New York City's mayor Michael Bloomberg took climate change out of the closet on Thursday by invoking the issue in his endorsement of Barack Obama.
The stunning snub to Mitt Romney, in the wake of Hurricane Sandy, at a stroke turned climate change from liability into a potentially winning political issue in this presidential election.
It might even embolden other Republicans, who do support action on climate change, to come out of the closet as well. At least, that seems to be partly Bloomberg's intention.
"The devastation that Hurricane Sandy brought to New York City and much of the north-east - in lost lives, lost homes and lost business - brought the stakes of next Tuesday's presidential election into sharp relief," Bloomberg wrote.
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Our climate is changing. And while the increase in extreme weather we have experienced in New York City and around the world may or may not be the result of it, the risk that it may be - given the devastation it is wreaking - should be enough to compel all elected leaders to take immediate action."
Businessweek, which is owned by Bloomberg, made the point even more trenchantly with a cover reading: "It's global warming, stupid."