By ELLEN KNICKMEYER
U.S. envoy John Kerry is on a diplomatic quest to stave off the worst scenarios of global warming, but he’s running into resistance from China, the world’s biggest climate polluter. Chinese officials are adamant that the United States must ease confrontation over other matters if it wants China to speed up its climate efforts. Rights advocates and Republican lawmakers say they see signs that China’s pressure may be working. They cite what they say is softening in the administration’s initially strong stand over China’s mass detentions and other abuses of its Muslim Uyghur minority.