Chris Moore of the Comet Research Group rebuts Boslough's pseudoskepticism (again!)
Recently, Mark Boslough (who else?) wrote yet another scathing piece about the Comet Research Group and the Younger Dryas Impact Hypothesis (YDIH) in the Skeptical Enquirer (he's a long time member of their college).
The Problem with Inadequately Reviewed Fringe Science | Skeptical Inquirer
In it, he holds himself judge and jury for an entire field of science; namely extraterrestrial impacts. Indeed, he infers the YDIH is is worse than pseudoscience; he regards it as a massive fraud, similar to Piltdown Man x 100.
But the YDIH is actually a complex scientific debate that has raged for nearly 20 years and has pushed the boundaries of the science of airburst impacts. Ironically, (given the volume's title - see above), Boslough doesn't address any of these emerging scientific issues. Instead, he tackles the people involved. As aleady pointed out by James Powell in his "Premature Rejection" and "Pillars of Salt" articles,
Peer review and the pillar of salt: a case study - James Lawrence Powell, 2023
Boslough's approach is itself Pseudoskepticism. It is not how we do, or should do, science.
The fact is, hundreds of articles in peer reviewed journals have published data supporting the YDIH. While dozens of articles, usually involving Boslough, have adressed their supposed deficienceies, including the most recent "Comprehensive Refutation",
Comprehensive refutation of the Younger Dryas Impact Hypothesis (YDIH) - ScienceDirect
these apparently refuting arguments have themselves been refuted,
In fact, most of their faulty arguments are based on poor statistical analysis, mishandling of data or other forms of poor scientific practice, including possible fraud,
In other words, articles that atempt to suppress the YDIH are typically co-authored by Bolsough (and/or Holliday) and of very poor quality, and this should be obvious to any scientist if they read more than just the abstract, while pro-YDIH papers are generally high quality.
The fact is, the YDIH is a live scientific debate. Christopher Moore, an established archaeologists and member of the Comet Research Group, has published a response to Boslough. It is much better than my effort here, so please go and read it.
Pseudoskepticism Isn't Skepticism: A Response to Mark Boslough
I asked ChatGPT 5 about the status of the YDIH. Here is what it said;
Here’s a summary of the Younger Dryas Impact Hypothesis (YDIH) as of late 2025 — what it claims, what evidence has been advanced, and how the scientific community views it now. If you want, I can also sketch unresolved issues and where future work is likely to be focused.
What is the Younger Dryas Impact Hypothesis
The hypothesis proposes that around 12,800 years ago (the onset of the Younger Dryas cold event), Earth (or some part of it) was struck — by an asteroid, comet, or multiple fragments — or at least affected by extraterrestrial debris (such as an airburst or comet dust) in a way that triggered abrupt climate cooling. Advocates link it to megafaunal extinctions, disruptions to human cultures (especially in North America, e.g. the decline of the Clovis culture), wildfires, and changes seen in geological / sediment records (e.g. spherules, nanodiamonds, platinum group element anomalies). The idea is controversial because it offers a dramatic single trigger for a complex event.
Recent Evidence & New Findings
In the last couple of years (including through 2025), there have been new studies both in favor and against aspects of the YDIH. Some key recent developments:
In favor / supporting evidence:
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Ocean Sediment Cores from Baffin Bay: A 2025 PLOS One paper reports that ocean sediment cores in Baffin Bay show a layer around ~12,800 years ago containing microscopic particles (metallic, spherical), platinum and iridium anomalies—elements often associated with extraterrestrial material. These cores are relatively undisturbed marine environments, which helps reduce contamination concerns. Phys.org+1
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Shocked Quartz at Clovis Sites: Another 2025 study (Kennett et al.) reports finding shocked quartz grains — a signature often interpreted as evidence of very high pressure/temperature, such as an impact — at classic Clovis-age archaeological sites (Murray Springs, Blackwater Draw, Arlington Canyon). These are alongside other impact proxies (nanodiamonds, spherules, etc.). Phys.org
Critical / skeptical views / refutations:
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Comprehensive Refutation (Holliday et al. 2023): A major recent review (published in Earth-Science Reviews, Dec 2023) argues that the YDIH should be rejected. The authors claim that many of the supposed indicators either are not unique to 12.8 ka, have contradictory dating, suffer from methodological issues, or are not reproducible. They find no solid evidence of a global-scale impact, and challenge many of the links to cultural/human or ecological catastrophe. ADS+1
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Chronological problems: A 2014 PNAS paper examined 29 sites from several continents claimed to show impact indicators at the Younger Dryas boundary, and found that only three of those sites have evidence securely dated to ~12,800 years ago. Many sites are undated, or their supposed “impact layer” is either older or younger than the YD onset. This undermines one of the core claims of the hypothesis – that there is a synchronous, global event. PNAS
Where things stand — scientific consensus / mainstream opinion
Putting together the evidence and critiques:
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There is some supporting evidence, including new data (e.g. in marine sediments, shocked quartz) that adds to previous claims.
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But there are serious unresolved problems — especially with dating, reproducibility, and whether the markers claimed are uniquely attributable to an extraterrestrial impact rather than other processes (fire, volcanism, sediment processes, etc.).
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Mainstream climate science and paleoclimate literature remain generally skeptical of the YDIH as a primary driver of the Younger Dryas period. The more conventional explanations — e.g. meltwater pulses disrupting ocean circulation (such as the Atlantic Meridional Overturning Circulation), feedbacks in climate systems, interactions of ice sheets — still have stronger empirical support in many quarters.
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The YDIH is not generally accepted to the level of a core theory; many view the hypothesis as still under scrutiny. Some proponents argue it's becoming more robust (some say nearing theory status), but most scientists feel more evidence is needed — especially evidence that is unambiguous, globally synchronous, physically plausible (in terms of size, energy, mechanism), and tied to the climate data.
Major Uncertainties and Criticisms
Here are the key open issues that most scientists think must be resolved before the hypothesis could gain wider acceptance:
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Dating precision and correlation: To show that various sites globally record the same event at ~12,800 years ago, with minimal lag. Some claimed sites have uncertain dates; some layers might not correspond exactly to the YD onset.
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Crater or physical large-scale signature: No confirmed crater (or impact structure) has been unanimously accepted that dates to the YD onset and is of sufficient size to cause the effects claimed. An airburst or small fragment scenario is sometimes invoked to explain the lack of crater, but that introduces its own challenges (energy, how many fragments, how the effects would work spatially).
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Attribution of markers: Many markers (microspherules, nanodiamonds, platinum group elements, iridium, soot/charcoal, etc.) can also be produced by more mundane terrestrial processes (volcanism, wildfires, sediment transport, post-depositional alteration). Distinguishing impact-specific versus terrestrial origins is difficult.
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Mechanism sufficiency: Even if some extraterrestrial trigger was involved, could it alone explain the abrupt cooling, biodiversity effects, human cultural impacts etc.? Or were there multiple contributing factors (e.g. meltwater, ice sheet dynamics, volcanism)?
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Geographical extent of effects: Are the supposed effects global, hemispheric, regional? How uniform is the evidence? Are there regions that show no sign of disturbance, but would under a global-impact scenario?
Recent Shifts & Trends
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There is renewed work: the recent findings from marine sediment cores (Baffin Bay etc.) and shocked quartz at archaeological sites are adding new types of evidence that were less well explored before. If these findings prove robust, they could strengthen the case.
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At the same time, the 2023 Holliday et al. paper has pushed back strongly, raising the bar for what counts as solid proof, and many in the field seem to have become more cautious rather than more convinced.
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Debate has become more refined: instead of “did it happen or not?”, more attention is being paid to how large an effect, what type of impact (airburst vs ground impact vs comet debris/dust), how this might interact with other climate forcings, and what regionally variable fingerprints of the event might be.
My Assessment (so far)
As of now, the YDIH remains plausible but unproven. It is an active hypothesis with some intriguing new data, but it hasn’t yet overcome the major hurdles of unambiguous evidence, reproducible sitewide/global correlation, and a coherent physical scenario.
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In my view, all these issues are already adressed quite convincingly - see above. Hence my confidence in the theory. To me, Boslough's position seems ridiculous and is itself a kind of conspiracy theory.
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