cliff is an expert but also famously sort of a "climate contrarian" and his takes are regularly cited by climate skeptics and conservative irritants here in the PNW. just noting his takes don't exist in a vacuum.
Cliff in an expert, he worked in the Obama administration on climate, and unsurprisingly, he is being cited for having opinions the support the thesis of the article.
anyway if anything it would probably be poisoning the well. really though it's just pointing out that cliff isn't a garden variety climate scientist and comes with something like a warning label.