Agence France-Presse: The top US climate negotiator said Tuesday he was more optimistic about reaching a new global warming treaty this year after two days of talks in Washington among major economies. “I come out of this meeting a bit more optimistic,” climate envoy Todd Stern told reporters after the talks. Representatives from 18 major economies met for two days in Washington to help lay the groundwork for December’s conference in Copenhagen which is meant to approve a new global treaty on …