Reuters: A U.S. plan to cut greenhouse gas emissions from power plants is not enough to achieve its goals for limiting climate change, and all nations will need to significantly step up actions to curb warming, a group of scientists said in a report on Wednesday. Washington announced plans on Monday to cut emissions from power plants by 30 percent below 2005 levels by 2030, as the centerpiece of a U.S. policy to fight climate change. Niklas Hoehne, of Ecofys - joint compiler of the Climate Action Tracker...