Appeal to authority is a fallacy. There is no authority in Science. Anyone can critique a paper. Content of the criticism is what matters, not the degree that the critic holds.
It is unfortunate that Science communication to "retail customer" too often appeals to authority. It is also unavoidable result of big business getting involved. Climate change is a lucrative billion dollar business now, where money mostly comes from governments and that attracts charlatans like fleas to manure.
It isn't a fallacy in the sense that it's useless. Appeal to authority and the closely-related ad hominem are useful arguments in practice, something like a heuristic.
It's true that an expert is more likely to give correct information than a non-expert, though it's not sufficient to prove or disprove the claims of either. In practice, you don't have time to give every claim from any source the same level of treatment, so you're probably going to "appeal to authority" when deciding whether to listen to your doctor or your aunt that's into woo.
Anyone can critique a paper but it is most definitely not the case that every critique carries the same impact. Peer review isn't done by randos for a reason.
Ok, now that's out of the way that leaves his only real public "critiques", such as they are, his interview with the Epoch Times, and his podcast with sacked SkyNews Australia journalist Chris Smith.
These are dealt with elsewhere at length and frankly riddled with demonstrably false claims by Clauser; he asserts that recent IPCC reports don't deal with clouds when they have chapters on them, he asserts models don't allow for cloud reflectivity when they in fact do, etc.
These are, embarrassingly, just long rambling examples of once distinguished old man yelling at clouds (literally) and proving only that has not read (or perhaps read and forgotten) the very source material he claims to debunk.
I believe (and by all means offer your thoughts) that the most generous interpretation here is that Clauser was riffing off of Richard Lindzen's 20+ year old thoroughly debunked Iris hypothesis that he (Clauser) hadn't really bothered to follow up on given it was all outside his ken.
I'm sure you're familiar with people that just mouth off objections to climate related science that they've half heard about but have never really looked at in detail . . .
We've all heard them .. some just have Nobel prizes for unrelated work.
It is unfortunate that Science communication to "retail customer" too often appeals to authority. It is also unavoidable result of big business getting involved. Climate change is a lucrative billion dollar business now, where money mostly comes from governments and that attracts charlatans like fleas to manure.