The article seems to define 'catastrophe' as corresponding to the alarmist scenario that Lovelock was previously pushing, though many of us might think that a scenario where only a small fraction of the current human population survive as being a bit stronger than just being a catastrophe.
There is an interesting switch in the BBC's terminology in describing Lovelock. He has now become a 'scientific maverick', which is really what he was all along, but their new use of the term seems to imply they want him to be seen as having less credibility than before.
Previously when Lovelock was pushing the more alarmist scenario (and therefore serving the Green agenda) the BBC often exaggerated his status. For example in this article from 2004 Lovelock is referred to as 'Professor Lovelock' all the way through the article. (he isn't a professor, he's a self-employed scientist who has worked from home since the 1960s).