SHANGHAI/WASHINGTON (Reuters) -China and the United States agree that stronger pledges to fight climate change should be introduced before a new round of international talks at the end of the year, the two countries said in a joint statement on Sunday. The statement came after a meeting between Chinese climate envoy Xie Zhenhua and his U.S. counterpart, John Kerry, in Shanghai on Thursday and Friday, China's environment ministry said. "The United States and China are committed to cooperating with each other and with other countries to tackle the climate crisis," their joint statement said. The...