Is CO2 the only greenhouse gas, or even the primary one?
C02 is not, by far, the largest of the greenhouse gases in the atmosphere.
Deniers use this as a tool to confuse people.
It’s easy for them to hide from reality behind these red herrings. They shoot out a bunch of links they’ve found to comfort themselves, to convince themselves that their willful ignorance is the correct choice for them.
So, if water is the largest greenhouse gas in the atmosphere does that mean that C02 can’t be causing our current rapid, unwanted global warming?
No.
It’s a meaningless red herring, useful to people trying to avoid reality.