Two-thirds of the atmospheric buildup of carbon dioxide, a heat-trapping greenhouse gas that can persist in the air for centuries, has come in nearly equal proportions from the United States and Western European countries.

• 美国和西欧国家排出了集聚在大气中的2/3的二氧化碳,其排放量几乎相等,二氧化碳是一种能滞留热量的温室气体，可在大气中存留几个世纪。