Thursday, September 23, 2010

CO2 levels have been 10 to 20 times higher than the present during multiple periods of Earth's history without causing a 'tipping point' of no return'

'An entire ice age came and went with CO2 levels about 11 times higher than the present throughout the Ordovician period' -- 'Antarctica abruptly transitioned from a warm, subtropical hothouse to the present solid ice sheet during a period when CO2 levels exceeded those of today by 10 times'