S. Franck, C. Bounama, and W. von Bloh
Potsdam Institute for Climate Impact Research, Potsdam, Germany
Abstract:
We present a minimal model for the global carbon cycle of the Earth containing the reservoirs mantle, ocean floor, continental crust, biosphere, and the kerogen, as well as the combined ocean and atmosphere reservoir. The model is specified by introducing three different types of biosphere: procaryotes, eucaryotes, and complex multicellular life. During the entire existence of the biosphere procaryotes are always present. 2 Gyr ago eucaryotic life first appears. The emergence of complex multicellular life is connected with an explosive increase in biomass and a strong decrease in Cambrian global surface temperature at about 0.54 Gyr ago. In the long-term future the three types of biosphere will die out in reverse sequence of their appearance. We show that there is no evidence for an implosion-like extinction in contrast to the Cambrian explosion. In dependence of their temperature tolerance complex multicellular life and eucaryotes become extinct in about 0.8–1.2 Gyr and 1.3–1.5 Gyr, respectively. The ultimate life span of the biosphere is defined by the extinction of procaryotes in about 1.6 Gyr.
This is the paper[1] that is by and large the cornerstone of Ward's book, The Medea Hypothesis. I'm chewing my way through what it means since I have finished the book. There are some troublesome assertions in there that I think ought to be brought a little more to light. I truly do not know how many people have been thinking about, commenting on, supporting or dismissing the whole Medea Hypothesis. So, I do know some of the paleo blog community reads here, so I m going to air some thoughts and see where and what I get smacked for...or who has similar qualms. There will be a flurry of relatively light weight posts as something of a point, but point basis over the next week. I truly hope that I get some discussion going. If you are going to join in, grab the paper and read. Please.
1. Available for free here. Hat-tip, Neil. Thank you.
PS. The Medea Hypothesis actually counts as a YAGUMET. *sighs* We will not get to Ward's Medea Hypothesis until at least Tuesday, possibly Wednesday. We're going to go over Franck et al's paper first. Without Franck et al's paper, its model, and its conclusions, Ward's stuff harder to grapple with: the book felt like there was a lot of assumption going on that we, the readers, were not privy to.
PPS I need a new label/keyword for this week's discussion. Suggestions?
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