My students were debating amongst themselves and one of them said that (something) which I can't remember was the cause of global warming.
I responded by saying that disposable diapers cause global warming.
They were puzzled. Finally one of them asked if my son wears disposable diapers, and I said that he did not--he wears washable diapers.
"Washable diapers? Wow! I guess they're coming up with new stuff all the time--what will they think of next?"