Fossil Cities

[Image: Art by Joe Alterio; view larger].

I'm thrilled to announce that BLDGBLOG and Wired Science have teamed up with Swissnex to host a live interview—free and open to the public—with University of Leicester geologist Jan Zalasiewicz, author of The Earth After Us: What Legacy Will Humans Leave in the Rocks?, from Oxford University Press.

The event will be from 7-9pm on Wednesday, December 17th, at Swissnex, 730 Montgomery Street, in San Francisco; here's a map.

Zalasiewicz's book offers a fascinating and sustained look at what will happen to the material artifacts of human civilization 100 million years from now, when cities like Manhattan are mere trace fossils in flooded submarinescapes, Amsterdam is an indecipherably fragmentary presence in the lithified mudflats of a new, future continent, and cities like Los Angeles and Zurich have been eroded away entirely by a hundred million years of rockslides and weather.

To quote an early chapter from Zalasiewicz's book at length:

The surface of the Earth is no place to preserve deep history. This is in spite of – and in large part because of – the many events that have taken place on it. The surface of the future Earth, one hundred million years now, will not have preserved evidence of contemporary human activity. One can be quite categorical about this. Whatever arrangement of oceans and continents, or whatever state of cool or warmth will exist then, the Earth's surface will have been wiped clean of human traces.

(...)

Thus, one hundred million years from now, nothing will be left of our contemporary human empire at the Earth's surface. Our planet is too active, its surface too energetic, too abrasive, too corrosive, to allow even (say) the Egyptian Pyramids to exist for even a hundredth of that time. Leave a building carved out of solid diamond – were it even to be as big as the Ritz – exposed to the elements for that long and it would be worn away quite inexorably.

(...)

So there will be no corroded cities amid the jungle that will, then, cover most of the land surface, no skyscraper remains akin to some future Angkor Wat for future archaeologists to pore over. Structures such as those might survive at the surface for thousands of years, but not for many millions.

The book goes on to explore buried cities, flooded cities, and cities destroyed by erosion; the long-term traces of different materials, from concrete and steel to nuclear waste and industrial plastics; and the future magnetic presence of urban metals that have been compressed into the thinnest bands of underground strata. We'll be talking about cities like New Orleans, London, Hanoi, and Shanghai; New York, Los Angeles, Cairo, and Geneva. What "signals" of their one-time existence will these cities offer in 100 million years' time? About Mexico City, Zalasiewicz writes:

Mexico City has a good short-term chance of fossilization, being built on a former lake basin next to active, ash-generating volcanoes; but its long-term chances are poor, as that basin lies on a high plateau, some two kilometers above sea level. The only ultimate traces of the fine buildings of [Mexico City] will be as eroded sand- and mud-sized particles of brick or concrete, washed by rivers into the distant sea.

With visions of cities become not spectacular, vine-covered ruins but but vast deltaic fans of multi-colored sand, the book looks at the future geological destinies of everything from plastic cups to clothes.

Alexis Madrigal, from Wired Science, and I will also have five copies of Zalasiewicz's book to give away to attendees, and there will be drinks and light food after the event, so it will be well worth coming out.

If you get a chance, please RSVP at the Swissnex site, so that they can keep track of expected visitors.

(With special thanks to Joe Alterio for the artwork!)