Claim: Permian extinction 252 million years ago '…a consequence of global climate change'

The Karoo Basin and the end Permian mass extinction

From the GEOLOGICAL SOCIETY OF AMERICA

This photo-like image of South Africa was captured on April 12, 2010, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite. CREDIT NASA

This photo-like image of South Africa was captured on April 12, 2010, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. CREDIT NASA

Boulder, Colo., USA – Earth’s biosphere witnessed its greatest ecological catastrophe in the latest Permian, dated to about 251.9 million years ago. The current model for biodiversity collapse states that both marine and terrestrial animals were impacted simultaneously, as a consequence of global climate change.

On land, South African vertebrate fossils, and the stratigraphic record in which they are preserved, are reported to document the extinction and recovery associated with the crisis. The pattern — reported as the end of the Dicynodon biozone and beginning of the Lystrosaurus biozones — has been extrapolated to other continents and hemispheres and used to recognize the boundary event globally. Yet, to date, there has been no age constraint placed near the turnover in vertebrate fossils in this, or any, area. In this new study forGeology, Robert Gastaldo and colleagues present new multidisciplinary data from the Karoo Basin and call into question our current understanding of the terrestrial response to the End Permian Mass Extinction. Paleoecological evidence does not support the reported coincidence of climate aridification, floral collapse, and tetrapod turnover. Similarly, magnetostratigraphic and geochronometric data, when conservatively interpreted, indicate that the turnover between the biozones occurred in the early Changhsingian, more than 1.6 million years beforehand, and was not coeval with the marine mass extinction event.

FEATURED ARTICLE

Is the vertebrate-defined Permian-Triassic boundary in the Karoo Basin, South Africa, the terrestrial expression of the end-Permian marine event?

Robert A. Gastaldo et al., Dept. of Geology, Colby College, Waterville, Maine 04901, USA This article is OPEN-ACCESS online; http://dx.doi.org/10.1130/G37040.1.

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100 thoughts on “Claim: Permian extinction 252 million years ago '…a consequence of global climate change'

  1. How long before this catastrophe is attributed to you, dear reader, and your selfish desire to use energy? If President Obama goes to the Paris conference in that solar powered plane, he should be congratulated for having the courage of his convictions…

      • You can still see the french idiot on CNBC spouting his shit about needing new, clean sources of energy for future employment and paradise.

      • They made it to Hawaii, had technical difficulties and because of weather are not expected to be able to resume until Spring. If you are going to break down better to do it in Hawaii than Uzbekistan!

      • Apparently the original batteries were completely screwed abd have to be replaced. After that, the weather has to be just right.

    • The narrative which likely will follow is: “We have proof of the catastrophe that climate change has on the bio-system and we must Pass The Paris Climate Change agreements to avoid disaster.”
      Along, of course, with the usual clamor and chanrting; perhaps, this time, lead by the Vatican.

    • What catastrophe?
      POTUS going anywhere sure won’t be based on his ‘convictions’. Lame duck drama queen posturing is nothing to congratulate anyone on.

    • Air Force One is solar powered. Millions of years ago solar energy hit the earth, and things happened that eventually resulted in crude oil. The oil was extracted from the earth, and refined into Jet A, which powers AF1, and, and Marine One, and that nice C-17 Globemaster that transports the presidential limo, which runs on 94 octane gasoline, and achieves a spectacular 8 mpg, (my F350 does twice that)

  2. That the Late Permian extinction of terrestrial tetrapods was separate from and preceded the massive marine extinctions at the end of the period was supported in the 1980s and early ’90s, but subsequently attacked, as not fitting the ruling catastrophic GHG global warming or climate change paradigm.

  3. The extinction was first on land, it then moved to the oceans, and then moved back for a second wave on land. Ninety five percent cumulative extinction. The Carbon meme is that the Siberian traps killed all the plants with Sulfur and Carbon dioxides, lack of oxygen and extreme warming caused a huge ocean anoxic event that wiped out the oceans, then methane hydrates scorched the land yet again.
    Doesn’t work for me.
    The really, really weird thing about the Permian extinction is that sea levels were so low. Where was all the water?
    https://geosciencebigpicture.files.wordpress.com/2014/03/lip-etc3.jpg
    The Carbo-Permian glaciation was over. Sea levels should have been high. The Siberian traps are a rather unimpressive large igneous province compared to the Cretaceous twin towers. Temperature and CO2 were nearly as high in the Cretaceous yet it was a paradise. Arguably the Cretaceous should be our planetary engineering goal rather than the Pleistocene.
    Something really bad happened in the Permian extinction. It does not seem to have been an impact as there is no horizon. We really need to no what caused this. Unfortunately we don’t have a clue.

    • Sea level may have been low during the Permian mass extinction because supercontinent Pangaea reached its maximum packing then. When the continental plates that formed Pangaea collided, they compressed and thickened the supercontinent’s crust. This led to a smaller landmass and a larger ocean basin for earth’s fixed amount of water. Also, heat could have accumulated underneath Pangaea, thermally lifting the supercontinent up relative to the surrounding ocean.
      Thermal uplift, causing the sea to fall in relation to the land, could have produced a marine regression of Pangaea’s continental shelves, exposing them to the atmosphere, with catastrophic consequences for the habitat of marine organisms.

      • Besides which, there still might have been ice sheets or glaciers over the South and possibly North Poles at the time of the extinctions, despite the worst of the Carbonifeous-Permian ice age being over.

      • From what I have read of plate techtonics, it is thought that it takes a massive hot spot to start the break up of a super continent. The continental crust insulates the mantle under it, allowing it to heat up, which starts a convection current, which eventually breaks up the super continent.

      • Agree on all counts. But you have to wonder what caused the continents to stack up. You might say a gnarly series of ocean ridges pushed them all into a pile, but those ridges would be lifting the ocean basins. Also, the isostatic weight of Pangaea should have had a water bed effect.

      • In addition to what you have stated, Gondwanaland’s interior was probably arid as continental interiors tend to be. Being a super-continent, it was probably super arid. The formation of Gondwanaland was the cause of the various extinctions lumped into the end-Permian “event”.
        The effects of Gondwanaland’s formation have been rigorously attacked by the “all things are CO2” crowd as “simplistic” since the 90’s.
        BTW, are you a professional, or do you just have an intense interest in this field like I do?

      • I guess I am a professional, since my livelihood depends upon understanding Permian and Carboniferous geology.
        I could go into more detail about the stacking up of Pangaea, but then this blog would become a geological site rather than a climate resource.

      • Gymno,
        You ask about the causes of the stacking up. But that happens whenever the continents collide to form a supercontinent.
        The driver of this stacking up is the plumes and superplumes in the layers of the earth below the crust. What controls their movements is a very interesting scientific and economically important question.

      • Mark W,
        IMO hotspots are not essential. They generally are where an ET impact has been so powerful as to pierce the crust. But that doesn’t necessarily lead to major tectonic volcanism.
        The classic example is the CAMP eruption at the Permian-Triassic boundary.

      • I would appreciate a reference to an ET event piercing the crust. I recall a talk given on the Sudbury Basin impact (~ 100 km sized impact crater) where the speaker claimed the impact was nowhere near the bottom of the crust but rather 4-5 km maximum (some speculated the crust was pierced and nickel flowed up from the upper mantle, while others believed the nickel came from the melt sheet in the upper crust, differentiated and remobilized). As the Sudbury Impact Crater is one of the largest ever found on the Earth, ET events piercing the crust would be extremely rare and easy to date. These events could be compared to periods of extreme volcanism to determine which had more impact (yes, pun intended) on Earth’s climate.

    • I question some of the data in your graph.
      The Siberian Traps was a very large and extended volcanic event, i read somewhere apparently the largest in the last 250 million years. The eruptions persisted over several million years, so the extinctions were not immediate like in a boloid impact, which is consistent with other evidence-i.e. a protracted event. I don’t have the references handy but i’m pretty sure they are bigger than what’s in your graph.
      Also, the world did get hotter and drier, also consistent with longer term high levels of volcanism. I’ve seen redbeds in Australia right at the end of the Permian, exactly where most of Australia’s coal-which is Late Permian- also suddenly disappears. Coal geologists tell you see this everywhere, lots and lots of coal and then none-you just dont see any coal in the Triassic after the redbeds appear at the end Permian-the reason being that all the plants and other organisms that formed the coal were now dead and extinct, and they didn’t re-evolve to form coal until about 10 million year later-there is a long coal gap here in the record.

      • The data on the traps comes from largeigneousprovinces.org. I was also surprised. These folks are serious about their LIP’s and you would think they got it right.There is some indication that the Siberian traps were a particularly nasty burn and it went straight into the atmosphere rather than being bubbled through the ocean like most of the Cretaceous extrusions.
        What you say about Australian Permian Coal agrees with everything I have seen.
        It is widely believed that no ocean floor exists from the PTr period. This is not true. Scraps persist in the Mediterranean and they are really weird.
        https://geosciencebigpicture.files.wordpress.com/2013/01/charybdis.png

      • What creates Redbeds? What creates coal?
        The hotter -dryer thingy is a bit misleading. It is derived from information fro sites that are mostly continental interior. Continental interiors are hot and dry. The hot is caused by the dry.

      • Gymnosperm,
        The Med would have been the Permian Tethys sea. At least that is what I remember being taught back in the late Pleistocene.

    • grrr, I meant Pangea, not Gondwanaland, thats what I get for reading blogs when I should be in bed tending my fever 🙁

    • Gymnosperm I’d like to draw your attention to Burgess and Bowring 2015 who have beyond a doubt lined up the Siberian Traps with the end-Permian mass extinction. Besides you seem to be oblivious to the fact that the Siberian Traps intruded into petroleum bearing sequences of the Tunguska Basin which happens to be the oldest known petroleum reservoir on Earth and a fairly big one too. Based on heating experiments of the current evaporites and a few simulations its estimated that between 58000-170000 Gigatons of toxic and climate altering were liberated from the region. If you don’t realise, that is at the lowest estimate 58 quadrillion kilograms (58 with 15 zeros behind it) of CO2, SO2, CH4, F, Cl etc. Besides there are other factors contributing such as the Araguainha impact into shale oils units in modern day Brazil at ~254 Ma and methanogenic expansion by rapid blooms of Methanosarcina coeval with the Permian-Triassic boundary due to nickel ash deposited into the ocean by the Siberian Traps. Your claim that the Siberian Traps is an unimpressive LIP shown an apparent lack of knowledge on the actual traps themselves

      • Calm down there, Jack. When you write numbers like 58000-170000 Gigatons of toxic and climate altering gases were liberated from the region. And: 58 quadrillion kilograms it looks like you’re trying to alarm folks.
        Use percentages, and compare them with now. That gives a common sense perspective.
        Or, use Olympic-sized swimming pools, or whatever.

      • My claim is that according to largeigneousprovinces.org the volume of the Siberian traps extrusion is minuscule in comparison to the Cretaceous extrusions. I allowed (somewhere in the discussion) that there is evidence the Siberian episode was a nasty burn. There is a city in the region today that burns the local stuff and everything is wasted down wind.
        The largest petroleum basins today are being rifted by the Red Sea arm. Where is the smoke?
        Look, there is little doubt the traps were a factor in the extinction. Our understanding of the event is very limited. My own instinct remains that the very low sea levels at the time and whatever caused those is how you get from a run of the mill mass extinction to a 95% event.

      • Burgess and Bowring are out to lunch. Focusing on CO2 from the traps is a losing game. They must then explain why the far larger Cretaceous extrusions and CO2 were innocuous.

  4. Humans were not around for that mass extinction event, so natural causes are to blame. If it is natural, us measly, puny insignificant humans can not alter such events. What it shows is that climate changes by natural means. All the climate action proposals in Paris are a load of dinosaur dung-they will do nothing except fertilize the pockets of those that promote the scam.

    • High Treason: ” If it is natural, us measly, puny insignificant humans can not alter such events. What it shows is that climate changes by natural means”
      Ahh thanks , someone that speaks truth. I would only add, “All the time”.

  5. Sorry chaps, that’s not what they are saying.
    Let’s get one thing clear…the Permian-Triassic extinction was a big one
    https://en.wikipedia.org/wiki/Permian–Triassic_extinction_event
    There are many suggestions about what caused it…and it likely had several causes.
    What Gastaldo and friends say is that the vertebrate fossil record in the Karoo Basin had been assumed to be the continental record of the end Permian event and recovery. Their dating work suggests that the Karoo Basin event was not coeval with the marine extinctions and probably does not represent the end of Permian event.
    So more research required [as it always is].

  6. The climate does not change arbitrarily. It has no will. Something happened that caused a change in the climate, perhaps, and that something would be the root cause to any thinking mind. That something though, will not give our political left any lever to pull, no disaster to attribute to human behavior they can exploit, so climate change it is because it, the climate, is such a delicate flower, don’t you know, and we can look to history blah blah blah to see this fragility and we’re running out of time, yawn.
    The world is traveling half a million KPH through space and nobody is driving. Once in a while, like a Google self-driving car, it will smack into something that will make a mess of things. It’s ok to talk about this. Plate tectonics is also in this ok to talk about category because plate movement does amazing things to the oceans. Panama vacation to anyone who can think of one such thing.

  7. The Permian Extinction may have taken millions of years to unfold, ending with the dramatic rise in ocean and atmospheric temperatures.
    The graph Global Temperature and Atmospheric CO2 over Geologic Time on the page Climate and the Carboniferous Period shows a precipitous drop in global temperatures and CO2 in the millenia preceding the event.
    Such is consistent with The Threat to Life from Eta Carinae and Gamma-Ray Bursts, which implicates near earth supernovae in producing deadly cosmic rays that triggered extinctions in Ordovician period (some 435 My ago), the late Devonian (357 My ago), the final Permian, (251 My ago), the late Triassic (198 My ago) and the final Cretaceous (65 My ago). Then, the supernovae jostled the Ort Cloud, raining down asteroids producing huge volcanic eruptions on the opposite side of the impacts.
    Sources for the Global Temperature and Atmospheric CO2 over Geologic Time graph are The Paleomap project by Christopher R. Scotese for temperatures and the paper Geocarb III: A Revised Model Of Atmospheric Co2 Over Phanerozoic Time provides the CO2 data.
    It’s worth noting that any specific threat from Eta Carinae is refuted by this paper, http://arxiv.org/abs/0705.4274

  8. The Siberian Traps series of eruptions that were blamed for this event lasted around million years and produced enough lava to cover the surface of western Europe to a depth of 1000 metres. It made the Yellowstone supervolcano look like a damp squip.
    I can well believe this adversely affected climate and caused widespread extinctions.

  9. One might look at “Celestial driver of phanerozoic climate?” by Nir Shaviv and Jan Veizer, 2003. The end Triassic is also at a time of near record low galactic cosmic rays when our solar system was between spiral arms of our galaxy and, if one believes Svensmark and company, would be expected to have few clouds compared to periods with a larger GCR flux and be significantly hotter.
    Here’s a link to Shaviv’s web page with a summary, pay particular attention to figures 4 and 5.
    http://www.sciencebits.com/ice-ages
    Please curb your Eschenbach on this one.

  10. I suggest that the various “traps” around the world are the antipodes of major impact events. The Deccan Traps of circa 66My ago were formed in what is now India, which would have been relatively near the antipodes of the Chicxulub impact near the Yucatan, the impact that killed off all the cute little dinos.
    Figure out where the Siberian traps were around the time of the Permian Extinction, and figure out where the point on the other side of the Earth might have been – and then look for signs of a whopping HUGE impactor. After 252My, there’s probably not much left, especially if it were an oceanic impact.
    Before Luis Alvarez forced paleontologists to OPEN THEIR DAMNED EYES and examine the evidence, any “catastrophic impact” theory was laughable, but I think we’ve been smacked more often than the “settled scientists” are willing to admit.

  11. The headline seems to be misleading. I mean, the press release itself says: “The current model for biodiversity collapse states that both marine and terrestrial animals were impacted simultaneously, as a consequence of global climate change.
    {…] In this new study for Geology, Robert Gastaldo and colleagues present new multidisciplinary data from the Karoo Basin and call into question our current understanding of the terrestrial response to the End Permian Mass Extinction. Paleoecological evidence does not support the reported coincidence of climate aridification, floral collapse, and tetrapod turnover.
    So the new study contradicts the current model that the Permian extinction is a consequence of climate change.

    • Quite so, Katherine. And if, as many readers do in this over-informed age, only read the first sentence, they will take home the message that it was all due to CO2 and we are all going extinct next year.

  12. There are those, I suppose, that wish to equate “climate change” that was caused by natural forces far greater than those in the purview of humans, and over a period hundreds of thousands or millions of years, with some event that is purported to devastate the world inside of 100 years. I, for one would not relish standing before my peers on stage and defend such a comparison.

  13. If one looks at the “official” end date for the Permian, the International Commission on Stratigraphic Nomenclature currently lists the end of the Permian at 252.2 ( + or – 0.5) ma. Over the past few iterations of the Geologic Time Scale, the date for the end of the Permian (beginning of the Triassic) has been steadily becoming later (when I was a student, the basal Triassic was placed at 225 ma).
    Regular WUWT readers may recall a post by Anthony on 06 March 2012, dealing with the problems of dating the Siberian LIP and the terminal extinction event:
    viz: *most the trap (diabase) was extruded AFTER the extinction
    *Anthony included a chart showing that for the 3 – 5 ma prior to the terminal event itself, there was already a fairly extensive extinction taking place; the end itself was just the culmination of a process which had been taking place for quite a while
    *whether the extinction could be tied to an impact was discussed; the single event which has now been ruled out was the Bedout structure, which is now thought to be something besides an impact.
    As has been pointed out, the geological evidence is that temperatures declined during and after the transition into the Mesozoic. While highly stylized and only somewhat useful, Scotese’s chart shows that CO2 levels were much higher than today, yet temperatures declined.
    WUWT?
    Vlad

  14. There have been several new studies recently which used improved dating techniques to to nail down the timing of the Siberian Traps volcanoes.
    The main eruptive event started about 300,000 years before the Permian Extinction event and continued for 500,000 years afterward.
    http://www.smithsonianmag.com/science-nature/massive-volcanic-eruptions-triggered-earths-great-dying-180956431/
    http://advances.sciencemag.org/content/1/7/e1500470
    It is hard to describe just how big the Siberian Traps magmatic flows were. 500,000 times bigger than the Laki eruption in Iceland for example.
    http://whyfiles.org/031volcano/images/paleomap.gif
    The Laki eruption killed one-quarter of the human population and half of the livestock just from the hydrofluoric acid and SO2 emissions from the eruption.
    Now imagine what the atmosphere was like during the Siberian Traps eruptions. It was likely very difficult for complex life-forms to even breathe the atmosphere without eventually succumbing to the poisonous gases. A million years of a poisonous atmosphere sounds very much like an extinction event to me. (No CO2 was involved in this logical explanation).

    • This is my compilation of the temperature and CO2 covering the Permian Extinction timeline.
      First point, is that CO2 rose long, long before the event, rising from about 350 ppm 268 Mya to 2100 ppm by 265 Mya. But this is still 14 Mys before the extinction. CO2 continued at very high levels, throughout the whole event timeline, getting to as much as 3,300 ppm by 247 Mya. There is no big CO2-induced global warming spike. It was already very high millions of years earlier.
      Secondly, global temperatures estimated from the reliable dO18 isotope record, had risen substantially as Pangea formed. Think of it as all the land-masses concentrated at the equator. Vast deserts, massive El Nino-like temperatures in the Paleo-Tethys sea. Global temperatures rose to as much as +10.0C above today by 265 Mya. Again, 14 million years before the extinction. The El Nino-like cycling in the shallow Paleo-Tethys probably got temporarily at times, too hot for complex life to exist in it. 42C is too hot. The Paleo-Tethys was periodically devoid of anything except bacteria.
      Then right at the Siberian Traps eruptions, global temperatures fell drastically. All that volcanic dust and SO2 caused a huge drop in temperatures. This downspike does not show up in other temperature reconstructions because they are smoothing the dO18 isotopes over too long of a period. Most are 50 million year smooths while my temperature estimate is using a 1 Million year Gaussian smooth.
      So there, not CO2 but Siberian Traps volcanoes. (some of the death in the oceans data is really because some of the oceans around Pangea got too hot for complex life-forms).
      http://s17.postimg.org/93bes725b/Permian_Extinction_Temp_CO2_Zoom_In.png

  15. Something changed. Regardless of what it was it can be called climate. So labeling the extinction as due to Climate Change says nothing.

  16. If the science article has a question mark at the end, do the science reporters add a second question mark or do they take it off entirely ????????????????????

  17. Where are the mass extinctions with the other flood basalts? These are not all that rare in geologic terms. Even some adjustment for the the scale of the Siberian deposition does not alter this valid question.

    • Advocates of flood basalt-caused extinctions point to the end Triassic mass event, which coincided roughly with the initial opening of the Atlantic (CAMP), and even the end Cretaceous, citing the Deccan Traps.

  18. The Permian extinction did not happen 252 million years ago it stopped at that time. That date is the low point in biodiversity – the point where rate of arrival of new species equals the rate of extinctions. The decline in biodiversity started 10 to 15 million years before that and increased gradually to the trough at 252 mya.
    Evidence supports the contention that the Permian extinction was caused by lack of CO2.
    For most of the Carboniferous and Permian CO2 was similar to current pre-industrial levels of 270 ppm. Photosynthesis is severely shackled at these concentrations. Then and Ice age started around 315 mya and oxygen levels increased to some 30 to 35% of the atmosphere for nearly 40 million years. Enough for many species to evolve using oxygen at that level.
    Oxygen in the atmosphere is determined by plant production of oxygen from photosynthesis versus oxygen removal by organisms and by chemical oxidation, principally ferrous to ferric oxidation by minerals like pyrite.
    The ice age covered much of the land with ice preventing oxidation of these minerals, that allowed O2 levels to rise.
    When the ice age ended around 270 mya the loss of ice exposed much crushed unoxidised rock that then used up the oxygen. Plants could not replace that oxygen fast enough due to the low CO2.
    Consequently O2 fell rapidly to 15% causing the oceans to become anoxic and allow sulphur bacteria to dominate. Sulphur bacteria produce H2S which is toxic to all life (more than cyanide)
    This then was the cause of the marine extinctions. On land the extinction was driven by low O2 which continued to drop to 12% for several million years after the extinction peak..
    At the peak of extinctions CO2, which had been rising as biodiversity decreased, reached a level of 1600 ppm and enabled plants to grow and reproduce at a rate sufficient to re oxygenate the ocean water and later increase the atmospheric oxygen. Animals that evolved after the extinction had a superior respiratory system that enabled them to survive the lower O2 levels.
    Least that is my take on the extinction – I would welcome any evidence to support or crush this hypothesis.

    • Plausible.
      While this descent has been questioned recently, it was previously thought that the ubiquitous Early Triassic mammal-relative, the “pig-lizard” genus Lystrosaurus evolved from burrowing creatures, so could tolerate lower O2 levels.

    • “…When the ice age ended around 270 mya the loss of ice exposed much crushed unoxidised rock that then used up the oxygen…”

      Unoxidized rock?
      Pyrite is Ferric Sulfide FeS₂ Pyrite can slowly oxidize, but well defined crystals are generally stable. Sedimentary layers with less well formed pyrite of organic origin are most prone to oxidation, often deriving their oxygen from water sources long before exposure to air.
      Glaciers would be unable to scour up enough sedimentary pyrite susceptible to atmospheric oxygen.
      Massive fires are the only efficient oxidizer.
      Fifteen percent oxygen is more than sufficient for life to continue.
      A person can rebreathe their own air several times before the carbon dioxide content becomes toxic.
      Similar changes in humans living above 10,000 feet altitude where the percentage of oxygen in the air is technically 21% yet the available oxygen is significantly lower. Even flatlanders can adapt enough to stay alive and healthy at high altitudes; sterile maybe, but healthy.

      • Thank you for your response. In referring to unoxidised rock I was of course referring to the pyrite component which I had mentioned earlier. While oxidation of pyrite might be slow this process happened over some 25 million years.
        You mentioned fires as being the only efficient oxidiser – problem with that is that if fires accounted for a reduction of 20% in O2 it would increase CO2 to 20% of the atmosphere – Since there is no equivalent rise in CO2 then the cause of the oxygen reduction cannot have been fires.
        Respiratory systems were not that efficient then, in fact one source claimed the Permian extinction had a major effect in the evolution of more efficient systems.
        Here is a extract from a paper by Raymond B. Huey* and Peter D. Ward
        (15 APRIL 2005 VOL 308 SCIENCE http://www.sciencemag.org)
        “A catastrophic extinction occurred at the end of the Permian Period. However,
        baseline extinction rates appear to have been elevated even before the final
        catastrophe, suggesting sustained environmental degradation. For terrestrial
        vertebrates during the Late Permian, the combination of a drop in atmospheric
        oxygen plus climate warming would have induced hypoxic stress and
        consequently compressed altitudinal ranges to near sea level. Our simulations
        suggest that the magnitude of altitudinal compression would have forced
        extinctions by reducing habitat diversity, fragmenting and isolating populations,
        and inducing a species-area effect. It also might have delayed ecosystem
        recovery after the mass extinction.”
        The rise in oxygen during the Devonian and early Carboniferous could be explained by the tremendous growth of plants during that period, but how would you explain the continued rise in oxygen after CO2 had dropped to 300 ppm around 340 mya and the reduced plant growth after the ice age started at 315 mya.
        Then between 270 & 252 mya oxygen fell by ~20% CO2 rose from 300 to 1600 ppm and extinctions increased.
        We know that the oceans became anoxic in that period and that sulphides increased. So what is your take on the decline of oxygen given that fires cannot be the explanation ?
        Your discussion on human respiratory systems is not pertinent to this period of time. CO2 does not become toxic until it is over 5000 ppm

    • Makes good sense for a number of reasons. The therapsids giving rise to the dinosaurs certainly had super-efficient lungs (unidirectional airflow, like birds with aid of air sacs, about 10x more efficient than our tidal lungs). Ocean anoxia was also definitely a big factor. CO2 almost certainly not. This looks elegant and parsimonious – is there a reference for this hypothesis?

      • Therapsids are the synapsid line that gave rise to mammals. Dinosaurs are diapsid sauropsid (reptile) archosaurs. Amniotes split into the synapsid (mammalian) and sauropsid (reptilian and avian) lines way back in the Carboniferous.

      • Gloria
        Yes Therapsid was an error, I meant Thecodont. I remember from a book years ago that in the Permian you had Therapsids and Thecodonts, ancestors of mammals and dinosaurs/pterosaurs respectively. I just got them mixed up. However – maybe “Thecodont” is now an obsolete term? Are synapsid and sauropsid more correct now?

  19. I went back in time and started a fireworks plant. I knew that velociraptors had a real thing for ladyfingers and roman candles and I knew I could corner the market. Little did I know those crazy lizards would start burning down forests with that stuff. Next thing you know, the atmosphere when kablooie and they find themselves extinct. Who would’ve thunk?

  20. BREAKING RESEARCH from Oregon State University:
    The big bang, origin of the universe 13.8 billion years ago, was caused by climate change!

  21. I saw a program on TV when Earth was completely ice bound. There was no separation of the present day continents. No plants no oxygen. But somehow life must have evolved. It was volcanoes that warmed up the atmosphere, and we got warmer. They think it was our orbit and lack of CO2 in our atmosphere. This is not revolutionary news folks. Atmospheric land, air and water pollution, human made, is our problem. Nothing to do with the human activities changing the climate. If some faced that problem we’d be OK.

  22. I don’t think there to be any question about the P/T mass extinction event being due to climate change. Makes perfect sense to me. Take a vast number of large comets, after having been shaken loose from the Oort Cloud, and have them drop into the inner solar system. Eventually one, or more will impact the surface of the planet, causing tremendous devastation. Voila!, almost instant climate change, causing the greatest species extinction event in the planet’s history.

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