Reuters: U.S. President Barack Obama should do much more to ensure Congress passes a greenhouse emissions bill, giving global climate talks a major boost, the head of the U.N. Climate Change Panel said on Thursday. Rajendra Pachauri, whose panel shared the 2007 Nobel Peace Prize with former U.S. vice president Al Gore, said legislation clarifying U.S. emissions targets would make all the difference to a climate conference in Copenhagen in December. “I personally feel that he ought to be …