Just throwing this out there but it seems to me we have been seeing an extra dose of green used thematically in this new season of Fringe. A subtle hint that the resolved universe with Peter returned will be the so called "green universe" with a whole new timeline? We'll find out by the intro sequence once Peter is finally back.
Below are a few of the examples of the usage of green. If we see "Green Eggs and Ham" we know it is a done deal!
Walter's vials transitioning from amber/orange to green.
Lincoln Lee framed in green.
Olivia and Broyles bathed in green during a transition to the bridge room.
And finally a distorted Walter also framed in green.
Green eggs and ham anyone?