President Obama , Chinese leader pledge to work to reduce carbon emissions . Move comes before referendum . Climate Change Conference in Denmark . `` As the two largest consumers and producers of energy , there can be no solution to this challenge without the efforts of both China and the United States , '' Obama said . China and Denmark are largest producers of greenhouse gases . Obama , Chinese President Hu ##an do n't have a timetable .
President Obama , Chinese leader pledge to work to reduce carbon emissions . Move comes before referendum . Climate Change Conference in Denmark . China and Denmark are largest producers of greenhouse gases . Obama , Chinese President Hu ##an do n't have a timetable .