Bloomberg: The deal struck by United Nations envoys this week to fight climate change gives the biggest polluters three options for a wider agreement by 2015, setting the stage for renewed discord between rich and poor countries. Negotiators from more than 190 nations agreed Dec. 11 to spend up to four years drafting a "protocol, legal instrument or an agreed outcome with legal force' to take effect by 2020. While the European Union says that calls for a treaty to limit fossil-fuel emissions in all countries,...