There are parallels between today’s and past greenhouse gas-driven climate changes
Howard Lee
Tuesday 1 August 2017 06.00 EDT Last modified on Tuesday 1 August 2017 06.02 EDT
Coincidence doesn’t prove causality, as they say, but when the same two things happen together over and over again through the vast span of geological time, there must be a causal link. Of some 18 major and minor mass extinctions since the dawn of complex life, most happened at the same time as a rare, epic volcanic phenomenon called a Large Igneous Province (LIP). Many of those extinctions were also accompanied by abrupt climate warming, expansion of ocean dead zones and acidification, like today.
Earth’s most severe mass extinction, the “Great Dying,” began 251.94 million years ago at the end of the Permian period, with the loss of more than 90% of marine species. Precise rock dates published in 2014 and 2015 proved that the extinction coincided with the Siberian Traps LIP, an epic outpouring of lava and intrusions of underground magma covering an area of northern Asia the size of Europe.
But those rock dates presented science with a new puzzle: why was the mass extinction event much shorter than the eruptions? And why did the extinction happen some 300,000 years after the lava began to flow?
Now in a new study published in Nature Communications, Seth Burgess of the US Geological Survey, along with James Muirhead of Syracuse University and Samuel Bowring of MIT, think they have the answer. As Burgess told me:
It’s clearly not the entirety of the LIP that’s guilty. There’s a subinterval that’s doing the work, and I set out to figure out which subinterval that was, and what makes it special.
Burgess noticed that the beginning of the mass extinction, as well as a jolt to the carbon cycle and abrupt climate warming, coincided exactly with a switch in the style of volcanic activity in the Siberian Traps. During the initial 300,000 years of the eruptions, basalt lava poured over a vast area of Siberia building to several kilometers thick. In this time there was some stress to life in the Northern Hemisphere, but no mass extinction. Life only began to disappear across the globe at exactly the same time that lava stopped erupting above ground, and instead began to inject as sheets of magma underground.
In Siberia you have got the Tunguska Basin which is a thick package of sediments that contain carbon-bearing rocks like limestone and coal. When you start intruding magma, [it] cooks those sediments and liberates the volatiles. So the deadly interval of magma in the entire Large Igneous Province is the first material to intrude and pond into the shallow crust
In other words, it wasn’t the lava, it was the underground magma that started the killing, by releasing greenhouse gases.
Norwegian scientist Henrik Svensen had earlier identified hundreds of unusual volcanic vents called “diatreme pipes” all over Siberia that connected underground intrusions of magma (“sills”) to the atmosphere, showing signs of violent gas explosions. This new work emphasizes the importance of Svensen’s 2009 conclusions:
The diatremes that have been mapped are the geologic representation of that gas escape on a catastrophic level. Our hypothesis is that the first sills to be intruded are the ones that really do the killing [by] large scale gas escape likely via these diatremes.
Svensen, who was not involved in Burgess’ study, commented:
The Burgess et al paper is a crucial step towards a new understanding of the role of volcanism in driving extinctions. It’s not the spectacular volcanic eruptions that we should pay attention too – it’s their quiet relative, the sub-volcanic network of intrusions, that did the job. The new study shows convincingly that we are on the right track.
Greenhouse gas as a killer
While other scientists have proposed that an array of killers may have been involved in the end-Permian mass extinction, from mercury poisoning to ultraviolet rays and ozone collapse to acid rain, Burgess argues that it was principally greenhouse gas emissions triggered by magma intrusions that caused the extinction through abrupt global warming and ocean acidification. I asked him to outline the evidence for that.
There are 3 primary lines of evidence that support that link. The first is: right before the onset of the mass extinction we have evidence for a massive input of isotopically light carbon into the marine system.
He went on to explain various lines of evidence that point to the source of that carbon being methane and carbon dioxide resulting from magma intruding and cooking organic-rich sediments. He continued:
Just prior to extinction and persisting after the mass extinction the sea surface temperature is thought to have gone up about 10°C. You get that increase by pumping greenhouse gas into the atmosphere. So that’s the second.
And then the third line of evidence is a physiologic selectivity to the marine mass extinction. Organisms that make their shells out of calcium carbonate suffer much higher mortality than organisms that make their shells out of silica, for example, which suggests that the ocean was acidified, and you get that by pumping gases like CO2 into the atmosphere.
That’s not to say that other factors had no role in ruining the environment:
There is a cacophony of kill mechanisms, and I think that this first pulse of sills is the trigger for quite a few of those, sitting at the top, and beneath it are a cascade of negative effects from ocean acidification to climate warming and on down the line.
A series of associated events
Coincidentally, Joshua Davies of the University of Geneva and colleagues have just narrowed down the trigger for the end-Triassic mass extinction, another of Earth’s biggest mass extinctions, to the underground phase of its associated Large Igneous Province. The Central Atlantic Magmatic Province (CAMP) is another enormous igneous province which stretches from Maine to South America, and includes the Palisade Sill visible from Manhattan.
They too used high precision rock dates on a vast sill that intruded organic rich sediments in the Amazon Basin, and found that this underground magma intrusion also coincided with the extinction. Like Burgess, Davies also argues that greenhouse gas baked from sediments drove climate change, which drove the mass extinction in a smaller repeat of the end-Permian events, this time 201.5 million years ago.
“I think CAMP is very similar to the Siberian Traps and that’s the reason why there’s an extinction at that time. I’m not surprised that they got similar results,” said Burgess.
Diatreme pipes from magma intrusions have also been identified as a likely cause for a more recent global warming and very minor extinction event – the Paleocene–Eocene Thermal Maximum (PETM) 56 million years ago. Again, prodigious quantities of greenhouse gases erupted from oil-rich deposits, although in that case it’s been hard to locate and date the “smoking gun” intrusions due to the fact that they are under the Atlantic Ocean.
Howard Lee is a geologist and science writer who focuses on past climate changes.
Read the full article here.
HT/WBWilson
One day of VEI5 eruptions in today’s world produces 0.5C of cooling lasting a few years.
1 million straight years of VEI7 volcanoes produces warming 251 million years ago.
Interesting.
Bi, its more complicated. It takes a minimum VEI5 to inject stratospheric aersols with sufficiently long lives to produce any cooling. Essay Blowing Smoke in namesake ebook. But not evem all VEI6 do this. St. helen’s is an example. Flood basalts never do by definition of the nature of the eruption.
“Flood basalts never do by definition of the nature of the eruption.”
The only flood basalt eruption in historical times (Laki 1783-4) most certainly did. Which is not at all surprising when you read the contemporary descriptions. Lava fountains up to 1,000 meters high, and “curtains of fire” hundreds of meter high extending for several kilometers. Such eruptions would easily generate enough heat to “punch through” the tropopause.
By the way Laki left a tephra layer in the Greenland icecap. How did that get there?
Here is a handy summation of the global effects of the Laki eruption:
http://seismo.berkeley.edu/~manga/LIPS/thordarson03.pdf
If the reader is supposed to infer that a past catastrophe was caused by greenhouse gases,
therefore we should worry about our current level of greenhouse gases, then this article is
totally misleading and leads the reader to a completely invalid conclusion. Much like trying to discredit a chemical that in large quantities can kill, but in small quantities can save lives.
A 10 degree Celsius warming is totally inconceivable as due to man-made emissions, as is an ocean acid enough to harm anything. CO2 is being accumulated in the atmosphere these days at a relatively slow rate and that rate will drop drastically with the advent of two imminent technologies :
advanced nucear reactors (molten salt, primarily, possibly accompanied by some small number of fast neutron reactors), and electric cars. We are at a point where it is impossible to deny that those technologies will not dominate the future. So arguing for the continued large scale usage of fossil fuel power generation a losing proposition : not even simple economics argues for fossil fueled power, or renewables either. I would argue that the future danger lies in too little CO2 in the atmosphere, which can have a deadly effect primarily on humans. Implying that man would ever or could ever produce the prodigious amounts of greenhouse gases described in this article is a complete, and quite stupid, fantasy. Current elevated levels of CO2 are totally beneficial – they have NO negative effects. This would also be true if those levels ascended from the current 400PPM to 500 PPM as well. Even doubling the levels to 800PPM would have relatively small effects – perhaps 1 or, less likely, 2 degrees warming. Articles like this will only have an effect on those who possess limited knowledge of the issues involved in global warming. Unfortunately, that includes a lot of
pretty ignorant and scientifically illiterate folk (Al Gore, for example) . But they can read, unfortunately.
Of course, irrespective of gas release, all those lava flows and near-surface magma would make biosphere temperatures warm considerably. Why the need for greenhouse gas ‘warming’?
That’s what I thought, too. Seems more reasonable than CO2.
No. The direct heat emission from even the largest eruption is small in a global context.
Lank, it’s a piece of cake when compared to the magical manmade trace gas in the outside air, especially when ocean temperatures are concerned.
http://oceanexplorer.noaa.gov/explorations/04fire/background/hirez/plate_boundaries_hires.jpg
The place of hottest water on earth: https://www.newscientist.com/article/dn14456-found-the-hottest-water-on-earth/
PETM, I don’t think so. Here is a chunk of redwood from 53 million years ago found at 300 metres deep in the Ekati diamond mine at the Arctic Circle. The volcanic pipe blasted to the surface in the middle of a redwood forest. Just because it was warm there is no need to start jumping on extinction bandwagons.
https://www.livescience.com/23374-fossil-forest-redwood-diamond-mine.html
Looks like Garden Earth to me!
How do they know that? They analyze sediments. The Earth’s crust can move around a lot in a million years. link I can see plenty of opportunity for error to creep in on that account.
What is usually thought to cause mass extinctions?
Global warming due to increased CO2 is a novel idea when it comes to mass extinctions. Just saying.
Missing in the article is any estimations of CO2 concentrations. If I am not mistaken, submariners become concerned when CO2 levels inside the submarines rise above 11,000PPM. I believe anything above 14,000PPM is lethal. We are currently at 395ppm, rising from 280ppm a few hundred years ago.
There are actually two issues at play. The first is llethality of high amounts of CO2 to life; the second and most studied is the sensitivity of CO2 to global temperatures. This article conflates the two issues, hinting that current increases of CO2 are synonymous to the CO2 increases associated with the Great Dying of 250 million years ago. But, the article failed to say what the CO2 levels were during that period.
So what, geologically speaking, was the CO2 concentration in ppm that wreaked all that havoc? Just like today…
The extinction events were likely caused by a series of disasters, ending in dead biomass accumulations and volcanism.
The paper The Threat to Life from Eta Carnea and Gamma-Ray Bursts argues that earth supernovae may have been the immediate cause, triggering sea life extinctions with deadly cosmic ray cannon balls 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 expanding supernovae shock wave jostled the Oort Cloud, raining asteroids upon earth.
The specific threat from Eta Carinae is refuted in this paper, Superluminous supernovae: No threat to life from Eta Carinae , owing, for example, to its distance from earth, about 8,000 light years.
The cause of the Paleocene-Eocene boundary event, on the other hand, is less certain. However, the introduction to Environmental precursors to rapid light carbon injection at the Palaeocene/Eocene boundary argues against a prior build up of greenhouse gasses: “The lag of 3,000 years between the onset of warming in New Jersey shelf waters and the carbon isotope excursion is consistent with the hypothesis that bottom water warming caused the injection of 13C-depleted carbon by triggering the dissociation of submarine methane hydrates, but the cause of the early warming remains uncertain.”
Add to the other comments, that most of the Siberian event actually took place during the Early Triassic:
Established boundary time: 251.94 ma (GTS 2016)
Siberian LIP: 252.4 to 248.2 ma
The ‘terminal’ (end of the Permian Period) extinction is thought to have occurred on a geologically-rapid time scale, about 100,000 years, and this estimate keeps getting shorter and shorter, as we find new information. About the time that the evidence points to less than 50,000 years for the ‘terminal’ event, it will become more difficult to tie-in some event in Siberia to a global extinction, in my opinion.
Regards,
Vlad
Climate scientists do not understand the earth’s long-term climate processes today, and we are now asked to believe that earth climate processes 250 million years ago can be understood with the additional complication of an epic volcanic eruption. Give me a break! Today’s eruption is the sudden spewing out of a lot of science fiction based on the largely disparaged premise that CO2 is the culprit of global warming. I see these stories as nothing more than obfuscation and fear mongering.
There are a series of leaps to conclusions in a cascading effect in the article.
Runaway global reasoning.
For some reason, your comment reminded me of this scene. https://www.youtube.com/watch?v=Fxf5GDZ_o1w
extinction happen some 300,000 years after the lava began to flow
===================
yikes. only 300,000 years to prepare.
It seems likely that a whole lot of bad thing could happen in 300k years, quite independent of the lava flows. how do we know it wasn’t one of these other ‘bad things’?
It really does sound like the paper started with a conclusion (CO2 is what done it) and then fit the facts to match, while ignoring other possibilities.
When the only tool in the toolbox is labelled “CO2”, then it is no surprise that all the answers are “greenhouse gas”.
The CO2 cult has gone full stupid and it’s infecting other areas of science.
The True Believers continue to throw anything and everything at the wall…
What a bunch of nonsense! This is beyond bad science, it’s not science at all. The so-called ‘explosive diatremes’ in Siberia are pingos, a perfectly natural extrusion of ice and melting of core ice that go on all the time all over the Arctic. Ask competent geomorphologist and he/she will confirm that they are NOT explosive and have nothing whatsoever to do with climate change.
As for the correlation between CO2 and global temp, remember that CO2 ALWAYS lags global warming, never precedes it, both long term and short term. The data is conclusive. Temp causes increase in CO2, not the other way around.
Well, now I’ve read the paper and also some of the papers they reference and I simply don’t understand how they get the results they claim. Everything hinges on precise dating of the events, but when you dig into it, it just doesn’t hold water.
Their dates for the beginning and end of the various stages of the Siberian eruptions are averages of averages while the actual individual radiometric dates vary by several hundred thousand years. Their placement of the main extinction pulse hinges entirely on matching radiometric dates from Siberia and China (there is no biostratigraphic control, since there are no marine deposits in the Tunguska basin). However when you line up the Chinese and Siberian sections their way the magnetostratigraphy doesn’t match at all, and it doesn’t even match between their Siberian sections. To me it all points to an uncertainty of the order of at least +- 200 ka for all the dates.
And even if their matching is correct it would seem that the main extinction pulse was actually near the end of the extrusive phase, not in the early sill-emplacement phase.
Extensive use of confirmation bias, gross assumptions and waffle words.
I find it interesting that early investigations (pre 2000) into this event are thorough and wide ranging in terms of multiple catalysts related to sudden flora and fauna change. But then climate change came into view for the Siberian Traps and suddenly CO2 was the only cause. There are still serious investigations that refute the “Only CO2 is the culprit” meme. But they don’t get much press. Not alarming enough I guess.
https://www.researchgate.net/profile/Bas_Van_de_Schootbrugge/publication/31955323_Floral_changes_across_the_TriassicJurassic_boundary_linked_to_flood_basalt_volcanism/links/0fcfd50504a3721f7d000000.pdf
Just a thought: Could this be the end stages of trying to squeeze the last drop of AGW money out of the tube? Take something that has been elsewhere studied and determined to be one thing, then restudy it so that it implicates CO2?
“Coincidence doesn’t prove causality, as they say, but when the same two things happen together over and over again through the vast span of geological time, there must be a causal link.”
Sorry, not true. Or at least not in the way you meant it to be interpreted. What you describe as “two things happen[ing] together over and over again through the vast span of geological time” is still just coincidence (a repeated coincidence, but a coincidence nonetheless). And it does NOT imply causality, at least not between the two things of interest. It is true that there is usually some “causal link”, but the link is often indirect, i.e., the two things are not linked directly in a causal relationship, but both are independently linked, in a causal relationship, to a third thing. For example (and at the risk of offending females everywhere, but sorry, this is the best example I could come up with on short notice), there is a “coincidence” of menstrual bleeding and moodiness in women. And it happens to a billion young women, every month, for as long as human women (and for that matter female mammals) have existed on this planet. So if you’re talking about the sheer number of times “two things happen together”, this has any coincidence you speak of here beat by 10 or more orders of magnitude. And yet, there is still no DIRECT causal relationship. The bleeding does not cause the moodiness and the moodiness does not cause the bleeding. Instead, both are caused by a sudden surge in the levels of certain hormones.
Now, after this error in the first paragraph, you go on to describe a “coincidence” that I would be hard-pressed to argue does not have a direct causal link. In fact, the argument is very convincing, and I would, until and unless some better theory comes along, accept as likely the direct causal link between underground lava sills (the cause) and mass extinctions (the effect), which is as close as any scientist can come to saying, “it’s true”. So for the sake of argument, let’s say it IS true that underground lava sills cause mass extinctions. That still does not make your opening general statement about coincidences and causal links true. Unless, of course, your use of “causal link” is intended to include indirect causal links such as the menstrual blood and moodiness link described here, and in the context of the article as a whole, that is clearly not the case.
(Note that i myself am guilty of misusing a word here. Usually, a “direct” causal link means that one thing causes another with no transitory cause/effect (being the effect of the ultimate cause and the cause of the ultimate effect) between them (i.e., the link between hormone surge and menstrual bleeding, technically is not “direct”, in this sense of the word, because the hormone surge causes the falopian tube to flush out the egg, which in turn causes the bleeding; but the link between hormone surge and moodiness IS direct, or at least as direct as we can understand when it comes to human psychology). But in the sense that I am using the word, a “direct” causal link can have multiple linkages (so call it a “multiple-order direct causal link), so long as there is a “one-way” line of causation through the all linkages from ultimate cause to ultimate effect.)