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Ordovician–Silurian extinction events

Ordovician–Silurian extinction events

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There are many theories of the cause(s) so take your pick. Which cause(s) do you think are the most likely?

https://en.wikipedia.org/wiki/Ordovician%E2%80%93Silurian_extinction_events

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@Metal-Brain

Not being a climatologist I have no idea. What idea are you promoting? Temp rises followed by increase in CO2?

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@sonhouse said
@Metal-Brain

Not being a climatologist I have no idea. What idea are you promoting? Temp rises followed by increase in CO2?
According to the Wikipedia article carbon dioxide levels dropped sharply, there is speculation about vulcanism increasing its absorption. In combination with this a supercontinent drifted over the South Pole causing sea levels to drop as ice sheets formed on it. Photosynthesis dropped so oxygen levels fell. The existing species were adapted to greenhouse conditions so mass extinctions ensued.

I don't know where MetalBrain is going with this. I don't see it helping his "no global warming here" position.

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@deepthought said
According to the Wikipedia article carbon dioxide levels dropped sharply, there is speculation about vulcanism increasing its absorption. In combination with this a supercontinent drifted over the South Pole causing sea levels to drop as ice sheets formed on it. Photosynthesis dropped so oxygen levels fell. The existing species were adapted to greenhouse conditions so m ...[text shortened]... where MetalBrain is going with this. I don't see it helping his "no global warming here" position.
"I don't see it helping his "no global warming here" position."

I have never said there is no global warming. Learn to read.

"vulcanism increasing its absorption"

How can vulcanism increase absorption of CO2?

Furthermore, the CO2 levels dropped sharply because the temperatures dropped sharply. You are clinging to the outdated myth that Al Gore made popular. You are very dogmatic.

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@metal-brain said
"I don't see it helping his "no global warming here" position."

I have never said there is no global warming. Learn to read.

"vulcanism increasing its absorption"

How can vulcanism increase absorption of CO2?

Furthermore, the CO2 levels dropped sharply because the temperatures dropped sharply. You are clinging to the outdated myth that Al Gore made popular. You are very dogmatic.
I was relating what it said on the Wikipedia page. The vulcanism increased silicates which absorbed carbon dioxide. I severely doubt that you can provide any evidence from that era concerning the timing of carbon dioxide levels and temperature.

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@deepthought said
I was relating what it said on the Wikipedia page. The vulcanism increased silicates which absorbed carbon dioxide. I severely doubt that you can provide any evidence from that era concerning the timing of carbon dioxide levels and temperature.
Yes, but it says CO2 levels dropped from 7,000 ppm to 4,400 ppm. That is 4000 ppm more than today.

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@metal-brain said
Yes, but it says CO2 levels dropped from 7,000 ppm to 4,400 ppm. That is 4000 ppm more than today.
I'd be a little wary of that figure as they give the average as 4400 ppm, the same figure for the Silurian, and the Cambrian. I'd want a better source before drawing conclusions.

Note also that a vast amount of the world's landmass covered the South Pole and the reflective cooling due to the associated icesheet would tend to offset the warming effects of carbon dioxide.

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@metal-brain said
"I don't see it helping his "no global warming here" position."

I have never said there is no global warming. Learn to read.

"vulcanism increasing its absorption"

How can vulcanism increase absorption of CO2?

Furthermore, the CO2 levels dropped sharply because the temperatures dropped sharply. You are clinging to the outdated myth that Al Gore made popular. You are very dogmatic.
https://www.nytimes.com/2018/12/07/science/climate-change-mass-extinction.html

Here is the latest on the Permian extinction event, now thought to be due to the oceans' O2 level dropping to the point that those animals could not breathe.

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@deepthought said
I'd be a little wary of that figure as they give the average as 4400 ppm, the same figure for the Silurian, and the Cambrian. I'd want a better source before drawing conclusions.

Note also that a vast amount of the world's landmass covered the South Pole and the reflective cooling due to the associated icesheet would tend to offset the warming effects of carbon dioxide.
Is there another source? I'm surprised there are any accurate estimates that far back in time at all.

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@sonhouse said
https://www.nytimes.com/2018/12/07/science/climate-change-mass-extinction.html

Here is the latest on the Permian extinction event, now thought to be due to the oceans' O2 level dropping to the point that those animals could not breathe.
It just goes to show that nature is and always has been the main source of climate change and man cannot cause extinctions on a scale even close to nature with CO2 emissions alone.
The article is ridiculous to assert we are doing the same thing. Just silly.

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@Metal-Brain
What makes you think there is not a mass extinction going on right now?

This is fake news?:

https://www.livescience.com/47046-earth-enters-sixth-mass-extinction.html

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@sonhouse said
@Metal-Brain
What makes you think there is not a mass extinction going on right now?

This is fake news?:

https://www.livescience.com/47046-earth-enters-sixth-mass-extinction.html
I think you should drop the word "mass". It is a man made extinction event that has nothing to do with AGW. It is a mild extinction event in relation to the Permian mass extinction event.

No parallel at all. Not even close.

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@Metal-Brain

It ain't over till it's over. So you have no empathy for the ones lose. Every species gone reduces the genetic diversity which is what gives the planet its resilience to stresses.

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@sonhouse said
@Metal-Brain

It ain't over till it's over. So you have no empathy for the ones lose. Every species gone reduces the genetic diversity which is what gives the planet its resilience to stresses.
Other species would evolve to take their place in time if that happened like always happens after every extinction event. In a way it makes life more adaptable in the end.
You are making a mountain out of a molehill though. Nothing that bad is resulting from GW. You are blaming GW for extinctions when GW has nothing to do with it.

This is what you are doing:

Blame "x" for "y" and pretend it is the same thing when it is not. Is that logical?

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@metal-brain said
This is what you are doing:
Blame "x" for "y" and pretend it is the same thing when it is not. Is that logical?
wtf?
Do you know what logic is?

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