Adhityani Arga: Governments hailed a deal on Saturday to start negotiations to adopt a new climate pact, but environmental groups said the agreement lacked teeth. The deal binds the United States and China to greenhouse gas goals for the first time and a two-year agenda would lead to the adoption in Copenhagen in 2009 of a tougher, wider pact to succeed the Kyoto Protocol after 2012. “This is the defining moment for me and my mandate as secretary-general,” U.N. Secretary-General Ban …