Some more thoughts added above:

Yep, he threw down the gauntlet, all right, but there’s a huge obstacle in the way of climate change action: a Republican Party that is utterly lost in a cloud cuckoo land of anti-science denial.

The Luddites of the right wing have totally convinced themselves that the world’s scientists are pulling an evil hoax on them; this delusion is fed and sustained by many millions of dollars worth of anti-science propaganda from a fossil fuel industry that benefits from the status quo. If President Obama is serious about taking action on this all-important issue, he’ll have to find a way to either reach these appallingly closed minds, or circumvent their efforts to sabotage him.