From the University of Massachusetts at Amherst
AMHERST, Mass. – For more than 30 years, climate scientists have debated whether flood waters from melting of the enormous Laurentide Ice Sheet, which ushered in the last major cold episode on Earth about 12,900 years ago, flowed northwest into the Arctic first, or east via the Gulf of St. Lawrence, to weaken ocean thermohaline circulation and have a frigid effect on global climate.
Now University of Massachusetts Amherst geoscientist Alan Condron, with Peter Winsor at the University of Alaska, using new, high-resolution global ocean circulation models, report the first conclusive evidence that this flood must have flowed north into the Arctic first down the Mackenzie River valley. They also show that if it had flowed east into the St. Lawrence River valley, Earth’s climate would have remained relatively unchanged.
“This episode was the last time the Earth underwent a major cooling, so understanding exactly what caused it is very important for understanding how our modern-day climate might change in the future,” says Condron of UMass Amherst’s Climate System Research Center. Findings appear in the current issue of Proceedings of the National Academy of Sciences.
Events leading up to the sharp climate-cooling period known as the Younger Dryas, or more familiarly as the “Big Freeze,” unfolded after glacial Lake Agassiz, at the southern edge of the Laurentide ice sheet covering Hudson Bay and much of the Canadian Arctic, catastrophically broke through an ice dam and rapidly dumped thousands of cubic kilometers of fresh water into the ocean.
This massive influx of frigid fresh water injected over the surface of the ocean is assumed to have halted the sinking of very dense, saltier, colder water in the North Atlantic that drives the large-scale ocean circulation, the thermohaline circulation, that transports heat to Europe and North America. The weakening of this circulation caused by the flood resulted in the dramatic cooling of North America and Europe.
Using their high resolution, global, ocean-ice circulation model that is 10 to 20 times more powerful than previously attainable, Condron and Winsor compared how meltwater from the two different drainage outlets was delivered to the sinking regions in the North Atlantic. They found the original hypothesis proposed in 1989 by Wally Broecker of Columbia University suggesting that Lake Aggasiz drained into the North Atlantic down the St. Lawrence River would have weakened the thermohaline circulation by less than 15 percent.
Condron and Winsor say this level of weakening is unlikely to have accounted for the 1,000-year cold climate event that followed the meltwater flood. Meltwater from the St. Lawrence River actually ends up almost 1,900 miles (3,000 km) south of the deep water formation regions, too far south to have any significant impact on the sinking of surface waters, which explains why the impact on the thermohaline circulation is so minor.
By contrast, Condron and Winsor’s model shows that when the meltwater first drains into the Arctic Ocean, narrow coastal boundary currents can efficiently deliver it to the deep water formation regions of the sub-polar north Atlantic, weakening the thermohaline circulation by more than 30 percent. They conclude that this scenario, showing meltwater discharged first into the Arctic rather than down the St. Lawrence valley, is “more likely to have triggered the Younger Dryas cooling.”
Condron and Windor’s model runs on one of the world’s top supercomputers at the National Energy Research Science Computing Center in Berkeley, Calif. The authors say, “With this higher resolution modeling, our ability to capture narrow ocean currents dramatically improves our understanding of where the fresh water may be going.”
Condron adds, “The results we obtain are only possible by using a much higher computational power available with faster computers. Older models weren’t powerful enough to model the different pathways because they contained too few data points to capture smaller-scale, faster-moving coastal currents.”
“Our results are particularly relevant for how we model the melting of the Greenland and Antarctic Ice sheets now and in the future. “It is apparent from our results that climate scientists are artificially introducing fresh water into their models over large parts of the ocean that freshwater would never have reached. In addition, our work points to the Arctic as a primary trigger for climate change. This is especially relevant considering the rapid changes that have been occurring in this region in the last 10 years.”
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Awesome! This is very interesting. Thx for posting Anthony…
If the Antarctic was actually melting.
Uh-huh. And the modern equivalent giant freezing cold melt-lake is where, exactly?
I just wrote a model that proved global cooling happened because the Paul Bunyan blew his icy breath eastward. With all the factors I considered, it’s guaranteed to be 99.9 percent accurate.
This article is one of the major reasons why your readership grows and grows, Anthony. Real meat for those in the know to debate before our very eyes. Excellent peer review. Thank you; thank you. Now, might a “field” of comet strikes have been part of the reason for the extraordinary melting…or was he cause something more intrinsic to Earth systems and cycles?
I take exception to the words “conclusive evidence” when referring to a computer model. A model (even a “high resolution” one) may be very illuminating but conclusive evidence means something else entirely.
“report the first conclusive evidence ….”
The output of a computer model is not evidence, sorry.
Evidence would be actually getting out of the office, going to the Mackenzie river valley and digging up some rocks.
The results of model runs are “proof”? Sorry, but that doesn’t fly. I need fossil evidence of any such drainage of meltwater before buying their claims.
Brian H has the right question:
“And the modern equivalent giant freezing cold melt-lake is where, exactly?”
The article is interesting, but Brian H’s question is exactly pertinent
Interesting read.
Back in June of this year Don Easterbrook made a quest post on WUWT challenging the single origin/North Atlantic origin of the Younger Dryas.
http://wattsupwiththat.com/2012/06/19/the-intriguing-problem-of-the-younger-dryaswhat-does-it-mean-and-what-caused-it/#more-65956
I am completely lost here. 13000 years ago was about the time that the last glacial ended and the Holocene inter-glacial started. What is this “big freeze”? The “big melt” I would have thought.
Interesting… I wonder how they explain the rather sizable difference in the deep channel to the continental shelf edge for the two river systems…
http://i50.tinypic.com/29or0ib.png
Very shaky stuff actually.
a) It is only an unproven hypothesis that Younger Dryas was caused by the draining of Lake Agassiz.
b) It is hard to see how fresh water draining down the Mackenzie valley could end up southwest of Greenland, “Narrow coastal boundary currents” seem highly unlikely since the straits through the Parry Archipelago were still blocked by ice (whales could not get through at the time, so it’s hard to imagine massive amounts of water doing it). Even today driftwood on SW Greenland comes from Siberia, not Canada.
c) Just what makes them think that deepwater formation must have occurred in the exact place where it does today? Given that there were still massive icecaps in North America it seems quite likely that it was further south.
I agree with Asmilwho, get out into the Mackenzie valley and find some evidence. This theory should be much easier to prove or disprove than drainage through the St Lawrence valley, where the complex history of the Great Lakes and the Champlain Sea obscures the evidence. The Mackenzie valley has been above sea-level since the Younger Dryas and there has been no major floods or drainage changes. Evidence of a massive flood event should be quite easy to find, perhaps even visible on satellite images.
Mark Luedtke says:
November 5, 2012 at 10:12 pm
I just wrote a model that proved global cooling happened because the Paul Bunyan blew his icy breath eastward. With all the factors I considered, it’s guaranteed to be 99.9 percent accurate.
I just did the same and replicated Prof Mark’s results.
“Mark Luedtke says:
November 5, 2012 at 10:12 pm
I just wrote a model that proved global cooling happened because the Paul Bunyan blew his icy breath eastward. With all the factors I considered, it’s guaranteed to be 99.9 percent accurate.”
You forgot to add: No you can’t V & V my program.
That is so flaky it makes my puff pastry look like shortbread.
They’re preparing the ground for a “look – global warming is causing global cooling” argument. Expect it within the next 1-2 years.
When are we going to see models proving UFO and their visit…. Taking into factor all the crazy people claiming all sort of things…. Signed by Simon, awake by a local earthquake! at 4:06am north of Montreal.
Yet another computer model. I’m guessing most of today’s active scientists grew up playing Sim City. They’ve moved on to more expensive computers and real money.
The modeling was done with much lower sea level and a closed Bering strait ?
http://en.wikipedia.org/wiki/File:Beringia_land_bridge-noaagov.gif
Bigger faster computers, ‘better’ models …unfortunately same old GIGO (but quicker)
First the melt then the freeze – CAGW is whatever they say it is.
stephen richards says:
November 6, 2012 at 12:43 am
That is so flaky it makes my puff pastry look like shortbread.
_____________________
You get the thread Gold Star, next to your name.
I see what they did here.
Freshwater draining through St Lawrence cannot cause the Younger Dryas, so they’ve gone, “OK, where else can we dump all this freshwater that COULD cause it? AHA! The Mackenzie! That could work!!!” With no qualitative facts to support the hypothesis.
If that’s right, this is science fiction. Not science.
It’ s always the same: they use computer- models and we should believe in them. But if you write down the conservation equations for hydrodynamics for one liquid and these equations are then exrtemely reduced, it is impossible even for small space areas and short time intervals to find numerical solutions.
OK, the model has generated a potential hypothesis – now go out and see if there is any evidence in the real world to support or disprove the model output.
Just remember that models cannot ‘prove’ or ‘show’ anything about what actually happened, at the very most they can produce an output consistent with observations.
Still a modeled scenario so I question it. No real evidence, like sedimentary core data, which would be fairly easy to collect and fairly decisive, and added to the paper. Also I was under the impression that the Younger Dryas was a global event not confined to Europe and N. America.
There is a complaint that kids in the UK are not doing practical science in the lab but using computer learning. Some can’t even turn on a bunsen burner. Sounds like these people had the same teaching.
Science is a practical subject and needs hands on experiment to learn not a computer.
Given the present day topography, isn’t it more likely that Lake Agassiz breached to the north following the Red River (current day boundary river between MN and ND and flows north into Manitoba) into Lake Winnipeg and then Hudson Bay?
Models can’t prove anything–they can only show what might be possible if they include all relevant factors accurately and if all of the assumptions that are built into a model are in fact true. This model assumes that the Younger Dryas was caused by changes in ocean circulation rather than by solar variation or some other process, so perhaps it might be wise to look at real-world data before making this initial assumption. As Chants points out, in June I posted data challenging this assumption.
http://wattsupwiththat.com/2012/06/19/the-intriguing-problem-of-the-younger-dryaswhat-does-it-mean-and-what-caused-it/#more-65956
In this short article, you will see strong evidence that the deep ocean current theory of the cause of the Younger Dryas doesn’t work because the sudden, virtually simultaneous, global climate change doesn’t allow a lag effect between the Northern and Southern Hemispheres and between the Atlantic and Pacific Oceans (a prerequisite for this theory to work). Therefore, any model based on the initial assumption that the Younger Dryas was caused by changes in deep ocean currents is doomed to failure.
Katphiche says:
“Given the present day topography, isn’t it more likely that Lake Agassiz breached to the north following the Red River (current day boundary river between MN and ND and flows north into Manitoba) into Lake Winnipeg and then Hudson Bay?”
No. Hudson Bay was the center of the Laurentide icecap at the time.
Climate models are still just means for story telling.
computing power continues to explode, giving even the lowliest minion in the CO2AGW-scientific complex access to hundreds of years of global simulation, so they will retell and rewrite the entire history of the planet with their models.
This could usher in an age of Darkness for the geosciences.
So their computer model has given them a hypothesis. Now the task is to look for real world physical evidence to test the hypothesis through attempted refutation. Does no one read Popper any more?
MODELS ARE NOT EVIDENCE!!!!
Chris Schoneveld says: @ November 5, 2012 at 11:26 pm
I am completely lost here. 13000 years ago was about the time that the last glacial ended and the Holocene inter-glacial started. What is this “big freeze”? ….
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The big freeze is the the Younger Dryas. You can see it on this temperature/snow accumulation graph: http://wattsupwiththat.files.wordpress.com/2012/06/alley20001.gif?w=640
WUWT articles on the Younger Dryas:
New evidence of Younger Dryas extraterrestrial impact
Younger Dryas -The Rest of the Story!
“We don’t believe the ice cores can be interpreted purely as a signal of temperature’”
Hope that helps.
Have to concur with comments above – it’s just a hypothesis, and needs some field work to gather real evidence one way or the other. For some reason, the Playstation crowd seem reluctant to get their shoes dirty with real data collection, preferring to offer models as ‘evidence’.
It reminds me of when Steve McIntyre took a few hours out from his vacation some years ago to collect tree cores – a straightforward task which most of his detractors were apparently reluctant to embark on.
A very interesting theory
A good use for a model
But they should have stayed away from any type of modern day guesswork comparisons to AGW
phlogiston says:
November 6, 2012 at 1:04 am
They’re preparing the ground for a “look – global warming is causing global cooling” argument. Expect it within the next 1-2 years.
_________________________________
Yes that certainly sounds likely.
They have already run through:
CRISIS: Global cooling
Catastrophic Global Warming ( while trying to erase the existence of the global cooling scare in the ’70s.)
Catastrophic Climate Change
Climate Weirding (CAGW caused hurricane Sandy)
Lets face it, the Team knows the temperature rise has stalled and the sun has changed. ( WUWT: The sun – still slumping ) So they sent in the troops, Judith Lean and Claus Fröhlich , to rewrite the solar activity graphs originated by physicists: Dr. Doug Hoyt and Dr. Richard C.Willson. Judith Lean was then appointed as the ONLY solar physicist to vet her own work!
Letters from Dr. Hoyt and Dr Willson and the comment from the Norwegian government are at Judithgate: IPCC consensus was only one physicist with the rest of the story.
Luboš Motl is even more scathing and shows Dr. Judith Lean is an ATMOSPHERIC physicist not a SOLAR physicist. As Motl says,
So yes it looks like they are busy grasping at straws to keep CAGW, the great moneymaker, alive. With all the publicity and trillions of dollars spent they literally can not back down.
Note: 2005 was toward the end of cycle 23. 23 was not as strong as 22. The Solar Cycle 24 Prediction Panel was convened in October 2006. link. Predicitions were made as early as 2003:
Janssens Solar Cycle 24 prediction chart: http://users.telenet.be/j.janssens/SC24.html
This massive influx of frigid fresh water injected over the surface of the ocean is assumed to have….
Ah, “is assumed to have…”, eh?
So it’s based on an assumption fed into an Xbox game a computer model.
Sorry, as an engineer I’m not impressed.
Lake Agassiz drained south into the Mississippi River through the River Warren drainage channel.
http://en.wikipedia.org/wiki/File:River_Warren_Valley.gif
http://geology.com/shaded-relief/northcentral.shtml
The continental divide here peaks at 977 feet at Traverse Gap Minnesota so when Lake Agassiz’s elevation became lower than this, it drained into Hudson Bay or when blocked by the glaciers over Hudson Bay, it just stayed there.
http://www.johnweeks.com/river_minnesota/pages/mnD20.html
http://en.wikipedia.org/wiki/File:Browns_Valley_flood_07.jpg
There is no over-topping point to the northwest in North America which is lower than this until you get all the way the Arctic Ocean near Cambridge Bay. It did not flow into the Mackenzie River Basin etc. which other papers have modelled.
http://www.nwas.org/meetings/nwa2006/Broadcast/Kelsch/watersheds/media/graphics/unit_3/NAshadedreliefUSGS_3.jpg
Now it is possible there were other melt-water lakes in the Mackenzie River drainage basin (the glaciers between the Rockies and the Laurentide ice-sheet melted back about 13,500 years ago when the first North American Indians made it through this passage) but any melt-water lakes here were not linked up to Lake Agassiz which was several hundred feet lower.
I’ve seen where areas of “downwelling” are identified around Iceland & Greenland.
But wouldn’t some downwelling occur wherever the sea-ice edge is actively freezing? When it freezes, salt is excluded from the new ice into the nearest surface water, making it saltier (heavier) than water below.
That’s just great. Another episode of Blame Canada.
🙂
John M Reynolds
I take exception to the words “conclusive evidence” when referring to a computer model. A model (even a “high resolution” one) may be very illuminating but conclusive evidence means something else entirely.
I agree completely with this statement. What they have shown is that the meltwater hypothesis is numerically plausible — it could have produced the observed result. It is probably not unique among physical phenomena that could have produced the desired result, and it isn’t clear how any bolus of water would have produced a result lasting 1000 years in this or any other “sudden trigger” model or hypothesis. That would require a long term change in the circulation, which is certainly possible but far from proven, as the freshwater would very likely have equilibrated by mixing with the salt at its boundaries fairly rapidly IMO. One has to posit a shift from one semistable cycle to another neighboring one that remained stable even after the driver of the shift disappeared, which is entirely possible but depends on a lot of unknown dynamics to happen.
Add this up and it is hardly conclusive. It simply addresses one of the objections of the previous statements of the hypothesis, that even if it happened it wouldn’t have made enough difference as the effect would have been too small. They’ve shown that if the water broke north instead of southeast, it wouldn’t have been too small (good for the hypothesis as it is now less unlikely to be true) but they haven’t come close to showing that it did in fact happen. That would take a different kind of evidence, a kind we may well never discover. Empirical evidence.
I, for one, do not think that it is the case that we can or ever will be able to positively resolve all questions like this one. It was a long time ago, physical evidence is rare and ambiguous (more than one possible explanation), and the real cause was very likely multifactorial — this AND this AND that, not just “this was the proximate cause of the Younger Dryas”. As I sometimes point out on these pages, we do not yet have a clear understanding of what causes ice ages in the first place (I’m speaking of the broad trend of climate towards glaciations that last millions of years with punctuating but short interglacials like the one that began some 2.5 million years ago). Lacking this understanding, I am extremely skeptical that we know enough to fully understand the factors that govern the glacial/interglacial modulation during the broader ice age. Orbital stuff, sure, maybe, but that seems unlikely to explain the broader trend over the last 50 million years from warm era (MUCH warmer than the present) that gradually cooled until it passed a critical point where temperatures dropped relatively “precipitously” (over a million or so years) into glacial/interglacial oscillation with a gradually descending glacial floor temperature and with a spontaneously shifting quasi-period.
What can explain this pattern? Orbital stuff, long term turnover of rocks in mountain ranges, subduction, long term variability in the sun, passage of the solar system through “stardust patches” of just the right sort to modulate solar intensity or otherwise affect atmospheric chemistry, feedback, volcanic activity — none of these (except solar stuff) seems sufficient in and of itself to produce the baseline variation around which the other factors perhaps heterodyne to produce the oscillations. Until we fully understand, and can quantitatively predict, this baseline and the primary first order correctors, how can we distinguish the YD as an “event” requiring “explanation” as opposed to mere multifactorial noise in a region of critical instability?
rgb
I am still holding out for the comet explanation.
A comet crashing into the ice sheets would have vaporized an enormous amount of water which could have fallen as snow over North America, Siberia, Northern Europe, and the the Arctic itself, increasing significantly the Earth’s albedo and affecting the ocean circulation too.
“Conclusive evidence” would consist of going up into the great white north, digging up some rocks, and showing beyond question that you’ve identified the actual outflow channels.
Many have looked. ‘Tain’t happened yet
On the other hand, since the YD impact hypothsis pretty much proposes that the LIS took a major hit from a fragmented comet along about that time, what does their cute little computer model say the climatic result of sending a few hundred thousand cubic miles of ice up into the atmosphere all at once as steam might look like?
Maybe the reason no one has ever positively identified the out flow channels for glacial lake Aggasiz is simply because there aren’t any..
Geologists have already found evidence that a major outbreak of Lake Agassiz, about 13,000 years ago, drained north through the Mackenzie River into the Arctic Ocean. Two references.
Murton, J. B., Bateman MD, Dallimore SR, Teller JT, Yang Z (2010-04-01). “Identification of Younger Dryas outburst flood path from Lake Agassiz to the Arctic Ocean”. Nature 464 (7289): 740–743. doi:10.1038/nature08954. PMID 20360738.
Schiermeier, Quirin (31 March 2010). “River reveals chilling tracks of ancient flood”. Nature.
retrieved 2010-04-05.
The draining of 13,000 years ago may be the cause of the Younger Dryas stadial. The draining at 9,900–10,000 years ago may be the cause of the 8,200 yr climate event. A recent study by Turney and Brown links the 8,500 years ago drainage to the expansion of agriculture from east to west across Europe; he suggests that this may also account for various flood myths of prehistoric cultures, including the Biblical flood myth.
On this occasion, Wikipedia offers a reasonable article. http://en.wikipedia.org/wiki/Lake_Agassiz
I was just this morning pondering precisely this issue….and lo! After a long absence from blogging, i tune in and here it is – and thanks Don Easterbrook for your comments – I will look up your work on this. My tuppence-worth is this: the thermohaline circulation is often touted as a means of altering the heat balance of the planet, but I have never quite believed it….firstly, the bottom waters spread out and are very slow moving as they head south…Lozier et al showed they do not maintain a discrete body of water, and I have yet to see a convincing calculation of the mass balance and associated thermal gradients made from actual measurements…models have a tendency to fit numbers in according to what they need to get out!
The main mover of surface waters, where the heat is held in the top few hundred meters, are winds…and the Greenland ice-cap data which show rapid shifts on a cyclic basis can only be interpreted as changes in wind and wind-driven ocean currents.
So – the THC may have been slowed by 30%…but this is not unusual. Bryden and his team found a 30% change within 14 years – it slowed down between 1990 and 2004, but then speeded up again. Also – the North Atlantic registered a steady freshening about a decade ago, and then this too reversed….have yet to see the most recent data to coincide with the latest Arctic melt-down, but notice there are no glaring headlines, so I presume not much has changed.
If the Younger Dryas was not caused by a release of melt-water, then this highlights the need to study other mechanisms…ways of swiftly altering wind patterns and ocean currents – the only way of significantly altering global heat balances.
So what formed the Laurentian Channel then???
I lost interest at ‘first conclusive evidence’ whilst understanding this was a model simulation.
I have always understood ocean circulation as being a way for warmth from the tropics to be released. Energy, whether from the Sun or forces on Earth generate heat. That heat has to be bled off. Ocean currents do that by moving that heat to the poles. Thunderstorms in the tropics also bled off heat but on a smaller and more localized scale.
So if flood waters blocked ocean circulation and kept the poles from warming then they also should have kept the tropics from cooling.
They need to find evidence of increased warmth in the tropics during this time to help prove their claim.
Or am I totally off base? (I have no degrees in any science)
“Using their high resolution, global, ocean-ice circulation model that is 10 to 20 times more powerful than previously attainable, Condron and Winsor compared how meltwater from the two different drainage outlets was delivered to the sinking regions in the North Atlantic. ”
Will this game be coming out for the XBox-360 or the PC in the foreseeable future?
Dennis Cox says:
November 6, 2012 at 5:39 am
Maybe the reason no one has ever positively identified the out flow channels for glacial lake Aggasiz is simply because there aren’t any..
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In Washington state you can see immense channel that were obviously cut by massive flows of water some time in the recent past. They are not rounded as one would expect if they were ancient.
Yet it took 50 years for Bretz to overcome the established thinking of the time. By that time all opponents to his ideas had finally died.
However, the problem for other researchers is the Bretz actually got out into the field and found the channels. Unfortunately for theorist these lead to the Pacific.
Conclusive evidence that the warmists continue to go to any length to push their fantasy agenda in the face of reality.
@ James Cross 5:16
“A comet crashing into the ice sheets would have vaporized an enormous amount of water which could have fallen as snow over North America, Siberia, Northern Europe, and the the Arctic itself, increasing significantly the Earth’s albedo and affecting the ocean circulation too.”
Great theory–now if you can weasel your way into access to a supercomputer you can PROVE it CONCLUSIVELY, all from the comfort of your own office!
“Conclusive evidence is, well, evidence that is conclusive,at least in the eyes of the beholder.
The evidence can be in any format : computer modelling that is based on very persuasive
assumptions and is driven by persuasive logic.
Conclusive evidence? What evidence? Get a mini sub up there and dig up rocks that shouldn’t be in the Arctic basin. Been done in other areas on the globe. The Montana area all the way down through Oregon’s Willamette Valley is strewn with boulders that geologically speaking, didn’t just grow there. Climate scientists who worship at the feet of their super duper rad computer haven’t a clue.
I believe Bill Illis is saying water flows downhill. If true, does that not contradict this “conclusive evidence”?
Sadly, the state of “science” is do a computer rendition based on your guess and voila, it proves it. Now you write a paper declaring it because everyone knows that “supercomputers” are smarter then men, right?
By the way, I disagree with the concept that they could only get their “high resolution model” because of the speed of a super computer. Unless there are idiocyncracies in the programming language for the super computer that can’t run on slower machines, then the same “resolution” was possible on slower machines, but it would have taken longer. It sounds like “programming hype” to me. Models are models of what someone “believes” to be the situation being analyzed, not necessarily the actual situation.
“Now University of Massachusetts Amherst geoscientist Alan Condron, with Peter Winsor at the University of Alaska, using new, high-resolution global ocean circulation models, report the first conclusive evidence that this flood must have flowed north into the Arctic first down the Mackenzie River valley.”
I’m an accountant, not a scientist. But in my profession, computer models don’t provide conclusive evidence of anything.
Keep up your excellent posts, rgb. There is actually a physical mechanism that could be used to simulate the authors’ conclusions; however, it might be quite expensive in that a physical model would need to be constructed in one of the nation’s water flow simulation tanks, a very detailed labor intensive undertaking, but it could be done.
AngusPangus says:
With no qualitative facts to support…
But in fact they have no support at all except to say that they have a bigger, better, quicker, slicker computer. This is science by children, or if they are not children, then an alternative explanation is that they put forth their super-model cum super-computer in the hope of hooking some super-funding. This critique does not sound nice, does it? But unfortunately, it is the age we live in and these corrupting influences need to be addressed, and climate modelers are among the worst offenders.
Re: cause of the Younger Dryas
Only factor where ocean currents could (but not necessarily ) cause glaciation in the far North Atlantic is some kind of temporary blockage in the Faroe Bank Channel, depriving the Arctic ocean of part of warm water inflow.
Faroe Bank is about 450m high, 200km long and only 50km wide.
The bathymetry of the Faroe Bank Channel
http://www.vukcevic.talktalk.net/FBC.gif
http://www.vukcevic.talktalk.net/G-Sr.gif
revels its very unusual shape, a clear obstacle to large volume of the Atlantic warm water inflow into the Arctic ocean. This is geologically active area, so sudden blockage (by soft volcanic tephra) and subsequent erosion would explain short duration of the Younger Dryas of only 1.3 k year.
Alternatively by removing section of the Faroe Bank (outlined in the red) would increase warm waters inflow, which could be sufficient to prevent the all year around Arctic Ocean freezing, necessary for the onset of any future glaciation.
Oh yeah!
I once built a computer model for my retirement fund. First I was earning 5% a year. After a few years, I redid the model and lowered the yearly earnings to 3% which was actual at the time.
Then the economy did the nose dive and that model was useless. Worse than useless as some of those steady earning blue chip stocks either went bust or darn near.
And I thought the model based on my actual yearly earnings was pretty darn good too.
So let’s see if I understand the model proposed in the above paper…
They believe in the meltwater scenario for causing the warming reversal back into a freeze.
So they built a model.
They refined the model, ran it on fancy equipment and in their minds. This model is now proof?
Har! Har! Har!!! What a bunch of religious zealot one track nerds!
What I’d like to see in this ‘proof’ process of a theory is the verification that cold fresh water will ride on top of the gulf stream and prevent; heat transfer, cooling and sinking of the dense salty water.
Giving how rapidly heat wants to rise and ‘conduct’ in water. I find the whole belief process for a cold water trigger for climate deep freeze darn loose. If the water is fresh enough so that it floats AND it is released north, it then freezes and floats wherever artic ice is blown. If it drains on top of a moving truly massive warm river of gulf water, then it is pushed north while getting warmer until it freezes and gets blown by artic winds. Just how different is fresh water versus frozen low salt ice?
More powerful computers do not produce better results. Given the same unverified data and the same unverified code, they just give the same crappy results faster.
rgbatduke says:
November 6, 2012 at 5:04 am
“. . . that last millions of years . . .
“. . . this AND this AND that, not just . . . ”
In the timeframe suggested, additional “ANDs” come into play. The closing of the Isthmus of Panama being one:
How the Isthmus of Panama Put Ice in the Arctic
Drifting continents open and close gateways between oceans and shift Earth’s climate
http://www.whoi.edu/cms/files/dfino/2005/4/v42n2-haug_2272.pdf
This might also be of interest:
http://motls.blogspot.com/2010/07/in-defense-of-milankovitch-by-gerard.html
. . . follow the link to Gerard Roe’s paper.
~~~~~~~~~~~
Some more “ANDs”:
The ice-margin lakes drained through various outlets in North America. Not mentioned in the post or comments was the Mohawk/Hudson and the now drowned canyon of that outflow. Interior passages (to the Mississippi) include the Little Miami (to the Ohio, at Cincy) and the Wabash (both receiving water from Lake Maumee (~~L. Erie), the Chicago R. drainage of lake water, and the Allegheny River (western PA & NY) marking the edge of the ice lobe in this region. Then there is the Missouri R. with its now shortened northern tributaries (isostatic rebound to the north). And, in the west, melt-water flowed catastrophically from Montana via the Columbia R. drainage.
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. . .their high resolution, global, ocean-ice circulation model that is 10 to 20 times more powerful than previously attainable, . . .” [from the paper]
The above makes me think of several Richard Feynman quotations.
This is not a “study”, but rather a conjecture based upon a computer model subject to GIGO like all computer models and proves nothing. If it had a face it would look like a bucket of snot.
“..Now University of Massachusetts Amherst geoscientist Alan Condron, with Peter Winsor at the University of Alaska, using new, high-resolution global ocean circulation models, report the first conclusive evidence that this flood must have flowed north into the Arctic first down the Mackenzie River valley.”
I hate to nit-pick but what they offered wasn’t evidence but conjecture. That is, unless computer simulations are now considered evidence. I understand where the scientists are coming from, but computer modeling isn’t the same as say soil or ice core samples. Evidence usually refers to hard physical things that can be measured and evaluated.
Out of curiosity, is there any guess or information about the change in Ocean PH because of this event?
I’m curious because I would expect a sudden and drastic change causing the immediately affected area to become more neutral, not unlike the current PH change.
And so this is how the era of giantism in climate computers began. Each new model and computational effort was superior to any that came before it and more and greater resources were fed into the rapidly evolving beast with natural advantages over the smaller, inferior types. This trend continued for eons and without regard to the tradeoffs, costs of operation, and absurdities involved. The bigger the better until the blunt truth fell from the sky and wiped the previous trend from the face of the earth.
Looking for something that causes mammoths to freeze with fresh flowers in their stomachs… using Occam’s Razor, the simplest way I can imagine this is by the notion of a pole shift, say if the North Pole had centred on the Laurentide ice sheet but suddenly shifted to its present position, due to a “fly-past”.
I say “sudden” but if we have another object in space doing the pulling, it would be gradual enough not to be felt as total seismic shocks though it might cause… changing sea levels in some places, as the Earth’s new polar flattening settled in… and perhaps some of the atmosphere is being dragged off… so the planet cools somewhat altogether… could this mean that rain/snow falls all the time while this is happening?…
…but hey, surely someone else has thought of all this?? I haven’t read Velikowsky and I don’t know what he said about the Younger Dryas though I get the impression that scientists rather ganged up on him for daring to think afresh. I’m just exercising my own freedom of thought.
Just starting from the assumption they have made that the fresh water somehow will cause enough turbulence to thoroughly mix with the colder denser salt water, I have basic problems with the entire post. Having watched the results of simulations of cold/hot fluid mixing from supercomputer modeling that were verified by physical experiments, it doesn’t happen smoothly, homogeneously, nor quickly. The real physical boundary layer can prevent, under some circumstances, any mixing at all. Sometimes the boundary oscillates for a long time. They have to have assumed that neither happened, because there is no discussion of the possibility.
NFS funding does require that you toe the line, don’t you know…
Arctic Basin salinity is a key variable.
Everything that I have read shows that Lake Agassiz either drained into Hudson Bay or south into the Mississipi River system. I dispute this finding
First of all some supportive statements for the article:
There is geological evidence that glacial lake outbursts did occur from Lake Agassiz into the Arctic Ocean via the McKenzie River at the times specified (I’m not going to supply the references because they are available to anyone willing to read Wikipedia).
The computer model they used shows that the likelihood of a glacial lake outburst via the McKenzie causing a thermohaline current disruption is far greater than through the St. Lawrence or the Mississippi.
Now some criticism of the article:
That a thermohaline current disruption caused the Younger Dryas period is an unproven hypothesis, there are several other hypotheses which are also unproven.
A simple glance at a topographical map shows that Lake Agassiz, given its location and depth, would also have been draining into the St Lawrence and Mississippi watersheds, both of which supply ample geological evidence of this happening. It couldn’t drain into Hudson’s Bay because the ice sheet was still covering that – of which there is also ample geological evidence. I think it’s also reasonable to assume that glacial lake outbursts could have occurred down those routes as well, since ice dams occur on a regular basis in rivers which form ice in the winter.
A computer model does not supply evidence, it supports a hypothesis based on the data supplied and the computations undertaken. Use of a supercomputer does not improve the resolution, the amount of data supplied improves resolution. A supercomputer only speeds up the processing of the data and the same can be done using desktop computers linked in a network and the reference of using it is only a canard to help lend legitimacy to their conclusion.
I realize that this is only an article about the research undertaken, so it would be interesting to actually read their findings rather than read quotes which have been taken and are possibly out of context. It would also be interesting to read about how their computer model was constructed so that its accuracy can be assessed and critiqued properly.
John Marshall says:
Science is a practical subject and needs hands on experiment to learn not a computer.
I’m beginning to think Science is dead. Or at least on its death bed.
I always hate these news blurbs written by people who don’t understand science.
The abstract is available at: http://www.pnas.org/content/early/2012/10/31/1207381109.abstract?sid=b776f87a-3326-4014-ad48-dc853b8dcd82
The article is paywalled.
hm – didn’t get the follow confirmation. Trying again
[Reply: That is because the comment “ignore – following comments” automatically goes into the Trash folder. Unless you can provide a good reason to post such a cryptic comment. — mod.]
Say,
what do Geologists say to this?
Is there any evidence of landmarks caused by such a truly diluvian flood – like washed-out canyons, grinded baserock, a massive outflow-delta or huge piles of gravel on the mouth of the Mackenzie River valley – known by Geology?
If so, I’d like to get a link for this, because I am truly interested in this matter – that is, gathering material evidence, rather than fiddling with code.
“…using new, high-resolution global ocean circulation models…”
They haven’t proved a damn thing, they’ve just been doing an advanced form of masturbation. *Eyeroll*
While this is interesting, it appears to be yet another computer model “best guess.”
My concern is that the model may be/is founded on what we know of the thermohaline circulation today to try to assess what might have happened nearly 13,000 years ago. I’m not sure anyone knows if the thermohaline circulation system today is the same as it was then. I seem to recall seeing articles suggesting that even the current understanding is different than it was just a few years ago.
I’m stunned. They say they have the “first conclusive evidence”. Then it turns out they have no evidence, only a model, and they appear to have made no attempt to look for any kind of supporting evidence. And then they give the reason for the finding: “if it had flowed east into the St. Lawrence River valley, Earth’s climate would have remained relatively unchanged“!!! So – the climate change had to be caused by this one event, not by anything else going on around the planet or in the solar system. I’m stunned.
In the timeframe suggested, additional “ANDs” come into play. The closing of the Isthmus of Panama being one:
No arguments. My statement of personal and perhaps collective human ignorance is unbounded from above. Add all of the ANDS that you like — perhaps we might argue about how plausible or implausible any particular condition is, but no matter how you slice it, it was probably multifactorial and we don’t even know the list of probably important factors.
Don’t forget, the really interesting ANDs are the ones we haven’t even thought of, or don’t know how to begin to measure or quantify. Dark matter modulating the size and hence intensity of the sun. Matter infalling from the Oort cloud. Fifth forces. The whims of a programmer, because we are all power units in The Matrix. God’s will.
There is absolutely no guarantee that we even have the full list from which the principle coupled causes could actually be selected.
rgb
John Marshall says:
Science is a practical subject and needs hands on experiment to learn not a computer.
I’m beginning to think Science is dead. Or at least on its death bed.
Computers are great for lots of purposes in science. Doing statistics (an important part of experiment) is way better with a computer than without. One can learn known science very well with the help of a computer. Finally, there are lots of situations where the physics is known but actually solving the math analytically is — erm — “difficult”, shall we say — where computers can numerically evaluate the known physics to more than adequate precision to solve otherwise intractable problems.
Simulations very much fit into the latter category, and I’ve done a bunch of numerical simulation in exactly these circumstances, as well as written a bunch of code to solve problems where the math is known but not otherwise solvable.
So I have to disagree with the breadth of John’s comment, while still agreeing that numerical simulation or computation is not necessarily a substitute for empirical evidence. In some cases, it is actually superior. In others, it is worthless. In this particular case, as I already commented, it is in between — it contributes to the discussion without coming close to being “conclusive”, and I agree with John that hard evidence is needed for anything like conclusiveness (and unlikely to ever be obtained in this particular case).
So not so broad a statement, please. Science isn’t on its death bed. One narrow aspect of climate science is ailing, no doubt, but most of physics, chemistry, biology is done with excellent scientific methodology and a fair lack of bias.
rgb
Michael Tremblay says—
I suppose you have your reasons for wishing to add support for this article. At your suggestion, I referred to Wikipedia articles, one on Lake Agassiz, one on glacial lake outbursts. The Wikipedia article on Lake Agassiz gave the Mississippi, Lake Superior and The McKenzie as drainage paths for Lake Agassiz, and gave “Geologists have found evidence that a major outbreak…. about 13,000 years ago drained north through the McKenzie into the Arctic ocean.”, but the article attributed the final and catastrophic drainage of L. Agassiz through Hudson Bay, raising sea levels .8-2.8 feet, about 8200 years ago. The glacial lake outbursts article gave no mention a YD flood event through the McKenzie, or of any such event through the McKenzie and so much for your references in support of the study’s assumptions, which support amounts to one bald assertion.
Go read about the scablands of eastern Washington if you wish to know what a catastrophic glacial lake outburst does to the landscape, and then come back and report what similar features are seen in connection with your YD catastrophic flood through the McKenzie. Maybe you can find some more Wikipedia articles for us to read.
It is obvious that the model-tinkers simply rigged the model to drain through the McKenzie and to forget about the rest, but you suggest that to inspect such model tinkering would be instructive. Have you nothing better to do? To those who embrace scientific rigor, such science dances around reality and is nothing but a waste of time.
I remarked some time ago on a similar post that I lived the first half of my life in the basin of Lake Agassiz so you can be sure we were taught a lot about this and visited all the various raised abandoned beaches and drove up the stranded sandy delta at Carberry Manitoba where the Assiniboine R. entered Lake Agassiz (no small feature it’s extent was 6500 km^2).
http://bing.search.sympatico.ca/?q=carberry%20manitoba&mkt=en-ca&setLang=en-CA
The authors are definitely wrong in their theory. I’m not arguing that all those cubic km of cold fresh water could do the job, but only if it rushed out in basically one fell swoop. Here is where the powerful computer fails. A little field work and data gathering, or even reading the papers on the lake and its demise, would have sent them looking for another reason for the Younger Dryas.
The Lake went out in a series of drops, spaced out sufficiently to allow for the mature development of new beaches and rear sand dune developent at each successive drop. The northern ice shore melted back, released water and re-advanced for possibly decades (aren’t all natural records and the stock market zig-zagged?). Most of the sub-parallel strand lines of the shrinking lake had been mapped by the time I began my geological survey work with the Manitoba Gelogical Survey in the late 50s. I was mapping the Precambrian hard rocks of the Canadian Shield when, much of it low-lying and boggy with more lakes than land. What to my surprise, going in on a compass traverse to a weird looking outcrop visible on the aerial photos, I entered a beautiful jack pine parkland with floor of dried moss which I walked over for several miles until I reached my destination to find, in the middle of the woods, a barchan (crescent-shaped sand dune) about 10m high with its beautiful horns pointing downwind away from where the lake had to have been on the other side of a beach, now thick with pine, moss and shrubs. I believe I discovered the last stand of Lake Agassiz in the middle of Manitoba, and I’m sure the water probably whent out the Churchill and Nelson rivers into Hudson’s Bay in a series of pulses.
Another damning piece of evidence is the topography. The lake would have to have climbed over a water shed several hundred metres high to get into the MacKenzie R. Note Lake Winnipeg location in south central Manitoba in the “green” topgraphic area.
http://atlas.nrcan.gc.ca/site/english/maps/reference/national/can_relief/referencemap_image_view
This would have been a sufficient review to reject their thesis. The St. Lawrence is out, too. It may be interesting to readers that the Missouri River used to flow northward into Hudson’s Bay, too, before the ice dammed it off and reversed the flow where it was captured from the south and cut a tie into the Mississippi. I used to drill for this channel in Southwestern Manitoba down 300 feet to tap into the sweetest water in quartz gravels with petrified wood and opal pebbles.
Lucy:
It’s unusual that I get to comment on one of your posts as you’re normally quite thorough.
I don’t think you mean a pole shift, but a change in the earth’s axis of rotation as that would be what actually changes what is artic versus near artic latitudes. The poles reflect the deep earth iron core’s currents and magnetic reversals occur regularly through geological time.
Your reference to the mammoths that have been found with fresh greens and flowers in their stomach, is a key question in the swiftness of the climatic change. Mammoths, frozen in place, whose last meals were undigested are data points matched against a supposed computer model proof of an immense freshwater flood to the artic sea that causes an interruption in the deep heat transfer ocean conveyer belt… But wouldn’t interrupting the deep heat transfer ocean conveyer belt take a long time to change climate weather?
Gail Combs says:
November 6, 2012 at 4:50 am
phlogiston says:
November 6, 2012 at 1:04 am
They’re preparing the ground for a “look – global warming is causing global cooling” argument. Expect it within the next 1-2 years.
_________________________________
Yes that certainly sounds likely.
They have already run through:
CRISIS: Global cooling
Catastrophic Global Warming ( while trying to erase the existence of the global cooling scare in the ’70s.)
Catastrophic Climate Change
Climate Weirding (CAGW caused hurricane Sandy)
Lets face it, the Team knows the temperature rise has stalled and the sun has changed. ( WUWT: The sun – still slumping ) So they sent in the troops, Judith Lean and Claus Fröhlich , to rewrite the solar activity graphs originated by physicists: Dr. Doug Hoyt and Dr. Richard C.Willson. Judith Lean was then appointed as the ONLY solar physicist to vet her own work!
Incredible! Is the a Leif Svalgaard perspective on this Judith Lean fiasco?
Generally, melting at an interglacial start will always release such ice dams. Therefore if the hypothesis in the above paper is correct, then we could expect to see a “Younger Dryas” pause/reversal at the start of many or most interglacials in the recent 2.5 million years. Do we see this? No.
“Lucy Skywalker says:
November 6, 2012 at 8:39 am
Looking for something that causes mammoths to freeze with fresh flowers in their stomachs…
Most have been found in permafrost in bogs – may have sunk under and subsequently froze. Bogs in Siberia and the tundra of N. America would probably have been cold and subsequent freezing would have finished the job. They are dated at 30,000 to 40,000 years ago some of them so it wasn’t too warm an environment anyway.
@chris Schoneveld:
We were coming out of the last glacial more or less on schedule, then something strange happened and a cold plunge hit for about 1 k years. That event is a mystery and unexplained (but lots of folks keep trying). That’s what this paper is about. That cold spike when in theory we were pretty much out of the ice age glacial and ought to have ‘locked up’ into hot.
@Lucy Skywalker:
There’s a peculiar aspect of spinning tops. They are VERY stable and don’t like to do “tumbles”, but CAN do them if the spinning tip ‘catches’ on something. The moon also stabilizes our spin. So a “pole swap” is unlikely. Yet… IF you could ‘whack’ the spinning gyro near the spin axis at one end, it would tend to a stability ‘issue’ and can either wobble to a new stability, or even have a ‘gyroscope tumble’. (that can be an issue for gyroscopic navigation equipment…)
So what could make the ‘gyro’ tumble? Maybe a ‘big rock from space’ hitting the ice sheet up in Canada… It would also toss up a giant tidal wave of frozen ice slush that would ‘quick freeze’ the poor critters it buried on the other side of the planet… (There are also warm type grasses and trees buried under dozens of feet of jumbled ‘stuff’ in the same areas). A gentle ‘wobble’ could also explain why the magnetic pole was offset and why the ice sheets were in places that do not now extend symmetrically south from the pole.
All in all, I think that’s the best fit to ALL the known data. Big rock from space, hits the ice sheet (and doesn’t leave too much evidence in the dirt a mile down… but there is some). This not only vaporizes a heck of a lot of ice, but sends a giant tidal wave of “slush” over the pole into Siberia and some into Alaska that accounts for the odd geologic layers and the ‘flash frozen’ animals.
The induced ‘wobble’ instability eventually stabilizes, but with the pole displaced just a little. This, then has consequences for ice sheet history being a bit less ‘centered’ over the present north pole, in keeping with what is observed. Not a full ‘tumble’ or ‘flip’, but an instability that then settles down, displaced.
Finally, there are various places with evidence of impacts on the ground including secondary ejecta re-entry impacts. IMHO a very nice job of researching and laying it all out was done here:
https://cometstorm.wordpress.com/
Has very nice photos of a lot of geologic features from Mexico to Canada that all date and point to a meteor swarm event.
There is also pretty good evidence that Comet Encke is part of what once was a much larger body that has broken up (leaving us with the Taurid meteor storms) and that various orbital mechanics issues have us getting periodic large and then small impact counts (but decreasing over time as things get used up and spread out).
http://chiefio.wordpress.com/2011/11/14/meteor-showers/
http://chiefio.wordpress.com/2011/11/03/lunar-resonance-and-taurid-storms/
So while I’d not expect a ‘pole shift’ (meaning a full on tumble and N / S swap) I would expect a large meteor swarm hit, with very large chunks, and probably caused a minor change of the ‘wobble’ (certainly enough to change climate patterns). It would also put a lot of stuff in the air, cause weather changes, and send a giant wall of ice slush into just the places with jumbled fossils and dirt / rocks flash frozen…
@All:
I have to add my voice to the chorus of folks pointing out “computer models are not proof” nor even much in the way of evidence. They are very useful tools for letting you precisely state your understanding and bias and seeing if that is consistent with the known facts and data; but they are proof of nothing.
I’ve spent far too many years of my life chasing bugs in code (some mine, a lot of other folks) to ever call a computer program “proof” of anything. Highly useful, yes, but also very prone to human error… in the programming.
So these folks have shown something is “consistent” with their theory, in a mathematical way, and nothing more. It is also perfectly consistent with the known data to say I will never die. After all, I never have. In fact, you can go further. So many people are alive today that more people are alive than have ever died. So one could say that it is ‘consistent with the number of people alive’ to say that ANYONE has a less than 50% chance of dying. Clearly this is a logical fallacy as it ignores the individual life span ‘issue’; but such is the stuff of ‘computer bugs’ in models….A logical fallacy gets coded into arcane computer codes and then doesn’t get closely inspected…
But it does not prove that 1/2 the people never die…
“This massive influx of frigid fresh water injected over the surface of the ocean is assumed to have halted the sinking of very dense, saltier, colder water in the North Atlantic that drives the large-scale ocean circulation, the thermohaline circulation, that transports heat to Europe and North America.”
This is the key sentence, in particular the “is assumed” part. There is not a single piece of experimental evidence that supports the idea that the circulation would be disrupted. It is nothing more than conjecture based on a vague (and in my view incorrect) notion of how the circulation is sustained.
This is going to sound a little odd, but WUWT just convinced me to be alarmed by climate-change. If this theory really checks out, the information on Arctic sea ice here:
http://wattsupwiththat.com/reference-pages/sea-ice-page/
now has me worried. Combined with this one:
http://wattsupwiththat.com/2012/11/08/co2-could-prove-to-be-our-salvation-from-the-next-ice-age/
I am now concerned.
I wish I had spotted this earlier: On Wednesday, I ran into a guy who happens to be, apparently, one of the world’s leading ocean-modellers. (He got both gravity and atmospheric effects into a single model.) I wish I could have asked him about this.
I have just learned my lesson about not checking WUWT every day.