Disaster films

Main article: Disaster film

A frequent theme among science fiction films is that of impending or actual disaster on an epic scale. These often address a particular concern of the writer by serving as a vehicle of warning against a type of activity, including technological research. In the case of alien invasion films, the creatures can provide as a stand-in for a feared foreign power.

Disaster films typically fall into the following general categories:

• Alien invasion — hostile extraterrestrials arrive and seek to supplant humanity. They are either overwhelmingly powerful or very insidious. Typical examples include The War of the Worlds (1953, 2005) and Invasion of the Body Snatchers (1956, 1978, 1993, 2007).
• Environmental disaster — such a major climate change, or an asteroid or comet strike. Movies that have employed this theme include Soylent Green (1973), Waterworld (1995), and The Day After Tomorrow (2004).
• Man supplanted by technology — typically in the form of an all-powerful computer, advanced robots or cyborgs, or else genetically-modified humans or animals. Among the films in this category are Colossus: The Forbin Project (1970), The Terminator (1984), The Matrix (1999) and I, Robot (2004).
• Nuclear war — usually in the form of a dystopic, post-holocaust tale of grim survival. Examples of such a storyline can be found in the movies Dr. Strangelove (1964), Panic in Year Zero! (1962), Planet of the Apes (1968), A Boy and His Dog (1975) and Mad Max (1979).
• Pandemic — a highly lethal disease, often one created by man, threatens or wipes out most of humanity in a massive plague. This topic has been treated in such films as The Andromeda Strain (1971), The Omega Man (1971), Twelve Monkeys (1995), 28 Days Later (2002) and I Am Legend (2007).

Time travel movies can also exploit the potential for disaster as a motivation for the plot, or they can be the root cause of a disaster by re-writing history following a particular date. For example, The Terminator series of films employs time travel in this fashion (see also "Time travel" below).