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The Great Dying: Redux?

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#1 Otto Piechowski

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Posted 26 July 2019 - 02:33 PM

I heard recently that some 260 million years ago a series of events occurred on earth which resulted in the death of 97% of all living things on earth.  (I do not know if that 97% meant of all individual living things, or represents the percentage of species which went extinct.  I would like one of you who is in the know, to clarify this point.)  This massive die-off has been called The Great Dying.

 

I have also heard that the cause was volcanoes in the area of Siberia filling the air with aerosols.  The primary killing aerosol was hydrogen sulfide.  Again, I would like one of you who knows the facts to clarify or correct this point.

 

Now to my questions.

- How does the earth, currently, stand in comparison to the climactic conditions which caused The Great Dying?  

- If the conditions (i.e. type of killing aerosol(s)) are the same, how close to the same concentrations is the earth at this time.

- If the conditions are the same, is there a cascade-point at which climactic feedback loops can be reasonably expected to cause the earth to reach a similar Great Dying?

 

Thank you.

 

Otto


Edited by Otto Piechowski, 26 July 2019 - 02:33 PM.


#2 xiando

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Posted 26 July 2019 - 03:21 PM

The Siberian traps are thought to have erupted  (and by erupted I don't mean the classic cone volcanoes) around 250 million years ago and covered vast areas with volcanic lakes. (from the last images I saw in some program on discovery or science channel a while back my impression is that they covered most or a very good portion of what is Siberia today) Afaik they defined the Permian Triassic boundary. In addition, as I recall they erupted for several million years continuously.

 

Honestly, although I know next to nothing about the event beyond what we learn in PBS specials and from various sources over the years in snappy info blurbs here and there, I doubt we (the modern world) can even come close to a single percent of the gases they released during their active period with the combined "exhaust" we've produced during the entirety of humankind.


Edited by xiando, 26 July 2019 - 03:23 PM.


#3 jrbarnett

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Posted 26 July 2019 - 03:47 PM

I heard recently that some 260 million years ago a series of events occurred on earth which resulted in the death of 97% of all living things on earth.  (I do not know if that 97% meant of all individual living things, or represents the percentage of species which went extinct.  I would like one of you who is in the know, to clarify this point.)  This massive die-off has been called The Great Dying.

 

I have also heard that the cause was volcanoes in the area of Siberia filling the air with aerosols.  The primary killing aerosol was hydrogen sulfide.  Again, I would like one of you who knows the facts to clarify or correct this point.

 

Now to my questions.

- How does the earth, currently, stand in comparison to the climactic conditions which caused The Great Dying?  

- If the conditions (i.e. type of killing aerosol(s)) are the same, how close to the same concentrations is the earth at this time.

- If the conditions are the same, is there a cascade-point at which climactic feedback loops can be reasonably expected to cause the earth to reach a similar Great Dying?

 

Thank you.

 

Otto

Hi Otto.  Ironically I'll be digging invertebrate fossils dating to this big die-off next week!  In researching fossil sites I found an article on how sponges exploded into prominence in the fossil record shortly after this Permian die-off event.  I'm looking for Ammonites, but if I find any sponge fossils, I may collect a sample or two.

 

As for extinction events the one you mention - at the end of the Permian - really isn't unique.  There's evidence of at least four other major extinction events in the fossil record; Devonian, Triassic and Cretaceous.  The Permian was most extreme, which may be why you are interested in it.

 

When you see the percentages associated with an extinction event, it is generally based on what percentage of known species in the fossil record leading up to the event are not evidenced after the event.  One thing that is really interesting (to me anyway) is that Ammonnid species had already started to materially decline in the fossil record well ahead of the big wipeout.  This suggests a more gradual rather than cataclysmic change, that started small and catalyzed to a massive crescendo over a ~1.2 million year period.

 

- Jim   



#4 ShaulaB

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Posted 26 July 2019 - 03:47 PM

Apples and oranges, I think.

 

It is documented fact that species extinction has accelerated due to human over-breeding, habitat destruction brought about by humans, and increased CO2 in the atmosphere causing higher temperatures of the air and oceans. The suspected too-high levels of hydrogen sulfide, which may have ended the Paleozoic era, will probably not come about in our time.
 

It is my understanding that climate change is a verboten topic here at CN.



#5 Ron359

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Posted 26 July 2019 - 05:03 PM

This wikipedia page answers most of your questions - specifically how it related to today's AGW environment:

 

"Further evidence for environmental change around the P–Tr boundary suggests an 8 °C (14 °F) rise in temperature,[17] and an increase in CO2 levels by 2000 ppm (for comparison, the concentration immediately before the industrial revolution was 280 ppm,[17] and the amount today is about 410 ppm[26]). There is also evidence of increased ultraviolet radiation reaching the earth, causing the mutation of plant spores.[17]"

 

https://en.wikipedia...xtinction_event

 

We are a long ways from seeing a 14F increase in global avg. temps and 2000 ppm CO2,  but things don't have to get that bad to lead to a very 'nasty place' to try and live.  

 

It is one of the fallacies of the GW denier arguments that the Earth has always gone through 'natural cycles' of warming and cooling.  Yes, thats true, but most of us couldn't survive breathing air with several times the CO2 levels, high sea levels and global temps of say the Carboniferous period of 60 million years, when most of the plant species thrived due to the high levels and temps and were 'put in the ground'.  Thats when most all of the carbon based petroleum and methane deposits we have now 'mined' and are releasing back into the atmosphere over only 150 years.  And of course those releases are 'not natural' and dwarf the minor contributions of CO2 from sporadic volcanic eruptions now.  



#6 Otto Piechowski

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Posted 27 July 2019 - 08:50 AM

Thank you for your comments and explanations Xiando, Jim, ShaulaB, and Ron 359.  Your comments helped me clarify in my mind what I most want to ask.

 

Venus seems to have had some type of deleterious climactic cascading feedback loop.  Also, it seems that The Great Dying and perhaps others similar events in earth's history also had such a cascade/feedback feature.

 

From the facts we know of the current increases in carbon ppm, temperatures, and other factors, what, in your informed opinions, is the possibility/likelihood of current climactic conditions on earth leading to such a deleterious cascade feedback loop?

 

Thank you again.

 

Otto


Edited by Otto Piechowski, 27 July 2019 - 08:51 AM.


#7 Otto Piechowski

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Posted 27 July 2019 - 06:35 PM

This forum is grayed out. What does that mean?

#8 llanitedave

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Posted 28 July 2019 - 05:04 PM

I heard recently that some 260 million years ago a series of events occurred on earth which resulted in the death of 97% of all living things on earth.  (I do not know if that 97% meant of all individual living things, or represents the percentage of species which went extinct.  I would like one of you who is in the know, to clarify this point.)  This massive die-off has been called The Great Dying.

 

I have also heard that the cause was volcanoes in the area of Siberia filling the air with aerosols.  The primary killing aerosol was hydrogen sulfide.  Again, I would like one of you who knows the facts to clarify or correct this point.

 

Now to my questions.

- How does the earth, currently, stand in comparison to the climactic conditions which caused The Great Dying?  

- If the conditions (i.e. type of killing aerosol(s)) are the same, how close to the same concentrations is the earth at this time.

- If the conditions are the same, is there a cascade-point at which climactic feedback loops can be reasonably expected to cause the earth to reach a similar Great Dying?

 

Thank you.

 

Otto

Conditions today aren't quite the same.  Without the huge volcanic eruptions, the aerosols are far lower.  At the End Permian times, the supercontinent of Pangaea occupied most of one hemisphere from poles to equator, while the huge Panthalassa ocean covered the other.  Atmospheric and oceanic circulation and temperature distribution systems were very different than today.  Over the long term, the climate seems to have been very unstable, producing a number of mass extinctions during the period leading up to the Great Dying.

 

One of the most notable aspects of this greatest of extinctions, IMO, is just how long the poor environmental conditions lasted.  Not only did the extinction itself display a complex series of patterns, seemingly affecting different groups at different times, but the recovery took a very long time, because the Earth apparently remained largely uninhabitable for possibly millions of years.

 

What's happening today is far more rapid, more comparable to an asteroid impact than a drawn out volcanic disaster.  The initial conditions are also different -- the Permian world was warmer to start with, we are warming from within an ice age.  An isolated southern continent today, Antarctica, and a restricted Arctic basin allow the accumulation of ice caps, which means lower sea levels than existed during End Permian times.

 

There are similarities, but there are also differences, these differences include the arrangement of landmasses and ocean basins, circulation systems, the types of plant and animal species and their interactions, starting temperatures and CO2 concentrations, the types of pollutants being emitted, the sources of pollutants being distributed rather than concentrated in a single region, global habitat destruction occurring independently of CO2 release, and the great rapidity with which today's changes are happening.  In short, it's not going to be easy to use one event to analyze the other.

 

I don't anticipate a drawn-out 4 million year long tail to this particular mass extinction, but that will be small comfort to the many species that disappear, and the many individuals who suffer for no good reason.



#9 Otto Piechowski

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Posted 28 July 2019 - 07:54 PM

as always Dave, thank you for a substantive and clear response to my questions!

#10 ColoHank

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Posted 29 July 2019 - 12:22 PM

The next major extinction event, the one we already seem to have embarked upon, might more accurately be described as a great killing than a great dying.  In addition to increased levels of carbon dioxide, we humans have produced a lot of persistent environmental toxins -- all in the name of progress.    


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#11 Otto Piechowski

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Posted 29 July 2019 - 05:09 PM

Hank, are there aspects of the current climate change which seem to you to be examples of or hold the possibility of a feedback loop cascade type event? Otto

#12 ColoHank

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Posted 29 July 2019 - 07:58 PM

Hank, are there aspects of the current climate change which seem to you to be examples of or hold the possibility of a feedback loop cascade type event? Otto

That seems to be a prevailing wisdom.  Loss of pack and glacial ice in polar regions decreases reflectance and increases the absorption of solar heat, which in turn promotes further melting.  Melting of permafrost pumps more carbon dioxide into the atmosphere, which increases the temperature of sea water and the atmosphere.  



#13 llanitedave

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Posted 30 July 2019 - 12:18 AM

That seems to be a prevailing wisdom.  Loss of pack and glacial ice in polar regions decreases reflectance and increases the absorption of solar heat, which in turn promotes further melting.  Melting of permafrost pumps more carbon dioxide into the atmosphere, which increases the temperature of sea water and the atmosphere.  

In addition, rising sea levels lift the bases of glaciers and Antarctic pack ice above the seabed, increasing their rate of flow into the sea, adding more melting ice volume to the system.



#14 KiwiObserver

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Posted 04 August 2019 - 07:38 PM

Another positive feedback to rising C02 levels is the acidification of oceans. The increased acidification limits the amount of ion the diatoms (and maybe other photo-synthesisers) can take up, affecting their growth and hence the amount of C02 they take out of the atmosphere. Diatoms make up around half the primary production in the oceans, so impacts of acidification on their ability to grow could lead to a significant drop in the amount of C02 absorbed by the oceans, raising atmospheric C02 levels and consequently also raising the amount of ocean acidification.



#15 BillP

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Posted 05 August 2019 - 01:55 PM

The next major extinction event, the one we already seem to have embarked upon, might more accurately be described as a great killing than a great dying.  In addition to increased levels of carbon dioxide, we humans have produced a lot of persistent environmental toxins -- all in the name of progress.    

 

That's ok.  All part of the natural process (yes, we are part of nature and not outside of it).  A good environmental pressure might very well be what is needed to cause directional selection so that homo sapiens can evolve into the next level/species.  We really do need that as IMO we've gone as far as we can with our current biology.  Clearly evident to me given the circumstances and our same old thinking and problem solving behaviors over the past millennia that we've definitely hit our wall so to speak lol.gif  The current brain just ain't gonna do any better.


Edited by BillP, 05 August 2019 - 01:59 PM.


#16 t_image

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Posted 05 August 2019 - 08:22 PM

Apples and oranges, I think.

 

It is documented fact that species extinction has accelerated due to human over-breeding, habitat destruction brought about by humans, and increased CO2 in the atmosphere causing higher temperatures of the air and oceans. The suspected too-high levels of hydrogen sulfide, which may have ended the Paleozoic era, will probably not come about in our time.
 

It is my understanding that climate change is a verboten topic here at CN.

Don't worry,

all the birth control seeping into drinking water and the streams will destroy life before the atmosphere does.

https://www.nature.c...icles/srep09303

 

"17α-ethinyl estradiol (EE2) is a component of combination oral contraceptives designed for women, of which approximately 16–68% of dose is excreted in the urine or feces."

 

Although "documented fact" of species extinction acceleration isn't reasonable because human's weren't around to "document" the rate of species extinction before humans existed....

So all we have is an incomplete fossil record compared with a more detailed way to notice patterns today, to say such as "fact" is bad science.



#17 llanitedave

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Posted 06 August 2019 - 12:41 AM

Don't worry,

all the birth control seeping into drinking water and the streams will destroy life before the atmosphere does.

https://www.nature.c...icles/srep09303

 

"17α-ethinyl estradiol (EE2) is a component of combination oral contraceptives designed for women, of which approximately 16–68% of dose is excreted in the urine or feces."

 

Although "documented fact" of species extinction acceleration isn't reasonable because human's weren't around to "document" the rate of species extinction before humans existed....

So all we have is an incomplete fossil record compared with a more detailed way to notice patterns today, to say such as "fact" is bad science.

Care to explain why, logically, species would NOT be currently going extinct at greater rates?

 

It doesn't matter, BTW, that the fossil record is incomplete in this context.  The extinction counts are always relative, and with marine organisms in particular, the fossil record is much more detailed than you seem to think.




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