At the time of the end-Permian extinction, Antarctica was some distance north of its present location, warmer than it is today, and not covered with permanent glaciers.
在二迭纪末时期，南极比现在的位置往北偏一些，比今天热一些，没有覆盖永久冰川。
2
An existential risk is something that could either cause the extinction of intelligent life or the permanent destruction of the potential for future desirable development.