Snowpiercer is boldly brutal, but brilliant filmmaking from writer/director Bong Joon-ho. Unlike many current films taking place on a dystopian Earth, the cause of the death of most of mankind is made clear at the outset. The progression of global warming caused a desperate attempt in 2014 to cool the planet by seeding a chemical into the atmosphere. The result was a cataclysmic Ice Age and almost everyone has died.