What Will Be Left of Us in a Hundred Million Years?

It's now generally accepted by scientists that humans have entered a new geologic era of their own creation–the Anthropocene. If you don't think that humanity has modified the environment of the Earth in a way that has affected the very geology of the planet, you need to visit the Art Gallery of Ontario for their exhibition, "Anthropocene", showing until January 6, 2019.

Anthropocene dramatically illustrates how we, individually and collectively, are leaving a human signature on our world.

World-renowned photographer Edward Burtynsky and multiple award-winning filmmakers Jennifer Baichwal and Nicholas de Pencier have created a powerful series of new photographs, including large-scale murals augmented by film extensions, film installations and augmented reality (AR) installations, that take us to places we are deeply connected to – but normally never see.

The artists travelled to countries on every continent, save Antarctica, documenting irreversible marks of human activity. Informed by scientific research, powered by aesthetic vision, inspired by a desire to bear witness, they reveal the scale and gravity of our impact on the planet.

We have reached an unprecedented moment in planetary history. Humans now change the Earth’s systems more than all natural forces combined. This is the central argument of the proposed current geological epoch: the Anthropocene.

It's a powerful and emotionally moving exhibition, well worth the price of admission if you can get to it before it closes. Seeing it raised an interesting question in my mind—what will remain of humanity in deep geologic time, say a hundred million years from now. Will anyone looking at or in the Earth in that far future be able to detect that some form of civilization had blossomed across the Earth? The answer appears to be yes.

In The Fossils of the 21st Century, Maddie Stone looks at what might remain of human civilization a hundred million years from now. It's clear that there would be evidence of our existence in the fossil record, although exactly what it would be remains open for debate.

And some scientists—Zalasiewicz and Bennet included—suspect the fossil record of the Anthropocene will be profound. For one, if humans to continue to drive up extinction rates worldwide, our geologic moment will feature a sudden, dramatic pruning of the tree of life, comparable perhaps to the five major mass die-offs in Earth’s history. At the same time, our industrial takeover has resulted an explosion of new, potentially-fossilizable things, analogous to the trace fossils animals leave behind in the form of nests and footprints.

Zalasiewicz told Earther that the number of potential technofossil “species”, while only roughly estimated, is “at least hundreds of millions”, far in excess of the biodiversity recognizable in the rock record based on fossil shape, pattern, and structure.

“The levels of techno diversity are huge,” he said.

These potential Anthropocene fossils are not only diverse in form, but in composition. For most of life’s 4-billion-year run on this planet, fossils have formed from precious few starting materials: mainly hard-stuff like bones, shells, and wood, and in rarer cases, soft tissues. Modern civilization has gone and expanded the stratigraphic ingredient pantry to include semi-natural substances like concrete, metals rarely seen in nature like aluminum, and things that never existed at all, including artificial glasses, plastics, and an entire family of new gems and minerals.

And then there are chickens, but you can read the article to find out about them.

There's another way of looking at the question. Could we detect a short-lived industrial civilization in the fossil or geologic record of the deep past? If it was like ours, then the answer is yes.

Now that our industrial civilization has truly gone global, humanity’s collective activity is laying down a variety of traces that will be detectable by scientists 100 million years in the future. The extensive use of fertilizer, for example, keeps 7 billion people fed, but it also means we’re redirecting the planet’s flows of nitrogen into food production. Future researchers should see this in characteristics of nitrogen showing up in sediments from our era. Likewise our relentless hunger for the rare-Earth elements used in electronic gizmos. Far more of these atoms are now wandering around the planet’s surface because of us than would otherwise be the case. They might also show up in future sediments, too. Even our creation, and use, of synthetic steroids has now become so pervasive that it too may be detectable in geologic strata 10 million years from now.

You can read the study on which the article was based on arXiv.org.