Since you been gone

"To see how the world would look if humans were gone, I began going to abandoned places, places that people had left for different reasons," says Alan Weisman, journalist, in a recent interview in Scientific American. After covering the aftermath of the Chernobyl disaster, Weisman became intrigued with the idea of just what would happen to the planet if humanity just up and disappeared. How long would it take for Nature to recover from humankind's many thousand-year attack, especially the last hundred years? And what would that look like? He attempts to answer these questions in his new book, The World without Us.

Visiting no-man's lands like the Korean DMZ, Chernobyl and ancient preserves provided some answers, as did voyages into the murky depths beneath New York City. Says Weisman:

I also went to the Korean DMZ, the demilitarized zone. Here you have this little stretch of land—it’s about 150 miles long and 2.5 miles wide—that has two of the world’s biggest armies facing off against each other. And in between the armies is an inadvertent wildlife preserve. You see species that might be extinct if it weren’t for this one little piece of land. Sometimes you’ll hear the soldiers screaming at one another through loudspeakers or flashing their propaganda back and forth, and in the middle of all this tension you’ll see the flocks of cranes that winter there.

Lacking the everyday maintenance that keeps them going, our cities would crumble and soon become overgrown with plants. Writing in the Daily Mail, Michael Hanlon summarizes Mother Nature's counterattack:

The big cities would crumble with remarkable ease. London or New York, like all large towns near the sea, would start to rot from their foundations up, as underground tunnels and conduits that carried trains and cables, roadways and sewage, started to fill up with water within days. The pumps that keep them dry would have simply ceased to operate.

Indeed, the recent floods in northern England showed just how much damage can be caused when human defences fail. Without people to patch them up, and the rumble of traffic continually to keep them at bay, weeds would win their long battle with the asphalt.

Within a few weeks, grass shoots would begin to shatter every road surface in the world. Within 15 years, the M1 would look like one of those roads built in Africa in the 1960s and never since maintained.

Within a decade, the combined onslaught of weeds, waterlogging from blocked drains and the freeze-thaw action of water seeping into cracks would combine to turn the foundations of the urban world to rubble.

Many buildings would start to fall apart within 20 years. Walls would groan and creak, roof tiles lift, joints between walls and roofs separate. Without central heating, with gutters permanently clogged and no maintenance, most of Britain's homes would be in ruins by 2040.

America's cities, with their generally harsher climates, would fall apart even sooner.

Some of the first buildings that would decay are, paradoxically, some of the newest. The shoddily built box-homes that have sprung up across Britain in the post-war era, the badly-made tower blocks and the cheap conversions, would collapse like houses of cards.

Large, well-designed modern buildings with steel-framed constructions might survive for centuries, however, as would some of the thick-walled buildings of the Georgian era and before.

Of course, some constructions would last a very long time. Massively over-engineered, the Forth Rail Bridge could stand for hundreds of years. And one structure which, interestingly, would survive far longer than you might think would be the Channel Tunnel.

Dr Weisman points out that it wouldn't flood because it is built deep under the seabed, in a single geological layer. That is why it might prove to be a vital conduit for the recolonisation of Britain by dozens of animal species long banished by man.

Meanwhile, as the buildings crumbled and decayed, what about the other works of man?

Our world is still very much the Iron Age, but iron - and its modern incarnation, steel - is the most transient of materials: strong but powerless against corrosion.

"Don't be fooled," says David Olsen, an American materials scientist, "by massive steel buildings, steamrollers, tanks, railway tracks... sculptures made of bronze (an extraordinarily resilient alloy) will outlast the lot".

Again, we are faced with the paradox that some of the oldest artefacts on Earth might outlast the newest. Within a century or two, nearly all automobiles would have rusted away. Within a millennium - without maintenance and painting - the steel fabric of our civilisation would have crumbled.

But bronze sculptures from the ancient world - as well as more modern bronze artworks - might last millions of years.

Indeed, by AD10,000,000, the world would still be littered with hundreds of semi-oxidised bronze artefacts - sculptures and statues, reliefs and delicate instruments. Add to that billions of copper-alloy coins, which might survive just as long. Humans might vanish at the height of the steel age, but it is to the Bronze Age that the Earth would return.

We live in the steel age, but we might also be said to live in the plastic age. Depressingly, it may be the plastic bag that proves to be one of mankind's most persistent legacies.

The billions of bags blowing across the Earth like tumbleweed would continue to blow. Come back in ten thousand years, and most of them will still be there.

Some scary stuff, for sure, but also sort of encouraging as well. Considering the tremendous impact humanity has had on the Earth is the point of Weisman's book.

And he offers a solution, of sorts. Environmental collapse looms ever nearer, at least from a human perspective, but is there anything short of self-extinction that we could do to stave off the worst of the effects of our own industrial lifestyle? Weisman suggests:

What if we tried one child per family for everyone? I don't want to deprive people of siblings, but I don't want to deprive people of species that are wonderful and part of our life. We can't live without them. If we could bring our numbers down, that would buy us some time to clean up our act.

Sticking to one kid per family, by the end of the century we could reduce the planet's population down to around one and a half billion people - about what it was in 1900. Perhaps that might buy us enough time if we also take the vital step of beginning a project of rapid de-industrialization that is the only solution that could both save humanity and the planet while at the same time preserving human freedom.