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.
I think there are loads of people who take it seriously but can't do anything about it. The biggest CO2 polluters are mega corporations and things like airplanes and cargo ships. Ordinary people can't fight that. One family living off the grid and producing zero CO2 won't help anything.
Ergo, most people are apathetic, as they should be. You're not going to change the minds of governments and mega corps.