On Mar 1, 10:32 pm, FlyBird <[email protected]> wrote:
> > "We found that the likely culprit was a major drop in greenhouse gases in
> > the atmosphere, especially CO2. From the temperature data and existing proxy
> > records indicating a sharp drop in CO2 near the Eocene-Oligocene boundary,
> > we are establishing a link between the sea surface temperatures and the
> > glaciation of Antarctica."
>
> I don't get it, what would cause that sharp a drop in CO2
> concentrations. How do they know the CO2 drop was the cause of the
> Global Cooling?
The CO2 drop was due to either the evolution of grasses, which can
function at lower CO2 levels, or the erosion of the new Himalayas
mountain range which can drawdown atmospheric CO2.
It was not necessarily a sharp drop in CO2. A slow fall would have
suddenly led a sharp growth of the snow cover due to the ice albedo
effect.
CO2 is a greenhouse gas and if you have less of it you will get
cooling.
> Maybe an asteroid hit or volcanic activity could have blocked out the
> sun, and the after effects could have been the drop in CO2?
There would have been evidence for the asteroid: a crated or iridium
layer, and the same with volcanic activity, but neither would have had
a permanent effect.
Cheers, Alastair.
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