Talks at the U.N. Climate Change Conference in Durban have entered their last official day, with focus now on a European Union-sponsored road map calling for a new climate treaty to be negotiated by 2015. The treaty would impose binding cuts on the world’s biggest emitters of the heat-trapping gases but would not likely go into effect until 2020. The E.U. plan has received support from key blocs at the talks, including a coalition of small island states and a grouping of the world’s least developed countries. But several of the world’s largest polluters, including the United States, China and India, have refused to back the deal so far.