The Younger Dryas Impact Theory is perhaps one of the most controversial theories currently being debated in the fields of archaeology and space science. Proponents – including alternative history author Graham Hancock – argue that a sudden, substantial dip in temperatures in the Northern Hemisphere around 12,800 years ago might have been caused by a series of comet fragments hitting the Earth.
As is often the case with new theories, many scientists have taken issue with the Younger Dryas Impact Theory, with a number of skeptical papers being published over the past couple of decades claiming to refute the idea. These papers suggest a different mechanism for the rapid cooling of the Earth at this time: the Meltwater Pulse Hypothesis, which suggests that the warming that was occurring as the last ice age was coming to an end caused a large amount of cold water – from the ice sheets that covered North America at the time – to be injected into the ocean, which interfered with heat-transporting ocean currents.
However, last month a new paper in PLOS One (“A 12,800-year-old layer with cometary dust, microspherules, and platinum anomaly recorded in multiple cores from Baffin Bay“) provided further support for the impact theory, with researchers finding “impact-related proxies” in ocean sediments from marine cores that span the Younger Dryas geological layer. The lead author, University of South Carolina archaeologist Christopher R. Moore, suggests that the two apparently competing hypotheses could actually both be correct:
The YDIH (Younger Dryas Impact Hypothesis) is often cited as an alternative to the Meltwater Pulse Hypothesis. What many don’t understand is that the YDIH proposes the impact event (potentially involving many thousands of impacts and airbursts globally) would destabilize the glacial ice sheet in the Northern Hemisphere, leading to the collapse of massive glacial meltwater lakes and subsequently shutting down the ocean’s conveyor belt. This shutdown of oceanic circulation is the most likely cause of YD climate change. In this regard, the YDIH is the trigger for the meltwater pulse.
Moore says that these latest results from marine cores put to rest one of the arguments used by skeptics of the YDIH, that the ‘impact proxies’ found so far in shallow terrestrial sites were a result of contamination by human-made sources.
Coincidentally, just a few days before this new scientific paper was released, Graham Hancock released a new video on his YouTube channel of a presentation he had recently given on the YDIH (embedded below for convenience). Recorded in April 2025, it consists of Hancock explaining the impact theory, and the general threat of comet impacts to the Earth, followed by an on-stage conversation with Dr Allen West, a leading member of the Comet Research Group, the team of scientists behind the Younger Dryas Impact Hypothesis. It provides an excellent overview and some answers to questions raised by skeptics (although to me, Hancock’s presentation was far more polished an convincing than the Q&A with Dr Allen West).
Hancock tells how, right from his research in the early 1990s – starting with his bestselling Fingerprints of the Gods – he “began to see the period of around 12,500 to 13,000 years ago as being incredibly important to the ancient civilizations that I was dealing with…and it seemed to be associated with some kind of cataclysm, but I didn’t know what it was.”
As he investigated the possible causes for a catastrophe at this time, he first became fascinated with the ‘earth crust displacement theory’ suggested by Charles Hapgood, which featured prominently in Fingerprints of the Gods. But, Hancock confesses, “there are a number of problems with that theory”. But then around 20 years ago he came across the first papers on the Younger Dryas Impact Hypothesis.
And I realized that the the cataclysmic incident that I was convinced had taken place between around 12,500 and 13,000 years ago was exactly being described by the Comet Research Group. That this is what they were focusing on: a global cataclysm precisely of the kind that could have wiped a civilization from our memory… It is not a fringe hypothesis. Everybody behind the Younger Dryas Impact Hypothesis is a solid, massively credentialed scientist. We’re dealing with people who are absolutely mainstream scientists.
No matter where you stand on the validity of the YDIH, I think one aspect remains relevant to us all: that Earth’s climate can change in massive ways – whether caused by a comet impact, a sudden ice water melt, or through anthropogenic causes – and have profound impacts on human civilization…and we should all be doing what we can to mitigate those risks and associated effects.
