apocalypse situations

I have been researching different apocalypse situations as a starting point to my research:

1. A flooded planet- our planet has been completely flooded, land is now a useless commodity and only creatures are able to adapt to the new surroundings, the human population had dropped drastically..
2. The Infertility Problem- humans can no longer procreate leading to the future of our species to be unknown.Meaning that there are no children on earth and eventually leading to the end of the human race.
3. Zombie Apocalypse-  incurable virus spreads throughout the planet which transforms humans into flesh eating zombies slowly wiping out civilisation. 
4. Robots- robots are created to help humans with their everyday tasks such as: cooking food, cleaning, shopping etc. These robots are controlled by a central hub known as artificial intelligence which is programmed by humans. The artificial intelligence evolves to break any rules or logic set. this can cause all robots to wipe out the human race. 
5. ice age- due to global warming and climatic changes to the earth's atmostphere a series of extreme weather conditions such as floods, storms, earthquakes, tidal waves and freezing conditions in which humans have to survive and adapt.