因为全球平均气温已经高于前工业化时期大约0.7摄氏度，这意味着在未来世纪，气温上升4摄氏度是完全可能的。
As the global average temperature is already about 0.7c above pre-industrial times, this implies that anything up to 4c during the coming century is possible.
比如诺德·豪斯所倾向的政策，将大气中的二氧化碳的浓度设定为前工业化时期平均值的两倍。
Nordhaus's preferred policy, for example, would stabilize the concentration of carbon dioxide in the atmosphere at a level about twice its preindustrial average.
不同的国家集团希望国际社会承诺，将前工业化时期以来的全球平均气温上升限制在2摄氏度，或1.5摄氏度以内，甚至有几个国家要求1摄氏度以内。
Different blocs of countries want the international community to commit to limiting the global average temperature rise since pre-industrial times to 2c or 1.5c, though a few are demanding 1c.
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