Today Obama announced carbon cuts for existing power plants. Many environmentalists are cheering this move, but even these limits leave society in a kind of climate-change limbo. The rules will chop emissions by 30 percent over 2005 levels by 2030. A paper published last year by Dutch scientists estimates that countries like the United States need to cut carbon by as much as half below 1990 levels by 2020 just to have a decent chance of staying within a 2-degree Celsius threshold of warming. For the past couple of weeks, I’ve spoken with climate scientists modeling the impacts of global warming all over North and Central America. They are now able to paint an ever more specific, vivid, and dire picture, via advances in climate modeling. The hotter we get (the further above 2 degrees), the more dramatic and frightening the future looks—more fires, more forests dying off in the Rockies, more water shortages, higher sea-level rise. Is it enough for the rest of us to begin doing our own calculations about the risks, choices, and sacrifices we’re facing?