Q: What should be considered the geological marks of the Anthropocene?
DG: There are a number of reasonable suggestions for this, but my favorite is the signature of the first atomic bomb tests. This produces a signature, both isotopic and in terms of new geological structures, that cannot be interpreted in any other way. And the symbolism is so potent — the moment we grasped that terrible promethean fire that, uncontrolled, could consume the world.
Now, it’s true that humans were altering the Earth before this time, as several scientists have pointed out — for example, land use, agriculture, urbanization and atmospheric carbon dioxide. But, you know, other species have come along and changed the world before and we don’t name a geological epoch after each of them.
What is really different now is that we are aware of our world changing role. Or potentially aware — some of us are at least. So for me, regardless of how you define the Anthropocene, this is when it gets interesting — when the mass of humanity starts to wake up to our world-changing role. And after the Bomb, certainly after Hiroshima, we could not see ourselves, with our world-changing technology, the same again.
Q: How likely is the possibility that we are now living through the planet's sixth mass extinction event? Is it already big enough to be detected in a future paleontology effort using our present methods and capabilities of investigation?
DG: I have heard differing opinions on whether or not the sixth great extinction is assured at this point, but either way it is obvious we are having a significant impact on the evolution of life on this planet and many species have not, will not, survive our presence here. Our impact will be detectable for the rest of time on this planet. (Wipe Out: History's Most Mysterious Extinctions)
For example, it is clear that the existing coral reefs on the planet will not survive our impact. We are going to lose them. This is inevitable now because of ocean acidification even in the best-case scenario.
It is slightly comforting that the reefs have disappeared before, due to past episodes of acidification, and they have returned. So they may be back in the future, but there will be a time of no coral reefs in Earth history that will forever be traceable to the actions we are taking now.
Q: Do you believe the Anthropocene should be classified as a new geological epoch within the Quaternary period, or does it stand for a larger time scale? Might the establishment of the Anthropocene geological time period include the presently known Holocene epoch?
DG: One interesting question about the Anthropocene is how long it might last. Geologically, will it be an event like the K/T boundary (which marks the extinction of the dinosaurs 65 million years ago), an epoch like the Paleocene or a transition like the origin of life?
I think it will either be a brief event recording the failed experiment of our so-called civilization, or it will be a transition to an entirely new planet in which intelligent life has a permanent role in managing the planet. But if we call it an epoch it represents an ambition for our species that is somewhere between these two extremes, and maybe that is OK for now.
Q: How do you rate the chances that the Anthropocene Study Group — established in June of 2009 — can convince the International Commission on Stratigraphy (ICS) in its 2016 meeting to add the Anthropocene epoch to the Geologic Time Scale?
DG: I don’t know. To be honest, I haven’t been following this too closely. It’s really not that interesting to me whether or not it becomes formally adopted as part of the geological time scale. What I’m interested in is the conversations going on about the Anthropocene and what it means to view ourselves as a part of Earth’s geological history. These conversations will continue regardless of what this Commission decides.