It's both. It's a reminder of a feedback loop:

   greenhouse  [IR trap]    increase of
   emissions -------------> global temperatures
      ^                       |
      |  [methane from        |
      |   melting permafrost] |
      -------------------------

It's a consequence, and a warning that it will happen again, and again, and again, until life on this planet is so hard for us that nations will be at each other's throats, just trying to survive, and then we can kiss human civilization goodbye.