Scientific American has scary news for you.Click here for Article
Mass extinctions in the past are linked to CO2 going over 1000 ppm (parts per million). They are now around 400 ppm, and predicted to rise at 3 ppm or better.
When CO2 is over 1000, Hydrogen Sulfide (H2S) is released in quantities that kill all oxygen based life (That's YOU, baby!)
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When they do, the atmosphere becomes unbreathable (stinky smell of feces, toxic) , and both plants and animals die. That's you and me. Mother Earth farts in a small room. You ever read stories about fat people farting themselves to death in a small unventilated hotel room? (yes, I know, methane is not H2S, but the analogy is so apt...)
In 2004 Bloomberg News Service reported how an obese man who was teased by his relatives for his excessive flatulence shut himself up in his room after a meal of corned beef, beans and cabbage. The next day he was found dead and was declared to have died as a consequence of breathing in methane produced by his own body. Three of his rescuers were taken ill and one was hospitalised.
The interesting part is the graphs correlating previous mass extinctions with the rises in CO2. They're not in the print article, but they look pretty conclusive. Learn a new word: chemocline.
Most troubling, however, is the question of whether our species has anything to fear from this mechanism in the future: If it happened before, could it happen again? Although estimates of the rates at which carbon dioxide entered the atmosphere during each of the ancient extinctions are still uncertain, the ultimate levels at which the mass deaths took place are known. The so-called thermal extinction at the end of the Paleocene began when atmospheric CO2 was just under 1,000 parts per million (ppm). At the end of the Triassic, CO2 was just above 1,000 ppm. Today with CO2 around 385 ppm, it seems we are still safe. But with atmospheric carbon climbing at an annual rate of 2 ppm and expected to accelerate to 3 ppm, levels could approach 900 ppm by the end of the next century, and conditions that bring about the beginnings of ocean anoxia may be in place. How soon after that could there be a new greenhouse extinction? That is something our society should never find out.