还有些人讨论夏季北极海冰——经历了大幅下降在过去的40年,现在比过去任何时候小年——作为一个系统的“临界点”。However, the science is pretty clear that there is no critical threshold in this system. Rather, summer Arctic sea ice area decreases roughly in proportion to the increase in global temperature, and if temperature were stabilized, we would expect sea ice area to stabilize also.