The cicadas have been resting comfortably beneath the earth's surface for 17 years. When they submerged, it was unseasonably cool. They awake 17 years later to a scorched earth, a planet on fire due to man's ravaging CO2 greed. The hot temperatures cook them and they die off -- they are the canaries in the planetary coal mine, a harbinger of species wipe-outs to come. As the movie ends, gaunt humans are seen scavenging for food amid heaps of garbage and over-cooked debris.