And once it thaws, that collapsing ground can drastically alter the vast expanse of the Arctic's tundra and boreal forest, and it can also threaten the homes and lifeways of Arctic residents.

一旦永久冻土开始融化，坍塌的土极区大片的苔原和部针叶林，这也威胁着极区居民的家园和生活方式。