When it thaws, methane is released, increasing the rate of warming.

当它解冻时，甲烷就会释放出来，加快变暖的速度。

Before adding: " Otherwise he'll come out when it thaws."

“要不然等解冻了，它会跑出来的。”

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，坍塌的土地会彻底改变北极地区大片的苔原和北部针叶林，这也威胁着北极地区居民的家园和生活方式。

The ice itself doesn't cause much harm, but when it thaws, the bubbles remain, which is a problem because the whole plumbing system relies on the inter-molecular attraction of water molecules pulling each other upward against gravity.

冰块本身不会造成什么危害，但当冰块解冻时，气泡仍然存在，这是个问题，因为整个水管系统是依靠水分子之间的分子间吸引力相互拉动，对抗重力。