By Valerie Volcovici WASHINGTON (Reuters) -China’s decision to halt bilateral talks on climate change with the United States has cast a cloud of doubt over whether the world can rally enough ambition to address global warming in time to avert its worst impacts. Tackling climate change has been a key area of cooperation between the two superpowers and two biggest emitters of greenhouse gas emissions. But China has suspended talks on the issue less than 100 days before the next landmark international climate summit, COP27, as part of its escalating retaliation over U.S. House of Representatives …