New York Times: Nancy Pelosi, the House speaker, met China’s two top leaders on Wednesday to discuss cooperation on energy and environmental problems, and Prime Minister Wen Jiabao said that Beijing would join Washington to "push for positive results" at the next global warming summit this fall in Copenhagen. Mr. Wen’s public statements, reported by the state’s Xinhua news agency, offered no specifics, however, and some experts here noted that the two nations’ official positions on reducing …