Bloomberg: President Barack Obama will attend climate-change talks in Copenhagen next month, offering an emissions-cut goal of about 17 percent by 2020 after legislation to reduce greenhouse gases stalled in Congress. The president will travel to the Danish capital on Dec. 9 during the first week of negotiations for a new treaty to replace the Kyoto Protocol, which expires in 2012, White House spokesman Robert Gibbs told reporters today. Obama will then accept the Nobel Peace prize in nearby …