“I think that the problem is a classic economic problem of tragedy of the commons—the fact that any one country is going to benefit if other countries reduce carbon emissions but is going to suffer when it itself does means there's always a tendency to want other countries to lead the way. Since the industrial revolution began, the US point of view is that we can't get anywhere unless India and China reduce carbon emissions, while India and China say if you look over the last one hundred years, the US is the one who put out all the carbon, and we're just finally getting a little bit richer and you want to cut us off at the knees.

There are arguments to be made on both sides, but the fundamental impediment is that 10 years ago, it just seemed really hard to see how we were going to get out of climate change and disastrous consequences, but r ...