Comment by photochemsyn | Hacker News Reader

Comment by photochemsyn | Hacker News Reader

A million years from now, there will be a sedimentary record as distinct and unusual as that caused by the Chixculub crater impact, coinciding with the 20th century human population explosion and widespread industrialization and fossil fuel use. From the article:

> "Years of debate among the group’s multidisciplinary members led them to identify a host of signals — radioactive isotopes from nuclear-bomb tests, ash from fossil-fuel combustion, microplastics, pesticides — that would be trapped in the strata of an Anthropocene-defining site. These began to appear in the early 1950s, when a booming human population started consuming materials and creating new ones faster than ever."

There's also just the sheer mass of material being moved and redistributed due to things like mega-dams, large-scale mining and earthmoving, construction etc.

> "Human activities have increased fluvial sediment delivery by 215% while simultaneously decreasing the amount of fluvial sediment that reaches the ocean by 49%, and societal consumption of sediment over the same period has increased by more than 2,500%."

"Earth’s sediment cycle during the Anthropocene" (2022)

https://www.nature.com/articles/s43017-021-00253-w

I don't know why anyone would want to deny this reality, other than to avoid international regulation of certain kinds of activities, like burning coal, for example.

This does not make us a geological era: we're an event. 200 million years from now, the descendants of some crafty octopus or african-grey parrot would most likely call us the 5th global extinction event: one certainly thin layer due to depletion of things to burn. Best case we're fusion-powered and the rest looks like The Expanse, worst case we lose technology for lack of resources and overabundance of conflicts, then it's clever hominids and their superstitions waiting for an asteroid, pandemic, volcanoes to come knocking...

A distinct layer arising due to unusual circumstances that did not exist before, or after, the time that the layer was created in the geologic record would, basically by definition, make it a geological era.

If we were studying an extraterrestrial planet and discovered that there had been intelligent creatures in the deep past of that world that then went extinct, who had altered their world while they were around as much as we have, we'd probably select it as the #1 dividing line in the geological record for that planet. And not just for intelligence-centric reasons. It would be a logical way to segment it. For example, you're gonna have long-lived synthetic isotopes in the layers above, and not in the layers below.

An era is too long. It is controversial as a proposed epoch/series which is two levels down from an Era/Erathem in the geological time scale hierarchy.

>we're an event

I've heard us described as the Anthropocine Extinction

https://www.nhm.ac.uk/discover/what-is-the-anthropocene.html

> then it's clever hominids and their superstitions waiting for an asteroid, pandemic, volcanoes...

..., global warming.

But in all seriousness, do humans alter the Earth's surface more than e.g., insects or worms do? Has anybody quantified this?

How can this question be serious? Across the street from me there is a 20 story building made with concrete that was hauled from dozens or hundreds of miles away, food from a thousand miles away with cars parked in the parking lot made with materials strip mined on the other side of the planet.

You severely underestimate the amount of earth moved by insects and worms, by a lot.

I was at the Australian Museum a couple weeks ago, and when I looked at the dinosaur skeletons I realized that one of the most confounding things future paleontologists would discover at this sedimentary layer would be all the completely intact giant birds.

Wow, that's an amazing thought! And then they'll have to come up with some theory like Punctuated Equilibrium, because they'll see these forms haven't changed in 66 million years...

It's worse than that. They completely disappeared. Just to reappear without a change 66 million years later.

(Or, alternatively, what happened would be completely obvious, but I still can imagine our scientific community divided over this and some convoluted explanation.)

Aren't those all models made of plaster?

If we're talking about the ones stored in museum vaults somewhere- then future species will think the hominids coexisted with those giant avians, possibly as their supplicants or praetorians.

> A million years from now, there will be a sedimentary record as distinct and unusual as that caused by the Chixculub crater impact

Are you a time-traveler or a prophet?

You can already see it by taking a sediment core from any undisturbed lake bottom in the world, just look for first appearance of the bomb radioisotopes and DDT residues as you go up the core from deeper to shallower layers.

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