David Mitchell is one half of the brilliant British comedy team that makes the show "That Mitchell and Webb Look", which commonly has skeptical themes to its humor. Mitchell has a series of short videos posted on The Guardian, and he made one about global warming that, like everything he does, is fantastic. They don’t allow embedding — hey Guardian, it’s the 21st Century now! — so I’ll just link to it and let you have a look.
Tip o’ the thermometer to Arthur Taylor.