Exploring abrupt climate change induced by comets and asteroids during human history

2019 AGU abstract supports Younger Dryas “exacerbated” by cosmic impact

But cosmic impact follows volcano?

Sharma, 2013

This week is “abstract reveal” week for the enormous annual conference of the American Geophysical Union (AGU) held each December (See Tusk at 2009 AGU). So each year around this time I search the AGU website for any coming presentations concerning the Younger Dryas and cosmic impact.

Fall Meeting 2019 San Fran turned up an interesting hit. Mukul Sharma, a geochemistry genius who has been in and out of the YDIH publishing maelstrom for years, presents a poster from a distinguished team led by Ji-Hye Seo and other Geo-forensic experts.

It is intriguing that Sharma et al. envision a stochastic volcanic eruption immediately preceding an extraordinarily energetic cosmic impact. It seems like it should be the other way around.


“These signals suggest that volcanism potentially induced the YD cooling, which may have been further exacerbated by an extra-terrestrial impact


C11C-1305 Younger Dryas Trigger Through the Lens of GRIP Ice Core

Monday, December 9, 2019, Moscone South

The Younger Dryas (YD) abrupt cooling event (~12,900 yr to 11,600 yr) represents a brief return to severe cold conditions in mid-to-high- latitudes in the Northern Hemisphere. The cooling is thought to have resulted from freshwater flooding of the northeast Atlantic and/or the Arctic Oceans that prevented deep water formation and promoted extensive southward expansion of sea-ice. Two different triggers that would lead to freshwater capping the north Atlantic have been proposed: (1) catastrophic drainage of proglacial Lake Agassiz and (2) a meteorite impact-related partial destabilization and/or melting of the Laurentide ice sheet. However, the physical evidence for these triggers remains elusive. Recent revision in the age of Laacher See volcano (Volcanic Explosivity Index = 6) in Eifel, Germany has led to the suggestion that the YD event was triggered by emplacement in the stratosphere of large amounts volcanic sulfur and halogens with sustained cooling resulting from a positive feedback involving sea ice expansion and/or AMOC shutdown. Thus, building of sea-ice rather than freshwater capping provides a trigger according to this hypothesis. Here, we use GRIP ice core to investigate whether the YD was engendered by a one-time catastrophic event or whether it was an integral part of a sequence of events that unfolded as the last ice-age came to a close. We sampled GRIP ice core every 9 cm from a depth of 1659.35 m to 1664.30 m corresponding to a time-resolution of 2-3 years spanning 12,939-12,810 yr b2k. Decontaminated ice-core was analyzed for δ18O, δD, major cations and anions, trace-elements, and osmium and lead isotopes. We find that a massive volcanic eruption occurred at 12,918 yr b2k and that immediately following the eruption the d-excess increases from 4 to 9 permil over a period of 37 years indicating a profound increase in sea-ice. During this time period, ratio of fluxes mantle to continental derived osmium also increases. Additionally, there is evidence of a 20-fold increase in extra-terrestrial osmium flux ~12,819 yr b2k following which the δ18O values display a steep and sustained decline to –40 permil. These signals suggest that volcanism potentially induced the YD cooling, which may have been further exacerbated by an extra-terrestrial impact.


5 Responses

  1. I’m betting they have the effects of the volcanism wrong.

    The energy budget for the eruption for the “Laacher See volcano in Eifel, Germany is too small and localized to the Northern Hemisphere.

    The YDIH ET impact proxies are world wide in scope.

  2. Here is a another paper: https://www.sciencedaily.com/releases/2019/10/191002110329.htm

    I think many scientists still think it’s potentially damaging, career-wise, to just outright embrace the impact theory, even if it makes sense. So they couch it in terms like this–just a minor blip on top of a conventional terrestrial event like a volcano.

    Notice also the very careful, almost apologetic, wording at the link.

  3. Patrick,

    A friend of mine and I have been debating whether “Science” and the scientific method survives the YDIH.

    Short form: The fair maid of money called AGW/Climate Change/”New Name of the moment here” has a huge impact on whether the YDIH is ever accepted in main stream science.

    The reality of ET impacts order of magnitude larger in global impact than we puny humans means the irrelevance of “Climate Change” as a tool of political power.

    This will not be accepted by either the ambitious people with money nor the purported scientific institutions that want to keep that income stream coming.

    The way to kill an idea whose time has come is to put it in a box, and bury the box government/institutional ill will.

  4. Unies who keep assigning causation for catastrophic effects to unie processes. Sorry. Crowbar applied to include improbable causes, including coincidence, and then they throw a sop to the YDB ET impactor – probably so when the Et impactor becomes the new accepted paradigm, they can say, “See? We pegged it back even before 2020!”

    Worse than Sweatman’s imagination.

  5. While we are hard-wired to seek cause/effect relationships, coincidental things happen too. So, yes, it is possible for huge volcanic eruptions to happen before, after or during a space debris impact event, with no relationship, other than temporal, between them.

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