AP: China’s top climate change official said Wednesday that countries have little expectation of reaching a binding climate treaty this year but instead will focus on narrowing their differences ahead of the year-end summit in Cancun. Xie Zhenhua, vice chairman of the National Development and Reform Commission and China’s lead climate official, said China aims to bring countries closer together when it hosts a weeklong U.N. climate meeting in the port city of Tianjin, the last formal …