Bloomberg: United Nations emissions trading needs to be less "patchy" to win U.S. backing, an EU official said today at the Carbon Market Insights conference in Copenhagen. The UN clean development mechanism, the second-biggest emissions trading market, "needs to be administratively less cumbersome" and "more ambitious," said Jos Delbeke, deputy director general of the European Commission’s environment unit. The U.S., the world’s biggest polluter, didn’t ratify the only international …