Requiem for the Younger Dryas impact hypothesis?

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:

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