New York Times: DURING the presidential campaign of 2008, Barack Obama distinguished himself on the economics of climate change, speaking far more sensibly about the issue than most of his rivals. Unfortunately, now that he is president, Mr. Obama may sign a climate bill that falls far short of his aspirations. Indeed, the legislation making its way to his desk could well be worse than nothing at all. Let’s start with the basics. The essential problem of climate change, scientists tell us, is that …