Thursday, February 19, 2015

the apocalypse: a timeline

If human beings were to instantaneously vanish from the face of the earth, our absence would be felt the very first day. Power plants burning fossil fuels will run out of fuel within two hours. Nuclear reactors would go into safe mode within two days. Within the span of two weeks, the earth would be bathed in a darkness not seen since the Stone Age. Hoover Dam, supplied by power from its reservoir (Lake Meade), will continue as long as conditions remain good. This could last from several months to a couple years, rendering Las Vegas as the last bright spot on the earth's surface. Hoover Dam's ability to generate electricity would be foiled by invasive mollusks covering the cooling vents. Overheating inside the dam would activate the alarm systems and the automatic shutdown. One-by-one the dam's machines would shut down; in time, Lake Meade would rise and spill over the freeways, gushing into the Colorado River. The failure of electricity would shut down the water pumps in subway systems below the water table around the world; in New York City, around 700 pumps remove thirteen million gallons of water a day, and within thirty-six hours, the tunnels would fill to the waterline. Our household pets, domesticated to depend on us for food, have to escape their homes; after feeding on their dead owners, animals will try to escape. Those who don't will die in the homes. Suburbia would be dominated by dogs scavenging for food. There are up to 300 different breeds of dogs, and few would be suitable for life after humans. The smallest dogs would probably be killed off within the first week. A hierarchy would develop, and the average dogs (the mutts) would have the best hope of surviving. Rats and house mice are dependent on our refuse, and they flourish in our waste. In our absence, these rodents will raid pantries and grocery stores. Then they'll turn to cardboard, cloth, and glue. Rodents will be forced to abandon buildings for the wild, making easy prey for marauding bands of feral dogs or wild birds of prey.

Within six months, the urban areas are beginning to run wild. The first animals to begin to colonize our cities would be herbivores followed by their predators. Coyotes and bobcats would be the first to prowl the empty city streets, but after them would come the bears, mountain lions, and wolves. The turn of the first year in our absence finds nature taking over. Plants can destroy man-made objects within the first few years. Dandelions sprout from cracked pavements; moss and lichen begin to form a carpet over the pavement. This feeble topsoil is colonized by clover, feeding on the nitrogen in the air. Lawns become fields, and deer wander suburbia. By now bears, deer, and abandoned animals live in our biggest cities. Vines scour the buildings, breaking up mortar, crumbling facades exposing buildings' innards. Forest fires run unchecked, scouring urban areas and even cities. Chicago, with its tightly-packed buildings reaching high into the sky, could be razed by even the smallest fire. The charcoal left in a firestorm's wake offers good feeding ground to growing soil. Weeds and trees grow out of the cracks in fractured concrete. Creepers and vines stretch up the sides of buildings, snake across roads, and climb tree trunks. Balconies become roosts for birds, and bells in bell towers are splattered with the feces of hanging bats. Swimming pools are long drained but reek as though filled with rotting corpses.

Five years after the disappearance of humans, and roads are following in our footsteps, disappearing underneath vines, moss, and a thin layer of topsoil sprouting shrubs and gnarled trees. Plants cover vehicles, and buildings are all but hidden behind nature's encroach. In cities below the water table, pumps keep subways and tunnels free of water. When these pumps cease to function, tunnels and subways begin to fill with water. Water would start sluicing away at the soil under the pavement, and streets would begin to crater. Sewers clogged by plastic bags and old newspaper mush remain clogged, leaf litter piling atop, and watercourses form above ground. Waterlogged subway ceilings collapse, the steel columns supporting the street exposed to wind and rain. Cities above the water table fare no better; especially in colder climates (March in Manhattan fluctuates between freezing around forty times), the repeated freezing and thawing make asphalt and cement split. Thawing snow feeds runoff into the cracks, and when the runoff refreezes, the water expands, widening the cracks. Weeds emerge between the splitting pavement, and top soil begins to stretch over the pavement, radiating outwards from the mulch fermenting in the gutters. This ever-spreading topsoil becomes deep enough for saplings to sprout. In time, the soil will be rich enough for oaks and maples.

A quarter of a century into our absence, concrete is cracking, paint is chipping, and eerie ghosts towns are being overwhelmed by nature. Animals turn buildings into ecosystems. Parking lots are marked by scours of broken concrete uplifted among tangled plants. Roofs have collapsed, and trees emerge out of houses. Shredded laundry still hangs on clotheslines. Fences and barbed wire are uniformly rusted. Fallen limestone facing lies in pieces; hunks of wall have dropped from building to reveal moldy and green-eaten rooms. Brick-shaped gaps show where mortar has already dissolved in building walls. Areas killed by radioactive forces are, within twenty years, refilled and flourishing. Cornfields have been invaded by trees, and wild dogs roam in packs. Cities below the waterline, like those of London and Amsterdam, have drowned. Windows are shattering as the window sealant goes rigid; filled with gaping holes, buildings catch windswept debris. Corroded lightning rods spark fires that consume the the buildings. Gutted floors become homes for birds. Pigeons flourish, using skyscrapers as cliff bases. Wolves, hunted mercilessly by humans, thrive throughout America. Wolves multiply their numbers six times a year; by a quarter of a century, there could be around half a million in the lower 48. As deer move into cities, the wolves follow.

Forty years into our world without us, most of our homes have collapsed. Ninety percent of American homes are made with wood-frame construction. Nature’s destruction of the home will probably begin on the roof. Most roofs are covered with shingling, which can last two to three decades. The shingles will begin to separate under countless barrages of rain, and water will sneak under the shingles. It’ll flow across four-by-eight-foot sheets of sheathing made either of plywood or woodchip board composed of three- to four-inch flakes of timber bonded together by resin. Moisture enters around the nails, and they begin to rust; as they rust, their grip on the wood loosens. The wooden sheathing in which the nails are rotting secure the house’s trusses—pre-manufactured braces held together with metal connection plates that keep the roof from splaying—and when the nails rust and the sheathing collapses, the roof splays and follows suit. Water has made its way into the house by other means, as well: through burst drainpipes from frozen water, rain blowing in where windows have cracked from bird collisions or sagging walls. The walls begin to lean to one side, and the roof caves in. A good house can last half a century to a century, tops. As the house breaks apart, squirrels, raccoons, lizards, and birds make their home inside, chewing holes in the drywall. Fallen vinyl siding fades early and becomes brittle and cracks as its plasticizers degenerate. Aluminum siding is in better shape, but salts in the air pockmark its surface. Stone or brick chimneys will last longer than the walls of the house, but after a century its bricks have begun to drop and break as the lime mortar is exposed to temperature swings, crumbling and powdering. Swimming pools become planter boxes, filled with the offspring of ornamental saplings or with banished natural foliage. The basement, too, is filled with soil and plant life. Brambles and wild grapevines snake around the steel gas pipes, which will rust to nothing within another century. White plastic PVC plumping yellows and thins on the side exposed to the light. The bathroom tile, whose chemical properties are like those of fossils, is relatively unchanged.

Within three quarters of a century, most of the world's 600 million cars lie in rusted remnants. Vehicles in desert climates last longer; those in coastal environments, subjected to the salt air and vicious storms, break apart quickly. Tires deflate within two years, though the rubber will be good for centuries. Most cars have been reduced to skeletons, the engines having dropped to the ground. Within a century, cars are no more than heaps of metal. Bridges begin to collapse. Without engineers working on them, they're exposed to the elements. Suspension cables, made of steel, are 98% iron. Iron reverts back to the minerals it came from. The wires rust and corrode, and as they snap, bridges begin to come down. The decks and railing warp and sway; the decks collapse, spilling their contents into whatever lies below.

Within a century, all suspension bridges will have come down. The Era of Collapsing (ca 100-300 years post-humans) sees the collapse of the Eiffel Tower, Seattle's Space Needle, and the Sears Tower in Chicago and Empire State Building soon following. Nature reclaims the biggest cities. New York City disappears, any remaining buildings all but recognizable. Most buildings have collapsed or imploded; indeed, the Era of Collapse began with the first unchecked fires. Lightning striking dried branches and leaves can spread unhindered building-to-building. Within twenty years, lightning rods have begun to rust and snap, and roof fires leap between buildings, consuming paneled offices with their paper fuel. Gas lines ignite, blowing out windows. The skeletal buildings, ravaged by fire, are now assaulted with rain and snow, and the concrete floors are exposed to the savagery of freezes and thaws; the concrete begins to buckle. The buildings’ stability is further corroded by clogged sewers, drowned tunnels, and streets becoming waterways; all of these weaken subbasements and destabilize the structure. As the buildings’ foundations become unstable, they are less of a match to violent winds. Buildings begin to sway, and then tumble; some will collapse into others, setting off a domino effect. The city becomes home to animals: first come the herbivores, and then those creatures that hunt them; domesticated dogs are thinned out by the competition, but the arrival of wolves eliminates all breeds of domesticated dogs; feral cats, though thinned out, hunt within the ruins of the city, always prowling and on alert.

Within 10,000 years, radio waves corrode into noise within 1-2 light-years. Our signals vanish, blending with the cosmic background noise of the Big Bang. Iron corrodes, concrete crumbles, wood and paper decays; the Great Wall of China crumbles, the Great Pyramid of Giza is swallowed up by sand, and the Hoover Dam breaks apart. Mount Rushmore will remain for at least 100,000 years; and it could be the last picture of what we looked like to whoever may replace us.

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