Designing global climate and atmospheric chemistry simulations for 1 and
10 km diameter asteroid impacts using the properties of ejecta from the K-Pg
impact

Toon, O. B.; Bardeen, Charles G.; García, Rolando R.

doi:10.5194/acp-16-13185-2016

Cited by 30 publications

(5 citation statements)

References 110 publications

(270 reference statements)

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“…Perhaps the most important is impact obliquity and the spherical shape of the Earth; the latter becomes increasingly important with distance from Chicxulub. We have also not considered heat conduction between particles and gas in the cloud, thermal radiation of hot ejecta (as in Goldin & Melosh, 2009), back reactions in the plume, coagulation of particles, and lofting of ejecta by solar radiation (Bardeen et al, 2017;Toon et al, 2016), all of which may alter the precise fate of ejecta on route to its final destination. These combined effects mean that temperatures in the cloud are not accurately modeled in our simulations.…”

Section: Critical Analysis Of the Current Simulationsmentioning

confidence: 99%

Global K‐Pg Layer Deposited From a Dust Cloud

Artemieva

Morgan

2020

Geophysical Research Letters

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Although it is widely agreed that the distal K‐Pg clay layer contains ejecta from the Chicxulub impact site, no current models can explain how these ejecta travel from the impact site around the globe. A widely accepted hypothesis is that impact spherules and shocked minerals in the layer were ejected from an expanding impact plume and traveled to their final destination on a ballistic path. Shocked minerals, however, are ejected at too low a velocity to reach distal sites, and plausible ballistic ejection models cannot explain the observed ejecta distribution. Using a suite of numerical simulations, we find that intense interactions between the ejecta curtain and atmosphere generate a fast‐moving dust cloud traveling at speeds of a few kilometers per second, which carries a substantial fraction of ejecta, including shocked minerals, to distal sites. We conclude that ejecta curtain material must make a major contribution to the formation of the distal K‐Pg layer.

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Section: Critical Analysis Of the Current Simulationsmentioning

confidence: 99%

Global K‐Pg Layer Deposited From a Dust Cloud

Artemieva

Morgan

2020

Geophysical Research Letters

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“…A recent model for the vaporization of target carbonate bedrock at Chicxulub suggests a modest 54 ppm rise in atmospheric CO 2 (Artemieva & Morgan, 2017). Global wildfires may have caused CO 2 to increase by 315 ppm (Toon et al, 2016), but the extent of these fires is contentious and may have been far less (Belcher, 2009;Belcher et al, 2003Belcher et al, , 2004Belcher et al, , 2005Belcher et al, , 2009Belcher et al, , 2015Harvey et al, 2008;Morgan et al, 2013).…”

Section: K-pg Boundary Comentioning

confidence: 99%

No Evidence for a Large Atmospheric CO₂ Spike Across the Cretaceous‐Paleogene Boundary

Milligan

Royer

Franks

et al. 2019

Geophysical Research Letters

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Currently, there is only one paleo‐CO2 record from plant macrofossils that has sufficient stratigraphic resolution to potentially capture a transient spike related to rapid carbon release at the Cretaceous‐Paleogene (K‐Pg) boundary. Unfortunately, the associated measurements of stomatal index are off‐calibration, leading to a qualitative interpretation of >2,300‐ppm CO2. Here we reevaluate this record with a paleo‐CO2 proxy based on leaf gas exchange principles. We also test the proxy with three living species grown at 500‐ and 1,000‐ppm CO2, including the nearest living relative of the K‐Pg fern, and find a mean error rate of ~22%, which is comparable to other leading paleo‐CO2 proxies. Our fossils record a ~250‐ppm increase in CO2 across the K‐Pg boundary from ~625 to ~875 ppm. A small CO2 spike associated with the end‐Cretaceous mass extinction is consistent with many temperature records and with carbon cycle modeling of Deccan volcanism and the meteorite impact.

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“…Human vulnerability to NEO collision has changed more substantially. Large NEO collisions can cause global firestorms, ozone layer damage and accompanying increased ultraviolet radiation, and reduced surface temperatures and precipitation and accompanying declines in vegetation (Toon et al 1997 ; 2016 ). The declines in vegetation could threaten global famine.…”

Section: The Natural Global Catastrophic Risksmentioning

confidence: 99%

Assessing natural global catastrophic risks

Baum¹

2022

Nat Hazards

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The risk of global catastrophe from natural sources may be significantly larger than previous analyses have found. In the study of global catastrophic risk (GCR), one line of thinking posits that deep human history renders natural GCRs insignificant. Essentially, the fact that natural hazards did not cause human extinction at any previous time makes it unlikely that they would do so now. This paper finds flaws in this argument, refines the theory of natural GCR, analyzes the space of natural GCRs, and presents implications for decision-making and research. The paper analyzes natural climate change, natural pandemics, near-Earth objects (asteroids, comets, and meteors), space weather (coronal mass ejections, solar flares, and solar particle events), stellar explosions (gamma-ray bursts and supernovae), and volcanic eruptions. Almost all natural GCR scenarios involve important interactions between the natural hazard and human civilization. Several natural GCR scenarios may have high ongoing probability. Deep human history provides little information about the resilience of modern global civilization to natural global catastrophes. The natural GCRs should not be dismissed on grounds of deep human history. Work on natural GCRs should account for their important human dimensions. A case can even be made for abandoning the distinction between natural and anthropogenic GCR.

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Designing global climate and atmospheric chemistry simulations for 1 and 10 km diameter asteroid impacts using the properties of ejecta from the K-Pg impact

Abstract: Abstract. About 66 million years ago,

Cited by 30 publications

References 110 publications

Global K‐Pg Layer Deposited From a Dust Cloud

Global K‐Pg Layer Deposited From a Dust Cloud

No Evidence for a Large Atmospheric CO₂ Spike Across the Cretaceous‐Paleogene Boundary

Assessing natural global catastrophic risks

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Designing global climate and atmospheric chemistry simulations for 1 and 10 km diameter asteroid impacts using the properties of ejecta from the K-Pg impact

Abstract: Abstract. About 66 million years ago,

Cited by 30 publications

References 110 publications

Global K‐Pg Layer Deposited From a Dust Cloud

Global K‐Pg Layer Deposited From a Dust Cloud

No Evidence for a Large Atmospheric CO2 Spike Across the Cretaceous‐Paleogene Boundary

Assessing natural global catastrophic risks

Contact Info

Product

Resources

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Designing global climate and atmospheric chemistry simulations for 1 and 10 km diameter asteroid impacts using the properties of ejecta from the K-Pg impact

No Evidence for a Large Atmospheric CO₂ Spike Across the Cretaceous‐Paleogene Boundary