On Wed, 15 May 2013 10:18:42 +0100, "Alastair McDonald"
wrote:
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But there is a greater danger. Here you can see another chart of temperature
against CO2 over the last 600 M yrs
http://deforestation.geologist-1011....mperatures.png
where the temperature makes step changes. That is my concern. Will CO2 pass
a tipping point where after a period of stability the global temperature
then jumps into a new extreme state.

What is causing the the leveling around 22C when the CO2 level
reaches very roughly 1000 ppm or higher? Why don't further increases
rise the temperature any higher?
Is it all snow/ice gone therefore no possibility to further reduce the
reflection of solar energy into space by white surfaces?

Bjørn Sørheim