According to various reports, Obama is making a speech today (Tuesday) in which he will announce limits on carbon dioxide emissions from existing power plants. These limits can be imposed by regulation, and are justified by court decisions requiring the Environmental Protection Authority to control greenhouse gas emissions.

Obama has been a disappointment in all sorts of ways, but effective action on climate change would be sufficient, for me, to redeem his presidency. None of the other things we are fighting about will matter unless there is a livable planet on which to fight.

Going from realistic hope to wishful thinking, a sufficiently positive reaction on this might give him the nerve to block the Keystone pipeline. But strong action on power plants would be enough for me – it’s really up to Canadians to stop the oil sands menace.