repeating the joke

No Impact Man has asked for some eco-jokes, so I've put up my lightbulb one. I first wrote about why there were no jokes about climate change here and ended the piece with a lightbulb joke I'd just made up. A few months later The Guardian included it in their six best eco-gags (if that doesn't prove the shortage, nothing does). My one went:

Q: How many climate sceptics does it take to change a lightbulb?
A: None. It's too early to say if the lightbulb needs changing.

This got picked up by Hot Topic and Deltoid and lots of people added their own variations. Here's a pared-down selection of the others:

Q: How many climate sceptics does it take to change a lightbulb?

A: None. It's more cost-effective to live in the dark.
A: None. We only know how to screw the planet.
A: None. Changing lightbulbs is for engineers.
A: None. Eventually the lightbulbs will right themselves.
A: First we need more research and we need more research about what that research will be.
A: I can't hear you! I can't hear you! I can't hear you!

Can jokes have an impact? Joe Smith, co-author of Do Good Lives Have To Cost The Earth? says it's important to lighten things up. Cartoonists tackle climate change here. The role of jokes in defeating communism is discussed here.