[Phil153]

I disagree that they vary a lot. The all go in the same direction and are within a fairly narrow range.

Simple question for both doubters and proponents.

I'm on an earth-sized planet orbiting around a stable star with a global temperature of 10 degrees celcius. The surface is bare and the atmosphere is composed of oxygen and nitrogen. The current CO2 concentration is 300pmm. Ok, here's my question:

If I increase the carbon dioxide level to 450 ppm, how much will the temperature increase?