mamooth
Diamond Member
Water vapor is quite abundant in the atmosphere, especially down in our Troposphere.
CO2 is (as a component part of the air around us) is NOT even REMOTELY as "abundant."
But they don't cover the same spectral frequency window, so the CO2 matters. Earth's atmosphere is pretty opaque over most of the longwave IR band. There aren't that many spectral windows in it to let the heat out, so squeezing down any of the open windows has an effect.
That is, if my house has 20 windows and 18 are closed (the water vapor), it still makes a significant difference in temp if I close the 19th window (CO2).