"Population Zero" initially covers the first hours, days, weeks, and months following humanity's disappearance, leading to many interesting yet still horrifying sights that the dueling show Life After People lacks (such as empty cars crashing into each other worldwide, airplanes falling down on earth and power going out in the span of hours if not minutes and so on), but the episode gets really eerie after the next Ice Age hits, turning into a Cosmic Horror Story where the narrator impresses us of mankind's insignificance on the cosmic timescale.
"When the Earth Stops Spinning". At least in "Population Zero", the humanity vanishes instantly, while here, we have an overview of five years of an excruciating extinction event, with the loss of air, the flooding of the northern regions, and all the other disasters strike gradually as the remaining people desperately fight for survival. In particular, there is the story of the American family whom we see noticing the first effects of the Earth slowing down, then struggling to flee to Kansas through the earthquake-ravaged US, then somehow managing in to the Kansas Habitat and adjusting to the new life… only for the concluding scenes to state that now that the Earth has stopped spinning completely, the survivors in Kansas are doomed (unless, by some miracle, they manage to reach the oceanographers' colony several thousands miles away). It's utterly chilling.
