Permafrost thaw is causing tundra to sink and pool water.

Staircases are separating from building and utility poles leaning.

The multinational company that operates the Red Dog Mine in Northwest Alaska says that thawing permafrost linked to global warming has forced it to spend nearly $20 million to manage its water storage and discharge.

The exact reason of the leak is yet to be established, but a statement from Norilsk Nickel company, which operates the site suggests it could have been caused - worryingly - by collapsing permafrost.