Associated Press: Former British Premier Tony Blair says the key to a global climate change agreement will be a deal between the U.S. and China — the world’s largest polluters. Blair says the agreement to be concluded in Copenhagen in December must have goals for reducing greenhouse gases by 2020. The Obama administration has said it doesn’t want the kind of binding 2020 targets being discussed at U.N. negotiations. Blair said Friday Obama has adopted ambitious goals, but the U.S. has a …