From the AGU today, I find they are moving the cause of ancient planetary disaster from comets impacts and volcanoes or other big events to CO2 causing acidification of the oceans, literally they have a blast from the gas, to make CO2 the villain here. Of course, it’s just another modeling exercise in uncertainty.
From Wikipedia, a clear cut case of “we don’t know“:
There are several proposed mechanisms for the extinctions; the earlier phase was likely due to gradual environmental change, while the latter phase has been argued to be due to a catastrophic event. Suggested mechanisms for the latter include large or multiple bolide impact events, increased volcanism, and sudden release of methane clathrate from the sea floor; gradual changes include sea-level change, anoxia, increasing aridity, and a shift in ocean circulation driven by climate change.
From the AGU Highlights:
1. Was ocean acidification responsible for history’s greatest extinction?
Two hundred and fifty million years ago, the world suffered the greatest recorded extinction of all time. More than 90 percent of marine animals and a majority of terrestrial species disappeared, yet the cause of the Permian-Triassic boundary (PTB) die-off remains unknown. Various theories abound, with most focusing on rampant Siberian volcanism and its potential consequences: global warming, carbon dioxide poisoning, ocean acidification, or the severe drawdown of oceanic dissolved oxygen levels, also known as anoxia.
To narrow down the range of possible causes, Montenegro et al. ran climate simulations for the PTB using the University of Victoria Earth System Climate Model, a carbon cycle-climate coupled general circulation model. The model’s highlights include dynamic representations of terrestrial vegetation, ocean carbon fluxes, and net primary production. The researchers ran nine simulations, using three different concentrations of atmospheric carbon dioxide, three modes of ocean floor topography, and two competing theories for the geography of the time.
The authors find that varying the ocean floor topography by adding deep ocean ridges increases the strength of the Meridional Overturning Circulation (MOC) – a convective cycle that mixes ocean waters. Also, the presence of the MOC was not abated by elevated atmospheric carbon dioxide as was found in previous research, suggesting that the ocean would have been well mixed and well oxygenated, restricting the chances of widespread deep ocean anoxia.
Further, the researchers find that if atmospheric carbon dioxide concentrations were 3000 parts per million by volume or higher, fitting within estimates for the Permian-Triassic boundary, the ocean pH would have been 7.34 or lower. At those levels, the authors say the ocean’s acidity would have had significant negative impacts on mollusks, corals, and other species that rely on oceanic calcium carbonate, suggesting ocean acidification may have been the main culprit in the Permian-Triassic boundary extinction.
Source: Paleoceanography, doi:10.1029/2010PA002058, 2011 http://dx.doi.org/10.1029/2010PA002058
Title: Climate simulations of the Permian-Triassic boundary: Ocean acidification and the extinction event
Authors: A. Montenegro: Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada, and Environmental Sciences Research Centre, St. Francis Xavier University, Antigonish, Nova Scotia, Canada;
P. Spence and K. J. Meissner: Climate Change Research Centre, University of New South Wales, Sydney, New South Wales, Australia;
M. J. Melchin: Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada;
M. Eby and S. T. Johnston: School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada.
Any ancient disaster is blamed on Climate Change (usually not spelling out the name of the evil gas, CO2); it’s a sign of a huge academic apparatus looking for justification of its existence.
I know how you Americans could slash your deficit.
Did somebody say we need a new Apollo project? Well it looks like you have one.
I just want to know, since the atmospheric CO2 levels increased roughly 800 years after each Ice Age melted into an Interglacial and these high atmospheric CO2 level should have been reflected in an “acidification” of the oceans, shouldn’t we have episodes of extinction 800 years after the conclusion of each Ice Age? Where’s the evidence for that? Since these extinction episodes would not be so long ago compared to the Permian-Triassic Boundary, certainly we would see some evidence of them, wouldn’t we?
Many commenters here doubt the modellers’ results, but I, for one, do not. Computer models don’t lie. In fact, if I lived in one of their computer models, let me tell you, I’d be very very scared right now!
Oh look, “Two and a Half Men” is on!
Ocean Acidification:
We owe Dr Craig Idso a great deal of gratitude for his very datailed 81-page report summarising factual science to the contrary [1]. Only a very knowledgable insider would be able pull this off. So here folllows a summary of his findings:
1) coral bleaching: scientists discovered that corals are not picky about the type of symbiotic alg (a dinoflagellate) they host, and are capable of adopting temperature-hardier variants of symbiodinium in a process named symbiont-shuffling. In fact, corals may have some hardier variants already as part of their customary algal lodgers. Once a coral recovers from bleaching, it proves to be hardier and not as easily bleached. So coral reefs adapt in a matter of months to years. Corals also respond favourably to warmer water by also growing faster (3-5% for one degree Celsius).
2) rising seas: many reefs are already limited in their growth by falling dry during spring low tides. Also fresh water floating on the surface, limits their growth. Fossil cores have shown that reefs have kept up with rising and falling seas during the ice ages and long before that. Most corals grow much faster than the worst-case predicted rise in sea level.
3) ocean acidification: because corals are encapsulated by live tissue within which the concentrations of minerals are controlled by the coral polyp, they are not very sensitive to acids outside. However, since their metabolism depends on that of their algal symbionts (who provide the food), they react favourably to raised levels of CO2, also producing skeleton faster. Warmth and CO2 work together, resulting in rapid growth, rather than decay.
And someone slipped up in mentioning the est. 3000 ppm CO2 level during that period, that’s over six times Hansen’s Eco-catastrophe tripping point, so, why aren’t we Venus?
Gee, and I was under some misplaced perception that the conundrum of the Permian extinction had been comfortably explained a couple of decades ago as simply a consequence of coalescence of continents via Continental Drift, (Pangea anyone?) reducing the available habitat for shallow sea marine organisms.
http://books.google.com/books?id=yfXJhKmp1wUC&pg=PA288&lpg=PA288&dq=stephen+jay+gould+permian+extinction&source=bl&ots=ldoCojHbX3&sig=a41eiMiZFfs8fpQLh4E6vvDfSDM&hl=en&ei=1KNeTqWjCIbeiAKUpoWzBQ&sa=X&oi=book_result&ct=result&resnum=3&ved=0CCcQ6AEwAg#v=onepage&q&f=false
Kevin Kilty says:
August 31, 2011 at 1:19 pm
John A. Fleming says:
August 31, 2011 at 12:22 pm
And the Deccan Traps are almost antipodal the Chicxulub impact. Interesting, no?
When it rains, it pours.
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An Iridium layer, presumably from Chicxulub, has been found between lava flows in the Deccan Traps. That would indicate that the volcanism started before the bolide arrived. I’d like to see a credible theory explaining how an area of magma flows induces an asteroid to strike the opposite side of the planet. I certainly can’t conjure up a remotely plausible explanation other than coincidence.
” Ocean’s Acidity during 1980 was pH:8.1. Ocean’s Acidity Today is. pH: 8.1. Where is Ocean’s. ACIDITY INCREASING. IS IT OCEANS ABSORBING. CO2?
If so much carbon dioxide were to be dissolved into the water so that the pH moved a perceptible amount, the amount of limestone formed in the bottom sediments would be off the charts. Do we see large sediment layers of limestone corresponding to this period? In order to change the pH of a buffered solution, one must first overcome the buffer. I am not a geologist, but I don’t recall hearing about any unexplained excessively thick worldwide limestone layers. Call me skeptical on this one.
“Further, the researchers find that if atmospheric carbon dioxide concentrations were 3000 parts per million by volume or higher, fitting within estimates for the Permian-Triassic boundary, the ocean pH would have been 7.34 or lower.”
Wait a minute! “would have been”? Did they use a computer model for this? This is an experiment that can easily be done. Anyone got access to a bucket of seawater and a pH meter? (ideally: materials, apparatus, procedure, observations, analysis, conclusions – that’s how we used to do “science”!)
Best,
Frank
“… if atmospheric carbon dioxide concentrations were 3000 parts per million by volume or higher, fitting within estimates for the Permian-Triassic boundary …”
But that’s way past the tipping point. How come we’re here?
So the tens of millions of animals that lived hundreds or even thousands of miles from the ancient oceans were killed by ocean acidification?
I’d like to hear them explain that one.
“jeez says:
August 31, 2011 at 2:15 pm
Gee, and I was under some misplaced perception that the conundrum of the Permian extinction had been comfortably explained a couple of decades ago as simply a consequence of coalescence of continents via Continental Drift, (Pangea anyone?) reducing the available habitat for shallow sea marine organisms.”
Nope, the extinction also affected land animals and land plants quite badly. And it hit deep water organisms if anything worse than shallow water ones. Also it is hard to see why the coalescence of Pangaea should cause extinctions on the North China and South China continental blocks, which were off by themselves somewhere out in the Panthallassic Ocean.
Kevin Kilty says:
“And the outpouring of HCl or SO2 from the volcanoes we know about, for sure, had no impact on ocean pH?”
I think you may have put your finger on the main sleight of hand there. I remember in the late 1980s that ocean acidification was one of the main candidates even then for the P-T extinction, and the main postualted source of this acidification was SO2 from either the Siberian or Deccan traps (I forget which). The specific reason why was that they are massive eruptions of basic lava, which is charactisitcally accompanied by high levels of SO2. Acidic lavas just won’t cut it for this. Here they have adopted this old theory, but seemlessly cut out the SO2 and replaced it with CO2, which better fits the next stage of the “we must end our evil fossil fueled society” narrative once people realize that the warming isn’t going to be anywhere near as large or destructive as the scare mongers want us to believe .
“Owen says:
August 31, 2011 at 2:41 pm
If so much carbon dioxide were to be dissolved into the water so that the pH moved a perceptible amount, the amount of limestone formed in the bottom sediments would be off the charts. Do we see large sediment layers of limestone corresponding to this period?”
No, The typical marine deposits of this interval are black organics-rich shales. interpreted as beeing due to anoxic conditions in the deep ocean. Incidentally this deposition of carbon rich sediments must have drawn down the CO2 level in the atmosphere quite a lot.
So it got so acid that all the buffer was gone….even though carbonates are…………carbon
…and that explains why we have no calcium carbonate fossils from that period ///////snark
Must be really hard on the paleo guys, to skip a million years………….
Three points
1 – this assumes that life then required absolutely the same chemical environment as life now.
2 – How did ocean acidification manage to kill off land animals?
3 – Where did the CO2 come from? It certainly wasn’t from Man’s activities.
Do you remember Snowball and Napolean, the two pigs leading the animals’ revolt against humans in George Orwell’s “Animal Farm” satire of Soviet communism? Snowball played a leading role in the opening “Battle of the barnyard” against the humans, getting peppered with shot gun pellets. By contrast Napolean plays minor role. However a few months later, Napolean takes power and drives away Snowball from Animal Farm.
Snowball and Napolean are satirical equivalents of Trotsky and Stalin. In the months and years following Snowball’s expulsion, Napolean and the ruling “panel” of pigs progressively re-educate the farm animals about the history of the Battle of the Barnyard, changing the account such that Napolean rather than Snowball was actually the hero. In the end they go so far as to state that Snowball was actually a traitor and fought on the side of the humans.
Something analogous to this is happening to climate science and climate history. CO2 and ocean “acidification” are playing the role of Napoleon, and climate palaeo history being re-written for political expediency so that, just as in Soviet Russia nothing was achieved without Stalin’s direct personal involvement, so no event in geological or climate history can have any explanation other than CO2.
Thus you will see that childishly spurious arguments, straw men and non-sequiturs are being used to attack any heretically non-CO2 explanation of past events such as extinctions. For instance: ” ocean ridges can speed up deep ocean circulation. Therefore, ocean anoxia cannot have taken place.” They ignore well-known sedimentary evidence for such anoxia:
There is evidence that the oceans became anoxic (severely deficient in oxygen) towards the end of the Permian. There was a noticeable and rapid onset of anoxic deposition in marine sediments around East Greenland near the end of the Permian.[109] The uranium/thorium ratios of several late Permian sediments indicate that the oceans were severely anoxic around the time of the extinction. [110]
Reference 110: Monastersky, R. (May 25, 1996). “Oxygen starvation decimated Permian oceans”. Science News.
link: http://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event#Anoxia
Then the author assert that levels of CO2 of 3000 ppm are sufficient to cause and “acid” pH of 7.3 [sic] and that this alone can cause the PT mass extinction. Again they conveniently forget that during the Cambrian era, where every single one of the marine phyla of organisms first evolved, CO2 levels were in the range 5000-10000 ppm. Thus their assertion is utter nonsense. In fact it is now known that several marine phyla including calcified forms (e.g. “small shelly species”) were in existence prior to the Cambrian, where CO2 levels would have been higher still.
This wretched excuse for a scientific study is an utterly despicable exercise, aimed not at scientists (any real scientist will immediately recognise it as twisted nonsense) but at the non-scientific public, contributing to a growing mood music where CO2 becomes more and more the villain behind every threat and catastrophe.
Just as in Animal farm under Napolean’s regime, every bad turn of events was blamed on sabotage by Snowball, now CO2 is the new Snowball. This is idiotically childish, sinister and totally dishonest but the reality of the current politicised climate “research” community.
Does anyone else object, as I do, to the use of the word “find” here (as in “The researchers find……”)? The results of a model which cannot be tested against the real world are not facts. One has created these results rather than “found” them. In true empirical research one does “find” or “discover” data. From models untestable against reality one only manufactures results. All of the predictions of the CAGW crowd are of this nature. They are creations, closer to fictions, that may or may not resemble truth. Without a test against empirical facts one cannot know their truth value.
As the Great Obama says, “Words matter…..” These “researchers” should be scorned for saying they have “found” something.
There appears to have been an oceanic anoxic catastrophe at the PT event, as shown in this Nature paper.
http://www.nature.com/ncomms/journal/v2/n2/full/ncomms1217.html.
“We discover a sulphur isotope signal (negative δ34S with negative Δ33S) that suggests episodes when porewater sulphate was converted nearly quantitatively to sulphide. This S-isotopic signal may have resulted from mixing of pyrites and suggests that shoaling of deep anoxic water may have contributed to the significant biodiversity loss before the final catastrophic extinction.”
Now an acidification event would have drive the process the other way, acidic oceans would have increased the atmospheric/oceanic H2S ratio and it would have auto-oxidized back to sulphate.
If the rock had hit a carbonate opposite it would explain both things, CO2 in the air and precipitation in the anoxic but alkali oceans.
Baa humbug reckons
Unless they believe another 3000ppm went into the oceans, in which case they’d have to explain where that total of 6000ppm came from.
Over time the ocean CO2 to atmospheric CO2 ratio is fixed. Google Henry’s law CO2 for the value of the ratio for CO2..
Pull My Finger says:
August 31, 2011 at 11:22 am
How can they model an enviornment about which we know practically nothing about?
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Well obviously enough is known to define the starting point for the model. Just because you don’t know doesn’t mean a bunch of other people also don’t know.
Nuke Nemesis says:
August 31, 2011 at 11:23 am
What exactly do we learn from simulations such as this? The models are full of assumption, best guesses and out-and-out fudge factors. You can’t duplicate the results except through another model, which hardly counts as validation.
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It means you have a whole bunch of predictions which you can compare to the results of other research derived from fieldwork that has already been done or will be done in the future. Then there will be a whole lot of debate over whether the model is correct or which observations are correct. Crucial pieces of missing information will
be identified and then the gaps filled in by more research. Eventually the contradictions will be resolved and a self consistent picture will emerge. This process could include changes to the original model that allow the model to work effectively over a wider range of climate conditions.
Mike Bromley the Kurd says:
August 31, 2011 at 11:27 am
AND: (CAPITALS INTENDED) ACIDIC=pH LESS THAN 7, and substantially so. The mistreatment of pH by climate science is ridiculous. Ocean acidification is a long way off, if ever. So QUIT this foolish pH-mangling and misnomering of everything from carbon to acid. Bunk.
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You’re just displaying your ignorance.
The use of the term acidity in this way is universal in technical fields that deal with water quality. Its not just the climate scientists who use this kind of terminolgy.
The use of the term acidity in this way has also been in place for decades and decades, well before ocean acidity became a topic of research.
So your pretending to be an expert on chemical terminology based on stuff you half understood from year 11 science, looks really really silly.
There was another study a few weeks ago that blamed a massive increase in dead-tree eating fungus with the extinction event.
Let me see, the biggest volcanic events in the history of the Earth kills 90% of the plants and animals, yet it was the fungus that grew on the dead vegetation which was the cause of the extinction.
Climate science relies on the scientists themselves to suspend their natural instinct to look for the obviously-true causes (and they DO IT).
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I also note that global temperatures prior to this event were about the highest that the Earth has seen in the history that we know about – around +10C compared to today with absolutely massive unlivable deserts in the centre of the Super-continent Pangea for example.
But right at the Siberian Traps volcanic events, global temperatures dropped by about 8C. So all that extra CO2 from the biggest volcanoes in Earth’s history actually resulted in one the largest cooling events also in Earth history.
GED says
lacked any ability to adapt to gradual decreasing alkalinity in the oceans as proposed here?
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Well it’s a good point, they would adapt, eventually. It’s just a question of how fast can animals adapt to changes in CO2 compared with how fast the change in CO2 was. If the changes in CO2 happen over 10-50k years many animal will not be able to adapt fast enough.