No, direct retention of radiated infrared energy is vary important. There are plenty of feedback cycles, but they don't all warm the planet so it really does take a lot to shift each of those 0.1C increases. People are directly responsible for ~1/4th of all carbon dioxide in the atmosphere which is not exactly a minor change. (We are around 391ppm and adding a little over 2pmm / year.)
> People are directly responsible for ~1/4th of all carbon dioxide in the atmosphere which is not exactly a minor change.
That huge change in CO2 is not a huge change in the atmosphere's ability to retain energy because (a) CO2 concentrations are fairly low and (b) other gasses have a much larger effect.
Note that the atmosphere's ability to retain energy is not dependent on where the CO2 comes from.... I mention that because the earth has had much higher CO2 concetrations.
