WARSAW — Discord and rivalry between Beijing and Washington have factored in international discussions of global warming since the United Nations climate treaty was established in 1992, contributing to the foundering of the 2009 talks in Copenhagen and much rough sailing since. But with China having recently surpassed the United States as the world’s largest emitter of greenhouse gases, the countries are finding that their interests increasingly overlap, climate experts and government officials say. The more productive relationship is raising hopes that the friction of recent years may be easing, paving the way for a new global climate change treaty in 2015. International delegates have been meeting in Warsaw to negotiate the provisions of that treaty. The conference is scheduled to end Friday. Zhang Haibin, a professor of international relations at Peking University who has served as an adviser to China’s Ministry of Commerce, said that while climate cooperation […]