The President spoke with President Hu on Tuesday night, October 20. They exchanged views on bilateral issues and climate change. Both leaders acknowledged each is taking significant actions to confront climate change and reduce emissions. President Obama noted the importance of working toward a successful outcome at the December Copenhagen Conference and the importance of leadership from the United States and China in that regard.
To that end, the two Presidents committed to having their teams redouble efforts to work with each other and other countries to achieve success at Copenhagen.
Barack Obama, Readout of the President's Call With Chinese President Hu Jintao Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/289917