One of Bell’s favorite techniques in his opinion pieces is the Gish Gallop, where the point is to score a rhetorical win by utilizing Brandolini’s law or the bullshit asymmetry principle, i.e. by swamping anyone who disagrees with nonsense PRATTs. So Bell will tell you e.g. that climate has changed before (true but irrelevant), that NASA studies report that the oceans are entering a new cooling phase (they don’t – hint: that an article contains the phrase “ocean cooling” in the headline doesn’t mean that it purports to show that the oceans are cooling; you ought to read beyond the headline), that the sea level hasn’t risen (simply wrong), that he Northwest Passage has been open before (not in recorded history), that Greenland ice caps have accumulated and snow growth (which is true, but predicted by warming – the major issue is the loss of ice at the edges), and so on, and so on. There is a good takedown of one of his efforts here (another representative example is mentioned here).
In 2017, Bell was one of the signatories of a petition organized by Richard Lindzen (https://rationalwiki.org/wiki/Richard_Lindzen) urging President Trump to pull the US out of the United Nations international convention on climate change. Lindzen desicribed his list as containing signatures from “more than 300 eminent scientists and other qualified individuals”. Bell, being not remotely a climate scientist, is presumably representative for that list of characters. Bell is also a recurring speaker at the Heartland Institute’s International Conferences on Climate Change, e.g. in 2014.
Diagnosis: A not completely insignificant force in the denialist circus. Though the denialism of many of his associates is obviously ideologically motivated, Bell often comes across more as a kind of Giuliani to the industry giants to whom climate change is really annoying. And no, he is not, by any stretch of imagination, an expert on climate.