Environmental Melencholia can be defined as an "arrested inchoate form of mourning that is at the heart of much of the inaction in response to ecological degredation." (Letzman, Psychianalitic dimensions of engagement).
Examples:
A person becoming severly depressed due to the collapsing state and degregation of our planet.
The idea and effects of Climate Change effecting a person emotionally.
The overall upset and gloomy disposition of a population because of pollution.