Countries are often gigantic though? There's plenty of state and local efforts going on in the United States despite the federal government currently backtracking for instance. Does that count as... worth burning tons of fossil fuels to bomb out of existence?

If they want to go to war over geoengineering efforts done by someone else, then yes.

They can sit on their asses, but going against people who actually try to do something to address climate change is a step too far.