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Shifting your mind to ‘geologic time’

Marcia Bjornerud on deep time and the planetary future

Photo illustration by Mark Riechers/Midjourney (TTBOOK)

Marcia Bjornerud would like to change the way you think about time. This is not so surprising for a geologist who spends days contemplating millennia and eons, which tends to put yesterday’s headlines in perspective.

Most geologists have an uncanny ability to look at a landscape and mentally erase the past ten thousand years or so. But Bjornerud, a professor of geology and environmental studies at Lawrence University, believes learning to think in longer timescales and about the planet’s deep past is essential for anyone who cares about the future.

Bjornerud wrote lyrically about Earth’s temporal rhythms in her landmark 2018 book, “Timefulness: How Thinking Like a Geologist Can Help Save the World.” Anne Strainchamps with “To The Best Of Our Knowledge” caught up with Bjornerud to see how her thinking has evolved since then.

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This interview has been edited for clarity and length.

Anne Strainchamps: Marcia, why do you think we have such a hard time relating to deep time? I mean, we know that we live on shifting tectonic plates. We’ve been to museums and marveled at dinosaur fossils. And yet, most of us can’t really conceptualize time in those terms. Do you think it’s because the numbers are just too big?

Marcia Bjornerud: I think it’s so many things, ranging from personal vanity and the fear of aging — we’re constantly told aging is a bad thing — to the way our economy and political systems run. We’re always on a two-year congressional cycle or an annual report business cycle, so we have a very blinkered view of time.

There’s also an irony in the fact that we’re living longer, at least in Western countries, which allows us to have the narcissistic idea that we’ll live forever. I think when people had to contend more with the fact of their own mortality, they were more aware of their place in the continuum of humanity.

So of course we’re intellectually aware of dinosaurs and the geological record, but I don’t think most people have had the opportunity to internalize what that means. So I’m trying to open the doors to people and help them see landscapes and rocks not as inert and insensate, but as fellow inhabitants of Earth that have stories.

AS: Yeah, when you write about the previous ages of the Earth, it feels like the past is not dead.

MB: Absolutely. I mean, the rocks that formed in the distant past, those old ones are still with us, and they shape the landscapes we’re familiar with. They’re interacting with modern day climate. So they’re not dead. One thing I often say in my intro geology classes is that rocks are not nouns, but verbs. They’re not static and inert, they’re active.

AS: There are Indigenous cultures that have the concept of rocks as alive and in some cases conscious. Does that resonate for you?

MB: It does in the sense that I think rocks are sentient and paying attention to their environment. But I hesitate to say they’re conscious in any simple human sense. I talk to rocks, but they don’t often reply to me. I can say that I have a relationship with some rocks — I love the beautiful purple Baraboo quartzite — but I think it’s probably an unrequited love.

So I hesitate to answer the question, but I know that for myself, having spent so much of my adult life in the company of rocks, they are good companions.

AS: In Western culture and in science, we draw a line between animate and inanimate. So is that a division that is meaningful to you? Or would you want to trouble it a bit?

MB: Well, as a structural geologist, I do think of rocks as animate. Mountains don’t just exist, they grow. They come into being through tectonic collisions, and we can model them growing. Rocks are moving. So in that sense, I will say, yes, rocks are animate. No question about it.

AS: And what about the Earth itself? Would you say Earth is conscious?

MB: Well, one recent definition that I’ve read for consciousness has to do with the degree of connectivity between components in a complex system. If that’s the criterion for consciousness, then yes, Earth is conscious, because everything is interconnected from the center of the earth to the surface.

There are so many examples. For instance, the process of subduction. That’s the signature tectonic process of earth, in which the ocean crust, once it becomes cool and dense enough, sinks back into the mantle and can generate terrible earthquakes and tsunamis in places like Indonesia or Japan. That process is essential for the long term habitability of the earth, because it unites the atmosphere and the hydrosphere system. There’s probably an ocean’s worth of water in the earth’s mantle, which is kind of a planetary savings bank. And eventually, that’s exhaled again through volcanism.

AS: Sounds like the planet itself is breathing.

MB: Yes, in the sense that volcanoes are exhaling and subduction is inhaling. And there’s some kind of deep wisdom there, because these aren’t just connected cycles, they’re processes that maintain some kind of steady state.

AS: Do you think the perspective of deep time can help with any of the existential fear and dread that comes with an awareness of climate change and global warming? Does being aware of the many long ages of the planet put climate change in perspective? Or make it more frightening?

MB: From a scientific point of view, I can say that Earth will be fine. The Earth will deal with the changes in climate that we’re causing and eventually, new ecosystems will emerge.

But the human part of me mourns what we’ve done and the rapidity with which old, well-established ecosystems and landscapes have been changed. And I worry for humanity, for what the next decades or century will bring as we cope with a new set of rules. That’s the scary thing to me. We’ve been able to understand the way the planet has worked through the Holocene, but now we’re changing the boundary conditions and parameters, and so many of the models we’ve developed aren’t going to be very relevant as we go further into the Anthropocene.

The past won’t necessarily be a key to the future. And there’s real sadness there. Our cultures have grown up with a certain version of Earth, and it’ll be radically different.

AS: So there are real stakes to thinking and talking about deep time. It’s not just about waking up to the geological wonder of life on this planet, or being able to perceive more of the magic beneath our feet — it’s about the future of the planet and our species.

MB: To me, it’s about recognizing that we’re part of a continuum. We live in geologic time, too, so there’ll be a geologic future. If there’s a deep time, there’s a deep future as well. And we should envision ourselves in that future geologic time.

The Anthropocene, for example, is an important concept that most people are aware of now. But in some ways, I think it’s preventing people from seeing past the current moment. The Anthropocene is all about the much-too-large footprint we are having on the planet. I’d like us to start thinking about a post-Anthropocene world, in the distant geologic future. How can we imagine ourselves living differently as human earthlings?

AS: Maybe by imagining what the Earth might be like without us?

MB: I’d like to think we will be here, that there will still be humans. I think we can do better.