Here is a graph covering the last 600 million years that I find interesting. If the climate reacts to CO2 with positive feedback, why didn't it superheat when CO2 was as much as 20 times current levels back in the Cambrian or 6 times current levels during the Jurassic? Current CO2 (350ppm) is lower than for most of earth's history. And we are in a general ice age climate unlike most of earth's history. How can one look at this graph and believe the current global climate computer models? Is this graph wrong, or are the computer simulations wrong? I question the global climate models that can't explain the temperature decline from the 1930s to 1970s.
