This is the worst idea I’ve ever heard and I have many reasons, replete with citations!

Ahahaha, this is probably the most the most reasonable take here!

could reply that eating food falls well within a communist system, therefore you can’t blame communism for famines.

Try again when you’re sober, that’s not a particular cogent argument.

A carbon tax falls well within a capitalist system (much the same as any other tax or method of dealing with externalities) so I’d put that as a failure of democratic systems more than anything.

I’m also not convinced communism would actually solve the problem. Communists have historically been pretty reluctant to share bad news, from letting folks know about mass starvations to, oh, most of the world news in China.