The latest Long Now podcast, by David Grinspoon, takes a very long view indeed. As we transition from the Holocene to the Anthropocene, he thinks, we’re not just entering a new geological epoch, as shown here:
That alone would be a big deal. But epochs are just geologic eyeblinks a few million years in duration. Grinspoon thinks we might be entering something way bigger. Not just a period or an era. We might happen to be alive now at an eon boundary, as shown here:
There have only been four eons so far. Each was a major transition in earth history — a shift in the relationship between life and the planet. Life first emerged at the beginning of the Archean era around 4 billion years ago, when things cooled down enough. Around 2.5 billion years ago, cyanobacteria learned to photosynthesize. They bathed the world in oxygen, caused mass extinction, and deeply entangled life with the physical and chemical workings of the planet. At the boundary between the Proterozoic and Phanerozoic, around 500 million years ago, life went multicellular, plants and animals appeared, and the modern eon began.
Will our descendants look back on the Anthropocene as the dawn of a fifth eon? Grinspoon makes a compelling case that they might. The Archean cyanobacteria that poisoned the environment couldn’t know what they were doing. We can. Our infrastructure is taking over the planet as surely as the oxygenated atmosphere did. But it is, at least potentially, under our conscious control. The hallmark of the Sapiezoic eon he envisions: intentional re-terraforming.
Grinspoon cites one shining example: the Montreal Protocol that will, if we stay the course, reverse manmade ozone depletion. “We are as gods,” says Stewart Brand, “so we might as well get good at it.”
I’ve listened to all the Long Now podcasts, some more than once. This one rates very highly. It’s a great talk.