In short, we aren't on track to an apocalyptic extinction, and the new head is concerned that rhetoric that we are is making people apathetic and paralyzes them from making beneficial actions.
He makes it clear too that this doesn't mean things are perfectly fine. The world is becoming and will be more dangerous with respect to climate. We're going to still have serious problems to deal with. The problems just aren't insurmountable and extinction level.
His whole point is that we should try not to think that way. Not "this side" versus "the other side". There's an endless space between "we're already fucked no matter what" and "everything is perfectly fine no need to act". And that's the point.
And you can very much notice what he worries about already. People are already utterly numb to news about climate disasters. We need a better way to show issues and showcase solutions that makes people motivated and hopeful to keep everyone pulling in the same direction.