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Earth’s worst extinction “inescapably” tied to Siberian Traps, CO2, and climate change

Posted on 14 October 2015 by howardlee

The latest batch of rock dates released by the MIT geochronology team "inescapably" nails the link between the end-Permian Siberian Traps eruptions and Earth’s worst mass extinction, pointing to the critical role of greenhouse gasses in the catastrophe.

The link

Seth Burgess and Samuel Bowring confirmed the long-hypothesized link by comparing new, high-precision dates from volcanic rocks with equally precise dates for the mass extinction measured from volcanic ash in sediments spanning the end-Permian boundary in China. By ensuring the same labs and chemical tracers were used in both sets of measurements, they were able to compare the dates at an unprecedented precision of 0.04% or better, even though the rocks sampled were from locations thousands of miles apart.

The Siberian Traps are an example of a rare geological phenomenon called a “Large Igneous Province” (LIP) which has been linked to 4 out of the “big 5” mass extinctions since animals evolved. The new timeline enables science to zoom in to the details of the terrible events 252 million years ago, in which more than 90% of marine, and some 75% of land life went extinct. 

Timeline for Earth's worst mass extinction

Timeline of Earth’s worst mass extinction. Redrawn and simplified from Burgess & Bowring 2015, annotations and photos added.

The timeline

The LIP began with explosive eruptions around 252.3 million years ago, as magma and lava encountered waterlogged, swampy terrain. These eruptions blanketed the region in volcanic ash, in some areas building to a kilometer thick. Then at 252.24 million years ago, lava flows took over: curtains of bright lava gushed from fissures, emitting CO2 and SO2, before flowing through lava tubes to advancing lava fronts. Fully 2/3 of the entire Siberian Traps lava sequence erupted this way over 300,000 years, building to 4 km thick of stacked lava flows that form the “traps” landscape of the Siberian Traps today. That’s some 3 million cubic kilometers of magma – with associated gasses - erupted before and at the onset of the mass extinction.

The end-Permian mass extinction began towards the end of those lava eruptions, at the same time as a huge spike in the carbon isotope balance, indicating that massive amounts of COand/or methane were released into the atmosphere and oceans from an exponentially growing pool rich in carbon-12. The rapidity of this isotope “excursion” strains the limits of even the new dating resolution, with a duration somewhere between 2,100 and 18,800 years. The smaller of those numbers is a mere 2 complete ocean circulations at today’s rates, fewer if circulation was more sluggish in the Permian. This matters because we expect abrupt global warming and ocean acidification if CO2 emissions overwhelm the oceans’ capacity to process them, as explained in this article.

Since life preferentially stores carbon-12 over carbon-13, this suggests that a large reservoir of once-living carbon was rapidly converted to CO2. Alternatively, it might indicate a mantle source unusually rich in carbon-12.

The mass extinction unfolded for about 61,000 years into the early Triassic. The uncertainty on the extinction episode means it might have been as short as 13,000 or as long as 109,000 years – a timespan during which complex life on Earth was nearly wiped out by the deteriorating environment and climate change.

Over the years leading into the mass extinction the oceans gradually became more acidic, resulting in the loss of shelly, carbonate producing animals, and leaving sea beds dominated by sponges. Then at the carbon isotope excursion even the sponges disappeared as the environment became heavily polluted. The terrestrial extinction happened at the same time, as acid rain fell and global temperatures soared some 10°C. As the seas warmed they became starved of oxygen so that even the worms that burrowed in the seabed disappeared. Temperatures remained high well into the Triassic, and it took 10 million years for biodiversity to recover.

As Burgess and Bowring point out, these symptoms:

“…all point to anomalously high atmospheric pCO2 as a critical driver of both terrestrial and marine biotic crises”

The mystery

The mystery is: what triggered the massive carbon release in the final few millennia of the eruptions, rather than any time in the preceding 300,000 years? As Burgess and Bowring say:

“The enormous total volume of LIP magmas might be less important than an aliquot of the total, erupted/emplaced in a very restricted interval.”

It may be that the progressive degradation of the Permian conditions brought the environment to a tipping point, such as the destabilization of methane clathrates in the oceans.  But a recent study suggests that by the end-Permian reserves of marine clathrates were largely tapped-out.

Burgess and Bowring suggest an alternative scenario:

“Early sill intrusion into, and magma transport through an untapped, volatile-rich basin may be this critical aliquot."

They dated the Noril’sk 1 underground igneous intrusion - the oldest found anywhere in the Siberian Traps – as beginning around same time as the carbon isotope excursion.  Noril’sk 1 marks the beginning of a new phase of the eruptions – the injection of many underground sheets of magma (“sills” and “dikes”) into the Tunguska sedimentary basin, a thick sequence of sedimentary rocks containing fossil fuels. Some sills reach 350 meters thick and extend great distances, and cumulatively the intrusions exceed 2 million cubic kilometers of magma.

Svensen et al showed in 2009 that these sills baked coal, oil and natural gas, salt, limestone, and organic-rich shales in the sediments, generating large volumes of methane and CO2, as well as a cocktail of noxious gasses, acids, ozone-eating chemicals and coal fly-ash. These gasses exploded into the atmosphere through thousands of pipe eruptions across Siberia, belching columns of gas and pollutants from vents up to 1.6 km wide, leaving behind mineral-rich pipes that are mined for iron ore today.

Earlier this year Fristad et al published a study of the carbon chemistry of one of those pipes, which showed that the carbon involved in its formation was indeed rich in carbon-12, strongly linking Permian pipe eruptions with the massive release of carbon-12 recorded in the isotope excursion.

Noril’sk 1 was amazingly long-lived, having 3 distinct magma injections over some 267,000 years. But many of the observed Siberian sills and dikes are dated to after the mass extinction, a time when the carbon isotope curve shows only minor variation. It may be that the sediments had limited reserves of carbon to bake-off. Within a few thousand years their fossil fuel reserves may have been exhausted.

Then and now

Then and now

As I outlined in this earlier article, emission rates matter a lot when it comes to our oceans’ ability to process them. Some LIPs, like the Paraná-Etendeka LIP, erupted slowly without causing environmental destruction and global climate change. These new dates suggest that the initial phase of the Siberian Traps had a relatively modest effect on the global environment, but later on during the eruptions, probably when widespread sill intrusions occurred and greenhouse gasses from baking of sediments were added to the load, this appears to have overwhelmed the already-stressed environment.

The irony is that back in the Permian the combustion of fossil fuels contributed to global warming and an environmental catastrophe so extreme that it came close to extinguishing complex life. Today we are embarking down a similar path, emitting at rates probably faster than in the end-Permian, even though our total emission quantities are smaller.

As new dates keep resolving the timeframes for these epoch-changing events in Earth’s past to ever-briefer intervals, their similarities with modern climate change increase. If Earth responded in a similar manner several times in its past, it is crucial that we focus research on understanding just how similar our modern path is, and how far along it we have already travelled, because the destination isn’t exactly a picnic spot.

References

Burgess, S. D., & Bowring, S. A. (2015). High-precision geochronology confirms voluminous magmatism before, during, and after Earth’s most severe extinction. Science Advances1(7), e1500470.

Burgess, S. D., Bowring, S., & Shen, S. Z. (2014). High-precision timeline for Earth’s most severe extinction. Proceedings of the National Academy of Sciences111(9), 3316-3321.

Black, B. A., Weiss, B. P., Elkins-Tanton, L. T., Veselovskiy, R. V., & Latyshev, A. (2015). Siberian Traps volcaniclastic rocks and the role of magma-water interactions. Geological Society of America Bulletin, B31108-1.

Paris, G., Donnadieu, Y., Beaumont, V., Fluteau, F., & Goddéris, Y. (2015). Geochemical consequences of intense pulse-like degassing during the onset of the Central Atlantic Magmatic Province. Palaeogeography, Palaeoclimatology, Palaeoecology.

Grasby, S. E., Beauchamp, B., Bond, D. P., Wignall, P., Talavera, C., Galloway, J. M., ... & Blomeier, D. (2015). Progressive environmental deterioration in northwestern Pangea leading to the latest Permian extinction.Geological Society of America Bulletin, B31197-1.

Majorowicz, J., Grasby, S. E., Safanda, J., & Beauchamp, B. (2014). Gas hydrate contribution to Late Permian global warming. Earth and Planetary Science Letters393, 243-253.

Svensen, H., Planke, S., Polozov, A. G., Schmidbauer, N., Corfu, F., Podladchikov, Y. Y., & Jamtveit, B. (2009). Siberian gas venting and the end-Permian environmental crisis. Earth and Planetary Science Letters277(3), 490-500.

Grasby, S. E., Sanei, H., & Beauchamp, B. (2011). Catastrophic dispersion of coal fly ash into oceans during the latest Permian extinction. Nature Geoscience4(2), 104-107.

Fristad, K. E., Pedentchouk, N., Roscher, M., Polozov, A., & Svensen, H. (2015). An integrated carbon isotope record of an end-Permian crater lake above a phreatomagmatic pipe of the Siberian Traps. Palaeogeography, Palaeoclimatology, Palaeoecology428, 39-49.

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Comments

Comments 1 to 7:

  1. Dear Howard Lee,

    Thanks.

    In terms of doubling of CO2 for that 10C rise what are we ~ talking?

    Then considering no ice back then, and that equilibrium climate sensitivity is ~50% with no ice compared to when ice is present, and that we have ice today, what are looking at if that time period can be taken as an some sort of analogy of now?

     

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  2. Ranyl,

    Tang et al (2013) estimated:-
    8.5 × 10^7 Tg CO2, 4.4 × 10^6 Tg CO, 7.0 × 10^6 Tg H2S and 6.8 × 10^7 Tg SO2 (Tg, Trillion grams)
    But they only sampled the igneous component, whereas it looks like baked sediments were a considerable contributer of additional carbon.
    Svensen et al (2009) extimated the additional contribution from such pipe eruptions to be:-
    CO2 equivalent flux of 0.8–2.1 Gt CO2/y for 6400 years, with subsequent 0.7–2.0 Gt CO2/y over a 50 ky period from contact metamorphism.

    Clarkson et al (2015) modeling from ocean acidification and the isotope signal estimated 2 × 10^18 mol C over
    10,000 years, ie emission of 24,000 PgC at a rapid rate of 2.4 PgC/year.

    That compares to modern rates of ~ 4.27 ± 6.83 PgC/y and total fossil guel reserves at ~5000 PgC (average rates of 2.2GtC/y since 1750 is a similar flux). They calculate Permian pCO2 jumping from about 3PAL to about 20 PAL, (about 2.5 doublings) with a warming of 15 Celsius, and an ocean acidification event lasting around 10,000 years.

    Just crudely taking Clarksons numbers that suggests an Earth system sensitivity of ~ 6C per CO2 doubling. Thats a very crude estimate and I would look to climate modelers to refine that or derive an ECS from it.

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  3. Thanks Howardless,

    So a crude 6C for equilibrium with no ice (12C with ice), quite high really and you get ~60-80% in 100 years with equilization over millenium.

    And were at ~0.43 of a doubling at 400ppm if starting at 280ppm with ice.

    Having said that the Antartic contential freezer was absent so maybe that increased the sensitivity??

    Although an early Pliocene CO2 of 350ppm (0.4 of a halving), as many suggest, at 3C-5C hotter than pre-industrial implies a ECS of 7.5C to 12C, with 60-80% in 100 years implies that 350ppm should induce a warming of between 1.125C to 2.4C taking 350ppm to be 1/4 of doubling from 280ppm. However if take past to equal future and take earth to a perfect climate model, then 3-5C for 350ppm implies 1.8C to 4C by 2115.

    Considering the extreme weather recently at 0.75C and it all seems rather daunting even at 350ppm therefore, and we are at 400ppm with no prospect of this lowering any time soon due to permafrost melting and the like. 

    And the rate is so fast, and this is a chaotic system.

    Do wonder if the rate will induce unexpected shifts in the global weather systems or new extreme events, isn't it sort of like sticking the heating ring on max for 5 minutes compared to slowly adding the heat over hours, you always to get a more turbulent response.

    And I can't help thinking a more turbulent response isn't a good idea in global weather.

    Does the rate as well as the scale of warming count in these mass extinctions?

    Can't help thinking it might.

    In these terms 350ppm means we have a carbon debt not a budget, and that has some deep implications, for it means all emissions add to the debt, rather than just using up a bit of a safe budget.

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    Moderator Response:

    [PS] Excessive white space removed.

     

  4. Dear Howardlee,

    Please excuse my calling Howardless, it was a typing error with no intent and I didn't see it, e and s are close on the keyboard.

    Maybe the moderator could edit it, as there is nothing less about your excellent blogs and posts.

    Ranyl

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  5. Ranyl - no worries, it's better than most of the things I have been called and it made me smile!

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  6. ... but to your other points:

    Martínez-Botí et al suggested that climate sensitivity in cold climates with ice is about double that of sensitivity in warm, low-ice climates. Ie today should be more sensitive than the end-Permian.

    The scale of end-Permian warming was a factor in the extinctions - studies have calculated that it left tropical latititudes lethally hot for complex life. Rate is crucial. It seems that if the rate exceeds the ocean overturn rate the long term negative feedbacks dont have time to mitigate the effects.

    A recent study by Dutton et al suggested that based on CO2 levels about todays level we should eventually get Pliocene-like sea levels of tens of meters above today:

    dutton et al

    The rate of that SL rise is hard to constrain but ive read that would probably take a few centuries to reach those levels. But Paleo studies of the Miocene suggest strong hysterisis in Antarctic ice sheet response with forcing levels at CO2 levels similar to today.

     

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    Moderator Response:

    [RH] Fixed image width.

  7. Thanks, HowardLee. Your summaries of evidence regarding past extinctions--mostly pointing to changes in greenhouse gases--are fascinating as well as frightening.

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