I'm Dave DeForest reporting. The climate summit begins in Paris: U.S. President Barack Obama urged world leaders to "rise to this moment," telling them their progress at the U.N. climate summit in Paris will be measured by "the suffering that is averted and a planet that is preserved." ____________________________________________ The summit participants are trying to reach an agreement on measures to keep global temperatures from rising more than 2 degrees Celsius above pre-Industrial Revolution levels. 戴夫`迪福斯特为您报道.气候大会在巴黎举行:美国总统奥巴马敦促各国领导人"在此时应采取行动",并对他们说道将用"是否能够避免环境危机和保护地球"这个标准来衡量各国在巴黎联合国气候大会上所取得的成就. 奥巴马说道:___________________________________________ 以工业革命前全球温度为基准,为了使未来全球温度增长保持在2摄氏度以内,与会各方试图就相应措施达成一项协议.