Post-Peak Oil

Nothing in this world is forever, and that includes fossils fuels. Sooner or later, they will run out. The world relies heavily on petroleum products not only for powering machinery, but for using that same machinery to transport products from A to B, to pave roads, to making plastics, to creating certain materials, to help making nitrogen-based fertilizers, the list goes on.

Bottom line, without petroleum, the world could very well go to hell. This trope explores that fact.

How it is explored depends on the work in question. In some works, it could just be a nasty bump on the road that lead to some troubled times, but was overcome by discovering a new fuel source, reverting back to a simpler time, or a third option. Typically though, this trope doesn't have a positive side, and is usually a device to explain why the setting sucks so much, or in a After the End setting, what caused the apocalypse. What little fuel remains to be sold will have sky high prices that only the wealthy can afford. Prices of everything else will be extremely high, thanks to increased transportation costs, usually leading to people starving in the streets. Law and order will break down as people become more and more desperate, resulting in mob rule in most cases.

In a worse case scenario, nations go to war over the last remaining fuel reserves, resulting in a massive global war, the outcome usually being an After the End setting, or at best, an even crappier world than before.

Anime and Manga

 * In Mobile Suit Gundam 00, oil has been supplanted by orbital solar facilities, with the result that the Middle East is even worse off because no one is interested in them anymore.

Film

 * Mad Max (or at least Mad Max 2) is a definite Trope Codifier for this, and a lot of dystopias where oil is valuable as gold are explicit references to the film. It is the oil shortages that began the nuclear war that resulted in the After the End setting.
 * Last Chase (1981)
 * The story of Americathon is set in a future United States where the gas shortage of the 1970's grew to a point where the automobile has been completely eliminated, except as a possession one can park permanently and live in.

Literature

 * The Uglies series.
 * The Windup Girl by Paolo Bacigalupi; having exhausted all oil the world is back to using human and animal power, which is wound into springs to be released at need. The one resource everyone's after are calories to power the muscles that'll wind up the springs.
 * Ship Breaker by the same author, which is set in the same universe. Old oil tankers are broken for scrap, and whatever pockets of oil they still contain are priceless finds that can make a man's fortune.
 * Julian Comstock by Robert Charles Wilson is set in a 22nd-century America where the oil has run out; the resulting society ends up feeling like a cross between 19th-century America and 4th-century Rome.
 * This one is a victim of Science Marches On, as the provable natural gas reserves in the continental United States would have been tapped long before anything like this scenario occurs (to say nothing of the biodiesel project sponsored by the Department of Defense, with the goal of making the US military completely independent of foreign oil supplies--the collapse of American military power due to lack of oil being a key point in the setup of the plot).
 * In Make Room! Make Room! by Harry Harrison, cities effectively become their own totally isolated city states when the oil becomes too rare to use. The only form of travel mentioned are large freighters (shipping food to the millions effectively trapped in cities).

Live Action TV

 * The made-for-TV Docu Drama Oil Storm. Notable for depicting, as the catalyst for the oil shock, a hurricane hitting New Orleans in September 2005... and did we mention that this was made just months before Hurricane Katrina?

Music

 * The song Endgame by Rise Against has the lyric, "the kerosene's run out," suggesting this is what did the world in.

Theatre

 * The play Clytemnestra reimagines the story of Clytemnestra's murder of Agamemnon in an After the End setting where oil has run out and society has descended into small tribal groups, living in compounds and slowly running out of food, and bands of 'ferals' scavenging outside.

Video Games

 * Fallout: Before the Great War, peak oil was the cause of the Resource Wars that devastated both Europe and the Middle East. Gas prices reached up to $1450.99 per gallon for regular. The United States (and possibly China) were only saved by going to an all-nuclear society, while the rest of the world ended up collapsing. It was all made moot however, when everyone started to sling nukes at each other.
 * Frontlines Fuel of War: The reason behind the war in the game. One of the loading text notes the irony of using fossil fuel-powered vehicles to fight a war fighting for the last remaining fossil fuels, mentioning that some citizens lamented that the last drops of oil would be burnt up by a tank.
 * Crime Craft: Peak oil lead to the society (for lack of a better term) in the game.
 * Deus Ex Human Revolution: An e-book mentions how peak oil lead to an economic crisis sometime before the game began.
 * Inverted with perhaps unintentional irony in Final Fantasy VII Advent Children. In the original game, Shinra Energy Corporation was literally sucking the life energy of the Planet dry in a not so subtle ecological metaphor. In the movie, the world having barely avoided destruction and Shinra having been taken down, this energy source is obviously no longer used. So what is former eco-terrorist Barret doing nowadays? "Cloud, I found some oil!"
 * The world of Homefront has gas prices reaching nearly $20 a barrel due to a war between Saudi Arabia and Iran.
 * Implied in In Famous, where gas prices in Empire City are just shy of $9 a barrel. However, that could possibly be price gouging after the disaster. Zeke also has a peak oil poster in his rooftop compound.
 * The transition to this and the aftermath is one of the main challenges in most Fate of the World scenarios. Depending upon how well you (literally) play your cards; the transition to a post-oil society can be anywhere from fairly painless to resulting in biosphere collapse and the extinction of humanity. Averted in the Cornucopia scenario, in which fossil fuel reserves are self-replenishing but still cause environmental havoc.

Web Original

 * The Alternate Reality Game World Without Oil.

Western Animation

 * Futurama: On the episode "Bendin' in the Wind", it is mentioned that oil preserves dried up in 2050, so cars now run on a more environmentally safe alternative: whale oil.

Real Life

 * It is somewhat debatable how much damage peak oil would do in real life, and it's generally only the fringe that believes that it would cause. The Economics page explores this in the Resource Halt section. A brief explanation, however, says that sellers of oil would start withholding stock to prepare for the scarcity, and oil's price, in event of supplies becoming less available, would slowly rise over time forcing humanity to adapt by either finding a new resource/technology, or increasing energy efficiency and, in some cases, possibly reverting to non-oil-powered technologies (electric trains, organic farming, et cetera). One of the most commonly cited effects, which is already being seen in some parts of the US now that $4 a gallon gasoline is a reality, is a reversal of the trend towards suburban development and a greater focus on city and town centers. Now, a sudden temporary decrease in availability (such as embargoes, disruption of some sort in production, or transportation routes being cut off), or a war for oil spilling over into a larger conflict, can have nasty consequences, but would most likely only to regional areas, rather than the entire planet.
 * This is happening now, to some extent. Currently in the US, 30 mpg is considered "good gas mileage" while 40 is considered really good. Look at articles from the era of the 1974 oil-embargo crisis - the first time since World War Two that there had been a gas-price shock - and be amazed at the references to 15 mpg "compacts" and how a 25 mpg VW Beetle was spoken of in terms now used for a 50 mpg Prius.
 * Technically, ways to produce liquid fuels from gas or coal do exist and resulting product is costly, but within reasonable limits. And there is really much coal on Earth. And even after coal exhaustion, there are ways to produce liquid fuels from biomass, that are in development even now, so-called biodiesel.