These days CO2 is actually quite commonly used in air-conditioners as a refrigerant, R-744. Fluorinated gases like Freon are being phased out due to being even worse for global warming.

▲

mark-r 3 hours ago | parent [-]

I thought it was ozone depletion, not greenhouse effects, that led to the fluorinated gas phaseout?

	▲	ajb an hour ago \| parent [-]
		The original ones yes. They are already banned - but the next generation of fluorinated refrigerants are apparently ok for the ozone layer but have a greenhouse effect. That's my understanding anyway, I'm far from an expert. Edited to add: https://en.wikipedia.org/wiki/Kigali_Amendment has some information on this.