Bloomberg: When Barack Obama was elected president, he was heralded as a possible savior for climate- treaty talks that had dragged on for years while George W. Bush rejected limits on U.S. greenhouse-gas emissions. “America is back” at the United Nations negotiating table, Democratic Senator John Kerry declared after the November election. Danish climate minister Connie Hedegaard said U.S. emissions policy moved forward 35 years overnight. Instead, Obama may send empty-handed envoys in …