Grist: So, I`ve got good news and bad news.
The good news: There is no substantial technical or economic barrier that would prevent the U.S. from reducing its greenhouse gas emissions 80 percent below 1990 levels by 2050, a target that would help put the world on track to limit global average temperature rise to 2 degrees Celsius. In fact, there are multiple pathways to that target, each involving a different mix of technologies. Achieving the goal would cost only around 1 percent of GDP a year out through...