So you want achieve everlasting fame by becoming immortalized in the rocks of our earth? Well, move to Amsterdam and join the local mafia! For the reasons why, you’ll have to follow me as I tell the longer story.
You and I will not live forever. When we die we will leave behind our bodily remains, writings, a lot of waste materials, some craft work and maybe some intangible traces like footprints. I’ve often wondered what the chances are that an archaeologist of the future will find these remains. On a grander scale, I wonder whether these traces are durable enough for future palaeontologists to unearth them in millions of years. And if they do, would they be able to recognize and reconstruct aspects of the human species? What will they learn from us, when they uncover their Lucy (or Lucas) ?
Having played with these thoughts before, I was amazed when I discovered a book hiding in a small corner of Waterstone’s in London, answering these questions ! I devoured the book in a couple of days and now want to convince you of its awesomeness.
In The Earth After Us by paleontologist Jan Zalasiewicz, an alien race discovers our earth 100 million years after the human race went extinct. The first part of the book covers the basics of geology, as the aliens (and the reader) first get familiar with the basic workings of our planet. Sedimentation, erosion and plate tectonics all get introduced as simple concepts such as ‘strata machines’ and ‘tectonic escalators’, which is perfect for a layman like me.
The book picks up speed after this introduction, as Zalasiewicz discusses the fate of the cities that we have built. Do these human environments have any chance of preservation? Can a city fossilize? The answer is yes, but most cities won’t last to see that day. Many inland cities will erode away entirely. Even the mightiest skyscrapers will topple when atmosphere and rain corrode their steel and turn their concrete porous. A thin layer of sediment will be all that remains of Beijing, Rome and Paris.
Like most fossils, a fossil city will have to be buried partly or entirely if it wants to enter the fossil record. Plausible candidate cities for fossilization include Amsterdam, London, New Orleans and Dhaka. As coastal cities they are likely to become submerged by the sea as it will rise in the coming decades. The river deltas on top of which they are built will make sure of the quick burial, as they continuously bring in new sediment.
After this unceremonious burial, the petrification of our cities will start. The weight of mud and sediment will crush and distort our former homes and factories. While paper and other decomposable materials will be food for the fishes, glass, bricks and concrete have better odds of survival. Most metals will dissolve though, leaving nothing but the plastic shells of all the electronic gadgetry that we have produced. Perhaps some iron interiors will turn into pyrite. Just think of those alien palaeontologists that will be admiring your pyrite laptop interior in 100 million years!
What about our own chances of fossilization? Our fossilization potential seems to be pretty high. First of all, with billions of humans living on our planet, at least some of us will be great candidates for fossilization. We inhabit one of the widest range of habitats, from the highest mountains to coastal regions, further increasing our fossilization odds. The cultural practice of burying human remains into the earth also helps a lot. Microbes and insects will still decompose the organic material, but the skeleton will largely remain intact.
But for the most ambitious fossils to be among you, this is not enough. If you’re serious about this fossilization business, you probably want to be preserved with soft parts and all, such as the creatures of the magnificent Burgess Shale and Chiangjiang deposits. Rapid burial in thick layers of mud seems to be the way to go. Upsetting some criminal elements and getting dumped in Amsterdam’s canals with a pair of concrete boots should do the trick! Such superb long term preservation comes at a cost of short term health, I’m afraid.
Luckily, Zalasiewicz isn’t afraid to steer the discussion about the future of mankind in the rocks beyond the technicalities. For example, what will the scientists of the future make of this strange creature with its upright posture and large cranium, so unlike the other animals of this planet? What will they think when they uncover our twentieth century graves of war? Will they make the link between the arrival of man and the current wave of extinction, sudden release of carbon dioxide and associated rise of temperature and sea levels? How will we be judged?
These are important questions to ponder. Not just for our future image, but for the future of our children and the rest of humanity. Jan Zalasiewicz phrases this eloquently:
The deeper the footprint that we leave, the greater will be the immediate calamity that awaits our children. [...] Best to leave as small a message as we can, to impress today’s human footprint as gently as possible into the strata of tomorrow: to diminish, in as far as we can, the stratigraphic signal that we leave behind us.
~ Jan Zalasiewicz (2008), The Earth After Us, p. 239
The Earth After Us is a wonderful and thought provoking book. I’ve learnt a great deal about geology, geochemistry, climatology and paleontology. Any book about the future of mankind and this world will be speculative, but Zalasiewicz lays out his arguments well, based on hundreds of years of advances in geological and paleaontological science.
On a last note, I hope that Zalasiewicz will write the science fiction version of this book one day, as fragments like these make me hungry for more:
It would be wrong to say we understand these long-dead city-builders. [...] Their extinction is a great pity. For all the possible dangers of contact with a species associated with such planetary instability, with such changes in their habitat, what might we have learned about them – and from them – had they survived?
~ Jan Zalasiewicz (2008), The Earth After Us, p. 219
You might also like: