Earthrise is the upcoming post-apocalyptic MMO from Masthead Studios, and a game with a substantial body of lore released already. Masthead Studios had a lore series on IGN in the past, and more recently MMORPG.com has been hosting dev blogs which explain the game's zones and how they are tied in with Earthrise's backstory. The latest dev blog from Masthead Studios is "The Boneyard", and focuses on the game's desert zone.
As with their past combinations of lore releases and zone previews, The Boneyard sets the tone for the game: Humanity was wiped out in World War III. Nuclear and seismic warheads obliterated civilization while nanomachine clouds unleashed bio threats which finished the job.