Keep in mind that if any subtype of the population is growing exponentially, then the whole population will also grow exponentially in the asymptote. I'd be hesitant to disagree with Hawking on this.
Not me. I'm always amazed at the things otherwise brilliant people say when they're out of their area of expertise. There was a reason we didn't reach Erlich's 20 billion by the year 2000, even though we could probably grow enough food to support that many.