The Knowledge: How to Rebuild Our World From Scratch (4 page)

Immediately after the termination of routine maintenance, nature will seize its opportunity to reclaim our urban spaces. Trash and detritus will collect on the streets and pavements, blocking drains and causing the pooling of water and accumulation of debris rotting into mulch. Pioneering weeds will first begin proliferating in pockets like this. Even in the complete absence of pounding car tires, cracks in the asphalt will steadily expand into crevices. With every frost, water pooled in these depressions will freeze and expand, crumbling the hard artificial ground from within with the same punishing freeze-thaw cycle that steadily wears down entire mountain ranges. This weathering creates more and more niches for small opportunistic weeds, and then shrubs, to become established and further break up the surface. Other plants are more aggressive, their penetrating roots pushing right through the bricks and mortar to find purchase and tap into sources of moisture. Vines will snake their way up traffic lights and street signs, treating them like metallic tree trunks, and lush coatings of creepers will grow up the cliff-like faces of buildings and spread down from the rooftops.

Over a number of years, accumulating leaf litter and other vegetative matter from this pioneering burst of growth will decay to an organic humus and will mix with the windblown dust and grit of deteriorating concrete and bricks to create a genuine urban soil. Papers and other detritus billowing out of broken office windows will collect in the streets below and add to this composting layer. A thickening carpet of dirt will smother the roads, sidewalks, parking lots, and open plazas of towns and cities, allowing a succession of larger trees to take root. Away from the asphalt streets and paved squares, the cities’ grassy parks and the surrounding countryside will rapidly return to woodland. Within just a decade or two, elder thickets and birch trees will have become firmly established, maturing to dense woods of spruce, larch, and beech trees by the end of the first century after the apocalypse.

BUILDINGS CRUMBLE AND NATURE RECLAIMS OUR URBAN SPACES, INCLUDING OUR STORES OF KNOWLEDGE LIKE THIS NEW JERSEY LIBRARY.

And while nature is busy reclaiming the environment, our buildings will crumble and decay among the growing forests. As vegetation returns and fills the streets with wood and drifts of windblown leaves, mingling with the trash strewn out of broken windows, piles of perfect kindling will collect in the streets, and the chances of raging urban forest fires increase. Tinder accumulated against the side of a building and ignited by a summer lightning storm, or perhaps by sunlight
focused through broken glass, is all that’s needed to unleash devastating wildfires that would spread along the streets and burn up the insides of high-rises.

A modern city wouldn’t be razed to the ground like London in 1666 or Chicago in 1871, the fire ripping rapidly from one wooden building to the next and leaping across the narrow streets; but blazes spreading unopposed by firefighters would still be devastating. Gas lingering in underground pipes and throughout buildings would explode, any fuel left in the tanks of vehicles abandoned in the streets only adding to the intensity of the inferno. Dotted throughout populated areas are bombs waiting to go off when a blaze sweeps through: gas stations, chemical depots, and the vats of highly volatile and flammable solvents in dry-cleaning stores. Perhaps one of the most poignant sights for post-apocalyptic survivors would be watching the burning of the old cities, sprouting thick columns of choking black smoke towering above the landscape and flushing the sky bloodred at night. After a passing blaze, the brick, concrete, and steel matrix of contemporary buildings would be all that is left behind—charred skeletons after their combustible internal viscera have been gutted.

Fire will wreak devastation across great areas of the deserted cities, but it is water that will eventually bring certain destruction for all our carefully constructed buildings. The first winter after the Fall will see a spate of burst frozen water pipes, which will disgorge inside buildings during the following thaw. Rain will blow in through missing or broken windows, trickle down among dislodged roofing tiles, and overflow from blocked gutters and drains. Peeled paint from window and door frames will allow moisture to soak in, rotting wood and corroding metal until the whole insert falls out of the wall. The wooden structures—floorboards, joists, and roof supports—will also soak up moisture and rot, while the bolts, screws, and nails holding the components together rust.

Concrete, bricks, and the mortar smeared between them are
subject to temperature swings, soaked with water trickling down from blocked gutters, and pulverized by the relentless pulsing of freeze-thaw at high latitudes. In warmer climates, insects such as termites and woodworms will join forces with fungi to eat away at the wooden components of buildings. Before too long, wooden beams will decay and yield, causing floors to fall through and roofs to collapse, and eventually the walls themselves will bow outward, then topple. The majority of our houses or apartment blocks will last, at most, a hundred years.

Our metal bridges will corrode and weaken as the paint peels off, allowing water to seep in. The death knell for many bridges, though, is likely to be windblown detritus collecting in the expansion gaps, breathing spaces designed to allow the materials to swell in the summer heat. Once clogged, the bridge will strain against itself, shearing off corroding bolts until the whole structure gives way. Within a century or two, many bridges will have collapsed into the water below, the lines of rubble and debris at the feet of the still-standing pillars forming a series of weirs in the river.

The steel-reinforced concrete of many modern buildings is a marvelous building material, but although more resistant than wood, it is by no means impervious to decay. The ultimate cause of its deterioration is ironically the source of its great mechanical strength. The steel rebars are cocooned from the elements by the concrete surrounding them, but as mildly acidic rainwater soaks through, and humic acids released by rotting vegetation seep into the concrete foundations, the embedded steel begins to rust inside the structures. The final blow for this modern construction technique is the fact that steel expands as it rusts, rupturing the concrete from the inside, leaving even more surface exposed to moisture and so accelerating the endgame. These rebars are the weak point of modern construction—and unreinforced concrete will prove more durable in the long run: the dome of the Pantheon in Rome is still going strong after two thousand years.

The greatest threat to high-rises, though, is waterlogged
foundations from unmaintained drainage, blocked sewers, or recurring floods, particularly among cities built along the banks of a river. The supports will corrode and degrade, or subside into the ground to create listing skyscrapers far more ominous than the leaning tower of Pisa, before inevitably collapsing. The raining debris will further damage surrounding edifices, or the buildings will perhaps even topple over into neighboring monoliths like giant dominoes, until only a few remain spiking above a skyline of trees. Few of our great high-rise buildings would be expected to still be standing after a few centuries.

So within just a generation or two after the Fall, the urban geography will have become unrecognizable. Opportunistic seedlings have become saplings have become full-blown trees. City streets and boulevards have been replaced by dense corridors of forest crammed into the man-made canyons between high-rise buildings, themselves now grossly dilapidated and trailing vegetation from gaping windows like vertical ecosystems. Nature has utterly reclaimed the urban jungle. Over time, the jagged piles of rubble from collapsed buildings will themselves become softened by the accumulation of decomposing plant matter forming soil—hillocks of dirt sprouting trees, until even the tumbled remains of once-soaring skyscrapers are buried and hidden by verdant growth.

Away from the cities, fleets of ghost ships will be adrift across the oceans, occasionally carried by the vagaries of wind and currents to ground themselves on a coastline, slicing open their bellies to bleed noxious slicks of fuel oil or releasing their load of containers onto the ocean currents like dandelion seeds in the wind. But perhaps the most spectacular shipwreck, if anyone happens to be in the right place at the right time to watch it, will be the return of one of humanity’s most ambitious constructions.

The International Space Station is a giant 100-meter-wide edifice built over fourteen years in low Earth orbit: an impressive assemblage of pressurized modules, spindly struts, and dragonfly wings of solar
panels. Although it soars 400 kilometers over our heads, the space station is not quite beyond the wispy upper reaches of the atmosphere, which exert an imperceptibly slight but unrelenting drag on the sprawling structure. This saps the space station’s orbital energy so that it spirals steadily toward the ground, and it needs to be repeatedly boosted back up with rocket thrusters. With the demise of the astronauts, or lack of fuel, the space station will relentlessly drop about 2 kilometers every month. Before too long, it would be hauled down into a fiery plunge through the air, ending in a streak of light and fireball like an artificial shooting star.

The gradual decay of our cities and towns is not the only transforming process that the survivors of the apocalypse will witness.

Since the Industrial Revolution and exploitation of first coal and then natural gas and oil, humanity has been fervently burrowing underground to dig up the buried chemical energy accumulated from times past. These fossil fuels, readily combustible dollops of carbon, are the decayed remains of ancient forests and marine organisms: chemical energy derived from the trapping of sunlight that shone on the Earth eons ago. This carbon originally came from the atmosphere, but the problem is that we are burning these stores so quickly that a few hundred million years’ worth of fixed carbon have been released back into the atmosphere in just over a hundred years, pumped out of our smokestacks and car exhaust pipes. This is far, far faster than the planetary system can reabsorb the liberated carbon dioxide, and there is about 40 percent more of the gas in the air today than at the beginning of the eighteenth century. One effect of this elevated carbon dioxide level is that more of the Sun’s warmth is trapped by the Earth’s atmosphere through the greenhouse effect, leading to global warming.
This in turn will lead to a rise in sea levels and the disruption of weather patterns worldwide, creating more frequent, heavier monsoon floods in some areas and droughts in others, with severe repercussions for agriculture.

With the collapse of technological civilization, emissions from industry, intensive agriculture, and transport would cease overnight, and pollution from the small surviving population would drop to practically zero in the immediate aftermath. But even if emissions were to completely stop tomorrow, the world will continue to respond for the next few centuries to the vast amount of carbon dioxide our civilization has already belched out. We are currently in a lag phase, as the planet reacts to the sudden hard shove we have given to its equilibrium.

The post-apocalyptic world is therefore likely to experience a rise in sea level of several meters over the following centuries from momentum already built up in the system. The effects could be much worse if the warming triggers other secondary effects, such as the thawing of methane-laden permafrost or widespread melting of glaciers. While carbon dioxide levels will decline after the apocalypse, they will plateau at a substantially elevated value and not return to their preindustrial state for many tens of thousands of years. So over the timescale of our, or any following, civilization, this forced cranking-up of the planet’s thermostat is essentially permanent, and our current carefree lifestyle will leave a long, dark legacy for those inhabiting the world we leave behind. The consequences for survivors already struggling to support themselves is that as climate and weather patterns continue to change over the generations, once-fertile cropland may be ruined by drought, low-lying regions become flooded, and tropical diseases become more prevalent. Shifts in local climate have caused abrupt collapses of civilizations in human history, and the ongoing global changes may well frustrate the recovery of a fragile post-apocalyptic society.

THE GRACE PERIOD

Thus we never see the true state of our condition till it is illustrated to us by its contraries, nor know how to value what we enjoy, but by the want of it.

D
ANIEL
D
EFOE,
Robinson Crusoe
(1719)

AFTER A PLANE CRASH IN A REMOTE AREA,
your main priorities for survival would be shelter, water, and food. The same requirements are paramount after the crash of civilization. While it’s possible to survive several weeks without food, and a few days without drinking water, if you’re caught outside in an inclement climate, you can die of exposure within a matter of hours. As the British Special Air Service (SAS) survival expert John “Lofty” Wiseman told me, “If you’re still on your feet after the big bang, you are a survivor. But how long you continue to survive is down to your knowledge and what you do.” For our purposes we’ll assume that, like more than 99 percent of people, including myself, you’re not a Prepper and have not stockpiled food and water, fortified your home, or made any other prior arrangements for the end of the world.

So during the crucial buffer period before you’re forced to start producing things anew, what remnants could you scavenge to ensure your survival in the post-apocalyptic world? What would you want to look out for when beachcombing the detritus left behind by the receding technological tide?