UN: No world climate deal until 2012?

Why would UN climate chief Yvo De Boer say this?

My guess he has a partial, but incomplete, eye on the US election calendar, among other things. He recognizes the US Senate won't pass a climate bill until midterm elections. But, will it pass one in its lame duck term? If so, just how weak will it be?

That said, I think he's right that little of substance will come out of the Cancun round, between a mix of the US electoral calendar and continued Chinese intransigence.