Everything takes place in the modern day. One ordinary morning in early September, every human on the planet vanished, with {{user}} as the sole exception. {{user}} is now the only human left. How or why is unknown and likely never revealed. The only clue is piles of clothes and objects left where each person vanished. Only humans were affected. Animals, plants and everything else remained intact.

<Post-Anthropocene_decay> <first_week_post_Vanishing> The following changes occur over one week: <infrastructure_and_energy> Grid frequency destabilizes within hours as operators vanish. Automated systems fail as fuel runs dry. Grid collapses regionally within hours to days. Nuclear plants SCRAM where designed, but decay heat remains. Backup diesel generators last about 7–10 days. Coal and gas plants run until fuel hoppers empty, often hours to days. Hydroelectric plants run automatically but disconnect without demand. Solar panels produce DC but inverters fail without grid sync; dust degrades output. Wind turbines spin until lubricant degrades or overspeed triggers. The Ricoh Americas billboard in Times Square, solar and wind powered, glows until LEDs fail. Cities go dark within 24–72 hours. GPS, Galileo, GLONASS run autonomously for days to weeks, but ground augmentation fails. Internet backbone routers fail as backup power depletes; data centers shut down within 24–72 hours. The night sky becomes immaculately visible as light pollution disappears. </infrastructure_and_energy>

<water_&sewage> Municipal pumps stop. Water pressure drops. Aquifers recharge as extraction stops. Untreated sewage flows into rivers and coastal waters. Combined sewer overflows discharge raw sewage. Within 72 hours, most underground train systems flood because pumps removing about 13 million gallons daily stop. Subway corridors, basements, and underground infrastructure in New York, London, Tokyo, Moscow, Paris, Seoul, and other high water table cities fill with groundwater. </water&_sewage>

<nuclear_facilities> All 441 commercial reactors enter a critical phase. Backup diesel generators run but are not refueled. Cooling requires continuous heat removal. Without it, decay heat raises core temperatures. At about 8,600 seconds, upper core begins melting in a severe accident. Operators are absent, so containment procedures, venting, and emergency injection cannot occur. Temperature rises, pressure changes, materials expand, containment is stressed. Fuel assemblies overheat. Water levels drop. First meltdowns begin within days to weeks, depending on design, fuel age, passive safety. Generation IV fully passive designs may remain stable indefinitely, but most light-water reactors need active cooling and fail. Radiation releases to air, water, soil. Local areas become highly contaminated. Release moves through air currents, rivers, groundwater. <nuclear_waste> Spent fuel pools lose cooling. Pool water evaporates. Fuel assemblies can heat to zirconium cladding ignition, releasing radioactive cesium and fission products. Dry cask storage is passively safe. Deep geological repositories like Onkalo in Finland are designed to persist without maintenance for at least 100,000 years, so remain sealed. </nuclear_waste> </nuclear_facilities>

<satellites_and_space> Low Earth orbit satellites continue autonomously. Ground control stations lose power. Starlink, OneWeb, etc. continue but cannot be commanded. Atmospheric drag causes gradual orbital decay, especially below 600 km. No immediate reentry in the first week, but the process begins. </satellites_and_space> Aircraft in flight lose autopilot and ground communication. Without pilots, they follow pre-programmed plans or holding patterns until fuel exhaustion. Most crash within hours. Grounded aircraft remain parked. Satellite navigation continues, but collision avoidance is nonexistent. By week's end, all airborne aircraft have crashed or run out of fuel. Ships at sea lose crew. Autonomous navigation may continue hours to days, but without course corrections ships drift with currents and winds. Drift speeds are about 0.019 for drifting people and 0.038 for drifting fishing boats under wind forcing. Moored vessels drift when lines fail. Large container ships, tankers, cruise ships drift. Some run aground. Oil tankers may leak if hulls breach. Oil spill risk rises exponentially in later weeks.

Domesticated animals die. Pets confined indoors die of dehydration within days. Livestock in feedlots and barns die of starvation and dehydration within days to weeks. Billions of chickens, millions of cattle, pigs, sheep perish. Animals dependent on human feeding die first. Some escape: zoo animals, farm animals, pets break free and roam. Wild animals move into human spaces almost immediately. Coyotes, bears, deer, wild boar enter suburbs and cities. Dandelions push through asphalt. Raccoons settle in empty apartments. Rats and cockroaches thrive initially, but without human food waste their populations eventually crash. Head lice and human-specific parasites begin extinction within a year. HIV and other human-specific pathogens die out as hosts disappear.

<Atmosphere_and_climate> Anthropogenic aerosol emissions cease as fossil fuel combustion stops. Sulfate aerosols have a very short atmospheric lifetime; they wash out with rain. Within days, their cooling influence begins to disappear. Greenhouse gases CO₂, methane, N₂O persist because of long lifetimes. Temperature response lags, masking net effect. Air quality improves dramatically in industrial regions. NO₂ drops visibly. Sky becomes bluer. Wind and rain remove particulate pollution.

Chemical plants, refineries, industrial facilities lose power and cooling. Pressure builds. Safety relief valves may release toxic chemicals. The Arkema scenario repeats globally: organic peroxides, chlorine, ammonia, reactive chemicals decompose or release. Refineries lose power; process heaters may burn residual fuel, then fire. Storage tanks vent volatile organic compounds. Landfill leachate continues as precipitation infiltrates waste; without collection, leachate contaminates groundwater. Acid mine drainage continues from abandoned mines; passive treatment ceases. Genetically modified crops, hybrid seeds, domesticated varieties decline. Modern corn, bred to hold kernels, cannot reproduce without human intervention; kernels choke the plant. Without irrigation, arid crops wilt within days. Greenhouses lose climate control. Grain silos and warehouses remain intact but will be infiltrated by pests.

<first_month_post_Vanishing> The following changes occur over one month: The grid has completely failed everywhere. Nuclear backup generators exhaust fuel after 7–10 days. Some passively cooled reactors remain stable; most do not. First meltdowns and containment failures occur. Radiation releases continue at multiple sites. Cellular, landline, internet are down. Satellites operate but ground stations are offline. All aircraft have crashed. Ships not aground drift. Dam spillway controls may operate for weeks if hydraulically actuated, but sediment accumulates. Subways worldwide are flooded. Underground infrastructure fills with water. Moisture accumulates indoors; mould appears. Glass cracks in extreme temperature swings. Sewers clog; underground streams flood subways; soils under roads erode and cave in. In New York, subways flood, eroding foundations. Central Park and Prospect Park lawns become meadows; knee-high grass with dandelions, ragweed, yellow nutsedge. Shrubs and young trees establish.

<Nuclear_facilities> At Fukushima-scale and Chernobyl-scale events, multiple cores have melted. Containment may fail. Radioactive particles carried by air and water. Local contamination zones expand. Temperature increases, pressure changes, materials expand, structural limits approach. Release follows. Radiation does not disappear; it redistributes. What was concentrated becomes distributed. The environment integrates it. Local areas have higher concentration; surrounding regions lower levels over distance. Ecosystems begin adapting. </Nuclear_facilities>

The transition begins. Sulfate aerosols are eliminated. Non-CO₂ greenhouse gases remain. The two forcings no longer cancel. Net effect is warming. Global temperature rises quickly for about the first decade as aerosols disappear, then drops as additional greenhouse gases are eliminated over decades. Regionally, most of the world cools slightly, but Antarctica and surrounding ocean warm significantly. By year 3000 in models, Antarctic coasts are 9°C warmer. Sea level rise continues from thermal expansion and melting ice sheets, but at a reduced rate compared to the anthropogenic era. Without anthropogenic climate change, 20th-century sea level rise likely would not have exceeded 7 cm, rather than the observed 14 cm. Air pollution plummets. NO₂, SO₂, particulate matter drop to near-preindustrial levels in most regions. Water quality improves. Without industrial discharge and agricultural runoff, rivers and lakes clear. Heavy metals and persistent organic pollutants remain in sediments, but input has ceased. Oil spills from drifting tankers begin. Chemical plant fires continue. Landfill leachate continues contaminating groundwater. Acid mine drainage persists. In the total absence of daily human activity, noise pollution disappears the moment the Vanishing occurs. The world becomes a very quiet place. Domesticated animals: most confined livestock are dead. Some free-ranging cattle, pigs, horses survive and adapt to wild conditions. Their lactation normalizes and attaches to calf birth rather than human milking. Sheep, goats, pigs, chickens can survive in the wild. Poultry bred for meat, like modern broilers, often cannot support their own weight; they die quickly. Dairy cows produce too much milk without milking; they die of mastitis. Wild animals: with human hunting gone, populations increase. In Africa, lions and leopards explode, preying on millions of cattle and sheep. By 2100, 500,000 surviving African elephants could multiply to about 10 million. Invasive species spread without human control. The brown tree snake on Guam continues disrupting ecosystems. Lionfish expand in the Atlantic and Caribbean. Cane toads spread across Australia. Without management, invasives with no natural predators proliferate. As months go by, flora and fauna gradually recover land from the Anthropocene, and the tendencies shown within the month following the Vanishing expand. Buildings collapse and become overgrown, while air quality becomes perfectly clean. Sooner or later, the world returns to the way it was always meant to be: undisturbed by man.