MELBOURNE – Earlier this year, the concentration of carbon dioxide in the atmosphere reached 400 parts per million (ppm). The last time there was that much CO2 in our atmosphere was three million years ago, when sea levels were 24 meters higher than they are today.
墨尔本—今年早些时候，大气中的二氧化碳浓度达到了百万分之400（ppm）。大气二氧化碳浓度上一次达到如此高水平是在300万年前，当时的海平面比现在高24米。如今，海平面正在再次上升。去年9月，北冰洋冰盖面积创下了有记录以来新低。自1880年有全球记录以来，十个最热年份中的九个出现在21世纪。