Climate Desk: George R.R. Martin`s wildly popular Game of Thrones saga--whose third season just launched on HBO--is, on the broadest level, a story driven by climatic change. "Winter is coming," warn the ill-fated Starks, a family of northern nobles who help guard the realm from the frozen beyond. In Martin`s world, winters and summers vary in length and can for last years or even a generation--and as the books advance, a devastating winter begins to descend, forcing southward migrations and an intense test of...