Carbon Dioxide is not a strong greenhouse gas, the spectrum of absorption/re-radiation for it is not all that broad, and therefore the graph of its increase in the atmosphere relative to warming is logarithmic.... Most of the warming is already "baked in" and as more is added there is exponentially diminishing returns. Even if CO2 were 4-5x its current levels warming would not increase much more than it must given current trajectories.

Carbon Dioxide is not a strong greenhouse gas, the spectrum of absorption/re-radiation for it is not all that broad, and therefore the graph of its increase in the atmosphere relative to warming is logarithmic.... Most of the warming is already "baked in" and as more is added there is exponentially increasing diminishing returns. Even if CO2 were 4-5x its current levels warming would not increase much more than it must given current trajectories.