Krugman appears ignorant of the actual contents of the leaked emails. There is clearly a smoking gun. Krugman wouldn't recognize a smoking gun if he had a flaming howitzer stuck up his butt.
From the video:
Krugman: "All those e-mails, people have never seen what academic discussion looks like, there's not a single smoking gun in there, there's nothing in there, the travesty is people are not able to explain why the fact that 1998 was a very warm year, doesn't actually mean that global warming has stopped"