Younger Dryas climate event solved via nanodiamonds – it was a planetary impact event

From the University of California at Santa Barbara -By Julie Cohen |

Most of North America’s megafauna — mastodons, short-faced bears, giant ground sloths, saber-toothed cats and American camels and horses — disappeared close to 13,000 years ago at the end of the Pleistocene period. The cause of this massive extinction has long been debated by scientists who, until recently, could only speculate as to why.

This graphic is used to illustrate the Younger Dryas event – it is not part of the paper discussed below – Anthony

A group of scientists, including UC Santa Barbara’s James Kennett, professor emeritus in the Department of Earth Science, posited that a comet collision with Earth played a major role in the extinction. Their hypothesis suggests that a cosmic-impact event precipitated the Younger Dryas period of global cooling close to 12,800 years ago. This cosmic impact caused abrupt environmental stress and degradation that contributed to the extinction of most large animal species then inhabiting the Americas. According to Kennett, the catastrophic impact and the subsequent climate change also led to the disappearance of the prehistoric Clovis culture, known for its big game hunting, and to human population decline.

In a new study published this week in the Journal of Geology, Kennett and an international group of scientists have focused on the character and distribution of nanodiamonds, one type of material produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million square kilometers across the Northern Hemisphere at the Younger Dryas boundary (YDB). This thin, carbon-rich layer is often visible as a thin black line a few meters below the surface.


Kennett and investigators from 21 universities in six countries investigated nanodiamonds at 32 sites in 11 countries across North America, Europe and the Middle East. Two of the sites are just across the Santa Barbara Channel from UCSB: one at Arlington Canyon on Santa Rosa Island, the other at Daisy Cave on San Miguel Island.

“We conclusively have identified a thin layer over three continents, particularly in North America and Western Europe, that contain a rich assemblage of nanodiamonds, the production of which can be explained only by cosmic impact,” Kennett said. “We have also found YDB glassy and metallic materials formed at temperatures in excess of 2200 degrees Celsius, which could not have resulted from wildfires, volcanism or meteoritic flux, but only from cosmic impact.”

The solid line defines the current known limits of the Younger Dryas Boundary field of cosmic-impact proxies, spanning 50 million square kilometers.

The team found that the YDB layer also contained larger than normal amounts of cosmic impact spherules, high-temperature melt-glass, grapelike soot clusters, charcoal, carbon spherules, osmium, platinum and other materials. But in this paper the researchers focused their multi-analytical approach exclusively on nanodiamonds, which were found in several forms, including cubic (the form of diamonds used in jewelry) and hexagonal crystals.

“Different types of diamonds are found in the YDB assemblages because they are produced as a result of large variations in temperature, pressure and oxygen levels associated with the chaos of an impact,” Kennett explained. “These are exotic conditions that came together to produce the diamonds from terrestrial carbon; the diamonds did not arrive with the incoming meteorite or comet.”

Based on multiple analytical procedures, the researchers determined that the majority of the materials in the YDB samples are nanodiamonds and not some other kinds of minerals. The analysis showed that the nanodiamonds consistently occur in the YDB layer over broad areas.

“There is no known limit to the YDB strewnfield which currently covers more than 10 percent of the planet, indicating that the YDB event was a major cosmic impact,” Kennett said. “The nanodiamond datum recognized in this study gives scientists a snapshot of a moment in time called an isochron.”

To date, scientists know of only two layers in which more than one identification of nanodiamonds has been found: the YDB 12,800 years ago and the well-known Cretaceous-Tertiary boundary 65 million years ago, which is marked by the mass extinction of the dinosaurs, ammonites and many other groups.

“The evidence we present settles the debate about the existence of abundant YDB nanodiamonds,” Kennett said. “Our hypothesis challenges some existing paradigms within several disciplines, including impact dynamics, archaeology, paleontology and paleoceanography/paleoclimatology, all affected by this relatively recent cosmic impact.”

– See more at:

h/t to David Hagen.

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August 29, 2014 8:35 am

Interesting science. Love the new presentation of WUWT!

August 29, 2014 8:36 am

There’s always going to be arguments about. Hopefully research & time will provide a reasonably solid answer.
The prospect of a devastating hemispheric blast so recent is a bit chilling.

Steve Garcia
Reply to  beng
August 29, 2014 1:26 pm

beng –
You haven’t heard it all yet. Google “8.2 kya event”. That is 4,600 years even MORE recent. And then if you dare, start googling different ancient people’s accounts of serious stuff going on in the sky and raining down stuff – not only in the time of man, but also in the time when the accounts are still around. Those accounts aren’t useful battling against entrenched scientific thinking, but they all seem to say that their people saw something happen.
So you’ve got reason to be chilled by the idea. That’s why some people are working hard to get NASA to do some space defending – at least begin to prepare.

Reply to  Steve Garcia
August 29, 2014 6:06 pm

“You haven’t heard it all yet. Google “8.2 kya event””
That’s BTW exactly the time Plato gave for the sinking of Atlantis.

Reply to  Steve Garcia
August 30, 2014 7:53 am

From wikipedia:
“The 8.2 kiloyear cooling event may have been caused by a large meltwater pulse from the final collapse of the Laurentide ice sheet of northeastern North America—most likely when the glacial lakes Ojibway and Agassiz suddenly drained into the North Atlantic Ocean.[10][11][12] The same type of action produced the Missoula floods that created the Channeled scablands of the Columbia River basin. The meltwater pulse may have affected the North Atlantic thermohaline circulation, reducing northward heat transport in the Atlantic and causing significant circum-North Atlantic cooling.”

Reply to  beng
August 29, 2014 3:22 pm

YD was caused by a large comet impact. Please see
Nearly 200 years ago, geologists at The Royal Society ‘proved’ that the lands presently occupied were not inundated by a global flood. True. But that conclusion assumed that the Earth has has its present amount of water since its beginning. That is demonstrably false; presently occupied landscapes were not flooded in this event.
I will present material similar to that found at the link, above, at the upcoming Geological Society of America conference in Vancouver. (The link is to slides from a recent Esri user conference.)
In the words of Plato, this massive comet caused an “extraordinary inundation” – a nearly incomprehensible amount of water….

Richard G
Reply to  Michael Jaye
August 30, 2014 12:28 am

Interesting read from that link Michael Jaye.

Reply to  Michael Jaye
August 30, 2014 7:57 am

From what I saw in a documentary about the YD extinctions, they believe it was a comet air burst, thus no crater, sort of a mega-Tunguska Event.

Steve Keohane
Reply to  Michael Jaye
August 30, 2014 9:27 am

Thanks for the interesting link

Reply to  Michael Jaye
August 30, 2014 12:00 pm

Submerged canyons on the continental shelf were carved by now submerged rivers flowing on land when sea level was 400 feet lower during glaciations. Those deeper than that are caused by outwash floods, plus submarine earthquakes. among other terrestrial sources. No need to posit a giant comet impact.

Richard G
Reply to  Michael Jaye
August 31, 2014 3:37 am

While I was skeptical of a 2500 km comet containing 25% ice impacting in such a recent geological period, I found the underwater geological formations interesting. I was aware of the features down to 400 ft. depth from the last glacial sea level, but not the features below that.
I find it interesting that they all seem to terminate near the same depth below sea level. We really don’t know anywhere near as much below the ocean surface as we do for what’s above it. I find it hard to understand how flood outflows could affect the topography to such a depth and then suddenly terminate sharply near the same depth throughout the globe.
Is it because we don’t have detailed imagery below that depth, so we don’t see the details further down?Could it be that sea levels were once at that level? You would think that flood outflows throughout the earth wouldn’t so uniform in volume to terminate at uniform depths.
While I haven’t read much of the literature on this, I’m aware of plate tectonics, undersea currents, flood outflows and landslides being proposed as having shaped the landscape of the seafloor. I’m sure someone well read in undersea geology could provide some knowledge or data.

Gentle Tramp
Reply to  Michael Jaye
September 1, 2014 7:16 am

These are interesting new ideas. BUT: Whereto has all the water gone which must have been on earth during e.g. the jurassic era when great areas of the continents were submerged under sea water???

Reply to  Michael Jaye
September 1, 2014 6:43 pm

If I am correct, the deepest canyon from a river draining into the ocean is the Congo. You can clearly see its canyon on Google Earth. You might add it to your list. While your thesis is interesting, it seems like a giant comet producing the volume of water you claim, would create such a huge difference in our understanding of the planet, that someone would have come up with the idea a long time ago. And I think that would have been an extinction event of nearly everything on the planet, far greater than any of the other impact extinction events.
I could see a small comet adding to the present volume of water and a combination of ice melt and comet water raising sea levels a few hundred feet, but to have the earth as dry as you indicate in one of your pictures seems very extreme. Especially since you think it was that dry a mere 6kya.

James the Elder
Reply to  beng
August 29, 2014 8:15 pm

Judging by the map, somewhere in or around NA there should be an impact site. I does fit nicely with the findings on the East Coast of a sterile sand layer from around that time period indicating a disaster that forced the Clovis survivors westward. There is an impact crater in the Hampton Roads/Norfolk area of VA, but it’s not a candidate, missing by some 35 million years.

M Courtney
August 29, 2014 8:39 am

This has appealed to me for years.
But I know it has been controversial for years too.
In The Younger Dryas impact hypothesis: A requiem previous such hypotheses were found wanting.
I quote,

In summary, none of the original YD impact signatures have been subsequently corroborated by independent tests. Of the 12 original lines of evidence, seven have so far proven to be non-reproducible. The remaining signatures instead seem to represent either (1) non-catastrophic mechanisms, and/or (2) terrestrial rather than extraterrestrial or impact-related sources. In all of these cases, sparse but ubiquitous materials seem to have been misreported and misinterpreted as singular peaks at the onset of the YD.

Maybe this time it’s different.

Reply to  M Courtney
August 29, 2014 8:49 am

The research publication goes to great lengths addressing this and other criticisms. James Kennett is an accomplished, careful, and thorough research scientist.

Steve Garcia
Reply to  Gary
August 29, 2014 1:55 pm

I agree. If you read all of the YD impact team’s papers, the “forensics” of it all will overwhelm you. He does his homework, and so do the others.
On the other hand, the field work is either sloppy in taking samples from the correct layer, or they take too wide of a sample, which waters down the sample in the lab – which then flattens out the spikes in the data. For several of their papers, the skeptics actually didn’t even DO any field work of their own – making those papers little more than opinion pieces. (I am not making this up.)

Reply to  M Courtney
August 29, 2014 9:51 am

It always was different. There was a (2012??) reanalysis of the work which found that the investigators with the negative findings had apparently not found what they did not want to find – confirmation bias. Reanalysis showed the very samples that were found negative for impact markers were loaded with them. The reanalysis work had a very critical discussion of the methods employed.

Steve Garcia
Reply to  Duster
August 29, 2014 2:07 pm

Confirmation bias is exactly what it seems to me, too.
James Wittke was the one with the rebuttal paper, and it basically shredded all the supposed falsifying evidence. But the skeptics were too dense to recognize that they had been body slammed.
The thing is now even some people that thought this was a possible real thing now think that the skeptics have been successful in tearing the idea down. But basically all the YD team can do is keep testing other evidence. The world seems to simply not get it.
They have probably more evidence for this YD event than Luis Alvarez and his supporters had for the dinosaur killer of 65 million years ago. Sites on 4 continents, more than half dozen materials normally associated with impacts (but, oh no, not in this case…). All that is needed is a crater.
But Peter Schultz working at NASA Ames convincingly showed that a hyper velocity impact onto an ice sheet will likely NOT leave a crater underneath. The crater WAS in the ice itself – which got shattered, melted, vaporized, and blown away. And with it went the crater.
Be aware that the ice sheet was deeper than Barringer Crater. In fact, it was about as deep as Barringer Crater is in diameter. With the ice attenuating the impact, any crater under that spot will likely be FAR differenrt from what is currently allowed as “good craters”.

Reply to  Duster
September 3, 2014 7:31 am

Wouldn’t that make it “infirmation bias” instead ? 😉

Steve Garcia
Reply to  M Courtney
August 29, 2014 1:50 pm

Actually, one of Kennett’s cohorts rebutted that supposed requiem quite thoroughly. I was just re-reading some of that this week. The samples taken were done as if by amateurs – because they sampled the wrong layers. They also did not have an impact specialist on their skeptical team, though they did have a good nanodiamond guy (Tyrne Daulton – who may be heard from again in the near future.
But as Ted Bunch communicated to a friend,

“…not to worry, Dalton is a competent scientist and did what he could do with the materials given to him. The problem lies with [Andrew] Scott and Pinter.”

That was back in 2010, about the “Requiem” paper.
You also have to understand that Andrew Scott is a forest fire guy. That is what he studies. But IMHO he also wants forest fires to be important – in much the same way, that Michael Mann and Phil Jones want climatology to be important. If someone comes up with a scenario that aces forest fires, especially if it is a catastrophic hypothesis, that would mean he has to fit his forest fires in as second fiddle.
I just looked them up the other day, and none of their “requiem” team was an archaeologist, with experience taking careful samples from the side of a pit.
In addition, that black layer with the nanodiamonds – spread over 50 million square kms makes it kind of more than just your evreyday, garden variety brush fire.

August 29, 2014 8:42 am

Well, I’m happy to read it was not CO2!

Alberta Slim
Reply to  Andres Valencia
August 29, 2014 10:28 am

Andres .. Please give the spin doctors a little more time ;^D

Reply to  Andres Valencia
August 29, 2014 11:18 am

A dry ice comet?

Reply to  inMAGICn
August 30, 2014 8:35 pm

Oh, that could be sublime!

August 29, 2014 8:51 am

“Well, I’m happy to read it was not CO2!”
Of course not… it’s CO2 that was responsible for the near-vertical temperature readjustment (7) though, as well as (1)… what else could explain it?
or… the proxies of 1/2, 5/6/7 are messed up for some reason. Without those anomalies it looks like a relatively smooth rise.

M Courtney
Reply to  kcrucible
August 29, 2014 8:57 am

One of the past theories was that the impact was from a radioactive comet.
This led to the disproportionate killing off of large animals (radioactivity built up in the fat cells).
Also, it was hypothesised that it led to the Carbon dating being messed up causing the recovery to appear like it happened overnight.
I can’t find the paper… I think it was by Firestone.
I remain sceptical but I do like the way “it is consistent” with the evidence

M Courtney
Reply to  M Courtney
August 29, 2014 8:58 am

It may have been this that I just found linked on Wikipedia.

Reply to  M Courtney
August 29, 2014 10:14 am

Firestone is the originator of the YD impact hypothesis. I heard him give the original presentation at the Clovis in the Southeast conference in 2005. The conference was hosted by an archaeologist, Al Goodyear – which made for some tiresome confusion ;-). The YD marked by an apparent radio-carbon anomaly that correlates with other environmental signatures that mark the YD. However, even if the anomaly is real, it doesn’t seriously change just how abrupt the onset and progression of the YD was.
The radioactive comet idea really is humbug though. Radiocarbon is caused by cosmic rays and not even a comet that glowed in the dark would be that radioactive to begin with. It could not under any circumstances be radioactive enough to generate a global anomaly. Besides, objects coming in from the Oort Cloud or the Kuiper Belt have been in deep space for very long periods, possibly since before the solar system formed. That means that only very long-lived radioisotopes would have survived, and the longer-lived the isotope, the less radioactive it is. No amount of biological amplification is likely to significantly increase the radiation hazard from such isotopes to the point that large mammals would be seriously affected.

Reply to  M Courtney
August 29, 2014 12:40 pm

Even if the comet was pure plutonium, after impact the remains would be scattered over half of the globe. The total radiation at any location would be too low to kill anything.
Regardless, as the KT impact showed, these things are most stressful on the largest animals anyway, even without postulating a radiation affect.

Reply to  M Courtney
August 29, 2014 5:54 pm

Firestone and Goodyear? Really? ROTFL.

August 29, 2014 8:52 am

Or, could it be related to the thunderbolts project?

Steve Keohane
August 29, 2014 8:53 am

Very interesting. Didn’t Velocovsky covern an ancient SW American Indian myth of something in the sky to the northeast prior to devastation?

Steve Garcia
Reply to  Steve Keohane
August 29, 2014 2:11 pm

Thanks for that. I will have to try to see about that. I read it like 40 years ago…

August 29, 2014 8:53 am

Where was the impact? Shouldn’t that crater be evident?

M Courtney
Reply to  tteclod
August 29, 2014 8:59 am

Thought to be over the N American Ice sheet.
It melted.

Reply to  M Courtney
August 29, 2014 9:00 am


Reply to  M Courtney
August 29, 2014 12:36 pm

That makes the stratigraphic reconstructions really difficult. That’s probably why they’re having such a hard time tying all the evidence together for the event, much less the location. Identifying the plume would be difficult as advancing/receding ices containing ejecta move around and then deposit after melt and runoff. I don’t envy them that task.

Steve Garcia
Reply to  M Courtney
August 29, 2014 2:14 pm

tteclod –
No, it is not “convenient.” With expanded glaciers covering down to 40° latitude it is ENTIRELY likely that it hit on the kilometer thick ice sheet. Just as it is likely (more so) for an object to impact the ocean instead of the land. And yet, Tunguska and Chelyabinsk air burst over LAND, which is only 29% of the Earth. Amazing, isn’t it?

Steve Garcia
Reply to  M Courtney
August 29, 2014 2:16 pm

Anthony –
I’ve got some interesting stuff on thadebris fieldt. At least A debris field. Not good enough to do anything with yet, though. But amazing and tantalyzing.

Steve Garcia
Reply to  M Courtney
August 29, 2014 2:18 pm

NielsZoo –
There are at least three lines of evidence that point to the Great Lakes – but dating on one of them is haywire, so it isn’t quite possible to tie it to the time of the YD onset.
I wish I was an OSL man right now…

Reply to  M Courtney
August 29, 2014 3:44 pm

Anthony – please see my comment and link, above. It was an extraordinary event – planet changing. Impact is evident at Google Earth/Maps(satellite view).

Joel O’Bryan
Reply to  tteclod
August 29, 2014 9:11 am

the 1908 Siberian Tunguska event completely flattened ~2000km^2. air bursting comet or meteorite less than 200meters in size. the YDB would have been substantially larger but it too could have been an airburst. or most heavier impacts over the ocean.

Reply to  Joel O’Bryan
August 29, 2014 9:35 am

Even Tunguska has craters. For a global event to produce the proposed evidence, carbon nano diamonds, either the air burst would be the source of the carbon, which requires still more complex explanation of the celestial body with adequate carbon to spark the event, or there is an impact site with abundant carbon. One may reasonably estimate a center of impact, then go hunting for the crater. Even glacial concealment should be easy to consider.

Reply to  Joel O’Bryan
August 29, 2014 1:00 pm

Or a swarm of icy Tunguska-sized objects. All air-blasts w/no craters & little stone or metals. The wide area of charcoal/nano-diamond layer supports that postulate.

Reply to  Joel O’Bryan
August 29, 2014 1:04 pm

How about a very large object that broke up in the atmosphere, impacting at a number of places across the NH?
/Mr Lynn

Reply to  Joel O’Bryan
August 29, 2014 3:49 pm
Reply to  tteclod
August 29, 2014 10:27 am

There was a paper out in 2007 which said much as the above and mentions nanodiamonds.

Abstract – 2007
Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling
A carbon-rich black layer, dating to ≈12.9 ka, has been previously identified at ≈50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at ≅12.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at ≈12.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.

Steve Garcia
Reply to  Jimbo
August 29, 2014 2:20 pm

KImbo –
Yeah, that is the paper that started it all.

Reply to  tteclod
August 29, 2014 12:50 pm

Tunguska created no craters.

Reply to  MarkW
August 29, 2014 2:14 pm

Check again.

August 29, 2014 8:55 am

Was the temperature graph part of the paper? I didn’t see it in the press release and was unable to view the whole paper.

Reply to  MinB
August 29, 2014 9:01 am

I’d like to know that too.

Reply to  MinB
August 29, 2014 9:27 am

No it was not. It appears to be something Anthony had on hand to help show what the Younger Dryas cooling period was.

Chris Schoneveld
Reply to  Jimmy
August 30, 2014 12:13 am

Could you give us the reference of that other paper?

John Boles
August 29, 2014 9:00 am

Yes, BTW, I like the new format, it flows better and is easier to read. Good work Anthony!

Reply to  John Boles
August 30, 2014 8:38 pm

I like the larger figures, and being able to address someone’s comment directly, instead of posting a reference to it waaaaay at the bottom.

Tom O
August 29, 2014 9:01 am

“Situation solved. No need to look here again. We’ve done this, now move on to something else.” It’s a nice theory, has some supporting evidence, but is it “solved?” Nothing that deals with the past through proxies is every solved, but it does present a possibility. When did scientists start saying “we solved this” anyway? I always understood that there was no solutions, just theories and possible explanations. How much better these new scientists are than they were, say 50 years ago, because whenever they take on a situation for study, they always “solve it.”

Reply to  Tom O
August 29, 2014 9:35 am

Tom, this is basically climatology. Expect outrageous and unwarranted claims of certainty.

Steve Garcia
Reply to  Tom O
August 29, 2014 3:07 pm

Tom O –
I laughed at that. A little bit of absolutism going back and forth between their papers. One side names theirs a “Requiem” for the YD impact hypothesis. So Kennett has to come back with an in-your-face, too.
Personally, the amount of “forensics” on this impact are quite strong and unassailable. The skeptics tried – and failed. They can only nibble around at the corners, like wolves trying to work a caribou pup out of the herd. They can’t do a thing to the core of it. Especially as there is a “suite” – several different lines of evidence, all pointing to the same thing – an impact. But if all of you think defending CO2 against warmists is a bear, try selling geloogists and astronomers on catastrophism only 170 years after they thought they’d buried The FLood forever.
I am telling you: They will fight this until they are blue in the face. You’ll have to claw Gradualism out of their cold, dead hands. Because if this is right, then during times of catastrophe Gradualism wasn’t working anymore, and that means they’ve lost control of geological history. Even comet Shoemaker-Levy hitting Jupiter 20 good whacks in 1994 (20 years ago now!) didn’t let some of them let loose of their “comets don’t hit planets in our lifetimes” mantra.
The Catastrophe Barrier will make the Clovis Barrier look like child’s play. ESPECIALLY if the darned thing hit on the ice sheet and there isn’t a pristine Barringer-type crater.

Doug Proctor
Reply to  Steve Garcia
August 29, 2014 11:36 pm

Geologists -I are one – recognize catastrophes as numerically insignificant but representationally dominant in the geologic record. The one in a thousand year flood wipes out all evidence of lesser floods AND creates a changs of such great character that it withstands the modifications of everyday processes.
The principle that has survived the Biblical fight re The Deluge, is that the processes we see today are the processes that existed yesterday. With local necessary modifications, they are universal processes, applicable to the surface of Mars and Titan today as much as the Earth of 350 million years ago. That being said, catastophism must be viewed skeptically. Like CAGW, the idea is that the period of concern is or was “special”; normal patterns or expectations are irrevevant. This is a dangerously simple and useful concept, especially if one has a career to consider (Michael Mann), a legacy to create (b. Obama) or a fortune to create for oneself or others (Al Gore).
Still … Comets …
There was a lot going on 12,900 years ago. It strikes me that while disasters generally results from a connected series of small problems, including an extraterrestrial coup-de-gras is a trifle melodramatic. Ain’t saying it’s untrue, just sayin’ the story is a little CNN to warrant grabbing and running with if you don’t like the taste of crow.

Reply to  Steve Garcia
August 30, 2014 10:03 am

Well said, Doug Proctor, below.

Joel O’Bryan
August 29, 2014 9:04 am

the KT boundary was recently revised to 66.038 ± 0.025/0.049 Mya.
Science 8 February 2013:
Vol. 339 no. 6120 pp. 684-687
DOI: 10.1126/science.1230492

Steve Garcia
Reply to  Joel O’Bryan
August 29, 2014 3:21 pm

Hahahahaha –
I freaking LOVE how they talk about things millions of years in the past as if they really bloody know it was 65 vs 66 – or 66 vs 67. Yep, the Miocene started at dawn on the 1st of January, 12.7000000000000 mya.
When the new Carbon14 calibration curves (IntCal13) came out the YDIH was no longer at 12.9kya; it was at 12.8kya. Literally, there was Analiese van Hoesel bitching and moaning a few weeks later that the whole YDIH is full of crap because some of the layers didn’t match up with the new 12.8kya date. She said they were off by 100 years. Which James Wittke took her to task about.
AS IF! As if they really, REALLY know it is 12.8kya now.
But they will run around the very next day after one of these shifts like the Out-Of-Town Experts that they all claim to be, spouting exact, ROCK SOLID dates – dates that are almost as certain to change in the next 25 years as I am to take another breath in 3, 2, 1.. . . YEP, still here, folks!
(And the FUNNIEST thing is that they pronounce REALLY tight C14 uncertainty ranges – like +/- 35 years at 13,000 years ago. I TOTALLY respect the guys doing it, but the uncertainty bars are just too tight – IMHO. I mean, they just adjusted the calibration curve by THEE TIMES THAT.)
But then people like van Hoesel take the damned things literally. If you are off 40 years, well, to her that is not a match. (Forehead slap time…)

Steve Garcia
Reply to  Joel O’Bryan
August 29, 2014 3:25 pm

And then there are the dates on the climate reconstructions. They all have error bars for the AMPLITUDE, but they never show error bars for the time element. And that DOE make a difference – especially when homogenizing multiple proxies and many different data sets – all of which DO have error bars on the ages of the samples. It shows up on every C14 test and is there for ice cores, too. But every age of every sample, every tree, is treated as if it, too, is accurate to 7 zeros.
What it does in homogenization of data is that if several close dates have their peaks or valleys shifted in time, that tends to flatten out the rolling averages even MORE. I’ve said before that that is ONE of the reasons Mann’s Hockey Stick has a straight shaft.
End of rant.

August 29, 2014 9:20 am

What’s the source of the Greenland temp graph in this article?comment image
Showing current temperatures almost as low as LIA 😕

Reply to  Greg
August 29, 2014 9:58 am

The Data looks like it came from a 1997 paper by Cuffey and Clow reported in the J. of Geophysical Research. The right side of the graph is incorrectly labeled. What is labeled as the MWP is actually the Roman warm period 2,000 YBP with a sharp Dark Ages cooling followed by the MWP 1,000 YBP. The arrow for the present global warming shows the LIA with the tiny blip at 0 BP. The scale of the graph makes the modern warming hard to discern.

Reply to  Suzanne
August 30, 2014 10:01 am

It’s not the Roman Warm Period. It’s the Sui-Tang WP, which occurred during the Dark Ages Cool Period. The Roman is to the left.

Reply to  Greg
August 30, 2014 12:16 am

It’s the GISP2 ice core data from Greenland, Alley et al. (2004):
The data start at 0.0951409, which is 95 years “before present”, where “present” is, by convention, 1950. So the point at which the data end, inexplicably marked “Present global warming”, is actually 1854.

Reply to  DavidR
August 30, 2014 4:55 am

The graph is somewhat misleading without it being clearly pointed out that ‘present global warming’ actually means 1854. To give proper context it needs to be brought up to date. The modern warming should be at least within touching distance of the MWP no matter what the scale of the graph

Reply to  DavidR
August 30, 2014 9:25 am

See post below for link to Kobashi et al. (2011). The measured average temperature at the GISP2 site for the decade 2001-2010 was -29.9C, which is almost exactly the maximum on the vertical scale on the above chart. However, note also that Kobashi et al. found higher temperatures in the MWP than Alley et al. using a different method. See figure 1 in the paper (it’s Open Access).

Steve Garcia
Reply to  DavidR
August 30, 2014 12:09 pm

BTW, for those who don’t know, with a resolution of greater than 200 years, ice cores cannot be used for high-res dating. The reason for this poor resolution is that the gases migrate up and down within the ice – giving a kind of a fuzzy view of what the gasses could possibly tell us.

Reply to  DavidR
August 30, 2014 2:27 pm

It was just a picture of the paper’s figure 1, which you can access from the first link. For some reason the system here didn’t like the format.

Reply to  Greg
August 30, 2014 12:47 am
Reply to  DavidR
August 30, 2014 9:50 am

The second link says ‘Forbidden’ so I cant see Figure 1

August 29, 2014 9:21 am

I think the missing salient point here is how did CO2 cause the Younger Dryas and the subsequent rebound? And maybe more importantly how did CO2 maintain the subsequent stable temperatures?
Could it be that maybe, just maybe CO2 is an inconsequential trace gas?

August 29, 2014 9:27 am

So if it hadn’t have been for the impact event the warming period would have been another ~4,000 years, pushing the interglacial out to over 14,000 years. Great to know that with this info we really could be on the cusp of a new ice age.

Steve Garcia
Reply to  BFL
August 29, 2014 3:37 pm

The dates are 18,000ya, 12,800ya, and 11,500ya, for the end of the Last Glacial Maximum, the Younger Dryas onset, and the Younger Dryas termination. The YD only lasted 1300 years. (Some say 1,000.)
Seeing as the vast majority of the Pleistocene – which we are still in – was ice ages, these last 11,500 years are distinctly an anomaly. If we head back into one there is SOME chance that it could “take” and we could be SOL.

D. Cohen
Reply to  BFL
August 30, 2014 7:52 am

The pattern of the past interglacial-glacial cycles is that the descent into a colder climate from the previous interglacial is, overall, a relatively gradual process, with the coldest temperatures occurring just before the next interglacial starts with a bang (that is, a rapid climb into a warmer climate). That is one of the reasons why the abrupt cooling back into icy conditions that occurred during the Younger Dryas stands out as something worth investigating. Another reason is that some specialists in human prehistory say that the rapidly deteriorating climate in areas which had enjoyed substantial population growth during the immediately preceding warm period may have led to the invention of agriculture to create a more reliable source of food.

August 29, 2014 9:33 am

There could have been an impact at the older YDB but we don’t need it to cause whatever the Younger Dryas was. The only proxy that cleary shows large deviations is water/ice isotopes, d18O, d2H and deuterium excess in the ice cores and speleothems of the northern hemisphere. There is not any other record or proxy that supports the conclusions we have drawn from that, on the contrary, nothing fits, for instance this one:
But it’s essentail to note that these three isotope excursions are exactly the same during the Dansgaard Oeschger events. Consequently, if you need an extraterrestrial event to explain the Younger Dryas, you’d need to find some 25 more extraterrestrial events during the late Pleistocene to explain the other Dansgaard Oeschger events as well.
More over many of the megafauna did not go extinct at the Younger Dryas boundary. Most species perished much earier world wide, but the iconical Woolly Mammoth thrived during the Yonger Dryas in Siberia and disappeared only well after the start of the Preboreal/Holocene. Moreover we keep witnessing the dismissal of young Mastodon carbon dates in America (and only mastodons), because that’s obviously impossible because the Mastodon died out at the Younger Dryas boundary, so that evidence must be false (what fallacy is that?)
But also youngest date of the extinct giant deer/ Irish Elk from Siberia is 7700 radio carbon years. So why do we think that the megafauna extinction is limited to the Younger Dryas boundary?
Comic impact, sure, why not, but you can’t blame it for all the things we see changing at the end of the Pleistocene.

Reply to  leftturnandre
August 29, 2014 12:03 pm

exactly where are the 25 other events

Steve Garcia
Reply to  leftturnandre
August 29, 2014 3:49 pm

Yes, people often point out that the Younger Dryas isn’t unique. (But don’t tell the biologists that! – THEY are the ones who made a big deal out of it, LONG before Richard Firestone et al came along with the YDIH.
And that is supposed to shut up YD impact people. None of the others actually says squat about the Dansgaard-Oeschger events. (BTW, don’t forget the Bond events – also at 1470-1500 year intervals, for what it is worth). But I’ve tentatively suspected that the D-O events and the YD impact ARE connected. How so? Well there is something called the “8.2 kya event” (google it), and THAT is one of the Bond events. And THAT one is also suspected of being an impact – by people FAR removed from Firestone and Kennett.
My thinking is very rudimentary, but basically it is to consider that all of the D-O events may possibly be impacts.
As you can tell from the GISP2 graph, those are SERIOUS temperature excursions – 10 or 20 or 30 times as big as what warmists are worried about. And they all come on so damned quickly. That is not Gradualism doing that. Internal system forcings I just don’t think can do that.
Crazy idea? Yeah, that is what everybody tells me. But ten years ago asserting ANY impacts connected with ONE D-O warming would have gotten one an invite to the straight jacket store… We now have TWO. As we here all know, correlation is not necessarily causation. But with two of them matching to Bond events and at least on of the two matching with a D-O event, it seems possible, if not probable.

Reply to  leftturnandre
September 3, 2014 7:47 am

“But it’s essentail to note that these three isotope excursions are exactly the same during the Dansgaard Oeschger events. Consequently, if you need an extraterrestrial event to explain the Younger Dryas, you’d need to find some 25 more extraterrestrial events during the late Pleistocene to explain the other Dansgaard Oeschger events as well.”
Multiple fragments of the same object. IMO this repeated isotope deviation is evidence for impact, not against.

Rud Istvan
August 29, 2014 9:35 am

There is much evidence that the Younger Dryas resulted from ‘sudden’ diversion of Lake Agassiz drainage (meltwater as the southern terminus of the Lauentide ice sheet) from the Mississippi valley hence the Gulf to the St Laurence hence the North Atlantic. This disrupted the thermohaline circulation until the fresh water pulse dissipated.
It is of course possible that a cosmic impact was responsible for the diversion rather than the theorized melting of ice dams.
It is not possible that the Younger Dryas itself was responsible for the North American megafauna extinction event at around this time. Those fauna were adapted to the ice age that was receding, and a return to those conditions per we would not have mattered. Clovis over hunting has always seemed a bit of a stretch. Too many animals, not enough hunters. This does provide a testible alternative. All the megafauna species would have disappeared from the fossil record at the time of the event. Worth researching whether that is true, for example at the La Brea tar pits or other known megafauna deposits like the recent cave (prior waterhole) discovery in Utah IIRC.
Refreshing to read about real science rather than climate ‘science’.

Tom J
Reply to  Rud Istvan
August 29, 2014 10:33 am

Those hunters had a nuclear weapon in the form of what would later be called a buffalo jump. Stampeding herd animals in the direction of a cliff could wipe out the whole heard. Thus they ended up killing far more than they had too but it was the easiest way to feed and provide animal skins to a tribe. The excess would, of course, rot.

Paul In Boston
Reply to  Tom J
August 29, 2014 12:39 pm

Buffalo jumps were used by the Indians in historic times. Here’s a description from the Lewis and Clark expedition.

Reply to  Tom J
August 29, 2014 1:04 pm

And more importantly much safer for the hunters

Reply to  Tom J
September 3, 2014 7:51 am

“Buffalo jumps were used by the Indians in historic times.”
And yet they never managed to make species extinct again. Figures…
Oh wait, what if something caused both the extinction AND the human migration ? We already know from both Triassic-Jurassic and Cretaceous-Paleogene extinctions that when something BAD happens, big animals suffer first and foremost while the most adaptable species strive and benefit from the destruction.

Steve Garcia
Reply to  Rud Istvan
August 29, 2014 3:56 pm

Actually, Wallace Broeker – the man responsible for the Lake Agassiz meltwater hypothesis – a couple of years ago admitted that that idea was a no go.
Check out this WUWT post from June 16, 2012:
Some people have been trying to resurrect the idea by invoking a Mackenzie River meltwater pulse instead – but that one comes out about 4,000 km away, on the farthest side of Canada you can go to from the mouth of the St Lawrence.

David L. Hagen
Reply to  Rud Istvan
August 29, 2014 7:32 pm

At Climate Etc, Rud Istvan refers to an opposing review disputing the cosmic impact evidence by Holliday et al., The Younger Dryas impact hypothesis: a cosmic catastrophe from J. Quaternary Sciences 29: 525-530 (2014).

Mike Smith
August 29, 2014 9:43 am

What, no models!
What kind of climate work is this?

johann wundersamer
August 29, 2014 9:45 am

Oh Ja, a planetary impact.
Extinctet mastodonts 13.000 years ago:we’ve got nanodiamonds ’50 million
square kilometers across the
Northern Hemisphere’:what so impactet planet earth:a SUV?
Or maybee:13.000 years ago 13.000 SUV’s impactet planet earth to produce some nanodiamonds colleterating mastotonts.
Time sharing with them other yellow pages all over the planet earth.
Astounded. Hans

August 29, 2014 9:50 am

I guess the theory that the extreme warming by the Bolling Oscillation which melted so much of the continental ice sheets so quickly thus changing the thermohaline circulation causing a re-glaciation, can be put aside into the corner … for now. So much science; so many theories; when will it all become settled?

Alberta Slim
Reply to  JimS
August 29, 2014 10:44 am

Jim… Ask al Gore. He knows everything…. ….;^D

Reply to  JimS
August 29, 2014 1:06 pm

Perhaps the comet caused the sudden warming

Steve Garcia
Reply to  JimS
August 29, 2014 4:02 pm

It will never be settled sa long as they keep putting patches on to SOMEHOW make the science explain what the previous idea couldn’t. Not without patches upon patches upon patches – ala MicroSoft and Windows. NOT a good model to follow.
I call the patches “crowbars”, because they pull them out ANY time the have a falsification, and they just pull speculations out of their BUTTS and try to force the new thing to make the old idea fit the inconvenient facts. But piling speculations on top of falsified hypotheses is not science. It’s just hip-shooting and hard heads.
The thing is, that they just need to throw OUT the falsified ideas and stop long enough to derive BETTER ideas from the bottom UP. But they identify too much with one idea, and they don’t seem to let it go. So, what e have is several falsified things still in the mix, cluttering up not only the overall, but the brains of those who stubbornly refuse to let it go.

August 29, 2014 9:55 am

YDB is rapid but not exceptionally so. Other changes around that period were as great in magnitude and not that much slower.
There was already a huge general cooling since the initial false start to the deglaciation.
The end of YD was more remarkable and this time it stuck.
CO2 levels were low enough at the glacial maximum that the increase would have had a GW effect acting as a positive feedback to whatever was driving warming. A positive feedback would also cause snap changes like YDB and YD end, it works both ways. Methane could also be a cause of GW +ve feedback.
That kind of latching behaviour is typical of +ve feedbacks ( which have to be bounded by stronger negative f/b ).

Bruce Cobb
August 29, 2014 9:58 am

Maybe. Or, it could be the heat was simply hiding in the deep oceans, like it is doing now. Heat is sneaky that way.

August 29, 2014 10:04 am

The temperature graph is mislabeled & misdrawn. The supposed Medieval Warm Period is actually the Sui-Tang WP, a warm interval during the Dark Ages Cold Period. The following peak is the Medieval & should be at least as high as the S-T but lower than the Roman. The stretch labeled “Little Ice Age” is the latter DACP. The real LIA comes after the Medieval Warm Period.

Bill Illis
August 29, 2014 10:06 am

Greenland and Antarctica temperatures over the last ice age for reference. How many Younger-Dryas-type cooling events can you count here.

Reply to  Bill Illis
August 29, 2014 10:20 am

Interesting graph, Bill.
Upto about 40ka BP the large events seems fairly well synchronised. I’d guess that phase shift before that are more likely time-scale calibration errors than bipolar disorder, though the main warming leading to deglaciation seems to have started a good 10ka earlier in SH.

Reply to  Bill Illis
August 29, 2014 11:35 am

As I mentioned earlier those alleged cooling events are the Dansgaard Oeschger events. But what you actually see is the oxygen and hydrogen isotope ratios in the ice cores, which are supposed to be proxies for temperature. However this is a logical fallacy. Affirming the Consequent. If it rains, the streets are wet. The streets are wet, hence it rains. Consequently: when it’s cold the isotopes are low. The isotopes are low, hence it was cold. Not necesarily. How about for instance arid versus moist?

Reply to  leftturnandre
August 29, 2014 12:53 pm

There are plenty of paleontological records that shows that the D-O events really were temperature shifts. Or at least that animals and plants (including humans) reacted as if they were climate shifts.

Steve Garcia
Reply to  Bill Illis
August 29, 2014 4:10 pm

One thing that we need to be aware of with the Greenland and Antarctic ice cores is that, being high latitude locations the cores may OR may not represent the rest of the world.
Especially if the YD impact idea is true, then Greenland was directly downwind of the event near the Great Lakes (as I see it, anyway). And if the burning in N America was from Alberta to the Carolinas, then that was a broad front of smoke headed toward Greenland, one that could hardly miss the place.
THAT could have had a very quick and very heavy effect on the ice in central Greenland. It would likely have been the most seriously affected place outside mainland N America.

August 29, 2014 10:13 am

“A new stomatal proxy-based record of CO2 concentrations ([CO2]), based on Betula nana (dwarf birch) leaves from the Hässeldala Port sedimentary sequence in south-eastern Sweden, is presented. The record is of high chronological resolution and spans most of Greenland Interstadial 1 (GI-1a to 1c, Allerød pollen zone), Greenland Stadial 1 (GS-1, Younger Dryas pollen zone) and the very beginning of the Holocene (Preboreal pollen zone). The record clearly demonstrates that i) [CO2] were significantly higher than usually reported for the Last Termination and ii) the overall pattern of CO2 evolution through the studied time period is fairly dynamic, with significant abrupt fluctuations in [CO2] when the climate moved from interstadial to stadial state and vice versa. A new loss-on-ignition chemical record (used here as a proxy for temperature) lends independent support to the Hässeldala Port [CO2] record. The large-amplitude fluctuations around the climate change transitions may indicate unstable climates and that “tipping-point” situations were involved in Last Termination climate evolution. The scenario presented here is in contrast to [CO2] records reconstructed from air bubbles trapped in ice, which indicate lower concentrations and a gradual, linear increase of [CO2] through time. The prevalent explanation for the main climate forcer during the Last Termination being ocean circulation patterns needs to re-examined, and a larger role for atmospheric [CO2] considered.”

Reply to  Jimbo
August 29, 2014 10:51 am

A drop from >400ppm to 200ppm around YDB for a drop of about 8 degrees C, that’s about 25 ppm/K getting sucked back into sinks on a multi centennial scale. Presumably mainly oceanic absorption.
Considerably larger than figures like 8-10 ppm/K I’ve seen coming from ice cores.
If the calibration is accurate here, it suggests that there is significant physical blurring going in ice samples.

Reply to  Jimbo
August 29, 2014 12:54 pm

Jimbo and Greg, one need to take the absolute CO2 levels of stomata data with a grain of salt. Stomata data have a much better resolution than ice core data, but they are a proxy for local CO2 levels over land, not background levels as the ice core CO2 data are.
Local CO2 over land in general is higher than background, as a lot of organic debris decays over the year(s). In cases of abrupt climate change like the Younger Dryas was, the amount of debris can change a lot, as plant growth (and this its debris) is a lot less at colder temperatures. With as result a change in local CO2 bias. The main wind direction also can have changed and the plant growth/plant types in the main wind direction…
Anyway, while the ice cores resolution is worse, that doesn’t change the average CO2 level of the ice core over the time of resolution, as there is no measurable diffusion in ice cores. Thus if the average of the stomata data differs from the ice cores over the period of the latter’s resolution, then the stomata average is certainly wrong.

Reply to  Jimbo
August 29, 2014 12:58 pm

The complete paper is avalable here:
It contains data from several öther stomatal studies that supports the results. There apparently really were rises and drawdowns of 100 ppm or more in just a century or so.

August 29, 2014 10:15 am

Bill Illis
August 29, 2014 at 10:06 am
The same D/O Cycles & Heinrich Events are evident in previous glaciations & transitions to interglacials, along with Bond Cycles within the interglacials.
If there were an impact around the time of the YD (which I doubt on the flimsy basis of the evidence), there’s no reason to imagine that the putative event caused the YD.
Does only Kennett’s team find support for their hypothesis? Is no one else looking?

Steve Garcia
Reply to  milodonharlani
August 29, 2014 6:48 pm

None of the other rapid changes in the D-O, the Heinrich events, nor the Bond events are coincident with a black layer with the nanodiamonds and other impact markers. (The only other layer with any similarities is the K-T boundary. And we know what that one did (we think).
The black layer shows up across N America from Alberta to the Carolinas and down to Blackwater Draw and other places, as well as in BELGIUM, and SYRIA, and in S America at the northern end of the Andes.
Like it says above, the black layer is found in an area that spans some 50 million square kms, so it was not small. It was not even medium nor Goldilocks-sized. This was the mother of all firestorms on one of the three biggest continents. And it reached across the Atlantic AND the Mediterranean, as well as the Gulf of Mexico and Caribbean. Obviously it sent monumental amounts of soot and smoke into the air, which if it laid down a layer in Syria stronly suggests that the smoke went around the world. We are talking of a smoke cloud that was
. That the impact “forensics” lie at the very bottom of that black layer at its interface with the next lower soils, indicates that the impact markers and the black layer occurred together. And that the black layer was added to, to make a thickness that averages about 10 cm (4″).
50 million km^2 is basically 10% of the Earth’s surface. That is far bigger than any natural event in the known history of mankind.

August 29, 2014 10:16 am

Greg sez: “Tom, this is basically climatology. Expect outrageous and unwarranted claims of certainty.”
Not at all. Multiple samples of the relevant strata–no magic single tree in Yamal. No tree rings, speleothems, or bat guano strata. No ad hominem arguments. No use of the terms “robust,” “consistent with,” “rigorous,” “transparent,” “open,” or “peer reviewed.” As near as I can tell, sufficient methodology is included to permit replication. But most of all, there is no de rigueur shibboleth/ecco la fica in the closing paragraphs stating that this study confirms CO2 as the source of all global warming.

Reply to  jorgekafkazar
August 29, 2014 10:36 am

Yes, it seems the unwarranted uncertainty was some editorial enthusiasm at WUWT. “Younger Dryas climate event solved via nanodiamonds – it was a planetary impact event”
Neither the press release nor the quotations from Kennet are making such claims. He always seems clear that it’s their hypothesis, not that it’s “solved”.
My criticism was misplaced.

Steve Garcia
Reply to  jorgekafkazar
August 29, 2014 6:13 pm

Hahaha – “As near as I can tell, sufficient methodology is included to permit replication.” Yet the skeptics of this couldn’t follow simple protocols and screwed up their effort at replication – and then they ran with their bogus results, bad-mouthing the YDB scientists.
Am I the only one here who thinks some scientists got their degrees out of Cracker Jacks boxes?
ROFL – I didn’t think so. 🙂

August 29, 2014 10:19 am

August 29, 2014 at 10:13 am
CO2 over 400 ppm in the late Allerød. Who knew that there were so many SUVs at the end of the Paleolithic?

Steve Garcia
Reply to  milodonharlani
August 29, 2014 6:16 pm

Germany had about 10,000 CO2 samplings in the early 1900s (up into the 1930s). It didn’t affect jack. Their weather was as crappy as it often is. And lest anyone thinks “Oh, what did they know way back then?” the sampling of CO2 was well refined by about 1850. Or so I’ve read.

gary gulrud
August 29, 2014 10:19 am

Not an expert but 13,000 years is like geologic yesterday. Point me to the crater, please?

Reply to  gary gulrud
August 29, 2014 12:57 pm

The Laurentide Ice Sheet was over 3km thick in places. Depending on the impact site, angle, energy etc. there may not have been a significant amount of crustal damage done and the melt alone could have erased it. There could have been no crustal damage done if it hit a thick area of ice. A bunch of unknowns here as the nanodiamonds would require the impactor be one of the more carbon rich meteorite types if terrestrial carbon was not the original source. Not enough data here to make that call but a missing impact site is not a falsification criteria here.

Steve Garcia
Reply to  nielszoo
August 29, 2014 6:30 pm

Peter Schultz did hyper velocity impacts experiments at NASA Ames. He got speeds of like 4 km/sec or so, and used super high-speed cameras. You are right – hitting dead center on about a 1 inch slab of ice. The loose sand underneath was still flat and basically unmarked. The ice? All OVER the place. It’s on a NOVA episode about the YD impact from about 5 years ago. One interesting aspect is that the highest velocity of ice was straight up, even with a 45° impact.
My best info is that the thickest ice at the Last Glacial Maximum was 2 km thick at its center – near the eastern edge of Hudson Bay. I assume that it tapered to the edges. But I have no idea how high at the edges. I don’t think anyone does. But certainly less than 2 km. If the calving ice at the edge of the Antarctic is any guide, the edge was maybe 100-200 meters, and maybe tapered sharply up to 500-1000 meters. (My guess.)
The hypothesis has the impact in the Great Lakes area. One guy – MIchael Davias – thinks that it was Saginaw Bay. And that the impactor was so big it made it THROUGH the ice sheet there and carved out the bay. With the ice being ejected along with bedrock, the rock probably ended up on the ice sheet not so far away. His idea has a lot of merit, but most scientists pretty much ignore it. After all, he’s talking about a catastrophe.
There’s no catastrophes in Gradualism!

Reply to  gary gulrud
August 29, 2014 3:49 pm

It’s in the Southern Ocean, southeast of Madagascar. Open Google Maps (satellite view) or Google Earth.

Steve Garcia
Reply to  Michael Jaye
August 29, 2014 6:18 pm

I believe that was Shiva – an entirely different time and a really big one in its own right. The tsunami must have been prodigious.

August 29, 2014 10:21 am

Or maybe Mesolithic. More advanced than the Paleolithic, but still, how did they produce so much CO2? They hunted in the forests. They didn’t burn them down.

johann wundersamer
August 29, 2014 10:47 am

why just let them collaborated ‘mastodons’ stay away and talk ’bout
Asking. Hans

August 29, 2014 11:09 am

That is not the explanation because many events similar to the Younger Dryas have happened through out the historical climatic record as Don Easterbrook so clearly shows.
If this was a one time isolated occurrence the theory they advance might of had some merit but the Younger Dryas event is not an isolated unique climatic event when one reviews the data.
My question is why is it only in climate science that data is some how ignored?
A much better explanation is these abrupt climate changes had to do with sea ice dynamics when the initial state of the climate was not to far from boarder line threshold values for glacial versus non glacial conditions moderated by solar variability and all the associated primary and secondary effects.
Don Easterbrook says:
August 21, 2014 at 8:41 am
A big problem with computer models is that the results depend not only on what assumptions you put into the model, but also what you don’t put in.
Some major problems with this particular model include:
1. “The rapid climate changes known in the scientific world as Dansgaard-Oeschger events were limited to a period of time from 110,000 to 23,000 years before present. The abrupt climate changes did not take place at the extreme low sea levels, corresponding to the time of maximum glaciation 20,000 years ago, nor at high sea levels such as those prevailing today – they occurred during periods of intermediate ice volume and intermediate sea levels.”
This statement is dead wrong–both the oxygen isotope ratios and temperature curves from the GISP2 ice core show that the most sudden warming that brought the last Ice Age to a close occurred abruptly 15,000 years ago when ice sheets were at their maximum extent and sea level was at its lowest. The ice sheets had been at their late glacial maximums for several thousand years when, out of the blue, temperatures suddenly soared 13 C (23 F) in something like 100 years, causing wholesale melting of the ice sheets. Then, just as abruptly, temperatures turned around and cooled 10 C (18 F) by 14,000 years ago. Temperatures then fluctuated up and down( but not so intensely) at intermediate levels for about 1,000 years. 12,700 years ago, temperatures took another nosedive into the Younger Dryas cold period and remained at full glacial conditions for 1,000 years. During the Younger Dryas, temperatures repeatedly changed abruptly from cool to warm (the Dansgard-Oeschger events). 11,500 years ago, another great warming spike caused temperatures to soar 12 C (21 F) in about 100 years (at one point, around 20 degrees in 40 years), then continued warming at slower rates for a total warming of 17 C (30 F) from 11,700 to 10,000 years ago. (Keep in mind that these temperatures are for Greenland, not global, but they correlate very well with temperature conditions in the rest of the world). These abrupt, multiple, intense changes (back and forth) at full glacial conditions (not ‘intermediate’) hardly sound like changes caused by gradual changes in ocean/atmospheric conditions.
2. All of the five most significant colder temperature changes that occurred during the past 500 years (the Little Ice Age) coincided with low sunspot intervals, lower total solar irradiance, lower solar magnetic flux, and increases in the production rates of beryllium-10 and carbon-14 (isotopes created in the upper atmosphere by increase in cosmic ray flux rates). These are not mere coincidences–such good correlation is not random chance, but must be due to cause-and-effect circumstances. None of this, of course, made it into the computer model simulations.
There are other serious problems with the methodology in this paper, but the bottom line is that (1) their initial premise of changes occurring only during ‘intermediate’ glacial conditions is dead wrong, and (2) sunspot intervals, lower total solar irradiance, lower solar magnetic flux, and increases in the production rates of beryllium-10 and carbon-14 argue strongly for other factors not included in their models. Thus, their conclusions cannot be considered

Steve Garcia
Reply to  Salvatore Del Prete
August 29, 2014 6:46 pm

“This statement is dead wrong–both the oxygen isotope ratios and temperature curves from the GISP2 ice core show that the most sudden warming that brought the last Ice Age to a close occurred abruptly 15,000 years ago when ice sheets were at their maximum extent and sea level was at its lowest.”
The standard model says that the Last Glacial maximum was between 22kya and 18kya, and that from 18kya to 12.8kya was the Allerod interstadial, when the ice sheets retreated. There is nothing about 15kya except it is in the middle of the Allerod. Nothing I’ve ever seen says the ice was at maximum at 15kya. And I’ve read scores upon scores of papers on this era. Glacial Max was at 18kya. THAT was when the big melt-off was.
The D-O events were spaced at an average of 1470-1500 years. You say that they happened repeatedly during the 1300-year-long Younger Dryas. That does not compute.
I agree that the abruptness and the magnitude of temperature changes are incredibly unlikely from internal forcings. For internal forcings, only when processes self-organize, like with the ENSO, can they cause changes, but the changes only amount to a few tenths of a degree C. Extrapolating 13°C or 10°C or more out of internal forcings is asking micro-forcings to do what need super macro forcings. So, yeah, you are thinking rationally there.
But I am befuddled as to where you got your dates.
I think there is a connection between D-O events, Bond events, and the YF onset. Some say that the D-O events prove that the YD was not an impact. But the “8.2 kya event” (google it) is considered both a Bond event and a probable impact, too (depending on who you ask). If one, maybe no connection. If TWO, then one has to think about it – what would THAT tell us?

Paul Hooks
August 29, 2014 11:34 am

When I read this 3 years ago I found it interesting
“Candle flames contain millions of nanodiamonds”
Just food for thought.

Steve Garcia
Reply to  Paul Hooks
August 29, 2014 6:50 pm

Dude, not all nanodiamonds are equal. Cubic ones are in fires. Hex ones are the ones that come from off Earth. It has to do with pressures and temps.

August 29, 2014 11:36 am

The arrow identifying the Little Ice Age is misplaced on the graph.

Reply to  DMOrchard
August 29, 2014 1:02 pm

So is the Medieval Warming Period.

Don Easterbrook
August 29, 2014 11:40 am

This appears to be a rerun of several earlier articles making the same claim–a cosmic impact caused the Younger Dryas. Four of these have appeared on WUWT (some with comments from me) at the dates listed below: You can read the articles in the WUWT archives by searching for ‘cosmic Younger Dryas.’
May 21, 2013 — (my comment) There are several compelling lines of evidence showing that the Younger Dryas (YD) was NOT caused by a cosmic impact or other single event. Aside from the fact that cosmic material in YD sediments doesn’t prove a cause-and-effect relationship (correlation isn’t proof of causation), the YD lasted for about 1,300 years, which is far too long for atmospheric dust not to have fallen to the ground. Even more compelling evidence is that the YD is not a simple, single climatic event–it was a series of repeated oscillations of climate each lasting several hundred years. In Scotland, Washington state, and various other places, glaciers advanced and retreated not only during the YD, but also during the preceding late Allerod cold period. The glaciers advanced and retreated as many as 8-12 times during Allerod/YD period and is thus not explainable by a single cosmic event. There were also a number of similar glacial oscillations during the preceding several thousand years. A cosmic event cannot explain the long duration (1,300 years) of the YD nor the multiple oscillations.
June 13, 2012 — (my comment) Before jumping on the comet bandwagon, a number of dots need to be connected and some critical questions need to be addressed. For example, how could a single event, even with multiple projectiles, cause an ice age that lasted for more than 1,000 years? Surely not from atmospheric dust and if not that, then what? The Younger Dryas is not the only climatic event during the post glacial maximum period—there are also a number of others spanning the time from 14,500 radiocarbon years (about 17,500 calendar years) to 10,000 14C years (about 11,500 calendar years). These are well known, well dated, and well documented in ice cores and in the global glacial record. So the question is, how could an impact event cause both multiple warming and cooling events over a 3,000 year period? Doesn’t seem logical at all for either impact or volcanic events.
Some other questions pertain to the evidence for the proposed cosmic event. Geologists are used to studying micro-images of rocks and looking at the two samples shown in the paper, it is obvious that both show definite flow structures that closely resemble glass flows from volcanic lava. The statement “Morphological and geochemical evidence of the melt-glass confirms that the material is not cosmic, volcanic, or of human-made origin. “The very high temperature melt-glass appears identical to that produced in known cosmic impact events such as Meteor Crater in Arizona, and the Australasian tektite field,” is very vague. What morphological and geochemical evidence? As for these specimens being identical to trinitite from atomic blasts, there is surely no flow structure in the photos shown so how can they be identical?
The bottom line here is—a lot more dots need to be connected and these critical questions (as well as a number of others) need to be addressed before concluding that the Younger Dryas was caused by a cosmic impact.
March 12, 2012 –(my comment) Before jumping on this bandwagon, consider the following:
1. There may well have been a meteorite impact near the beginning of the Younger Dryas (YD), but that doesn’t prove it was the CAUSE of the YDs. It’s the same logic as saying the cause of the 1978-1998 warming coincided with rise in CO2 so the cause must be CO2. Bad logic.
2. The YD is just the most prominent of many Dansgard-Oerscher abrupt climatic events.
3. The YD ended just as abruptly as it began a little over 1000 years later.
4. The YD corresponds with changes in 10Be and 14C production rates, suggesting changes in incoming radiation and pointing toward a Svensmark type cause.
5. The problem with single event causes (e.g., volcanic eruption) is that they cannot be sustained for the length of time of the climate change. If the idea is that the cooling was caused by ejection of dust into the atmosphere, that wouldn’t last for more than 1000 years.
6. If the YD was caused by dust in the atmosphere, it should show up in the Greenland ice cores (where even very small, annual accumulations of dust from summer ablation are well preserved). There is no such evidence of dust from an impact event throughout any of the well preserved YD ice core record.
7. The list goes on and on–too many to include them all here. Perhaps a longer response later. The bottom line is that a single event, meteorite impact event doesn’t prove the origin of the YD.
I also wrote two articles explaining the issues (posted on WUWT).
The issues are clear cut and spelled out in these comments and articles. In a nutshell, the Younger Dryas includes so many very sudden, intense climate changes over a period of several thousand years that it couldn’t be related to a single cosmic event. Even if there was a cosmic event as the authors postulate, it certainly didn’t cause the Younger Dryas.

Reply to  Don Easterbrook
August 29, 2014 1:06 pm

Exactly. The question should be what made the temperatures rise so suddenly 14,500 BP (nr 1) and 11,900 BP (nr 7). It are these two moments in time responsible for the abundance of these tiny diamonds.

Reply to  Robertvd
August 29, 2014 1:18 pm
CC Squid
Reply to  Robertvd
August 29, 2014 5:01 pm

Dr. Easterbrook,
You are trying to to take a scalpel to a gun fight! Trying to replace the “CO2” meme with the knowledge of “it’s the sun stupid” will take many more years. Remember the movies where the witch doctor points to an eclipse of the sun and everyone starts to dance and sing to the gods? IMHO this is currently how the “deniers” are being depicted.
My prediction is that it will take another 15 more years for the “climate science” departments and many others to be condensed and or elimated. This will only happen after the “old” scientists die or retire and when the newer scientists can publish without the obligatory bow to CO2. “It’s the sun stupid” is threatening to take food off of too many people’s plates! Follow the money!

Reply to  Don Easterbrook
August 29, 2014 1:43 pm

I agree. It appears to this old geologist that two unrelated events are being conflated. The extinction event is much more likely due to impact of extraterrestrial material with the atmosphere – perhaps the Carolina Bays and other apparently time-equivalent impacts are related – think about 500+ concurrent Chelyabinsk events – and the resulting disruption in the atmosphere and on the ground below.
The climate shift was quite probably associated with other completely independent influences. That they appear at about the same time is purely coincidence.

Reply to  Don Easterbrook
August 29, 2014 3:12 pm

Don Easterbrook, after each sizable cosmic impact on Earth always follow 3 phases: 1. A sharp downdip of temps, followed by 2. a temp rebound to a level substantially HIGHER than at the cosmic impact date and finally, the last phase, 3,. a temp regress back to the lower temp level of the impact date — this mechanics produces a Z-shaped or high-voltage sign e.g. in the Greenland GISP2 temp time series. More on relation on effects of cosmic impacts and Z-type temp evolution at,
there is no point of wild speculating around with volcanoes, dust, time span without first doing some reading on the empirical relation and the effects of a cosmic impact on climate change…regards JS

Steve Garcia
Reply to  Don Easterbrook
August 29, 2014 7:13 pm

Don –
“the preceding late Allerod cold period. ” Actually, the Allerod was not a cold period. It was the interstadial, when temps reached close to today’s.
NO, they have not addressed the question of the length of the YD. Yes, of course 1300 years is too long to have dust up in the air. By a factor of 100 or more. The YD researchers have been bogged down dealing with the carping of their skeptics on the impact materials – which are very real. As this paper shows. Saying that materials that MUST be heated above 2200C are not indicative of an impact (and not possible with any Earth processes on the surface), and all the different ones are all spiking right there – what does it take for you to even look at their data? It ain’t ONE material that convinces – it is the suite of materials. Right now the focus is on making the case for the impact materials. The other questions can’t be dealt with just yet. It’s not an excuse; it’s reality.
The black layer being on 3 continents and with some evidence of it in northern S America, too, indicates a natural event larger than any in known human history. With essentially the same suite of markers in Syria and Belgium, something happened that was big. Super big.
I myself think that the single biggest question is that 1300 years – and then the even more abrupt RISE in temps.
At the same time, I do not take Greenland ice now or 13,000 years ago as a valid proxy for the state of the climate. The D-O events may simply be an artifact of the location. The GISP2 core suggests very big changes in temps, over seemingly impossible time periods. Nothing within the climate can do changes that big. They are all micro-forcings, with no capacity to do much more than a few tenths of a degree. Either something (perhaps at multiple times?) from outside the system intruded or we should consider that we are getting a false picture from the ice cores. At least as it pertains to global climate.
At the same time, it was not Firestone and the other YDIH researchers who first made a big hoopla about the YD. It was biologists and climate guys. And they have been at it for DECADES, with no resolution on the horizon. Firestone and all of them can’t help it if their C14 numbers kept coming back with 12.9 kya written all over them. If the dates came back with 37 kya on them some other scenario would have had to be dealt with.
And when they found mammoth bones immediately UNDER the black layer – with the black layer draped ON the surface of the bones and staining them – what were they to think? No connection at all? Not even. There they are, at 12.9 kya (now 12.8 with IntCal13), black layer, mammoth bones, spikes in nanodiamonds, spikes in several other markers for impacts. ONE marker is one thing. A suite of them is a whole other ballgame.
The 1300 year conundrum will still be out there. First things first.

August 29, 2014 12:07 pm

Don Easterbrrok is 100% correct. This is the wrong explanation.

August 29, 2014 12:11 pm

Exactly Mr. Easterbrook.

August 29, 2014 12:13 pm

I thought my first comment did not go through. Sorry for the duplicate.

August 29, 2014 12:42 pm

I’m skeptical. The event was more likely caused by electrical interaction between the planets that scarred them all in a solar system upheaval.

DD More
August 29, 2014 12:49 pm

Can someone please vacuum off the frozen mastodon, the frozen one with food in the stomach, and find the dust and micro diamond.

Charles Brecknell
August 29, 2014 12:50 pm
August 29, 2014 1:03 pm

One of the most interesting talks on catastrophies I’ve seen.

August 29, 2014 1:09 pm

Based upon what I have learned about extinction of mammoths and other mega fauna, I find the comet hypothesis woefully inadequate. It is hardly settled science at this point.

Reply to  Jbird
August 29, 2014 1:34 pm

Correct. The pattern & timing of extinctions doesn’t support the impact hypothesis.

August 29, 2014 1:26 pm

Dinosaures were killed by a comet; Mammoths were killed by a comet ; humans will be killed by CO2

Reply to  fritz
August 29, 2014 1:59 pm

Not a comet in either case. A meteor contributed to demise on the non-avian dinosaurs. The meteor hypothesis for the demise of the Pleistocene megafauna is thin at best. The same & similar species also went extinct outside the region allegedly affected by an ET impact.

Reply to  milodonharlani
August 29, 2014 6:01 pm

Read Otto Muck’s work for a full explanation. This is old news

August 29, 2014 1:28 pm

Megafauna extinctions in North America do not correspond closely with the YD, although C14 & calendar year comparisons make for difficulty. In any case, different species & populations went extinct at different times, as nearly as evidence can be resolved.
For instance, island populations of ground sloths survived for thousands of years longer than on the continent.

Steve Garcia
Reply to  milodonharlani
August 29, 2014 7:24 pm

Actually, at Blackwater Draw there were mammoth bones immediately under the black layer – which has been dated to 12.8 ya on many occasions. Not only was the mammoth there, but the black layer lay over and conformed to the bone. Not only that, but the black material was in intimate contact with the bone and stained the bone.
Outside the pygmy mammoths, no mammoth in the world dates past that 12.8 kya.
C14 vs calendar dating is a simple matter of looking the carbon14 (calendar) date on the IntCal13 graphs. Or, if you are lazy, there is software to do the comparing. It’s not difficult at all.
As to the claims of different times, people say that. So far in all my reading of papers on that, no one has shown any that lived past 12.8 kya. That mammoths died earlier? If the LIVED earlier, then of course they DIED earlier.
Pleas can you point me to the ground sloths? I’d be quite interested.

August 29, 2014 1:52 pm

1.) How is a North American event supposed to have caused South American extinctions but not, apparently, Eurasian or African?
2. How is an event which caused a blip in temperature indistinguishable from a great many others supposed to have caused extinctions even in areas in NA which were west of the supposed fallout area? (But not outside of NA.)
3.) Why does UofC@SB think ‘science is magic’/’science is settled’ reporting appeals to the public? “..until recently, could only speculate as to why.”

Steve Garcia
Reply to  Lark
August 29, 2014 7:31 pm

1.) and 2.) both good and very valid questions. And ones that the researchers are well aware of. I’ve been on this for about 7 years or so, and I can tell you that the researchers on it are bogged down just trying to get people to accept their “forensic” results. There is a small group of hacks that the researchers think they have to please, so they are spending all their time on that. They do not have unlimited manpower. Give it time.
There are considerably more PRO papers and researchers than there are CONs. Some of them came out of the blue. Like last year some researchers at Harvard and Princeton found supporting evidence.
If you go into the voluminous lab tests in the Appendices to the different papers, you will see that this is serious stuff, very real. Some of the materials are impossible to create without the super-high pressure and temps in a hyper-velocity impact. So, if not an impact, then what? If it looks like a duck, quacks like a duck, and has duck feet. . .
There are multiple lines of evidence.

August 29, 2014 1:52 pm

At least in those days they had climate change you could believe in. I wonder if they too had high priest predicting the end of the world. When exactly did they have their tipping point.

Steve Garcia
Reply to  Robertvd
August 29, 2014 7:35 pm

I’ll tell you what:
If you ever get around to reading the accounts of some of the indigenous peoples, it is not hard to start thinking that something actually DID come out of the sky, with a tail like a dragon, blah blah blah and killed a whole lot of people and shook the earth and caused all kinds of havoc.

David L.
August 29, 2014 2:20 pm

So humans didn’t hunt everything to extinction?

Reply to  David L.
August 29, 2014 3:04 pm

Evidence still suggests that we did indeed have a big impact among the naive megafauna of the New World.

Steve Garcia
Reply to  David L.
August 29, 2014 7:42 pm

Hahaha –
Yeah, the idea of a few thousand guys on foot scouring the entire N American continent – in 200 years – and were able to FIND all of them, much less kill them. That soudnds plausible to me.
Especially when they were killing something bigger than elephants and curing and hauling the 5 tons of meat back – still on foot.
And THEN consider this:
There are only 14 kill sites on the whole continent, and those are where? Basically, like 95% of the Clovis sites are in the SE of the USA. (A site comprises ANY Clovis point, even one – even a broken one.) Google “clovis sites map” THERE ARE A LOT OF SITES. And hardly ANY out west. Where the mammoth kill sites are.
But how many kill sites are in the SE of the USA?
Their families were back east, and they were out in Texas and NM and Arizona, killing mammoths and butchering them. To take the food WHERE? Back to Alabama? From New Mexico?

Steve Garcia
Reply to  Steve Garcia
August 29, 2014 7:46 pm

And BTW, they came up with that Clovis, Extinctor of Mammoths thing when they assumed that the only hunting Clovis man did was for Mammoths.
And you know what they are only now beginning to find out? They hunted rabbits and deer and raccoons and foxes – stuff you can sling over your shoulder and take back to camp to cook for dinner tonight – just like all hunting societies did.
So, with 95% of Clovis in the SE and lots of deer and such to hunt there, what were they doing out west, 1500 mile away?

Jim Reekes
August 29, 2014 3:06 pm

Global effects of comet impacts and volcanoes (which can be triggered by comet impacts) has been a topic I’ve followed with great interest. I’m convinced they are effecting things on this planet much more so than we realize. Not only effecting the weather, but civilizations.
The last major impact coincides with the time of the Pleistocene–Holocene, and the Holocene extinction event. It’s the 6th great extension event on the planet.
Wooly Mammoths, Saber Tooth Tigers, Giant Sloths, and so many other animals, were pushed into extinction. Or, in the case of the early human inhabitants, were nearly made extinct. Humans then re-populated the N America with a second wave of migration. That’s the one you were probably told about in your high school history books, but humans were here for much longer.
Also coinciding with the time of the impact was the end of the last ice age, when much of N America was covered by a glacier. As the ice melted it created a huge fresh water lake covering cover of Manitoba, northwestern Ontario, northern Minnesota, eastern North Dakota, and Saskatchewan. It made all the “great” lakes added together seem like ponds in comparison. It was approximately the size of the Black Sea, about 170,000 sq miles.
As the lake filled, it eventually broke through draining through the Mackenzie River and then into the Arctic Ocean. That’s a MASSIVE amount of fresh water pouring into the salt water in the Arctic. So much so it would be a likely source of flood myths. This water was even flowing south through the Mississippi River.
This must have altered the global climate, and it would have altered the Thermohaline Circulation (aka Atlantic Conveyor Belt). Then there was another great draining around 8,200 years ago (or 6200 BCE), after more ice had melted. This last great melt happens to coincide with the the 8,200 yr climate event. Evidence for this event can be found in Greenland ice cores.
These melts were so large they would have increased global sea levels (~6ft).
The disruption to the Thermohaline Circulation would have likely triggered global cooling. Possibly by as much as 10 deg F. The total duration of the cooling was ~150 years, with sudden cold periods of ~60 years. Even more curious, global CO2 levels dropped ~25ppm.
Such a dramatic impact on the Atlantic’s thermohaline circulation would likely cause a shift in the latitude of the jet stream. This is like the current Polar Vortext, which is when the jet stream has shifted south and pushes the colder air from the Arctic over warmer lands. It would also effect global precipitation. Some ares become much wetter, while others become much drier.
Africa went through ~500 years of drought. The event likely given Mesopotamia the support for their irrigation, which gave rise to agriculture and the surprise of food. This in turn gave rise to the advancements of civilization. But then very suddenly (~100 years) the global climate seems to have corrected itself, and ended this unique weather phenomena.
The Burckle Crater may be the result of comet impact around 2900BCE. It’s about 18 miles in diameter, and it’s under the Indian Ocean at 12,500 feet below sea level. If this does turn out to be an impact crater, it would have caused a mega-tsunami of biblical proportion (e.g. mythical flood event that would have wiped out civilizations along the coasts).
It’s another example of how natural causes come along every few thousand year and dramatically change the global climate. There are a number of comet impacts that has effected civilization. I wish the historians were talking with the paleo-climatologists, and comparing their timelines.
The end of the Medieval Warm Period (MWP) created the Great Famine of 1315. The rise to the population explosion as a result of the good climate during MWP. It all came to an abrupt end with the shift to cold weather. The end of the MWP saw millions died after as crops failed for several years. The following few decades were some of the worst weather on record.
Along with the cooler temperatures were heavy rains throughout Europe. So much so crops failed and people starved. Without the hay to feed livestock, the animals also died. People were more concerned with survival than enlightenment. It wasn’t until the global climate recovered that we enter the Renaissance.
Meat preservation during this period became difficult and unaffordable since it was based on the use of salt, which was produced by evaporation but became nearly impossible due to high humidity.
Natural forces effected civilization was the Dark Ages. It was actually “dark.” There was hundreds of years of vocalic eruptions triggering global cooling. Hekla blew its top in 1300 and continued to spew its guts for one full year! It was called the “Gateway of Hell” by the Europeans.
There’s a scale for measuring eruptions, the Volcanic Explosivity Index (VEI). When you get a VEI 4 you’re at the point where it will effect climate. Not only was Hekla a VEI 4, but it was spewing its guts throughout the Dark Ages. That’s just one volcano. Then in 1362 Iceland’s another monster blows it’s top and is bigger than the famous Mount Vesuvius that buried Pompeii. You can find a history of volcano eruptions throughout the Dark Ages.
The destruction of the very advanced Minoan civilization was caused by the Santorini eruption in 1645 BC. This monster was a mega-eruption at VEI 7. It was an island, and when it blew its top the island was gone. This left a crater below sea level, causing the ocean to rush into the gaping hole causing an even bigger explosion. All that water (~20 TRILLION gallons) was instantly vaporized, and thrown high into the atmosphere. Some of it froze and remained floating around the world as tiny particles of ice (mirrors). This reflected solar radiation for several years, causing an even longer and colder volcanic winter.
The Santorini eruption was seen in ancient Egypt. They even had a tsunami wave reach their coast. That eruption also triggered the expected famine and diseases. In fact, the story of the Exodus and the ten plagues of Egypt can be explained as a result of a volcano.
The Huaynaputina eruption in 1600 triggered a couple years of volcanic winter, causing the Russian famine of 1601-1603 when more than half a million people died.
I’m amazed by the irony of how Briffa’s work on tree ring and climate is so focused on CO2 levels and temperatures. That same data can be used to show the effect of volcanoes, which should be correlated to events in civilization.

Reply to  Jim Reekes
August 29, 2014 4:58 pm

The warm & cold centennial-scale climatic cycles observed during the Holocene & prior interglacials & glacials are not caused by volcanic eruptions.
Hekla for example was more active during the Medieval Warm Period (c. AD 900-1400) than it was during the Little Ice Age (c. 1400-1860) or so far in the Modern Warm Period (c. 1860 to present). Here are its VEI 3, 4 & 5 eruptions for each cycle. The year given is for when the activity began, but six lasted more than one year or included back to back annual eruptions.
Medieval WP Eruptions of Hekla (~500 years):
1104: 5
1158: 4
1206: 3
1300: 4
1341: 3
1389: 3
Little Ice Age (~460 years):
1510: 4
1597: 3
1636: 3
1766: 4
1845: 4
Modern WP (~154 years to date):
1947: 4
1970: 3
1980: 3
1991: 3 (same year as Pinatubo)
2000: 3
If there be any correlation at all, it’s that great activity warms rather than cools the climate, which is indeed what researchers have generally concluded, despite short-term cooling of weather for a year or two, possibly a few years for the very biggest, tropical eruptions.

Jim Reekes
Reply to  milodonharlani
August 29, 2014 7:35 pm

The warm & cold centennial-scale climatic cycles observed during the Holocene & prior interglacials & glacials are not caused by volcanic eruptions.

Just to be clear, I’m not claiming volcanoes are driving climate. I was talking about how comets and volcanoes can disrupt civilizations. They also effect weather, in a number of ways.
As for the large time scale changes in climate, my understanding is that it’s driven by the Milankovitch cycles.

Steve Garcia
Reply to  Jim Reekes
August 29, 2014 7:52 pm

Jim –
Good stuff. Keep at it.
But dump the Lake Agassiz thing. It didn’t happen. The ice was still too far south at the Holocene start. The ice was not retreated enough in time to do any of that. Wallace Broeker was the guy who came up with that idea, and he admitted a few years ago that he had to abandon the idea.
But he didn’t come out very very vocal admitting his mistake, and so many people don’t even know that he dumped the idea.
OTHERS, though, think that an outflow down the Mackenzie River and exiting into the Arctic Ocean up near Alaska is just as good. But that is like 4,000 miles and at the other far corner of Canada. Even f fresh water went that way, it had to make it past the Canadian Archipelago and Greenland in order to end up east of Iceland and screwing with the Gulf Stream.
Anyway, that is a dead horse.

NZ Willy
August 29, 2014 4:23 pm

The historical temperature graph at top, if accurate, shows the Younger Dryas could not be an impact event as the temperate drop was in stages over hundreds of years — an impact event would be abrupt. A sensible cause would be that the Bering Strait opened up giving the Pacific access to the totally frozen Arctic ocean, and when an undersea current connected the Pacific and the Atlantic underneath the miles-thick Arctic ice cap, then the oceans were inundated with new cold water which caused the cooling of the Younger Dryas. Thus the stages of the Younger Dryas shows the progress of that progressive melting out of the Arctic ice.
As for large animals, it astounds me how scientists are still looking for fairy tales to explain the mass deaths, when it was obviously human hunting. Where people went, the large animals were hunted to extinction — this is not hard. Of course the Clovis hunting culture and the large animals vanished at the same time. Here in NZ there is the same pattern: the Maori arrived c1100 and their first culture is known as the “moa hunter” culture as they hunted the native giant birds. About 300 years later the moa went extinct and the “moa hunter” culture ended. This is not hard.
By the way, the historical temperature graph at top mis-identified the MWP, it’s the next little hill to the right.

Steve Garcia
Reply to  NZ Willy
August 29, 2014 8:14 pm

Don’t be too hasty. That “temperature” graph is not measured temperature. It is INFERRED. And not just the temps, but the timing also, all of it is VERY low resolution. Ice cores CANNOT DO high resolution – i.e., 200 years.
So don’t think that those curves are real. Even the data points – the line you see? It can be doing all sorts of things in between the data points as they’ve inferred from the 18O proxies. Most of these have straight lines and when it drops really fast, and the next point is 200 years later – did it drop even MORE straight down from the upper point? Or did it go flat first an THEN drop straight down? The LINE is a guess, when you start looking at short time periods. When you zoom in. YOU can zoom in, but the data can’t.
As to the humans hunting EVERY single mammoth on the ENTIRE continent –
(Most people don’t know most of this…)
1. 95% of Clovis people lived in the SE USA (based on the number of Clovis sites, which are QUITE numerous)
2. There are ZERO mammoth kill sites in the SE USA.
3. Wouldn’t you think that they would have killed afew mammoths near where they lived?
4. Why would they go out to Arizona and Montana from Georgia or Alabama, just to kill a 5-ton animal – to carry 3 tons home? ON FOOT?
5. There are at last count FOURTEEN Clovis kill sites.
6. N America is like 98 MILLION square miles.
7. Clovis entire history in the world only lasted about 250 years.
8. Lifespans back then were about 25 years.
9. The Overkill Hypothesis was thought of when it was assumed that Clovis ONLY hunted and ate Mammoths and other megafauna.
10. Anthropologists only now are discovering that Clovis hunted and ate rabbits and deer and elk and bear and foxes and raccoons, etc. They ARE revisiting their Mammoth extinction machine understanding of Clovis.
11. Clovis points did NOT come from over the land bridge at Beringia. The tool technology in NE Siberia is another tech altogether.
12. The only close relative to the CLovis point is the Solutrean point from Spain and France. As long as the Clovis Barrier existed (saying that no one was in the Americas before Clovis at 13,300 years ago) there was a 5,000 year gap between Solutrean points and humans in the New World. Since 1997, when the Clovis barrier was broken, human evidence in the New World has been pushed back to more than 20,000 years – about a 2,000 years overlap with Solutrean points – plenty of time for Clovis to develop from Solutrean. So now there are researchers who assert that the Solutrean point came with people from Europe, and the people came much earlier. And if they did, they would have most naturally come to the SE USA – right where we find 95% of the Clovis sites.
So, don’t be so certain. Evidence is coming up all the time that keeps changing our understanding of the settlement of the New World and about Clovis.

NZ Willy
Reply to  Steve Garcia
August 30, 2014 1:19 am

Verbiage is no substitute for logic. Consider the Petri dish if you think the North American continent is “vast” — no more vast than is the Petri dish to a single yeast bacterium which fills it up in a day. As I said, “this is not hard” — full stop.

Reply to  Steve Garcia
September 3, 2014 9:01 am

“Lifespans back then were about 25 years.”
That’s an average (and a very low estimate I find dubious, to begin with: most papers give 34 or 35 average) between a big peak at the range 0-5 and a rising tail beyond the age of 60. Reconstructed modal age from primitive hunter-gatherer is 62 to 64 years old. 80-years-old were merely uncommon.

Christopher Hanley
Reply to  NZ Willy
August 30, 2014 2:08 am

Similar story in Australia:
“New evidence based on accurate optically stimulated luminescence and uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction of megafauna in Australia. The dates derived show that all forms of megafauna on the Australian mainland became extinct in the same rapid timeframe — approximately 46,000 years ago …” (Wiki).

August 29, 2014 6:00 pm

Seriously? This is news? Otto Muck detailed the event over 50 years ago.

August 29, 2014 6:03 pm
This answered all the questions – why has it been supressed?

wayne Job
August 29, 2014 6:04 pm

Major upsets to the world like this one would not be a comet. More likely a glancing blow from something bigger and a shower of accompanying debris. There was a period where humans almost became extinct, being adaptable as we are the event must have been severe and affected the entire globe.

Steve Garcia
Reply to  wayne Job
August 29, 2014 8:19 pm

Sure. And comet Shoemaker-Levy 9 didn’t hit Jupiter in 1994. Comets never hit planets. Everybody knows that.
Except Jupiter has been hit by two other comets.
Something bigger? They can’t even find the crater for THIS one.
Actually, I think it is MUCH more likely to be a big, solid meteor. But one as big as the biggest piece of Shoemaker-Levy would do us in. How big was that? 1.3 km. And that WAS a comet.
It’s plume was bigger than Earth.
And there were THREE of them of 1 km or bigger. Three would do us in.

Reply to  Steve Garcia
August 29, 2014 11:57 pm

For the large impact area with no crater, it could have been the near passing of one of the gas planets of an inbound large loose comet that was gravitationally fragmented into hundreds of thousands of smaller pieces, that impacted the earth over several hours upon arrival, starting in the SW USA/Mexico area moving North East as the earth revolved and the last of it swept into Europe.
The resulting shock wave moved as a front with the central bulk of the material striking the Glacial Ice sheets, blasting most of the polar Ice into the Siberian area of frozen standing mammoths and mastodons covering them instantly with meters of snow and ice chunks. There is some research that shows the southern trajectory ice chunks so liberated fell in a swath of the South Eastern USA and formed the Carolina Bays as they splashed impacted, along the southern rim of the secondary ejecta pattern.

Steve Garcia
Reply to  Richard Holle
August 30, 2014 12:06 pm

“For the large impact area with no crater, it could have been the near passing of one of the gas planets of an inbound large loose comet that was gravitationally fragmented into hundreds of thousands of smaller pieces, that impacted the earth over several hours upon arrival, starting in the SW USA/Mexico area moving North East as the earth revolved and the last of it swept into Europe.
The resulting shock wave moved as a front with the central bulk of the material striking the Glacial Ice sheets, blasting most of the polar Ice into the Siberian area of frozen standing mammoths and mastodons covering them instantly with meters of snow and ice chunks. There is some research that shows the southern trajectory ice chunks so liberated fell in a swath of the South Eastern USA and formed the Carolina Bays as they splashed impacted, along the southern rim of the secondary ejecta pattern.”
At this time no one knows if the proposed YD impact was perhaps a fragmented body with multiple impacts. Some people think so. If so, it is far too early for figuring out what multiple impacts would have done or where. It is probably premature to go in that direction, but who knows?
One of the important peripheral questions DOES have to be, “If the impact was in N America, then that could explain the extinctions in N America, but how did that make mammoths in extreme northern Siberia also go extinct?” If this all goes that far, then your conjecture is going to be one of many to answer that question.
As to the Carolina bays, yes, because of the non-hyper-velocity nature of the bays, some other process must have caused them than a full-speed body from space.
For those that don’t know, those are nearly 44,000 elliptical depressions, mostly in the SE USA, in an arc from FL to NJ. They are aligned in each region – north to south – and the alignment changes gradually, in such a way that they all seem to point to the centroid of the arc that they seem to form. They have been known about since about 1930, and NONE of the posited explanations so far has worked. Despite it failing as an explanation, the people who advocate winds claim to have the answer. This explanation has been ruled out as a FAIL on more than one occasion, but it doesn’t stop the “aeolian” people from claiming they have the answer.
As to secondary impact – of ejected materials landing far from the initial impact site – that IS being studied by some people, with me on the periphery of that. I can say that I favor that, but it is a LONG way from being accepted. (When I use the term “arc” above, I DO mean it, too. It is, in fact, a very tight arc – amazingly. Both the alignments and this arc show a centroid near the Wisconsin border with Illinois. This dual alignment is something that the aeolian folks couldn’t explain, even if they wanted to. They would only be able to invoke “coincidence” to explain it.) The aeolian people claim the high ground, but when I look at their work, I see many assumptions that are not sustainable.
Another thing about the Carolina bays is the difficulty in getting a date for them. Depending on where the dating samples came from, the dates range from about 11,000 to about 300,000. One guy I know says it is either 40,000 or 130,000. And this is in the times when we have REALLY GOOD dating techniques! C14 may or may not be useful, because it is only good up to about 55,000 years ago. But there is precious little organic material to work with. The sampling issue comes from the assortment of sampling locations. Almost all are just outside of the bay rims, but some ore ON the rims, and some under.
The bays have one more interesting feature. There is a layer of very pure quartz sand, draped over the bays. It tends to be about 1 meter thick, at the bays, but in the surrounding region the sand layer is up to about 10 meters thick. The sand is so pure that it can be scooped straight out and made into very good glass – even without any further processing. It is thinkc enough in other places that fully grown, fallen, bald cypresses are found deep inside the layer. And these cypresses are hoisted out and made into furniture – even though they are perhaps 40,000 years old. The quartz sand is perfect for OSL dating, but they keep getting WAY different ages.
So, for now, the Carolina bays are, IMHO, undated. They MAY be connected to the proposed YD impactor, but those around me are all skeptical of that. I don’t know, myself. Obviously, if they go back to 40,000 years, there is no connection.

August 29, 2014 6:04 pm

I read this book maybe 20, 25 years ago, after finding it browsing in the local library, and for ME, the “secret” of Atlantis was pretty much a resolved question from that point forward… Not that Muck necessarily had all his science right (especially considering he wrote this book at a time not even the Big Bang theory had been “proven” over the Steady State theory of the universe), but that I DO believe he proved a small comet or meteorite hit in North America and probably bouncing into the Atlantic 10-12,000 years ago.
I JUST finished watching a new, 2-hour show on the History Channel about the origins of Clovis Man on North America and the “curiosity” about why and how both Clovis AND 80% of all large land mammals on North America suddenly VANISHED about 13,000 years ago, and then about 2,000 years later, they start seeing human artifacts again… Ice cor samples revealed that just as the ice age was retreating, allowing humans to setle North America, a second, shorter “ice age” of about 1,000 years QUICKLY descended upon the planet, and Alan West of the University of Michigan has discovered microscopic metalic balls and “microdiamonds” at the level at that EXACT point in the geologic layer ALL OVER NORTH AMERICA that indicate the distribution of materials from a comet or meteorite — materials that RARELY exist anywhere but in OUTER SPACE.
Of course he apparently never heard of Otto Muck, and he thinks his idea is ALL NEW and that said meteorite hit the ice mass in Canada, and he could be right — or they BOTH could be wrong…

August 29, 2014 6:52 pm

It seems highly unlikely that the stories from antiquity were simply made up. more likely there were catastrophic events over large areas; and that we simply assume all were local events. how long ago they happened, passed from generation to generation, none can say with certainty. however, they were large enough to remain with us many generations later.
two events stand out. the great flood and the day/night that took too long. Perhaps we underestimate how long ago these events happened. 13,000 years is what, 650 generations?

Reply to  ferdberple
August 30, 2014 6:09 am

“In the section “A Collective Amnesia” of Worlds in Collision, published in 1950, Velikovsky outlined his principal psychological thesis. His theory of collective amnesia explains the inability of people to look at the overwhelming evidence of global catastrophes — from all parts of the world — that is unequivocally there, and the unwillingness to see the implications of that evidence. Velikovsky put this as follows in Worlds in Collision:
The memory of the cataclysms was erased, not because of lack of written traditions, but because of some characteristic process that later caused entire nations, together with their literate men, to read into these traditions allegories or metaphors where actually cosmic disturbances were clearly described.”
All of these attempts to explain away impacts stem from the collective trauma buried in our racial memories. We need to feel we are important and have some control over our lives and the world, however the delusion of human control is snuffed out by the uncaring destruction that is unleashed on the world by what have been repeated impacts of celestial bodies. So, they didn’t happen, and we live in a very slowly changing world where we are important and powerful beings.
It could also be argued that the irrational fixation on anthropogenic climate change is the other side of this collective mental illness. We need to feel important and find it almost impossible to believe we are not, so, anthropogenic climate change that can destroy the planet.

Steve Garcia
Reply to  tobyglyn
August 30, 2014 1:22 pm

““In the section “A Collective Amnesia” of Worlds in Collision, published in 1950, Velikovsky outlined his principal psychological thesis. His theory of collective amnesia explains the inability of people to look at the overwhelming evidence of global catastrophes — from all parts of the world — that is unequivocally there, and the unwillingness to see the implications of that evidence. Velikovsky put this as follows in Worlds in Collision:
The memory of the cataclysms was erased, not because of lack of written traditions, but because of some characteristic process that later caused entire nations, together with their literate men, to read into these traditions allegories or metaphors where actually cosmic disturbances were clearly described.”
All of these attempts to explain away impacts stem from the collective trauma buried in our racial memories. We need to feel we are important and have some control over our lives and the world, however the delusion of human control is snuffed out by the uncaring destruction that is unleashed on the world by what have been repeated impacts of celestial bodies. So, they didn’t happen, and we live in a very slowly changing world where we are important and powerful beings.
It could also be argued that the irrational fixation on anthropogenic climate change is the other side of this collective mental illness. We need to feel important and find it almost impossible to believe we are not, so, anthropogenic climate change that can destroy the planet.”
A good observation. And true, about the written accounts, though many were pre-writing and were kept as oral traditions until writing came into vogue. Those ancient accounts WERE very clearly describing big, bright, burning objects descending to the earth and causing havoc – quakes, huge explosion sounds, rains of fire, inundations, many or most of the people being killed.
The amnesia was willful on the parts of the first western readers of/listener to those accounts – insisting that the ancient peoples were all illiterates with minds like infants, and isn’t it a shame how they make things up?
Well, if it was one account out there in isolation, no problem – it is someone’s fantasy. When the same kinds of accounts show up in hundreds of ancient societies, scientists need to wake up and smell the commonality in the accounts.
Yes, the amnesia is there, – and it occurred in the last two centuries or so. And it has gotten in the way of us learning our own history, by replacing it with the silly transliterations of the early archaeologists.
Velikovsky did a decent job of accumulating these accounts, as well as pointing to things like the mammoths in Siberia, the erratic boulders, the bone caves – even if his astronomy was way off course. Like early archaeologists trying to prove the literal truth of the history in the Bible, Velikovsky seemed to be trying to do the same thing, about the Exodus and manna, etc. And all he did was embarrass himself – though Harlow Shapley of Harvard was an asshole in the way he dealt with it.

August 29, 2014 7:45 pm

when it was obviously human hunting.
hunting does not explain the sudden demise of Siberian mammoths 12000 years ago, with the rapid freezing of many specimens.

Ted Clayton
August 29, 2014 8:24 pm

Proceedings of the National Academy of Sciences PNAS
vol. 106 no. 43, Todd A. Surovell et al, 18155–18158
October, 2009
An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis

Based on elevated concentrations of a set of “impact markers” at the onset of the Younger Dryas stadial from sedimentary contexts across North America, Firestone, Kennett, West, and others have argued that 12.9 ka the Earth experienced an impact by an extraterrestrial body, an event that had devastating ecological consequences for humans, plants, and animals in the New World [Firestone RB, et al. (2007) Proc. Natl. Acad. Sci. USA 104:16016–16021]. Herein, we report the results of an independent analysis of magnetic minerals and microspherules from seven sites of similar age, including two examined by Firestone et al. We were unable to reproduce any results of the Firestone et al. study and find no support for Younger Dryas extraterrestrial impact.

Use the Data Supplement page link beneath the PNAS abstract for a PDF download providing lab procedures, sample sites details, and data table.

Steve Garcia
Reply to  Ted Clayton
August 29, 2014 8:35 pm

Ted –
Yes. This is the Surovell paper in which he failed to follow the proper methodology when taking samples, so he screwed the pooch. This work was well rebutted. Surovell hasn’t tried gathering samples again, from all appearances.
For some reason the YDB skeptics still haven’t enlisted an archaeologist who know how to take proper samples from a dig.

Ted Clayton
Reply to  Steve Garcia
August 29, 2014 9:26 pm

Steve Garcia,
Are there sources for these objections to the Surovell et al work & qualifications?

Steve Garcia
Reply to  Ted Clayton
August 29, 2014 10:21 pm

I have one somewhere from 2009 or 2010, but am finding it hard to locate. In its stead, I will provide 3 or 4 others.
Blog post with the main thing being the LeCompte paper just below here…
The first one LeCompte et al 2013 Evidence for deposition of 10 million tonnes of impactspherules across four continents 12,800 y ago has this:

Whereas most independent studies concluded that the YDB spherules formed during a high-temperature cosmic impact event, one study by Surovell et al. (10) was unable to find any YDB spherule peaks at seven sites. However, LeCompte et al.(13) repeated the analyses at three of those sites and verified the previous observations (1), concluding that the inability of Surovell et al. (10) to find YDB spherule peaks resulted from not adhering to the prescribed extraction protocol (1, 7). For example, Surovell et al. did not conduct any analyses using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), a necessary procedure clearly specified by Firestone et al. (1). In another study, Pigati et al. (14) confirmed the previously reported YDB peak in spherules at Murray Springs, Arizona, and also claimed to find several non-YDB spherule peaks in Chile. However, the Chilean sites are known to contain abundant volcanic spherules (22), and yet Pigati et al.(14) did not perform any analyses of candidate spherules with SEM and EDS, which are crucial for differentiating impact-re-lated YDB spherules from volcanic spherules, detrital magnetic grains, framboids, and other spherule-like particles.
In another study, Pinter et al. (11) claimed to have sampled the YDB layer at a location “identical or nearly identical
”with the location reported by Kennett (2–4), as part of three studies that reported finding no YDB spherules or nanodiamonds (11,23, 24). However, the published Universal Transverse Mercator coordinates reveal that their purported continuous sequence is actually four discontinuous sections. These locations range in distance from the site investigated by Kennett et al. (2) by 7,000 m, 1,600 m, 165 m, and 30 m (SI Appendix, Fig. S1 B),clearly showing that they did not sample the YDB site of Kennett et al. (2). Furthermore, this sampling strategy raises questions about whether Pinter et al. (11) sampled the YDB at all, and may explain why they were unable to
find peaks in YDB magnetic spherules, carbon spherules, or nanodiamonds.

One fully independent one, with the link broken to the article, but much of the article pasted into the post (Sept 2012):
Here is another blog post. With post comments by George Howard who is sometimes a co-author Unfiltered: Surovell – Holliday in PNAS, 2009:
–An earlier rebuttal to more failures to replicate–
The full paper Lecompte et al 2012 “Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis.”:
Also you might want to take a watch of the slide show presented by Malcolm LeCompte (astrophysicist at Elizabeth City State University in North Carolina)………..
Abbreviated YDB evidence at 2011 Bern, Switzerland, INQUA Conference:
I think these will give you a good picture.

Ted Clayton
Reply to  Steve Garcia
August 29, 2014 10:29 pm

Thank you! Off to recharge, but will go over these carefully tomorrow.
Fascinating topics – both the Younger Dryas, and the lively debate!

Ted Clayton
Reply to  Steve Garcia
August 30, 2014 7:10 am

People and camps can & do disagree and debate, sometimes on large demographic scales over long spans of time, without it being necessary for anyone to have “screwed the pooch”, or to not “know how to take proper samples from a dig”.
I – we – needed to see real support for denouncing the competence of Surovell – and several others, and their many coauthors – and that isn’t addressed at CosmicTusk. George Howard, Steve Garcia et al simply have other work-results, interpretations and opinions … none of which puts a dunce-cap on Surovell.
On the contrary; to all indications Surovell is the solid professional, academic career scientist that he appears to be, and so are the others who publish findings & work at odds with the proposal that a large impact initiated the Younger Dryas.
I certainly have no basic personal aversion to the general idea of a big strike at 12,800 ya. I once ventilated excessively at the Carolina Bays phenomena … and am still sentimentally attached to their mystery. Reluctantly, I removed the Bays from the evidence-table.
The problem with this strike-hypothesis, is the lack of impressive, widespread, compelling evidence of it. The necessity to fuss over details of the sampling procedure, to wax pedantic on the use of the microscope and lab-techniques for sorting tiny artifacts, is inauspicious to the point of irony.
We’re talking about the virtual obliteration of our world, figurative, geologically, late last week some time’, yet the aftermath of this cataclysm is not glaringly obvious and perfectly well-known to every Junior High kid? I believe the event described would in fact leave “overwhelming” evidence, “most everywhere”, yet the evidence offered is more tentative than thundering.
I live on the Olympic Peninsula, which was the site of a major terminus lobe and spectacular transition to the Holocene. We don’t have to indulge in fine argumentation to show convincingly the evidence of events 14,000 or 11,000 years ago. They are glaringly and even hair-raisingly clear, even to young children. Tweens soon learn to spot ‘fossil’ shorelines of the extinct Lake Elwha, and labor through Olympic National Park brush, following their contours across the rugged, densely-forested hillsides. They point across the valley and correctly identify where the far shoreline of the now-gone ice-dammed montane Lake would have been.
And our part of the planet was severely smote 12,800 ya, yet we aren’t all perfectly aware of it, from ubiquitous & prominent evidence?
Nooo … we know of other events & processes at the same time, and evidence of them is sophomoric to find, assess and understand. Eg, many early-Holocene volcanoes far & wide left big & little calling-card layers in every local bog, and all the lakes. So should have a major extinction-strike in the same time-frame … yet it isn’t there, although it should be easily spotted between other datable horizons. Same story, all across the continent.

Steve Garcia
Reply to  Ted Clayton
August 30, 2014 1:27 pm

Ted –
“I – we – needed to see real support for denouncing the competence of Surovell – and several others, and their many coauthors”
You obviously did not even bother reading the papers and their “real support”. It’s called laboratory tests – empirical science.
How Surovell couldn’t even give Daulton proper samples to work with. How Surovell did sloppy science, as opposed to the volumes of testing done by Kennett et al. The lab results mean nothing. Lab results aren’t science to those who don’t want to see actual test results. And Surovell’s bad science put up against Kennett’s – Ted, there is no comparison.

Steve Garcia
Reply to  Steve Garcia
August 30, 2014 10:40 am

Ah, but Ted, Surovell and Pinter and Daulton – they are the ones who put the dunce cap on the YD “team”. Oh, they have mocked. And EVERY time they talk to a science editor, it is with derision and disrespect – always a “Requiem” or “bury the YD impact.” Kennett et al are just trying to do the science.
And it isn’t a mattre of opinion alone, or interpretation. When nothing terrestrial can achieve 2200°C but the evidence says it got that hot, is it interpretation to say it wasn’t a volcano and wasn’t a forest fire? No, it is admitting what the physics tells you.
And then Surovell et al are quiet about that – until they have a 50-year difference they want to quibble over – and decalre the wole thing dead again – because of THEIR not wanting anyone to “interpret” anything along lines they don’t approve.
No, the interpretation b.s. is coming from the other side, while the “forensics” is done over and over and over again – to try to get past this impasse with these “skeptics, without evidence”. People in these comments ask “Well why did it last 1300 years, when no dust can stay in the atmosphere that long?” Exactly! And there is no capacity to address such questions, not yet, not when the basics are beclouded by people who can’t do science right and then take their own inadequacies and declare them superior. So Kennett et al go out and spend another year on ANOTHER “forensic” refutation of their nonsense rebuttals.
Also, don’t take comments (even by George) at CosmicTusk as more than commentary. The real work is being done by others.
“The problem with this strike-hypothesis, is the lack of impressive, widespread, compelling evidence of it. The necessity to fuss over details of the sampling procedure, to wax pedantic on the use of the microscope and lab-techniques for sorting tiny artifacts, is inauspicious to the point of irony.”
The only real “compelling evidence” of a strike that the world will certaiinly accept is a crater. Nothing short of that will convince anyone. And with it seeming to have been in a location that was under maybe half km of ice, a crater may never be found. In case you don’t know it, an impact was NOT what the Kennett et al crowd were thinking about at the beginning. It was the impact material spikes in the black layer – specifically at the BOTTOM of the black layer – that led them to it. Firestone originally was simply looking for why the C14 curves were weird at certain times. Nobody went out and said, “Let’s go out and find some evidence we can claim to have been a comet!”
If you FIND such materials, just as Luis Alvarez found the Iridium in the K-T boundary, what do you DO with it. BTW, those two layers are the only ones in the geological record, it seems, that are narrow, quite visible layers. That makes them both exceptional and significant. But that layer was an accidental discovery of the whole thing. Like I said, Firestone was just wondering why C14 levels were weird. Then other stuff started showing up as well, and all at 12.9 kya.
“You go where the evidence takes you.”

Steve Garcia
Reply to  Steve Garcia
August 30, 2014 10:54 am

Ted: “We’re talking about the virtual obliteration of our world, figurative, geologically, late last week some time’, yet the aftermath of this cataclysm is not glaringly obvious and perfectly well-known to every Junior High kid? I believe the event described would in fact leave “overwhelming” evidence, “most everywhere”, yet the evidence offered is more tentative than thundering.”
Actually, Ted, you are wrong on this, this degree of obviousness. The biologists and climatologists have been working on the YD for a LONG time, wondering WTF???? It’s VERY obvious to them, the ones who have to deal with it professionally. They have been trying to explain it since it was first discovered. It was a VERY significant change in the flora – very noticeable. And if junior high kids were out sampling stuff one to six meters under the ground, YES, they would find it. Find the black layer and wonder about it.
The evidence is NOT tentative. The understanding of it is, but not the evidence. Those spikes are not tentative. That they all come at the same age – that is not tentative. That they are materials previously always associated with impacts – that is not tentative, either.
What you have is a group of skeptics who can’t do their own science worth a damn and THEY play little pouting games about how they don’t WANT it to mean what it means to anyone who has dealt with impacts before. They claim it doesn’t mean what it DOES mean. The Pinter people used to work on floods on the Mississippi River and such and forest fires. They have about as much expertise in this as President Obama – yet they don’t WANT it to be true, so they deny any clear presentation of the evidence, pouting all the way.

August 29, 2014 8:33 pm

Muck’s thesis accounts for the Frozen mammoths

Steve Garcia
Reply to  nargun
August 29, 2014 8:44 pm

I liked Muck’s book. I think I had a first edition, too. But Muck totally missed it on the Carolina bays. There is zero evidence that they were comet pieces. The shallowness of them precludes hyper-velocity impacts. It doesn’t preclude much slower impacts, like from the ejecta from an impact elsewhere, but a hyper-velocity event has far too much energy to produce the bays.
And BTW, someone has done an actual count of them, using LIDAR imaging – which shows up ones that are completely invisible to the naked eye. And a LOT of them are invisible like that. They total 43,900. Some people believe there are as many as 500,000, which seems reasonable, but it is only 43,900.

August 29, 2014 8:43 pm

DirkH – 8.2kya is not when Plato dated Atlantis. Plato was about 520BC, Atlantis, by his account, 9000 years earlier = 11.5kya just around the Younger Dryas warming, more or less.
Platos account would be consistant with a neolithic civilization on the shores of the Med. being inudated by the YD warming.

NZ Willy
Reply to  Larry
August 29, 2014 11:11 pm

Plato’s account is easily understood by dividing everything by 10, the years, the size of the city walls, etc, which shows that Atlantis was Thera and the destruction was that of the Minoan culture by the Theran volcano. Remembering that 900 years before Plato, the “Pillars of Hercules” referred to the Sicilian pass (later called “Scylla and Charbides”). The Egyptian accounting which Plato recorded in “Timaeus” used units which interchanged by 10.

Steve Garcia
Reply to  NZ Willy
August 30, 2014 10:43 am

It’s rather funny the way everybody assumes that Plato meant this when he said that, and all on different aspects of his tale. It’s created an industry – “Let’s second-guess Plato!” Some do it on location, some on dating. Like Plato, perhaps the most educated man of his time, didn’t know where the Pillars of Hercules were. And like he didn’t know how to count.

Dr Burns
August 29, 2014 9:14 pm

What caused the 11 degree warming in 100 years at the end of the Younger Dryas?

Steve Garcia
Reply to  Dr Burns
August 29, 2014 9:45 pm

Doc –
That is one of the $64,000 Questions. I am the only one who has even tried to answer that, that I know of. But don’t take that 100 years at face value. No matter what chart you see, the only source we have for temps and timing is GISP2 and other ice cores – and they are LOW res proxies, as are all ice cores. Even TWO hundred years s too high res for them – they can’t really do that. It’s the nature of the bubble migrating a little up or down within the core. Kind of like fuzzy vision. So if you see a ONE hundred year number, you can look at it a s guess.
Not only that, when you see those steep slopes, they have a straight line between the two points. But the actual line might go straight down from the upper point and maybe even go past the lower one and come back up to it. So that slope is shown at its MINIMUM slope. That 100 years may be 100 days or 100 hours coming up from the lower temp to the upper one.
In fact, the latest I read on that one was that it was less than a year – and a shorter time even than the drop INTO the YD. Based on what? They start with the one graph, maybe this one, and then maybe find with some other proxy that there should be another point – or maybe the one had a point straight up from the lower one. OR NOT. Who KNOWS?…LOL
But the short time coming out of the YD seems to have quite a bit of support. If someone knows they haven’t told anybody I know. And the people I know would say if THEY knew.

NZ Willy
Reply to  Dr Burns
August 29, 2014 11:19 pm

I reckon it was the completion of the melting of what had been a solid Arctic ice cap which started out at miles thick.

Ted Clayton
Reply to  Dr Burns
August 30, 2014 7:35 am

The sudden end of the Younger Dryas is not unique or mysterious, within the broader Pleistocene, which shows a continuous record of sudden cooling followed by sudden warming, ‘on all time-scales’.
Events like the Younger Dryas decorate the history of the Ice Ages. That any one of them starts with suspicious suddenness, and/or ends strangely-abruptly, in neither suspicious nor strange, within the overall climatic regime of the Pleistocene.
Looking at the Ice Ages overall, there is no call for any ‘special dispensation’ on the Younger Dryas. Either to start or end it.
Explain the Younger Dryas, and we explain the Ice Age.

Steve Garcia
Reply to  Ted Clayton
August 30, 2014 1:32 pm

“The sudden end of the Younger Dryas is not unique or mysterious, within the broader Pleistocene, which shows a continuous record of sudden cooling followed by sudden warming, ‘on all time-scales’.
Events like the Younger Dryas decorate the history of the Ice Ages. That any one of them starts with suspicious suddenness, and/or ends strangely-abruptly, in neither suspicious nor strange, within the overall climatic regime of the Pleistocene.
Looking at the Ice Ages overall, there is no call for any ‘special dispensation’ on the Younger Dryas. Either to start or end it.
Explain the Younger Dryas, and we explain the Ice Age.”
You can deny it all you want. People are coming around. See this NatGeo article with eminent Wallace Broeker (the oceanic conveyor) prominently included:

Some opponents of the hypothesis—and there are many—want so badly for it to go away that they have attempted to declare it dead. “My only comment is that the pro-impact literature is, at this point, fringe science being promoted by a single journal,” one of them, Nicholas Pinter of Southern Illinois University, said last week. The journal in question is Proceedings of the National Academy of Science.
Other researchers are trying to keep an open mind.
“Most people were trying to disprove this,” said Wallace Broecker, a geochemist and climate scientist at Columbia University’s Lamont-Doherty Earth Observatory. “Now they’re going to have to realize there’s some truth to it”—though maybe only a spherule or two.

BTW, PNAS is a journal that the Pinter side has used themselves in the debate.

Reply to  Ted Clayton
August 30, 2014 1:46 pm

Steve Garcia:
Little wonder that Wallace Broeker is attracted to the well-falsified YDIH, since he believes that humans caused the natural slight warming from 1977 to 1996, & are still warming a cooling world.
Anyone who has managed to convince himself that the Modern WP needs a special explanation, while the LIA, Medieval WP, Dark Ages Cool Period, Roman WP, Greek DA CP, Minoan WP, Holocene Climatic Optimum & 8.2 Ka cooling event don’t, would naturally be attracted by special pleading for the totally natural & terrestrial YD.

Steve Garcia
Reply to  milodonharlani
August 30, 2014 3:24 pm

Actually, Broeker is getting smarter in his old age. He has abandoned the Lake Agassiz flood, for example, because the recognized that the ice front had not receded enough and that that drainage path was not open in time.
In addition, the scouring that would have occurred – there was no evidence whatsoever, anywhere near the southern end of Lake Agassiz.
That has not prevented others from pushing the same issue, with the outwash going UP NORTH along the Mackenzie River and out into the Arctic Ocean near Alaska. HOW they could think that an outpouring of fresh water into the western Arctic is going to magically stay fresh all the way to the N Atlantic east of Iceland and only THEN sink, it buggers the imagination. I see it as being retarded, myself.
But I have not seen that Broekers is part of that.
I had the same attitude toward Broeker as you do. When he backed off the Lake Agassiz ice dam breakup, I was impressed.

Reply to  Ted Clayton
August 30, 2014 1:47 pm

Meant Broecker. Sorry. Followed Steve’s misspelling.

Ted Clayton
August 29, 2014 9:29 pm

Proceedings of the National Academy of Sciences PNAS
vol. 109 no. 19, Jeffrey S. Pigati et al, 7208–7212
April, 2012
Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis

The Younger Dryas impact hypothesis contends that an extraterrestrial object exploded over North America at 12.9 ka, initiating the Younger Dryas cold event, the extinction of many North American megafauna, and the demise of the Clovis archeological culture. Although the exact nature and location of the proposed impact or explosion remain unclear, alleged evidence for the fallout comes from multiple sites across North America and a site in Belgium. At 6 of the 10 original sites (excluding the Carolina Bays), elevated concentrations of various “impact markers” were found in association with black mats that date to the onset of the Younger Dryas. Black mats are common features in paleowetland deposits and typically represent shallow marsh environments. In this study, we investigated black mats ranging in age from approximately 6 to more than 40 ka in the southwestern United States and the Atacama Desert of northern Chile. At 10 of 13 sites, we found elevated concentrations of iridium in bulk and magnetic sediments, magnetic spherules, and/or titanomagnetite grains within or at the base of black mats, regardless of their age or location, suggesting that elevated concentrations of these markers arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event.

A Data Supplement page is linked beneath the PNAS abstract for a PDF of methology & data.

NZ Willy
Reply to  Ted Clayton
August 30, 2014 12:12 pm

Fine point, Ted, I remembered seeing that but could not think where to find it. About the impact event, as Laplace said, “there is no need for that hypothesis”, and Occam’s razor says throw it out.

August 29, 2014 11:06 pm

I think it probably hit the ice sheet, that is why there is not evidence of a crater in the crust. The ice took the hit. melted water ran into the gulf stream, and across the continent.
iron brian

Grey Lensman
August 29, 2014 11:55 pm

Re the very rapid warming, watch the video posted above by Robert Schoch.
Solar storm.
Dont forget the eruption of mount Toba induced a thousand year cooling.
Archeology in Bahamian Blue Holes has revealed massive African dust storms inundating the islands then. This would be in agreement with massive American fire storms, drawing air and dust from Africa.

Steve Garcia
Reply to  Grey Lensman
August 30, 2014 11:37 am

The Toba and 1,000 year assertion is interesting. May I ask where you got that? If Toba’s effect lasted 1,000 years that would mean the YD lasting 1,000 years is not impossible.
I will be looking into that myself, but if you have a source it could help.

Reply to  Steve Garcia
August 30, 2014 12:19 pm

The effect of Toba did not last 1000 years. Its effect on weather, not climate, might have lasted six years. Lane, below, finds a mild (1.5 degree C) effect for 20 to 30 years, which would get it into the climatic range.
In any case, Toba occurred while earth was already well into its cooling process during a major glacial phase, not coming out of one & previously warming, as with the YD.
And its eruption would have produced far more powerful gas & particle effects than the hypothesized but essentailly evidence-free comet impact.

Steve Garcia
Reply to  milodonharlani
August 30, 2014 2:47 pm

Yep, and 1.3 km Fragment G of Shoemaker-Levy 9 had a plume bigger than the planet Earth – in the gravity of Jupiter. The gravity of Jupiter is about 2.5 times that of Earth.
So, how little of a plume do you think a 1.3 km impact on Earth would be? And that is not to even mention the after effects. And not to mention the smoke from the nearly continent-wide firestorm – of which the black layer is clear evidence.
Yep, the black layer being all the way over in Belgium is to be completely ignored. And Syria.
It was just your everyday garden variety brush fire. It didn’t mean anything, and it didn’t have any effects anywhere.

August 30, 2014 3:43 am

Book your seats.

Bill Illis
August 30, 2014 5:11 am

I think alot of the megafauna drowned when all that ice was melting at its most rapid rate. They got stuck on islands that flooded, they died trying to ford across the massive rivers that all flowed south at the time.
At certain times during the ice sheet collapse lasting more 1,000 years, no animal was getting across the Mississippi river for example unless it had a canoe. The North American continent was isolated into three parts, the ice-sheet north, the west and east.
It only takes a small change in survival rates, or the number of surviving herds to make a megafauna species become susceptible to extinction.

August 30, 2014 5:32 am

The Bolling-Allerod (Northern hemisphere warming at 14,600 yrs ago) and Younger Dryas (subsequent 1000 yr cold interval) were parts of the last deglaciation which were driven by oceanographic processes. There is no need for an atmospheric deus ex machina. Over the deglaciation starting as early as 22yrs ago the general picture is steady changes in Antarctica contrasting with unstable fluctuations in the NH driven by the Atlantic Meridional Overturning Circulation (AMOC). The root cause of this is an instability in the AMOC arising from a positive feedback which it possesses.
Cold water formation and downwelling in the Norwegian sea drives the gulf stream – reactive flow of Carribean warm and – critically – saline water across the Atlantic to north west Europe. This gulf stream water has high salinity, and this makes the cold water formed in the Norwegian sea even more dense than would result from its temperature alone. So this cold and saline water sinks all the way to the Atlantic floor and is one of the principal drivers of the global thermo haline circulation (THC). Now more of this “deep water formation” at the Norwegian sea actually speeds up the gulf stream – something has to replace all that sinking cold super-salty water so this is supplied by the gulf stream. Thus the positive feedback – more gulf stream leads to more cold supersaline Norwegian sea downwelling leading to more gulf stream etc.. Where you have a positive feedback in the system you have the conditions for nonlinear oscillation. This is directly analogous to the ENSO in the Pacific, the positive feedback of the Bjerknes mechanism (cold upwelling strengthens trade winds strengthening cole upwelling etc.) giving rise to the ENSO nonlinear oscillator, although the AMOC operates over much longer – century and millenial – timescales than ENSO (decadal).
So a basic oceanographic feature comparing the NH with the SH in the palaeo record is more fluctuation and instability in the NH and more stable, gradual changes in the SH. The nonlinear instability of the AMOC is the root of this. Also, there is a clear signature of interhemispheric bipolar seesawing, whereby when the NH moves in one direction, the SH moves in another. This is not universal however – sometimes at the moments of biggest transition, NH and SH move together.
About 22 kYa (thousand years ago) Antarctica started warming. The NH at the same time slightly cooled. However at about 14 kYa the “Bolling-Allerod” (BA) happened, i.e. the NH abruptly warmed, as evidenced by Greenland cores. This caused a reciprocal pause and slight reversal in the (already long established) gradual Antarctic warming – the bipolar seesaw again. At the time of the BA there was a sharp rise in global sea level – 20 meters in 500 years. Weaver et al 2003 (link below) show that this was caused by a collapse of the gradually warming Antarctic ice sheet. The pulse of fresh meltwater from Antarctica had the effect of speeding up the AMOC and the gulf stream in the NH, bringing rapid warming to the NH and the BA.
The bipolar seesaw continued – as the NH became sharply warmer, there followed in the SH the “Antrctic reversal” where temperatures went slightly into decline. However down in the deep ocean, interactions between cold bottom water formed in the Antarctic and Arctic caused – about a thousand years later – an abrupt stoppage of the AMOC and the gulf stream. In fact the cuplrit was Antarctic Intermediate water (AAIW) – see again Weaver et al. With the interruption of the gulf stream the NH went cold again – the Younger Dryas. In response – by now you get the picture – the Antarctic turned to gradual warming. After about 1000 years of NH cold with no gulf stream, the effect of the Antarctic collapse subsided allowing the AMOC and the gulf stream to resume. Now followed an exception to the bipolar seesaw – both NH and SH warmed together, around 12 kYa. This marked the final end of the last glacial and the Beginning of the Holocene.

August 30, 2014 5:49 am

The scariest thing about the graph is: That the Earth’s temperature maybe many, many degrees cooler on average than we’ve experience over the last 20,000 years?

Steve Garcia
Reply to  Scott
August 30, 2014 10:57 am

Yes. For most of the last 2.5 million years it has been MUCH cooler. And as recently as 11,500 years ago. The end of the Last Glacial Maximum was at about 18,000 years ago.

August 30, 2014 5:55 am

Dust from an impact event could have initiated rapid melting by decreasing albedo of the icecap. Even if the dust fall lasted only a short time the decreased albedo would be effective long-term, resulting in the rapid melting and meltwater discharge discussed above, extending for hundreds of years. An impact event (or volcanism) could definitely be a part of this picture. It’s dangerous to attribute these rare events to a single cause when a confluence of factors may be (and probably are) at work. Also, the marked temperature decrease indicated in the ice cores could be an artifact caused by repeated fractionation of O16 away from O18, first by freezing of the glaciers, then by evaporation over the meltwater pool, followed by precipitation onto Greenland.

Ted Clayton
Reply to  pochas
August 30, 2014 7:53 am

Even if the dust fall lasted only a short time the decreased albedo would be effective long-term, resulting in the rapid melting…

The trouble with dust-driven melting is that once a thin layer of new snow falls on the dust, it ceases to cause melting. Buried dust has zero effect on albedo.
Glaciers and icefields commonly contain many dark layers, buried beneath recurring new snowfall. The amount of plant-pollen alone that becomes visible on ice & snow over the course of each summer, can be downright startling.
Melting is indeed driven by dust, but fresh dust has to be laid down each spring, after the winter snowfall stops. Either that, or snowfall in the cold season has to cease.

Reply to  Ted Clayton
August 30, 2014 10:15 am

You can see the effect of tire dust every spring. While precipitation exceeds melting, the dust is indeed buried, but when melting exceeds precipitation the dust layers collect and the snow along side the road melts much more rapidly than elsewhere. That is the effect I am talking about. When insolation is reduced below a certain point and precipitation exceeds melting, the albedo effect accelerates the advance of glaciers. When insolation favors melting over precipitation, a “tipping point” of sorts, than buried dust will be exposed at the surface and a reverse albedo effect will accelerate melting. It is often said that the Milankovitch effect is inadequate to produce the glacial cycles. With the albedo effect working to advance glaciation and the dust accumulation effect working to destroy them, there are powerful amplifying forces at work.

August 30, 2014 8:30 am

Comets are thought to bring bad luck. What is the origin of this superstition?
A large comet impact in the ocean could throw thousands, perhaps millions of cubic miles of water high into the stratosphere. Much of this would fall back to earth as ice.

Steve Garcia
Reply to  ferdberple
August 30, 2014 11:03 am

Good question. In many, many ancient peoples there are accounts of burning objects or “stars” or “suns” blazing down and causing great noise and quakes and fires. These objects didn’t just appear in the sky one day – they were seen on their way here, as what we call comets, and the archaeologists have normally transliterated as “gods”.
Any connection with “not having a good day”?
As to an oceanic impact, we don’t WANT one of those. Hills and Goda tried to calculate the size of tsunami from stony or iron meteors impacting the ocean. The worst case – at 1500 km away – was about 2 km of run-up from the tsunami. I don’t have the source in front of me, but can find it if you’d like.

August 30, 2014 8:46 am

Something about that dispersal pattern that bothers me. It almost seems backwards. In other words, imagine the winds in the Northern Hemisphere were backwards from what they are today and then look at the pattern. It would look like an impact around Turkey somewhere then dispersed these things across the rest of the Northern Hemisphere. The shape of the pattern given almost defies physics with winds going mainly west to east. One would expect to see relatively little material to the west of the impact site with the amount of debris fanning out as it is dispersed by winds to the east.
Also, there are a large number of places where such an impact could have occurred but have been completely erased by natural forces. For example, much of what is now under water in the Gulf of Mexico was dry land at that time as the glaciers had not yet melted enough to raise sea levels enough yet. Sea levels would have been about 200-ish feet lower than today so everything that is currently under about 200 feet of water would have been land.
The Mississippi River would have transported an absolutely incredible amount of sediment from glacial till and loess. You think it is muddy now? When the glaciers were retreating it must have been extremely thick with extremely fine silt.
One way to find the location of impact might be to sort the debris by weight assuming that the heavier samples settled out of the atmosphere closest to the event.

Steve Garcia
Reply to  crosspatch
August 30, 2014 11:15 am

It is possible you are misunderstanding that dispersal map.
1. The area in N America is not where the wind was taking the dust. That was the area that was burning.
2. Those only happen to be the areas SO FAR where they’ve found the black layer.
3. In addition (my guess here) the Heinrich events (of which the YD onset is considered H0) are universally interpreted as “ice rafted debris”. The evidence for the Heinrich events is layers on the N Atlantic, layers of dust. (I originally thought it was talking about full-sized rocks, but then found out it was dust. Given the timing of H0 at the same time as the YD onset, which is the same time as the BOTTOM of the black layer on land, and since the dust reached across to Belgium and to Syria , it seem logical to assume that the dust also fell onto the N Atlantic and sank. If this happened at the same time as H0, then the dust should either be mixed with the H0 dust – or it could BE the H0 dust. It might be an interesting thing to do – to compare, or to see if these same materials are in the Heinrich dust. It is certainly a falsifiable hypothesis, and falsifiable conjectures are what solid science is built on. Of course, if found to be true, this would definitely have repercussions about all the other spikes in the ice cores and the other layers of Heinrich dust.

August 30, 2014 9:38 am

So there was no new snowfall for hundreds of years that coated the ash and dust with immaculate white stuff.

August 30, 2014 9:59 am

Other glacial-interglacial transitions during the Pleistocene show the same pattern as the onset of the Holocene.
The YD & the rapid 8.2 Ka cooling are nothing unusual during deglaciations. In fact, they’re similar to Heinrich Events during glacial phases, the periodic armadas of icebergs launched into the North Atlantic from the Canadian, Greenland, British & Scandinavian Ice Sheets.

Reply to  milodonharlani
August 30, 2014 10:35 am

I agree – its about ocean circulation driven bipolar seesawing plus the effect of freshwater pulses from ice cap collapse during deglaciation. See my post 8 posts upstream.

Steve Garcia
Reply to  milodonharlani
August 30, 2014 11:23 am

At the same time, you should understand that nobody knows the causes of those other “nothing unusuals” during deglaciation. But you should also include the D-O events BEFORE the deglaciation.
Saying that they are there in the ice cores is one thing. Saying that these two are explained because of the existence of the others – which are unexplained – doesn’t answer anything.
As to the Heinrich events, the YD onset is pretty much accepted as Heinrich event H0. The YD caused dust to fall across the Atlantic. Heinrich events are interpreted as due to “ice rafted debris” – DUST – in the N Atlantic sediments, one of which, H0, coincides with the YD onset. Both are about dust. Could there possibly be a connection? Even if it isn’t accepted as such, if both happened at the same time then there should be YD onset dust mixed in with H0 dust. And that could mean what? Among other things, the idea that the H0 dust is ice rafted debris may need reinterpreting. (DO NOT take this as part of Kennett et al and their YD research; this is just my own thinking.)

Reply to  Steve Garcia
August 30, 2014 12:30 pm

Heinrich Event ice rafted debris is not “dust”. It’s referred to as gravel, ie greater than 2mm in diameter, although the sediments might contain “sand” as well.
There are good physical climatological explanations for D/O events during glacial phases & Bond Cycles during interglacials. No special explanation is needed for the YD, any more than for the Medieval & Modern Warm Periods or Little Ice Age.

Steve Garcia
Reply to  milodonharlani
August 30, 2014 1:51 pm

“Other glacial-interglacial transitions during the Pleistocene show the same pattern as the onset of the Holocene.
The YD & the rapid 8.2 Ka cooling are nothing unusual during deglaciations. In fact, they’re similar to Heinrich Events during glacial phases, the periodic armadas of icebergs launched into the North Atlantic from the Canadian, Greenland, British & Scandinavian Ice Sheets.”
No. You are only going by the ice cores. These are not just things that show up on that curve.
The YD IS a very unusual and unique period in the Pleistocene. It was first noticed by climate scientists and biologists, and tehy have tried to identify its causes for a very long time.
The 8.2kya is not just about cooling. It is about the impact it had on forest fires, vegetation response, sea levels, etc.
BOTH of these periods have a long way to go before we fully understand what happened. It isn’t just pointing at a graph and noting that there was a blip.
Similar to Heinrich events? Do we really know what caused Heinrich events? They say “ice rafted debris.” And where did that come from? It was dust settling to the bottom of the N Atlantic – at the same time the (proposed impactor caused) continent-wide conflagration in N America was sending smoke and dust across to Belgium and Syria. If both happened at the same time, then there should be N American continental dust in the Heinrich dust.
And that is exactly what is there.
But they looked around for a mechanism within Gradualism and decided it was icebergs.

Gary Pearse
August 30, 2014 10:08 am

“nanodiamonds, the production of which can be explained only by cosmic impact..”
I suppose it is redundant to say the diamonds are made from plants and animals – a kind of grisly observation to comtemplate – this is real climate change impact!
Steve Garcia
August 29, 2014 at 1:50 pm
“none of their “requiem” team was an archaeologist, with experience taking careful samples from the side of a pit.”
Geologists probably taught archeologists this skill. Indeed for a job like this, I’d go with the geologist/paleontologist.

Steve Garcia
Reply to  Gary Pearse
August 30, 2014 1:54 pm

Not so. Archaeologists have to get more precise samples. One inch can be 500 years. For geologists, what do they care about 500 years? For archaeologists 500 years is twice the life of the USA.

August 30, 2014 10:17 am

Suffice to say for now that this premise has been on the table for a long time. I even wrote a book on the event in 2009 “Sudden Cold” An Examination off the Younger Dryas Interval. Also Steve Garcia is correct when he states there were other lesser impacts likely at about 4200 BP and 8200 BP., and too at 3600 BP, 500 A.D. and 1500 AD. I also think that in addition to the map of YD coverage that Africa was also affected by the 12800 BP, as many animals became extinct there also. I am just in the process of writing a book on the Ice Age mammal extinction as well. Thank-you Rod Chilton,

Steve Garcia
Reply to  Rod Chilton (mystery seeker)
August 30, 2014 11:26 am

Hey, Rod. For those who don’t know, Rod is an actual climatologist.

August 30, 2014 10:43 am

Humans were responsible for the megafauna extinctions. Natural climate perturbation of the glacial maximum followed by the BA and YD probably contributed to this.

Steve Garcia
Reply to  phlogiston
August 30, 2014 11:31 am

Actually, it isn’t so cut and dried as that. The Overkill hypothesis is just one of (now) four competing hpytheses.
1. Overkill
2. Climate change
3. Disease
4. Impact
1, 2 and 3 do not explain why Clovis man himself also went extinct at that same time. It was another 1000 years before others showed up in the record. Overkill people never mention that one.
As to the BA and YD contributing, why didn’t the earlier D-O events – dating back to 110,000 years ago – cause these extinctions?

Reply to  Steve Garcia
August 30, 2014 11:52 am

D/O events occur during glaciation. The YD was during deglaciation, when previously prevailing temperatures were much warmer.
Climate change doesn’t work, since many of the same species survived earlier deglaciations & interglacials. The same pattern of Older Dryas cooling, Allerod warming & YD cooling appear in prior deglaciations, leading to interglacials. The difference between the Holocene & prior transitions was effective human big game hunters.
Overkill advocates most certainly do deal with the effect of over-hunting on humans. There is no evidence that they went extinct after first appearing in North America. Humans are omnivores, not obligatory big game hunters. In fact, human numbers greatly increased after the Clovis/Folsom transition. The two tool industries overlap, so the putative 1000-year gap doesn’t exist.
The impact hypothesis of megafaunal extinction doesn’t explain extin