The Younger Dryas was a cooling event about 12 kyr ago - see the wikipedia article, which still has the pic I drew in it. It is an example of rapid climate change, and was probably caused by THC shutdown caused by meltwater from the Laurentide icesheet, though exactly how is unclear.
However, some people would like it to be caused by a comet. That was first suggested in 2007, and RC said we doubt it. Then again in 2009 some more evidence was produced, and RC said we still doubt it. Others were less cautious; and Unscientifc American gushed over it as did Nat. Geog.. Bits of their work turned out to be non-reproducible, and it also fails various subsidiary tests. See-also Skeptical Inquirer ⢠May/June 2010 by David Morrison, which also notes the dubious pseudo-science precursors of the idea.
More excitingly, now Comet Theory Comes Crashing to Earth says the entire theory is nonsense, and possibly fraudulent too. I know nowt of the "Kennett" mentioned in that article, but he can't be famous (well, because I've never heard of him, and) because he has no wikipedia article. It looks a bit like K-the-elder (confusingly, there seem to be two of them, one the son of the other) is the influential crusty old type gone Emeritus who is getting more respect for his theory than it deserves. Or then again, he may have been traduced*. But the villain may be West, who is really called Whitt, if my source is to believed. If the new article is right (or if only the Skeptical Inquirer is right) then the motto is the usual one: don't believe a sexy new idea just because it appears in a high-profile journal.
* Kafka joke.
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I was always dubious about this idea. It is unlikely to be the reason for the ending of the Clovis culture and mass extinctions of North American megafauna.
Ok, I'll raise your snark with this.
Actual evidence always trumps snark. My interests in the possible Laurentide impact and its verification or refutation have always been more hydrogeological than paleontological. And then, there are little tangential tidbits like this. Grok that.
Crackpot ideas can be useful to the open minded. That wouldn't be you, I guess.
[Other than being impolite, I'm afraid I missed the point of your post. Could you be a bit less opaque? -W]
Re #2 It's a poster of four deniers giving their uninformed opinion, there's nothing to debunk?
[Well it was before I deleted it, sorry :-) -W]
My point, William, is that crackpot ideas deserve snark, but the investigation of crackpot ideas often result in useful ideas, such as for instance microscopic fossilized cosmic particles as useful proxies (particularly robust long lasting particles such as nanodiamonds), and the originators of crackpot ideas should be encouraged to continue to come up with crackpot ideas, and not ridiculed by people who haven't ever had an original idea in their lives. One of the reasons we have an impact hypothesis is that the origin of the Younger Dryas transition remained unclear to almost everyone interested in it. That situation appears to be changing, in part by the motivation provided by the crackpot ideas, such as, for instance, an impact.
It would also be helpful if both you and the author of the article quoted could differentiate between a theory and a hypothesis, and understood the definition of nonsense.
[Then I think the point you are missing is, when do the originators of Novel and Interesting ideas give up on them in the face of mounting evidence against them? In this case it looks very much as though the impact idea has long outlived its worth (indeed, it may well have done actual harm; and if the allegations of fraud are true, may have wasted lots of peoples time), but is nonetheless being held tenaciously by its originators. This is not an unusual pattern, and of course has parallels in the GW denial world -W]
All emeriti want have louie alverez envy
Then I think the point you are missing is, when do the originators of Novel and Interesting ideas give up on them in the face of mounting evidence against them?
In the case of West and Firestone, and particularly Kennett, when the refutations becomes convincing to them.
[Err, well that is potentially never, then, just like the GW denialists -W]
I have seen nothing convincing in any refutations beyond my own discussions with Mark Boslough where we both agree that certainly a four kilometer comet breaking up over the continental US doesn't seem plausible, and that a sub kilometer volatile rich impactor hitting the ice sheet directly is a far more plausible scenario.
[Did you read the skeptical inquirer piece, which details a number of other problems? -W]
Certainly if West fraudulently mishandled the sample preparation that would be worth investigating, but to go after Kennett for misconduct over a 'hypothesis' is to me beyond the pale.
[You're reading things I didn't write. I'm not suggesting that. What makes you think I am? -W]
Of course, I'm not totally married to the hypothesis by publication, but I do find highly modified versions of it (sub kilometer impactors producing ozone depletion effects and land bridge and/or ice dam breaking megaflooding for instance) as eminently 'entertainable' and it continues to me to be a useful hypothesis considering the effect it has had on the nanodiamond and cosmic particle proxy ideas. And if any of its detractors can come up with more than hand waving or ridicule as definitive refutation of the concept of Holocene ice sheet impactors, I would be more than willing to look at it, but thus far what I have seen is superficial looks at sediments far removed from the hydrogeological sites of interest, or examinations of a single particle. Hardly convincing refutation in my view.
What is more disturbing to me is the attack on author credibility rather than attacks on the data and evidence, and the great enthusiasm shown by the people quoted in the article for credibility as an indicator of veracity.
[You think that having one of the authors change their name to hide a conviction, and a dodgy book, is irrelevant? -W]
Another Benny Peiser favorite bites the dust, then, and this is a little closer to his field.
I'm glad that AFAICT he's not done much more work lately promoting climate denialism.
You think that having one of the authors change their name to hide a conviction, and a dodgy book, is irrelevant?
You know William, yes, I just can't see how that is relevant to the problem of the hydrogeological aspects of the Younger Dryas transition, that is, if according to Rayburn et al, the Champlain Sea was open at the YD transition and a century long flow from Lake Agassiz followed a catastrophic outburst, and when the only known outlet at that time was through Lake Nipigon and that are was blocked by the Laurentide ice sheet, then yes, I think that something catastrophic must have happened right there.
Yes, I have severe problems with the original Younger Dryas impact hypothesis of a continental wide atmospheric bolide catastrophe with paleontological consequences, and I have always been suspicious of Firestone and particularly West with their previous nutty ideas, but I also have severe problems with the characters involved in the refutation of that hypothesis, the manner by which they carried out their investigations, the very weak evidence that they have put forth to refute it, and language they have used (physical and statistical impossibility and all that), and their complete ignorance of the hydrogeological problems of the Younger Dryas and the obvious existence of a nexus of catastrophe in the area just south of Lake Nipigon, in addition to the weak but growing body of evidence available in the form of cubic nanodiamond and carbon proxies of every form in the black mat Younger Dryas transition layer.
In my opinion the Firestone et al. THEORY has been refuted, but the impact hypothesis is still quite viable and still continues to yield plenty of useful surprises if one takes the time to investigate them, and that is quite independent of Allen West's reputation and credibility. It's about the evidence, and that has nothing to do with one's character.
I suggest anyone interested start right here.
No, one doesn't have to invoke a sub kilometer sized impact to expain what happened in the area of Lake Nipigon thousands of years previous to the Nipogon phase of the Laurentide ice sheet collapse, but one has to invoke something unusual to explain the evidence, and an impact still can explain the plethora of unusual hydrogeological and geomorphological evidence. The other explanations still remain mysterious and elusive.