由于全球变暖，气候系统极有可能在达到某个临界阈值之后出现整个系统的崩溃，造成类似于电影《后天》中的后 果。多年冻土退化被认为是气候系统中一个重要的气候突变要素。在全球变暖的背景下，多年冻土正在迅速退化，并将释放 出巨量的碳。多年冻土热融喀斯特现象的存在，并综合其他气候突变因素，有可能在政府间气候变化专门委员会（IPCC） 提出的2 ℃目标以内达到地球系统行星边界的阈值，从而对气候系统产生不可逆的影响。

 Climate system is likely to collapse when such climate factor getting a tipping point under global warming, resulting in the consequences similar to the disaster film of “The day after tomorrow”. Permafrost degradation is considered as an important abrupt climate factor in the climate system. In the context of global warming, permafrost is rapidly deteriorating and will release a huge amount of carbon. Especially the emergence of permafrost thermokarst, combined with other climate tipping point factor, may reach the threshold of planetary boundary of the earth system within the IPCC target of 2 ℃, which will have an irreversible impact on the climate system.