This is not an interview specifically about the information he's researched and presents so lucidly in his famous long presentations, and in his many books - all of which are packed with references, anecdotes and encyclopaedic detail. It's more about the man behind his mission; what makes him tick, and what keeps him going; the source of his inner resolve; and, notably - anyone who mistakes David for a doomsayer, take note - his vision for Planet Earth: "The idea that this might not all have a successful outcome", he told us, "Never occurs to me."