Peter Ward, Robert Scribbler, and others have de facto been collaberating on a hypothesis that current climatic conditions strongly resemble those of the end Permian "Great Dying", and that we are headed toward the same conditions. Although easily refuted, this idea has been recently spreading among climate-fanaticists, and receiving more publicity than it deserves.
Some of their work can be found at http://robertscribbler.com/2014/01/21/awakening-the-horrors-of-the-ancient-hothouse-hydrogen-sulfide-in-the-worlds-warming-oceans/, http://robertscribbler.com/2013/12/18/through-the-looking-glass-of-the-great-dying-new-study-finds-ocean-stratification-proceeded-rapidly-over-past-150-years/, and other links contained within.
Let's proceed to the important facts, which punch holes in this speculation.
At present, our atmosphere contains ~ 300 billion tons of CO2. During the end-Permian extinction (the largest mass extinction in geohistory), a combination of massive volcanic activity (greatest we know of) and CO2-producing bacteria may have injected more than 40 times that much CO2 in a short period (http://www.bitsofscience.org/permian-triassic-mass-extinct…/), along with massive amounts of methane and sulfur dioxide, the latter a deadly gas. This resulted in "a doubling of carbon dioxide levels from 2,000 parts per million to 4,400 ppm [11 times today's levels]." (http://thinkprogress.org/…/doubling-of-co2-levels-in-end-t…/) This would have risen the global temperature then from 6-7 degrees above the present to 8.5 - 9.5 (my calculations; the article says three degrees), although whether this is pertinent is uncertain.
.
According to
current theories, the combination of very high CO2, along with SO2,
would have caused the ocean depths to become anoxic (lacking oxygen,
like the Black Sea today). This in turn would have lead to enormous
blooms of hydrogen sulfide (also highly toxic) producing bacteria in those depths,
which, along with SO2 and the higher temperatures, exterminated almost
all life in the sea and on the land.
AGW/CC enthusiasts have been unable to resist drawing parallels with current conditions; and indeed, there is a partial, superficial resemblance. But just as clearly the numbers aren't remotely close (nor does any trend extrapolation lead to such a situation); also, the Earth's continents were all joined at the time, changing oceanic and atmospheric currents in many ways which could have made the extinctions worse.
Please, give it up already.
AGW/CC enthusiasts have been unable to resist drawing parallels with current conditions; and indeed, there is a partial, superficial resemblance. But just as clearly the numbers aren't remotely close (nor does any trend extrapolation lead to such a situation); also, the Earth's continents were all joined at the time, changing oceanic and atmospheric currents in many ways which could have made the extinctions worse.
Please, give it up already.
