The Knowledge: How to Rebuild Our World From Scratch Read Online Free PDF Page B

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 sunlightfocused 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 aresubject to temperature swings, soaked with water trickling down from blocked gutters, and pulverized by the relentless pulsing of