This is the strong conclusion of a new paper in the Earth Science Reviews by Pinter et al (via Scribd). From their abstract:
The Younger Dryas (YD) impact hypothesis is a recent theory that suggests that a cometary or meteoritic body or bodies hit and/or exploded over North America 12,900 years ago, causing the YD climate episode, extinction of Pleistocene megafauna, demise of the Clovis archaeological culture, and a range of other effects.
…
The physical evidence interpreted as signatures of an impact event can be separated into two groups. The first group consists of evidence that has been largely rejected by the scientific community and is no longer in widespread discussion…. The second group consists of evidence that has been active in recent research and discussions:…. Over time, however, these signatures have also seen contrary evidence rather than support.
…
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.
The YD impact hypothesis made a big splash at AGU in 2007, and we’ve written about it a few times since. Our assessment was (in 2007), that this would need a lot of confirmatory evidence to get accepted, and even if it was, it did not provide much explanation for other, very similar, abrupt changes in the record. In 2009, we were still skeptical and noted that “the level of proof required for this extraordinary idea will need to be extraordinarily strong”. Unfortunately, as this paper makes clear, neither a lot of confirmatory evidence nor extraordinarily strong proofs have been forthcoming.
This paper is unlikely to the very last word on the subject, but it is likely to be the last time the mainstream paleo-climatologists are going to pay this much heed unless some really big new piece of evidence comes to light.
However, while the specifics of this particular hypothesis and its refutation are interesting in many ways…
The YD impact hypothesis provides a cautionary tale for researchers, the scientific community, the press, and the broader public.
Let’s be specific…
… since there are indeed lessons that can be drawn here:
- ‘Bold’ ideas can get published and get serious people to pay attention. The claims about the YD impact were entirely at odds with mainstream views, yet taken seriously and looked at by a wide variety of other researchers.
- Like most bold ideas that initially raise skeptical eyebrows, the evidence for this one decreased with time. This is not inevitable, but it is not unusual.
- Science is self-correcting because other scientists take the time to look for new evidence backing up or refuting initial ideas, and go back and re-interpret what was previously done.
- Even eventually discarded ideas can provide abundant directions for good science to get done. For instance, a fair amount of research into nanodiamonds has occurred because of the interest in this idea.
- The media loves the ‘radical new idea’ presented by ‘outsider’ scientists (3 documentaries on this so far, a big NYT piece). It fits a lot of the romantic archetype of what science is supposed to be about. It has controversy, narrative and outsize personalities. Whether the ideas are good or not is barely relevant.
- The Feynmanian ideal of a single scientist both proposing and refuting their own new idea is very rare. In practice, the roles of proposing and refuting are far more often done by the scientific community as a whole, not an individual.
- Scientists gain credibility for doing careful work and not going beyond the evidence in interpreting it. This is opposite to what gains readership on blogs. :-)
The Younger Dryas, an extremely abrupt, and still mysterious, interval of climate change, will no doubt continue to excite people across the field of paleo-climate, but we hypothesize that the impact hypothesis has had all the impact it’s going to.
But I did no such thing.
I’m really not directing my comments to you, I’m more or less directing them to the broader impact and geophysics community.
I said that as yet you have failed to support the hypothesis with sufficient evidence.
Whereas I have produced a feature in the critical hydrogeological position which appears to be an ice sheet related impact astrobleme, and noted that cubic diamonds are purported to exist in YD related Greenland ice and YD related black mat sediments in Europe. We know that cubic nanodiamonds exist in abundance in carbonaceous meteorites, and we think some of them were formed in the solar nebula, and there are wide variety of plausible shock and plasma related chemical vapor deposition synthesis routes capable of producing them in impacts and simple meteor and dust reentries and presumably via recondensation of hot plasma impact plumes.
Furthermore, the authors have explored none of these natural diamond formation and deposition scenarios, and they have also failed to offer any estimated formation and/or impact rates and sedimentation fluxes for the cubic nanodiamonds that they have observed, nor have they bothered to check for the existence natural nanodiamonds in any other control sediments. At least none of them have reported any of those results yet.
there is no evidence of an extraterrestrial impact related cause of the YD.
I find it extremely difficult to rationally engage anyone who uses the phrase ‘no evidence’.
51, Thomas,
I looked more closely at their manuscript. I’ll retreat from “no evidence” because I’d never give the most recent paper final say, but from their abstract:
The paper itself gives a lengthy discussion of nanodiamonds, and I’m not sure what to make of your statement that they have explored none of the natural formation and deposition scenarios. What they did do was to review and summarize all of the work that has been done to date, and to point out the large number of contradictions or failings which make such evidence suspect, at best. Given that it is the only line of evidence that appears to have withstood attention without being debunked (but also without finding incontrovertible support), while all other issues have been put to rest or cast into doubt, it would seem that anyone who clings to nanodiamonds as a smoking gun (as you appear to be doing) has an emotional rather than logical attachment to the process and the outcome.
I’m not saying an impact event is impossible. That has not been determined. But at the moment, the evidence for it is extremely unlikely, and the visual appraisal, with no substantive work, of a potential impact crater (one which is just as easily interpreted as a mere flood basin beside a ridge formed through a natural geologic fault — I’m out of my depth here, so hopefully a geologist can chime in and offer the possible/likely scenarios for its formation) does not add any weight whatsoever to the argument.
Sorry, but if you want to put forward the case that the area near Lake Nipigon is an impact crater, you are going to have to drive up there and get some hard evidence to support your case. “It looks like one on Google Maps” isn’t evidence, or science, it’s easy, armchair pseudo-science. It’s what an army of climate change deniers do all day long at WUWT.
Can you tell us any more about the hypersonic gun experiments with pellets into ice?
Most of it is documented and all I know is from what I’ve seen of the slow motion imagery of the actual oblique angle impact experiments. These experiments were carried out at the NASA Ames Hypervelocity Facility by Peter Shultz and I presume Ted Bunch. Very clear easily distinguishable lateral wave fronts were observed when the pellet punctured the ice sheet.
It looks like one on Google Maps” isn’t evidence, or science, it’s easy, armchair pseudo-science.
Which explains why I deduced something of a highly unusual hydrogeological nature must have occurred in the area of Lake Nipigon, when I went searching for evidence of unusual hydrogeological activity in that area using brand new Google Earth terrain map data, I almost immediately discovered an unusual geomorphism.
Those preliminary discussions are well documented here. I am completely open to alternative interpretations if they have any credible geophysical basis, but thus far none have been offered, except ‘it’s not an astrobleme’.
So you see, the (non) argument works both ways. I’ve already long ago been in contact with numerous field workers and have already made plans to visit the area and worked the permitting to import the samples into the United States across international boundaries, Bob. Timeframes for these activities are measured in years.
@42 Hi Bob –
B – I’m not sure what you’re saying here.
“And here I have to disagree with you, completely. Besides the hydrocarbon markers, there are gross neutron and proton signatures, and we have gross climate change, rapid simultaneous species extinctions, and there is a sudden quarry abandonment, indicating the death of roughly 95% of the population of North America.”
B – “According to Pinter et al, as per to OP, there are no valid signatures for an impact event.”
Re: Pinter et al., Locating the YD layer, sampling it, and processing those samples is non-trivial. Its not like dealing with the KT layer.
B – “The fact that there was gross climate change, rapid simultaneous species extinctions, and population loss in North America says something happened in the YD, yes, but not that it was impact related. You can’t say something like “there was an effect, so X must have been the cause.” There was an effect, so there must have been a cause, but there is no evidence yet as to what the cause was.”
Ahhh, but you left out of your list the neutron and proton production evidenced in 14C and 10Be samples – which is what got Firestone involved in all of this in the first place.
While Firestone attributes these to nearby supernova, my current estimate is that in a massive impact photons reach an energy level capable of splitting neutrons and protons out of what is now called the nucleon (which you and I were taught was the nucleus of an atom). If one takes a look at the 14c calibration charts, the peaks appear to be tied to impact.
“That said, the paper discussed in this OP seems to say pretty unequivocally that it was not an impact event because the signatures of such an event do not exist. Until evidence is produced to the contrary, that particular option is off the table.”
That’s not to say someone can’t produce evidence tomorrow. If so, we can argue it tomorrow. Today, there is no such evidence.”
There is another item of data which I did not mention because it is widely denigrated by the “scientific” community, and that is Native American oral histories. Anyone who wishes to claim that an impact did not occur has to come up with an explanation as to why they would create such stories out of whole cloth, and why their histories’ details would correspond so closely to such unusual events.
54, Thomas,
Well then I wish you good luck. It sounds exciting and worthwhile. I similarly have my own efforts which I will keep to myself until they amount to something, if ever.
But don’t put the cart before the horse. Showing up here and touting it as if the scientists are somehow remiss in not taking you seriously, or that this post is in error because you think you’ve found the smoking gun, is inappropriate.
You have an idea, possibly a good one, and you’re doing the work to see if it comes to fruition. Good. If it does, you publish and you’re famous. If it stands up to scrutiny, you’re even more famous. If it doesn’t, you move on.
But casting aspersions on other scientist’s work, or defining your intuition as a “problem” that they are ignoring, before you yourself have done sufficient leg-work to make the claim relevant, is wrong. It is armchair pseudo-science if all you’ve done is blog about it, and until you’ve done something more definitive.
Showing up here and touting it as if the scientists are somehow remiss in not taking you seriously, or that this post is in error because you think you’ve found the smoking gun, is inappropriate
But I haven’t done that. Those who know me know already full well that my perspective on right and wrong in science is far looser than you imply.
And I’ve already learned a great deal from the Younger Dryas impact hypothesis, right or wrong, and the anomalous Nipigon geomorphism isn’t going anywhere. It is easily accessible for anyone who may want to take a look at it, and I’ve already done my obligatory due diligence with respect to it.
Indeed, I now hypothesize that trillions and trillions of microscopic nanodiamonds are available for anyone to take a look at, examine in detail and categorize, since they appear to … ahem … erode very, very slowly, and it’s quite possible now that they may be literally … almost everywhere!
I will be patiently awaiting any interesting conclusions they may draw from them.
E.P. Grondine,
Do you have any idea how offensive and off-putting a “comment” like this is?
People who “disagree” with you — and back it up with substantive work and publication — do not deserve to be “imprisoned” in quotes.
If you have a scientific point to make, prove it. Until you do, it is guesswork that you can label as a theory or a hypothesis, but no amount of Internet posting puts any substance behind it. It’s all hearsay until you (or Firestone) produce firm, reproducible evidence. This has not yet happened. Talking about it as if it will happen is a waste of time. Current, published science says “YD yes, impact no.” It stays that way until contrary evidence is produced.
Conjecture about Native American oral histories, which could reflect anything from a religious belief or moral analogy to a simple, ordinary meteorite fall at any point in the past 100,000 years, anywhere in North America, with no relationship whatsoever to the YD, is mere conjecture. In fact, meteorite strikes are so common that to attribute oral history to anything other than an ordinary event in the relatively recent past is really stretching it. Do you really think that an oral history might have survived a population decimation and 13,000 years of time to exist today in any reliable form and to provide any remotely relevant information?
Such conjecture has no place whatsoever in a scientific discussion, unless you can figure out a way to prove its veracity and applicability.
Note, from just some random googling (trying the find specifically what you’re talking about in the first place… and I’ve failed):
In Australia:
And also:
Did all of these events cause massive climate change? It’s no wonder “scientists” dismiss such “evidence.” It goes hand in hand with the search for Atlantis, Intelligent Design, ozone killing all of the trees on the planet, and climate change denial.
David @45 You are correct. The 8/2010 Glaciology paper emphasizes that their YD dating and findings are preliminary due to the study scope and are intended to foster more directed, intensive efforts. It appears their methods (using the edge of the ice sheet at the presumed YD boundary) necessarily raises issues about how accurate they can estimate the age of the surface where the nanodiamonds are located. I have no dog in this hunt and in fact did a long piece for UMaine’s magazine about Denton and Broecker’s late 1980s work on the shutdown of the conveyor as being a suspect driver of the YD. But any finding of an ET layer of stuff in Greenland is very interesting regardless of whether it drove the YD or not.
The UMaine Climate Change Institute has a free PDF download of the Glaciology paper. Look under 2011 pubs.
http://climatechange.umaine.edu/research/publications/
Bob, so far you have claimed here that there is ‘no evidence’, that all scientific publications must ‘prove something’, that the sole reason for doing science is ‘fame’, and that the internet is not a valid scientific communication medium. If you have anything substantive to offer with respect to the topic at hand, I will be patiently waiting here in order to hear it.
Hi Bob –
\Do you really think that an oral history might have survived a population decimation and 13,000 years of time to exist today in any reliable form and to provide any remotely relevant information?\
Yes. It is fairly stunning, but YES. It survived more than impact as well – it survived the conquest and \cultural genocide\.
I’m not alone in my views on the interplay of racism and science. For Adrian Major’s views on the denigration of Native American traditions, see her book.
A shorter collection of North American Native American YD traditions is available at http://cosmictusk.com
If you have any other reason why they should have made up details about impact events, the burden is on you to provide it.
Now back to the hard evidence, which you attempt to kite-by.
You have no explanation for the observed neutron and proton production.
The burden is on you to provide one.
E.P. Grondine
Man and Impact in the Americas
Hi Bob –
(Excuse my typos – my stroke damage is catching up with me.)
If you have any other reasons than that they observed impact for them to make up the extra-ordinary deatils contained in these traditions, then produce them. In other words, they were here, and remembered in some detail what they saw.
(PS – you’re absolutely right about posting to the internet, as TEL is doing here, we have Dennis Cox over at Cosmic Tusk doing the same thing, and it does get wearying.
But in regards to formal publication, it would help if Dr. Morrison and his associates stopped passing themselves off as impartial referees: Mueller’s Nemesis injection mechanism is by no means the standard paradigm.)
E.P. Grondine
Man and Impact in the Americas
Douglas Watts @59 — I found and read the paper before commenting. Pinter et al.’s requiem severely criticises Kurbatov et al. on page 31 and seem to indicate that n-diamonds were actually not observed; they seem to require an independent analysis.
Be that as it may, I opine it is too early for even last rites, much less a requiem. Thmos Lee Elfiritz seems to find something unusual about Lake Nipigon; in comment #2 I pointed to Charity Shoal as a possible YD-date impact crater; in the previous-but-one thread on YD I linked to a potential YD-date impact crater near the Louisiana/Mississippi border, although the dating seems to be otherwise. I’ll add another: off the Carolina coast there is a massive, fairly recent geologically speaking, clathrate blowout feature. Such might be due to a bolide impact and ought to be detectable as such via a magnetometer survey. If so, then a sediment coring ought to be able to roughly date the feature.
If E.P. Grondine would indicate where in the anthropological literture one can find those Amerindian legends, I would pay attention. There is little doubt that the Navajo tibal story is essentially correct back at least to their time in/near the Queen Charolette Islands as they are Na-Dene speakers.
While such a Clovis Comet as not necessary to explain YD, it certainly would directly explain the end of Clovis Culture and the simultaneous extinction of 33 genera of megafauna, including the North American llama, but not, it seems, wapiti and certainly not bison.
Bob S: Do you really think that an oral history might have survived a population decimation and 13,000 years of time to exist today in any reliable form and to provide any remotely relevant information?
EPG 61: Yes. It is fairly stunning, but YES. It survived more than impact as well – it survived the conquest and cultural genocide.
BPL: Can you identify any other legend in the world that has survived 13,000 years? I’m not aware of any, especially since written history only goes back 6,000.
It’s great to be for Native Americans, but you don’t have to be a racist to doubt that a particular legend is 13,000 years old.
-BPL
Brother of the Crow, Charlotte, North Carolina, 1976.
Hi BPL –
There is a collection (not complete yet by any means) over at http://cosmictusk.com.
Enjoy.
I know of no other oral corpus that goes back that far.
As far as the “scepticism” goes, you surely are aware that many Native Americans will just call all scientists “Nazis” for good reasons.
Within the archaeological community, naturally if you can show 13,000 years occupation, it brings NAGPRA into play at many sites here in the US that were previously “fair game”.
E.P. Grondine
Man and Impact in the Americas
60, Thomas,
Wow. Were you really able to pack that many blatant misinterpretations of what I’ve said into one sentence? Anyone can go back and read it, you know.
No evidence: No, what I \claimed\ (stated, actually) was that you have refused to provide evidence each time you have been asked. You offer lots of gish gallop, but when I ask for details on the models you used to simulate impacts, you evade. When I ask for evidence of not merely an impact but the timing of the impact, you evade. You have not provided evidence, only claims.
Oh, wait, I did say there’s \no evidence,\ as in \no firm evidence\ of an extraterrestrial impact related to the YD because that is the case (according the paper supposedly under discussion here, which you seem to too readily dismiss). If there were firm evidence, the discussion would be moving in a different direction. If you have firm evidence, cite it. Or continue evading, as you’ve done so far.
I never said scientific publications must prove something. I did say that if you have a claim to make, the burden falls on you to prove it, with the understanding that if you have proof of a substantive claim, then publishing it would be the most beneficial thing to do (i.e. get it out where everyone can see it and use it). See the difference? Not that publications must prove something, but rather that people wandering into blogs making elaborate, extreme claims must prove them. Simply making the claim over and over again is ridiculous.
I never said the sole reason for doing science was fame, I said that if you turned out to be right you’d be famous. See the difference?
I never said the Internet was not a valid scientific communication medium, but it certainly is a place where one can find a lot of nonsense and crackpots, and one has to see through all of the gish gallop and recognize those with a Galileo complex for who they are. Fortunately, this site is normally relatively immune to such nonsense. I’m not sure why this has gone one for so long, however…
But as far as you patiently waiting for me to provide something substantive… LOL. I’m not the one making fantastical and totally unsupported claims. Once again, if you can support your position with anything more than \look, look, it looks like an impact crater, see\ then I’m patiently waiting here in order to hear it.
Re: #65 (E. P. Grondine)
I looked at your linked site, and in my opinion, your claim that the oral history is reliable evidence of a YD impact event is not plausible. I’m tempted to compare to Velikovsky.
I’m not the one making fantastical and totally unsupported claims. Once again, if you can support your position with anything more than \look, look, it looks like an impact crater, see\ then I’m patiently waiting here in order to hear it.
I already provided you with several paragraphs delineating my lines of evidence in support of my fantastic and totally unsupported modified YDB hypothesis. Hydrogeological arguments concerning catastrophic and longer term LIS retreat and advances, cubic nanodiamonds in YD sediments and ice, some CVD nanodiamond and carbon fragment synthesis routes in electrically charged, volatile rich, plasma impact plumes, an ozone catastrophe related to volatile injection into the stratosphere, and a putative impact feature in the correct position and of the correct size and geometry to explain the hypothesis. Your responses are exactly what I was expecting from this.
Thanks. At least that particular hypothesis was verified.
Hi tamino –
I understand what you mean by “reliable” – in other words hard, physical evidence, and I don’t make such a claim for the historical traditions.
And I can understand you wanting to compare my analysis with Velikovsky’s – but that comparison is simply not fair in any way. In my analysis, physics is given more priority than any verbal or written account, as is the “hard” data, including anthropological hard data.
My analysis also accords with modern physics and cosmology, as they are understood today. (I should point out here that Mueller an Morrison’s hypothesis on comet and asteroid impacts are in no way considered to be “the standard paradigm” within the international impact research community.)
Velikovsky’s writings did neither, from what I know of them – I never read them. (Leroy Ellenberger can give you more information about Velikovsky, if that’s who you are interested in.)
And that is why my book is so much better than anything Velikovsky ever wrote, and why it is groundbreaking and paradigm shifting – it is the first anthropological work to take into account somewhat comprehensively the effects of comet and asteroid impact on a portion of mankind.
Bob above mentions the Australian Aboriginal traditions, and they have successfully been used to locate impact events. If Gene Shoemaker had not of passed on in that traffic accident, he might have been the first to do what I did; if Peter Snow had not passed, he might have been the first. As it is, I am the first. (While Kennett’s YD/clovis work is far better than mine, I do span more impacts in my book.)
What I do think, and am willing to argue with anyone, is that Native American oral and written traditions do remember impact events, and that with archaeological data they can be used to limit the search for physical evidence of impacts, making that process more efficient.
Once again, if you want to see how impact science has progressed, take a look at Mueller and Morrison’s Nemesis hypothesis, then take a look at Clube and Napier’s hypothesis; or take a look at Chicxulub, then take a look at Shiva.
At this point in impact research, there is nothing done and over with.
And if you’ve been at it for any length of time, you know you will make mistakes.
My book has a correction sheet pasted inside the cover of every copy.
TLE –
Bob wrote to you:”No, what I \claimed\ (stated, actually) was that you have refused to provide evidence each time you have been asked. You offer lots of gish gallop, but when I ask for details on the models you used to simulate impacts, you evade. When I ask for evidence of not merely an impact but the timing of the impact, you evade. You have not provided evidence, only claims.”
I invite you over to the cosmic tusk to discuss your claims with Dennis Cox.
Prediction:
> This paper is unlikely to the very last word on the subject,
> but it is likely to be the last time the mainstream paleo-
> climatologists are going to pay this much heed unless some
> really big new piece of evidence comes to light.
Corollary: an explosion of blog science on the topic ….
Here’s why I love RealClimate.org: “gish gallop”. What a perfectly delightful term!
Duane @72 — I once listened to Duane Gish gallop:
http://rationalwiki.org/wiki/Gish_Gallop
I invite you over to the cosmic tusk to discuss your claims with Dennis Cox.
No thanks. I have my own blog, and the only reason I’m posting here is that the original hypothesis, whether it’s true or false (and large impacts that recent are indeed only true or false) has already yielded incredible insights into the (cubic) nanodiamond phenomenon. I am of the opinion that the original Firestone hypothesis was a huge overreach, and so I’ve now narrowed it down to these last few related outstanding unresolved issues. Once these last few issues are resolved, I’m ok with abandoning it. I’m intrigued with the concept of ice sheet impacts, especially one that’s now gone.
TLE –
Well that is too damn bad. Over at the Tusk Dennis does the same thing you’ve done here with “features” that he’s located through Google Earth, and will spend copious amounts of time simply re-iterating his claims. I was hoping that the two of you would have an interesting “conversation”.
Ok, Ed, I give up. Bob is right, it looks like a lake bed.
Case closed. Snark off.
Though looking at a single locale’s Ice Sheet record is revealing (the Younger Dryas is visible in both Greenland & Vostok cores), it should be a pointer to describing the behavior of the Ice Ages.
When I look at Vostok (and extensions) Ice Core record, I see what appears to be two main waves. When they coalesce (or occupy overlapping time frames) the result is contructive (much like the behavior of light waves). When they pull apart, they are roughly half the height of the same two waves that are on top of each other. The Younger Dryas looks to me to be the result of two waves that last coincided 330,000 years BP. The two waves are nearest separation at 570,000 YBP and 640,000 YBP.
If this process is correct, then the next interglacial will be pulled apart into two lesser interglacials.
Hi TLE –
“Ok, Ed, I give up. Bob is right, it looks like a lake bed.
Case closed. Snark off.”
Oh well, that’s something else you and Dennis have in common.
And here I was so looking forward to the two of you competing in making baseless claims to greatness through finding THE YD event or events.
Now if I could only have harnessed your obliviousness to deal with Dennis’s, then what a delightful turn of events that would have been!
Well, TLE, here’s bit of encouragement: someday somebody will find all of the YD impact related data. And they’ll be Great with a capital “G”. So some on over and share insults with Dennis.
PS – Bob, no need to thank me, [edit – out of order] there’s a special on “Man and Impact in the Americas” over at the cosmictusk.com. I think that you’ll have a better perspective on other peoples after you read it.
Ok, Ed, I give up. Bob is right, it looks like a lake bed.
Sisli Arcelik Servisi
Case closed. Snark off.
My analysis also accords with modern physics and cosmology, as they are understood today. (I should point out here that Mueller an Morrison’s hypothesis on comet and asteroid impacts are in no way considered to be “the standard paradigm” within the international impact research community.)
Sisli Arcelik Servisi