Some say it is because CO2 is the biggest contributor to global warming. Not quite right! Other GHGs such as methane (CH4) and nitrous oxide (N2O) are equally potent.
In fact, the global warming potential (GWP) for CO2 is just one, whereas GWP for CH4 and N2O are 28 and 265, respectively.
Meanwhile, naturally occurring GHG such as from water vapour, which is...