I can't find a statement in the article that he didn't get funding for a show to attack global warming.

The sad fact is that since I said I didn’t believe human beings caused global warming I’ve not been allowed to make a TV programme.

That sounds different to me. If he didn't get funding for a show because BBC thought the topic wasn't part of his core competences, that's just fair enough.

If he didn't get funding for a show unrelated to the topic of global warming because of his opinion, then it's a witch hunt.