An ice age is a slow, gradual kind of apocalypse, one that is difficult or impossible to prevent, undo or mitigate. Most other kinds of stock apocalypses are typically fairly dramatic and immediate in scope, and there is usually something that can be done to keep them from happening or to recover afterwards — divert the asteroid, cure the plague, defeat the zombies, ride out The Great Flood, rebuild society after the nuclear war. They may be devastating, but there is a clear agent that can be faced and overcome. An ice age, however, is quite a different beast. It's slow, usually — it takes some time for it to set in, ranging from a few years to a few centuries of gradually cooling weather, and it's often possible for multiple generations of people to live and die without it making a significant impact on their lives. However, ice ages are in a very literal sense the Mighty Glaciers of apocalypses — they may take a long time to truly set in, but eventually the glaciers will come to your doorstep, and when they do there will be very little you will be able to do about them.
This is the other key aspect of glacial apocalypses — there's usually little to nothing that can be done to prevent or undo them, at least on a global scale. Most other global disasters typically give the main characters an obvious target to deal with — even a disease is a foe to fight against. This provides the heroes a means of undoing the end of the world and a discrete figure to serve as the narrative's antagonist. An ice age does not do this — what are you supposed to strike against? The snow? The chilling air? The darkness? The lack of food? A specific villain may sometimes be responsible for these events, but the majority of the time global ice ages are the result of grand climatic, geologic or cosmic events happening beyond and in spite of humanity, and which are entirely beyond human civilization's ability to affect. When the ice age is caused by human action, it's typically the result of some kind of blunder — nuclear winter is a common culprit, as are attempts to undo Global Warming Gone Horribly Right — that broke the global climate beyond repair.
Consequently, a core element of these stories is the overwhelming presence of a hostile and unpersonal world — something too diffuse to rail against or hate even in effigy, as humanity is brought to its knees by the uncaring clockwork of the universe. Characters may be able to ensure their own survival or those of others, perhaps even establish a community of survivors, but very rarely will they be able to preserve more than a fragment of civilization in a cold and barren world.
In practical terms, the main perils of the ice age are hostile climate and resource scarcity. As the glaciation grinds on, more and more land becomes covered by snow and the advancing glaciers; this buries cities, freezes farmland and destroys forests, gradually starving civilization and the global ecosystem alike of food, resources and living space. The environment itself becomes the enemy, as survival becomes impossible outside of artificially warmed areas and every breath is painful.
Civilization must adapt or be destroyed, and survival will be hard. In early stages of these events, society often breaks down gradually. True collapses will begin in polar and then temperate areas, the first to freeze over, although warmer climes may experience their own issues with fleeing refugees and political disturbances even before feeling the first hints of chill themselves. Once the ice age has progressed further, sometimes to the point of turning the world into ice planet, civilization will endure only in isolated pockets of survivors, usually huddling around or within artificially warmed areas, and food and resources will be scarce and extremely valuable for anyone who doesn't feel like Braving the Blizzard to forage for whatever's left in the frozen ruins of civilization. Survival typically comes at a cost, and in extreme cases humanity will be ground into nonexistence no matter what it does. Prevailing feelings of hopelessness or despair are often present as civilization slowly recedes and pockets of survivors are snuffed out over time.
It's also not uncommon for some kind of societal regression to occur. Some works may have surviving enclaves resort to totalitarianism or zealotry in order to maintain the control they need to survive. In other cases, humanity may regress to the state it lived in during the last great ice age — even mammoths may reappear.
- Sailor Moon: The 1990s anime has one of these to explain how Crystal Tokyo of the 30th Century was formed with Usagi becoming Neo-Queen Serenity and ruler of Earth. As it was an addition to the anime and not part of Crystal Tokyo's backstory in the original manga, little is known exactly about the event. The only tidbits are that sometime in the 20th/21th century Earth ended up in a new ice age, and humanity was sent into a deep slumber. It's only centuries later that Usagi, with the power of the Silver Crystal, was able to restore Earth and awaken the populace.
- Magic: The Gathering: The Ice Age was a period of Dominaria's history started in consequence of the Brothers' War, when Urza ignited the Golgothian Sylex, devastating a continent, annihilating Mishra's forces, igniting his own Planeswalker spark, and ushering in a period of plunging global temperatures. The period immediately following the blast, referred to as the Dark, saw four centuries of slowly cooling temperatures, dwindling resources and shrinking civilizations, while zealotry and despots rose to power to lead increasingly lost and frightened people. The Dark culminated in the Ice Age, which lasted over 2000 years and saw the gradual collapse of much of civilization as glaciers covered great swathes of land and primordial monsters such as dragons, mammoths and dinosaurs roamed the world. When the Ice Age eventually ended, however, the ensuing Thaw also proved incredibly destructive — the rise in warmth and humidity fostered widespread plagues, while floods and rising sea levels spread further devastation and caused the continent of Terisiare to fragment into an archipelago of islands.
- Fire and Ice: The villains are conquering the world by pushing a giant glacier across it, turning subjugated kingdoms into icy wastelands and forcing humanity to retreat south towards the equator. The last kingdom in his way is situated on volcanic land and can resist his glacier by releasing a lava flow against it.
- A.I.: Artificial Intelligence: This is heavily implied to have occurred during the end (set two thousand years after the main story), as humans have gone extinct and New York is now buried beneath vast ice sheets.
- The Colony (2013) revolves around a colony of people trying to survive a new Ice Age brought upon by weather manipulation machines trying to reduce global warning and working way too well at that. By the time the film starts people are losing their minds, and much to the horror of the protagonists a cannibalistic cult has found them.
- The Day After Tomorrow: The world is struck by a series of disastrous cold storms as a result of the warm ocean currents shutting down, ironically due to initial manmade Global Warming melting the original polar ice sheets no less. The storms cover most of the polar and temperate latitudes in snow, forcing the people living there to either perish or emigrate south en masse, leaving the land and cities to the ice and wildlife. In the end, the main characters are able to survive and help other refugees hold out until they can be rescued and brought south, but the world is left locked in a new ice age and everything north of Florida is a frozen wasteland.
- Snowpiercer: In an attempt to reverse a warming climate, the governments of the world released the cooling agent CW-7 into the skies to lower global temperatures. This worked all too well and sent global temperatures crashing, enveloping the planet in ice and killing nearly everyone on Earth. By the movie's time, the cold is so intense that survival outside the titular armored train is literally impossible, forcing all of humanity within to accept the despotic rule of the train's engineers.
- Sunshine: The Sun is inexplicably going out, gradually causing the Earth to freeze into a snowball and become uninhabitable. The plot revolves around a group of astronauts sent to try and reignite the Sun with a massive bomb to avert this fate.
- Tropic Thunder. Played with. There is a trailer for Tugg Speedman's latest action film Scorcher VI: Global Melt Down that has his character save the world from an ice age while protecting two babies.
- Fallen Angels: An attempt to counteract Global Warming worked altogether too well and lowered the Earth's temperature enough for large glaciers to form, which in turn have been reflecting away enough light and heat to cool the Earth more and more the larger they grow, resulting in a runway global cooling event. Canada and most of the northern United States have been destroyed by the advancing ice, while barbarism and feudal systems have formed along their advancing edges where government and civilization are breaking down. Winnipeg has managed to keep itself thawed in the middle of the ice through solar power beamed down from space stations, while the US government's totalitarian rulers largely refuse to admit that any problem exists.
- "History Lesson", a short story by Arthur C. Clarke, opens with a tribe of primitive humans migrating south to avoid the glaciers of an oncoming ice age caused by a chance cooling of the Sun. This caused a gradual growth of the polar glaciers, driving living things further and further south. By the 30th century, when the story opens, humanity endures only as Neolithic primitives and finds itself doomed when, on reaching the equator, it meets the Antarctic glaciers approaching from the south. The ice eventually closes, driving humanity extinct, and leaving only scattered bones and artifacts to be studied by intelligent beings who eventually arise on a Venus rendered cool enough to support life.
- Moon Crash Series: An asteroid impact sends the Moon closer to the Earth, causing it to exert a stronger gravitational pull that, in addition to powerful storms, extreme tides and tidal waves, causes increased volcanism worldwide. The immense quantities of ash and dust sent into the atmosphere cover much of the sky, dramatically lowering the Earth's temperature; frosts become common in August at the mid-latitudes and agriculture becomes effectively impossible, leading to widespread famine. The novels are told through the diaries of a number of teenagers caught in the cataclysm as they try to survive the lack of food, intense cold, gradual collapse of society and unpredictable weather extremes.
- In "A Pail Of Air", a short story by Fritz Leiber, the Earth has been thrown out of its orbit by a rogue "dark star" and is flying further and further away. It is so cold that even the air has frozen.
- The Wandering Earth: The Earth entering a new ice age is the natural consequence of transforming it into a Planet Spaceship and send it flying away from the Sun (to escape it becoming a red giant several billion years too early). The cold, which is capable of instantly killing a person if they are not protected, is one of the greatest threats in the journey to save the planet when it threatens to crash with Jupiter.
- In A Song of Ice and Fire the planet has seasons that last for years and the story starts as a prophetically harsh winter is coming. And there's an undead army coming down from the north side of the kingdom's giant ice wall.
- Dinosaurs ends with Earl's attempts to fix the environmental damage caused by WESAYSO backfiring and starting the Ice Age when attempts to create more rain to boost plant growth create volcanic cloud cover that will take thousands of years to dissipate. It eventually becomes clear that the snow is not going away, and that the dinosaurs will die out completely. The final scene of the series has news anchor Howard Handupme telling the audience "Good night... goodbye."
- The Twilight Zone (1959): Zig-Zagged in "The Midnight Sun". Most of the story is focused on the Earth getting hotter and hotter because it is moving closer and closer to the sun, with the ever-increasing and unbearable heat slowly killing off Earthly life and humanity with it. But it turns out it's All Just a Dream — in reality, the Earth is getting colder and colder because it's moving away from the sun, and will eventually become an uninhabitable ball of ice.
- The Witcher: The White Frost is an apocalyptic event that occurs throughout The Multiverse in which the story takes place. No one knows if it's an Eldritch Abomination, an ever-expanding Eldritch Location, some sort of Doomsday Device or just the inevitable Natural End of Time, but it slowly creeps along different planes of the multiverse, and any plane currently in its grip suffers a slow and gradual icy doom. Finding a way to stop it is a priority of almost every major character, whether heroic or villainous. In one case, Geralt and an ally travel through a world that has been ravaged by the White Frost and reading the Apocalyptic Logs there give a horrific impression of what it's like to slowly realize that the snow piling outside your doors is never going to stop and that it'll just keep getting colder and colder...
- Dungeons & Dragons:
- The supplement Dungeon Master's Guide 2 has the Killing Frost of Ghulurak, which is meant to end the world by freezing it in an eternal ice age.
- Father Llymic, one of the Elder Evils, aims to do this alongside The Night That Never Ends. Should he be released from his prison, the Sun will start rising later and later and setting earlier and earlier every day, until it will cease appearing at all. This will come with a corresponding drop in temperature as the Sun's warmth vanishes, plunging the planet in an ever-worsening ice age. Should Father Llymic not be stopped, the world will become a lifeless ball of ice that will never know light or warmth again.
- Savage Worlds: Hellfrost is set in a standard swords-and-sorcery land that is facing an incoming ice age, with the titular mega-glacier growing bigger and bigger and sweeping over the land at a slow, relentless pace.
- Battlefield 2142 takes place in a future where a new Ice Age has taken almost all of the fertile land not placed on the Equator, and rival armies fight for what remains.
- Endless Legend: Auriga is a dying world doomed by a growing ice age. Every few months, it's plunged into abrupt winters that kill crops and production. As the game goes on, the winters become longer and longer until the world is plunged in an eternal ice age past turn 300. The eight empires of Auriga are trying to get the hell off their world before that happens. In Endless Space, a few centuries after the ending, Auriga is a lifeless ball of ice and rock, and only two of the factions are confirmed to have survived, one of them only partially.
- Fall from Heaven: Age of Ice takes place during the setting's Age of Ice, characterized by a bitter winter lasting for generations after Mulcarn, the god of winter, rose to power, marking the end of the previous Age of Magic. The long winter results in the powerful civilizations of the Age of Magic collapsing, as few are able to survive the snowy wasteland.
- Frostpunk: A series of massive volcanic eruptions and also maybe a meteor knocking Earth out of its normal orbit cause global temperatures to drop precipitously and leave only a few isolated pockets of civilization huddling around generators. The player takes control of New London, and will have to carefully manage resource gathering and consumption in order to keep the little island of heat going in the cold. A central aspect of the game is the struggle against a hostile environment that humanity is not suited for, and the forced choice between morality and survival — the player is presented with only two viable paths for survival, one leading to military despotism and the other to theocracy, and is left to figure out how much is too much and how much is justified to ensure that the city lives on.
- Icycle has you play as the lone survivor of the new ice age, who is a naked man riding a small blue bicycle and following a trail of frozen bubbles. He attempts to find any remnants of humanity left in the frozen world, but only finds a gorilla.
- Soul Series: This result is revealed to be the true goal of the Soul Calibur. The Calibur is opposed to its progenitor and counterpart, the Soul Edge. Soul Edge seeks endless war, bloodshed, torment and chaos across the world while Soul Calibur wants peace, harmony and order. Its preferred method of attaining this, however, would be by freezing the whole world over. In certain bad endings, we are shown such an apocalyptic scenario as ice envelops the world.
- Transarctica: In the past, civilization decided to counteract Global Warming by detonating nukes at the poles to induce nuclear winter. This worked altogether too well and created a permanent cover of thick clouds that blocked out the sun and plunged the Earth into a civilization-ending ice age. The game is set seven centuries after this happens, in a world where humanity is barely hanging onto existence (in some cases having degenerated into Mole Men living in old subway tunnels), a system of heavily armored trains are the only way to cross the wastes, and a fanatical cult — that's you — that worships a mythical ball of light and warmth beyond the clouds is on the warpath to end the ice age. Also, mammoths are back.
- Kurzgesagt: The Rogue Earth video is an extreme example of this trope, where a glacial apocalypse is caused by the Earth being flung out of the Solar System by a rogue star. As the planet gets farther from the Sun, temperatures gradually drop below the coldest points in Antarctica, the water cycle ceases, polar glaciers cover the entire planet, and, as Earth reaches the Kuiper Belt, temperatures become cold enough to freeze the atmosphere itself into nitrogen and oxygen snow deposits. Eventually, Earth becomes a frozen over Rogue Planet locked in a permanent ice age, killing off all living things save for some extremophiles in deep-sea hydrothermal vents.
- Serina: The last geologic period in Serina's history, the Ultimocene, is marked by drastic global cooling caused by the halting of volcanic activity (and thus of the main means by which carbon in the deep crust is released into the atmosphere) and by the locking of large quantities of carbon dioxide into the soil by earlier eras' flourishing plant life. This loss of natural greenhouse gases leads to the onset of runaway ice age conditions, as glaciers creep down from the poles and winters grow harsher and harsher. The tropical biomes are the first to collapse under the strain of cooling weather and refugee species fleeing from the temperate areas, the southern continent becomes entirely encased in ice, and a catastrophic loss of biodiversity generally ensues. Life manages to survive and thrive despite these conditions, for a time — a holdout of the temperate forests endures for a long time on the northern continent's southern coast, and numerous plant and animal species adapt to thrive in the bitter tundra further north — but as the glaciation continues the temperate refugium is eventually snuffed out and even the cold-adapted species slowly go extinct, as the world slowly becomes too cold and barren for any kind of life to survive.
- The Adventures of Jimmy Neutron: Boy Genius: In "Jimmy on Ice", Jimmy is hoping for a snow day and decides to cool off the atmosphere with a giant bottle of sunblock. After the kids play in the snow for a day, Jimmy wakes up to discover it's -30 degrees Fahrenheit outside and that he caused a second ice age. The adults are leaving to go hunt for meat like they're nomadic cavemen, and the townsfolk think they need to sacrifice Jimmy to stop the snow.
- The Future Is Wild: In the cartoon, C.G. is a girl from ten thousand years in the future where, as the intro says, "a mega ice-age is threatening humanity". She's tasked with Time Traveling into the future and finding a more suitable habitat for human civilization to resettle.
- Johnny Test: In "Johnny Degrees Below Zero", Johnny and Dukey take a Magnetism Manipulation gun too far and cause Earth to realign, making their hometown Porkbelly the new North Pole. As piles of snow start falling and polar bears move in, they must urgently set out to restore Earth's alignment before the town freezes to death.
- Mega Man: In "Ice Age", Dr. Wily uses a super refrigerant to create artificial glaciers in order to freeze over the world's major cities and replace its officials with his robots.
- The Penguins of Madagascar: In "It's About Time", following Kowalski stopping his Chronotron from erasing all of reality, Skipper suggests he make something less destructive next time, like a snow cone machine. ...Gilligan Cut to New York completely buried in food-colored shaved ice.