The Younger Dryas Impact Hypothesis (YDIH) is based on the claim that around 12,800 years ago the Earth had an encounter with a very large asteroid or comet that broke up in an airburst over North America and of which some fragments possibly hit the ground directly(a).
Many effects have been linked with this event with varying levels of enthusiasm including a suggested association with the demise of Atlantis. Elsewhere, megafaunal extinctions, cataclysmic floods, the disappearance of the Clovis people and the creation of the Carolina Bays(g), have all been proposed as consequences of this episode.
In 2006, Richard Firestone, Allen West & Simon Warwick-Smith published the foundations of the YDIH in The Cycle of Cosmic Catastrophes . A year later the hypothesis had a more public airing at the American Geophysical Union Press Conference, Acapulco, Mexico, on May 23(d). This was followed the same year by the publication of a formal paper in the Proceedings of the National Academy of Sciences of the United States of America(f).
Since then volumes have been written on the subject, both pro and con(c).
A 2014 paper(h) entitled Nanodiamond-Rich Layer Across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP by Charles R. Kinzie et al., has developed further the idea of this event being associated with the Younger Dryas. In a similar vein is an article(f) from Megan Gannon.
December 2014 saw Graham Hancock raising the issue of a cometary cause for the Younger Dryas and its possible association with ancient Egypt(e).
Martin Sweatman brought further evidence to bear on this debate in an article(i) on the Graham Hancock website. This focuses on the investigations at Hall’s Cave in Texas described in a paper by Sun et al, where the team concluded that the trace elements found there could indicate a volcanic rather than an impact as the cause of the Younger Dryas cooling! Sweatman disagrees with their conclusions claiming that there seems to be an element of selectivity in choosing data, leading to a wrong conclusion.
2019 also gave us a paper that included an extensive bibliography and overview of the YDIH debate(k).
In 2020, the eminent geologist James Lawrence Powell published Deadly Voyager , which offered further support to the YDIH. This book was instrumental in changing the negative stance of a number of ardent sceptics including Michael Shermer(j).
In 2022 Powell concluded a paper reviewing the YDIH debates with the following
“Finally, we can now assess Sweatman’s suggestion that the YDIH may be ready for promotion from hypothesis to the status of theory. If we combine the definitions of “theory” from the National Academy of Sciences and the American Association for the Advancement of Science, it would read something like this:
‘A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed.’
Those who have read this article and Sweatman’s have the information to decide whether the YDIH meets this definition. In this author’s opinion, there is a strong case that it does. Moreover, it should not be forgotten that no other single theory can explain the YD and its associated effects.”(l)
I note that Robert Schoch claims that there is no evidence to support the Younger Dryas impact theory, instead, he believes that “it was most likely due to reduced solar activity at that time, a solar shut-down.”(n) Schoch’s wide-ranging critique has been refuted by the Comet Research Group.(o)
In 2012, Jennifer Marlon et al published a paper, now made available by Marlon on the Academia website, in which they present “arguments and evidence against the hypothesis that a large impact or airburst caused a significant abrupt climate change, extinction event, and termination of the Clovis culture at 12.9 ka. It should be noted that there is not one single Younger Dryas (YD) impact hypothesis but several that conflict with one another regarding many significant details.”(m)
>Scienceopen.com is a website offering “A peer-reviewed open-access journal collection covering all aspects of airbursts and impacts on Earth by comets and asteroids”. October 2023 brought the publication of five papers on the subject(p).<
(k) YDIH: Younger Dryas Impact Hypothesis | Thongchai Thailand (tambonthongchai.com)
Ragnarok: The Age of Fire and Gravel  by Ignatius Donnelly, who took the title of his book from the word ‘Ragnarök’, which in Scandinavian mythology describes the destruction of the world of men and gods. He claims to have written this 450-page book in seven weeks in 1882. Some later editions have misleadingly added The Destruction of Atlantis to the original title, as Atlantis is only peripheral to the subject in a book title will always help to inflate sales.
>A number of contemporary press reviews of Ragnarok when it was originally published have been made available on the Atlantisforschung website(e).<
Coincidentally, just two centuries earlier Edmund Halley had also speculated that a cometary encounter with the Earth had led to the biblical Deluge(d). William Whiston offered a related theory.
Donnelly seems to have anticipated the work of Immanuel Velikovsky when he wrote of a close encounter or actual impact with the Earth by a comet. He presents an array of geological evidence to support this contention. In addition, he proposes that this celestial clash is also a displacement of the poles. Again this is an idea that was taken up by a number of writers in the succeeding century and is still strongly supported today. Like Velikovsky, Donnelly postulated that the resulting catastrophes were recorded in mythology and biblical texts. One of the specific consequences of this encounter was the destruction of Atlantis, which he expanded on in his previous book, Atlantis, concerning Plato’s sunken civilisation. Both of Donnelly’s books are available on the Internet(a).
The catastrophism of Donnelly’s Ragnarok can be seen as anticipating aspects of the more recent theories of Richard Firestone and his colleagues that have come to be known as the Younger Dryas Impact Hypothesis (YDIH).
In 2013 experts in Norse mythology announced that a Viking apocalyptic ‘Ragnarok’ was due on February 22nd 2014! (b) The claim, which I suspect was a publicity stunt, was downplayed on February 23.
Michael Shermer (1954- ) is the founding publisher of Skeptic magazine and Skeptic.com. >For eighteen years he wrote the ‘skeptic’ column for Scientific American(h).<
Suffering as he does from terminal scepticism, Shermer could not resist offering his views on Atlantis(a), which basically assume that Plato created the myth of Atlantis to support his political philosophy.>This idea has been put forward by many sceptics. However, nobody seems to have suggested that while Plato may have been promoting his political philosophy with the Atlantis story, there is absolutely no reason why he could not have been using real historical events to achieve the same result. This explains how the late Professor Kontaratos was able to point out at the 2005 Atlantis Conference that Plato states directly and indirectly, twenty-two times, in both Timaeus & Critias, that the story of Atlantis is true [629.79].<
Shermer does accept that Plato mixed history with myth but does not suggest how we might separate the two, instead, he is content to dispose of both baby and bath-water. I consider fatuous, his comment that “Plato’s Atlantean dialogues are essentially an ancient Greek version of Star Wars.” This silly comparison was recently (2018) echoed on an Australian website(d).
Georgeos Diaz-Montexano responded to Shermer’s views with a 2005 article, contentiously entitled Errors, Fallacies and Lies.
Shermer wrote an article(b) for Scientific American (Jan.1.2016) on the subject of ‘Homo Naledi, which generated a highly critical response, noting that “Shermer preferred to speculate without evidence and publish an essay without fact-checking.” Even Shermer nods!
However, to give credit where credit is due I must acknowledge that recently (2020) Shermer, among others, has back-pedalled on their previous sustained opposition to the idea of the Younger Dryas Impact Hypothesis(e). The impetus for this volte-face seems to have been provided by James Lawrence Powell, also a former sceptic, and his book, Deadly Voyager .
>In June 2023, Shermer published an article in Skeptic magazine attacking Graham Hancock‘s theories in general and the Netflix 2022 eight-part series Ancient Apocalypse(g) in particular.<
(g) Skeptic » Reading Room » Alternative Civilization and Its Discontents: An Analysis of the Alternative Archaeologist Graham Hancock’s Claim That an Ancient Apocalypse Erased the Lost Civilization of Atlantis *