The problem isn’t that someone has a BS in physics, it’s that they didn’t establish expertise in a relevant field – for example, a physicist grad who studied atmospheric physics or how the sun’s fluctuations affects temperature would have something relevant to say.
The trend is quite pronounced: people saying climate change is real and poses a serious threat have spent decades studying it but the multiple orders of magnitude smaller group of people dismissing it studied unrelated things, and demand to be treated as peers despite doing none of the actual work. For example, John Clauser is clearly highly intelligent and if you had a question about quantum entanglement or light particles he’s clearly qualified. However, he’s never published a paper related to climate change and his big argument is about one factor (cloud cover) which has been studied heavily and is incorporated in the models used by actual climate scientists to make predictions. Those predictions have a half century of increasing accuracy so any criticism would need to account for that, as well multiple other lines of evidence supporting the scientific consensus.
Most papers in climate change are not theoretical model heavy. They are empirical / methodology papers. If a graduate level Physics or Chemistry training does not equip one to read and understand what those papers are saying, then there is something seriously wrong with that graduate program or the person.
On the other hand, it is indeed hard for many scientists who do climate change work to understand or critique theoretical physics papers, which are mostly abstract algebra or topology papers these days.
I like to read IPCC tech section and papers referenced there and these are not, barring a few exceptions, hard to read.
To claim Nobel laureates in physics or chemistry cannot opine on these is absurd level of gatekeeping.
The statement made was not that John Clauser cannot express an opinion.
The opinion offered was that John Clauser's 60 odd years of work in Quantum mechanics don't magically make him authoritive or even well versed in the practicalities of cloud cover.
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.
I bet none of the experts on either side have BS/MS/PhD in Climate Sc.