Science Daily - The Permian Extinction May Have Been Triggered By Sudden, Massive Carbon Release

[hatrack]

EDIT

In the July issue of the Geological Society of America Bulletin, Payne presented evidence that a massive, rapid release of carbon may have triggered this extinction. "People point to the fossil record as a place where we can learn about how our actions today may affect the future course of evolution," Payne said. "That's certainly true: The deep geologic record provides context for modern events. We may miss very important processes or underestimate the magnitude of changes in the future by using only the past couple thousand years as a baseline."

EDIT

More than 90 percent of all marine species disappeared from the Great Bank of Guizhou and other end-Permian fossil formations 250 million years ago. Land plants and animals suffered similar losses. Douglas Erwin, curator of the Paleozoic invertebrates collection at the Smithsonian National Museum of Natural History, has dubbed this event "the greatest biodiversity crisis in the history of life." An unusually long period of time passed before biological diversity began to reappear. Scientists disagree on the causes of this extinction. However, nearly all explanations cite the high levels of greenhouse gases, including carbon dioxide, low levels of oxygen in the oceans and high levels of toxic gases.

Siberian traps

In 1991, scientists reported that the largest known volcanic event in the past 600 million years occurred at the same time as the end-Permian extinction. Magma extruded through coal-rich regions of the Earth's crust and blanketed a region the size of the continental United States with basalt to a depth of up to 6 kilometers. The eruptions that formed the Siberian Traps not only threw ash, debris and toxic gases into the atmosphere but also may have heated the coal and released vast quantities of carbon dioxide and methane into the atmosphere.

Rapid release of these greenhouse gases would have caused the oceans first to become acidic and then to become supersaturated with calcium carbonate. In the July Bulletin, Payne presents evidence that underwater limestone beds around the world eroded at the time of the end-Permian extinction. This finding, coupled with geochemical evidence for changes in the relative abundances of carbon isotopes, strongly suggests an acidic marine environment at the time of the extinction. The rock layers immediately covering this eroded surface include carbonate crystal fans, which indicate oceans supersaturated with calcium carbonate. "This end-Permian extinction is beginning to look a whole lot like the world we live in right now," Payne said. "The good news, if there is good news, is that we have not yet released as much carbon into the atmosphere as would be hypothesized for the end-Permian extinction. Whether or not we get there depends largely on future policy decisions and what happens over the next couple of centuries."

EDIT

http://www.sciencedaily.com/releases/2007/08/070809104722.htm

[phantom power]

1. It makes my heart swell with pride...

to know that we're actually competing with a continent-sized supervolcano.

Go humans! Go humans!
:bounce:

[Dead_Parrot]

5. Gives you a warm feeling, doesn't it?

Just like a freshly laid dog-turd.

[GliderGuider]

2. That's related to the "Green Sky" stuff we talked about yesterday

A big question for me is whether the rate of injection of CO2 into the atmosphere is a factor as well as the ultimate volume of CO2. Peter Ward makes the point in his book that the world could adapt to a much larger rise if it was slow, gaving biological mechanisms more time to mitigate it. A much more rapid rise could overwhelm those mechanisms even if the total input was smaller. The reason this is an issue is that Ward claims in his book that the CO2 rise is 100 (not 60 as I said yesterday) times faster than that seen during the Permian extinction.

Another critically important question that needs to be answered is what role a disruption of the thermo-haline circulation may have played in the creation of these toxic oceans. The global conveyer may have been shut down by rapid global warming that caused the injection of large amounts of fresh polar melt water into the ocean at a critical point in the circulation - the polar downwelling points. Although I don't know enough oceanography or climatology to draw informed conclusions, the shapes of the pieces match too well for my comfort.

[OKIsItJustMe]

3. Original Article (Subscription Required)

http://www.gsajournals.org/perlserv/?request=get-document&doi=10.1130%2FB26091.1

[OKIsItJustMe]

4. NOVA Science Now

Ran a fairly good piece on this theory last November. You can watch it on-line.
http://www.pbs.org/wgbh/nova/sciencenow/3318/01.html

[truedelphi]

6. Thanks for this link on the weather collapse n./t

[bahrbearian]

7. Thanks for the Link. N/T

[OldTymeDem]

8. So What?

So mother nature was just doing its thing....

[GliderGuider]

9. So this

Pick up paleontologist Dr. Peter Ward's recent book "Under a Green Sky". He makes a pretty good case that if we keep on pumping out the CO2 at the rate we are it will do more than just raise the sea a few feet. We may be on the road to a do-it-yourself Permian extinction.

That's so what.