial vaults.