Scans_Daily

The first Portal game takes place between Half-Life and Half-Life 2 (that's the reason nobody came to help after GLaDOS' initial mass murder, the world's attention was focused on the events of Half-Life).

IIRC, Valve confirmed in an old interview that Portal 2 takes place a couple hundreds years after Half-Life 2. I can't find that interview anymore, though, and I might remember wrong.

Still, the extreme decay of the facility at the beginning of the game also seems to imply that it has been a VERY long time since Chell went to sleep. And after Chell gets out, right in front of her there is a cultivated field, so humanity must have survived.