Aftermath: Population Zero

Aftermath: Population Zero (also called Aftermath: The World After Humans) was produced in Canada, but premiered on the National Geographic Channel. Its premise was Exactly What It Says on the Tin, a hypothetical scenario of what would happen if all humans suddenly vanished without a trace. Eventually, more follow-up episodes were produced based on the same concept of coming up with a hypothetical scenario, doing copious research into what exactly that change to the status quo would impact, and then filming an episode the occurrence of the scenario as well as its aftermath.

Tropes used in Aftermath: Population Zero include:

Series

After the End: Every episode leads to an apocalypse and either culminates in humanity's extinction or a post-apocalyptic future where humans have adapted to the hypothetical scenario.
The End of the World as We Know It: Every single episode has this happen. It's obviously the whole point of Population Zero, given that it deals with the aftermath of humanity's extinction, but even the scenarios that one would least expect to lead to an apocalypse do.
Next Sunday A.D.: When each scenario occurs
Shown Their Work: In excruciating detail. The narrator explains exactly what the scenario changes, why it has changed, and what a particular changed thing's status quo depends on in our reality that has been removed with the scenario.
Speculative Documentary: The whole point of each episode.

Population Zero

Humans as a species, have existed for a relatively short time in Earth's history and are still relatively young compared to certain other species. Yet of all species that have walked the earth, humans are unique in that we are the only species known to have created lasting structures and buildings and to have hed a lastingly massive impact on the earth's ecology. However, on June 13 of an unspecified year, all humans have vanished without a trace for no explicable reason. Population Zero then details what has happened to the artifacts that humans have left behind after the long years without usage or maintenance, as well as what happens to the earth's ecology after humans have been removed from the equation.

Humanity's Wake: The whole point of this episode. Humans inexplicably vanish and the focal point is how the earth's ecology is impacted in different time periods after humanity's extinction as well as the eventual destruction of humanity's artifices, one by one.
Humans Are the Real Monsters: As the narration points out, there are multiple ways in which the lives of multiple species are improved in the long run once humans are removed from the equation.
Next Sunday A.D.: Humans vanish without a trace on June 13 of an unspecified year.

Red Giant/Swallowed By the Sun

The sun is a star and, like all stars, is aging. It will eventually turn into a red giant, but is currently a yellow dwarf and our sun that is the center of our solar system, the thing that makes our existence possible, and an object we see everyday to the point where we simply take it for granted. This episode posits a hypothetical scenario where the sun ages millions of years overnight and rapidly ages into a red giant at an accelerated rate.

Beneath the Earth: Where humans are eventually driven due to the levels of radiation and heat.
Heat Wave: As the sun rapidly ages, the earth's temperature also rises.
Humanity's Wake: This scenario leads to human extinction on Earth.
Irony: Despite the fact that it gets too hot for humans to walk on the surface of the earth without a spacesuit, at that very same point, there is not enough oxygen for flames to be possible.

When the Earth Stops Spinning

This episode is unique among the episodes of Aftermath in that nothing happens specifically overnight. The earth's rotation is already slowing, though at such a low rate that it's barely even measurable. It's just that one day, right out of the blue, this slowing starts to accelerate to the point where the earth stops spinning entirely 5 years after the start of the earth's rotation's accelerated deceleration.

Crapsack World: What we finally end up with when the world finally stops spinning entirely. Most of the world's population has died and what humans are left have been forced to retreat to isolated colonies with no hope of progressing beyond subsistence.
Depopulation Bomb: Given that Most of the world has been made unsafe to live in, in some cases by what constitute natural disasters, until the only habitable areas are by the coasts of the new mega-continent by the polar oceans, what else would you expect?
The Insomniac: The lengthening of days as the earth's spin slows to a stop messes up everyone's sleep cycle. Their ability to sleep is impaired during the times when practically speaking, it is daytime and yet time-wise, it is still night.
Sleepyhead: The lengthening of the days, as well as making everyone in the world The Insomniac when the sun is out when it is usually nighttime, also turns people into this when it is dark during the traditional daytime.

Population Overload

It is a fact that in the last two centuries, the world population has increased at a much faster rate than in all of human history. As the world population count has gone through each billion mark, it has been increasingly more often that the question of just how many people can the planet support has been raised. Because of issues of poverty in certain areas and segments of the population, there is also the question of just how many can live an adequate life without draining the planet's resources. Population Overload exploits this hot topic, especially the fact that the world would soon hit the seven billion mark at the time of production. This episode presents the fact that the world's population is presently roughly 7 billion and then postulates what would happen if the world population suddenly doubled overnight to 14 billion.

The Apocalypse Brings Out the Best In People: Inverted with the United States closing its borders entirely because of the influx of refugees and migrants. Played straight, however, in that the various problems that result from the increased population result in scientists uniting to solve them and, most importantly, in ways that ensure everyone's survival.
Depopulation Bomb: The ironic result of this scenario. The world population is 4 billion 35 years after the world's population doubled overnight to 14 billion.
The Plague: The first variant happens as a result of the increased population. The plumbing is strained from multiple people flushing the toilets, causing the waste water to taint the supply of drinking water, causing outbreaks of cholera.
Water Source Tampering: An unintentional variant. Desperate attempts to grow enough food to feed the increased population as well as strains on the plumbing result in much of the world's water being unsafe to drink, if one can even find or attain any of it.

World Without Oil

The oil crisis is currently^[when?] a hot topic and the fact that there is only a limited amount of fossil fuels to drill has been a point that many politicians have repeatedly mentioned. Therefore, this episode was produced, postulating this question: "What would happen if the world's remaining oil reservoirs suddenly disappeared?"

Days of Future Past: Eventually, people start growing their own food and keeping livestock as people usually did prior to the 20th century.
Ludd Was Right: As social infrastructure collapses, it turns out that the old-fashioned way is the best way. Those who grow their own food and keep livestock, as well as doing other things that aren't mentioned the old-fashioned way, make it through the crisis. Even 40 years after the oil supplies ran out and humanity has adapted to this new fact of life, society is still agrarian, growing their food locally and growing only what they need.