Eon, Epoch, Era - Orders of Timely Magnitude

Yes, yes. We all know that humans are causing global climate change. We’re responsible for increasing CO2 levels, and the resulting increase in temperatures. It seems, though, that we’ve been doing it for a lot longer than just since we started burning fossil fuels.

(Preemptive anti-anti-global-warming comment: So even if we have been affecting the climate for a lot longer than we thought, the amount of CO2 we’re putting into the atmosphere now is way above what we were doing back then. It’s like having some Scotch and thinking, “Well, that didn’t kill me. All those teetotalers are full of crap,” and then going out and drinking a bottle of rubbing alcohol.)

But this isn’t about global warming. It’s about time scales, and how self-centered we are. And I don’t mean that necessarily as a bad thing, just that we quite naturally center everything around us: right here, right now. Take this pair of sentences from the first paragraph of that linked article: “It started 200 million years ago and ended 55 million years later, give or take. For the past 12,000 years, we’ve been living in the Holocene.” When I read that, I hiccuped.

55 million = 55 * 10^6 = 55,000,000 12 thousand = 12 * 10^3 = 12,000

Three orders of magnitude! Really? One epoch is on the order of tens-of-millions of years, and another is on the order of tens-of-thousands? At this point, are we really talking about the same thing? Does the word epoch really apply that broadly?

Oh. Yeah, well, I guess it does.

But still! It seems rather self-centered to consider our measly 10^4 years on planet earth to be on the order of the rest of life. I mean, in the race of life, we’re just barely past the starting blocks. If our 12,000 years of civilization were a mile, then I (as a representative of human civilization) have walked from my house to Constitution Avenue; the lowly cockroach is somewhere off the west coast of Australia.

Sure, we’ve probably had more short-term global impact than the cockroach. But that’s not my point. We have trouble imagining more-than-our-lifespan of years in any given direction, at best. Do we really imagine our civilization is going to make it to even a hundred-thousand years? Can we even comprehend making it to even just one million years?