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Global Anoxia Ruled Out As Main Culprit In the P-T Extinction
Garin writes "The late Permian saw the greatest mass extinction event of all-time. The causes for this extinction are hotly debated, but one key piece of the puzzle has recently been revealed: while the deep-water environments were anoxic, shallower waters showed clear signs of being oxygenated. This rules out global anoxia, and strongly suggests that other factors, such as the Siberian Traps vulcanism, must have played a dominant role. From the article: 'Rather than the direct cause of global extinction, anoxia may be more a contributing factor along with numerous other impacts associated with Siberian Traps eruption and other perturbations to the Earth system.' See the full research article (behind a paywall) here."
The meteorite in the Yucatan was at the end of the Cretaceous period, they are referring to a proposed impact over 400 million years earlier due to some discoveries of a potential 300 mile wide impact crater in Antarctica... The Cretaceous extinction even only killed off about 75% of species as compared to 90% being killed off in the extinction that this article is about.
Apparently, the super volcano in this case erupted for nearly a million years, warmed the oceans to 100 degrees F and forced all organic growth (as measured by coal deposits) to the poles. Whether caused by an impact or mantle event, it would be incredibly destructive to any 'society' living on the planet
Sure, read Skeptical Science. Those quoted figures are from one single location and may not reflect what was happening elsewhere. This site is an excellent example of good science and they have extensive responses to the common denier arguments. I would recommend spending some time there.
Also, keep in mind that the issue is what is forcing the increase. The 400PPM is not going away in our lifetime nor our grandchildren's lifetime. This problem will get worse not better. And of course 12,000 years ago the population was a lot smaller. The total world population probably never exceeded 15 million inhabitants before the invention of agriculture so with 7 Billion people alive today the impact of a warmer environment is likely to be higher than it was 12,000 years ago.
Over-zealous potty training can be lethal.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."