Big Questions in Time

Earth time - a planet in and out of equilibrium

Misha Velthuis

work@mishavelthuis.nl

Thu 13 Feb 2025

Today

Intro

Seeing Earth

Earth as a time planet

Dynamic equilibria

Adding the Anthropocene

The past in the present

The present in the future

Intro

Earth time

#1 Earth: planet in and out of equilibrium

#2 Deep Time

#3) Time is money

#4 The nuclear question

Assignments

Today

No assignment

Mon 17 Feb

Aabsolute and relative dating

(check yes/no)

Thu 20 Feb:

The times they are a-changing

(check yes/no)

Mon 24 Feb:

Graded exam

(N.B.: not 100% sure)

Seeing Earth

Blue Marble

What is happening here? #1

What is happening here? #2

Earth System Science

Earth as a time planet

How old is this?

Form and substance

Agency from the past

Preserving form as elite prerogative

Frantic search for persistence

Survival of form over time is special

It is something rare

Why?

The moon

Time planet Earth

Dynamic equilibria

Another major insight of ESS: Gaia hypothesis

Seemingly contradictory insights

Earth is constantly changing. Time heals all wounds.

Earth remains remarkably similar over time.

Dynamic equilibria

Don't think of a bruised toenail

Tendency to equilibriate

Carbon cycle

Sustainability

For a renewable resource - soil, forest, fish - the sustainable rate of use can be no greater than the rate of regeneration of its source.

For a nonrenewable resource - fossil fuel, high-grade mineral ores, fossil groundwater - the sustainable rate of use can be no greater than the rate at which a renewable resource, used sustainably, can be substituted for it.

For a pollutant the sustainable rate of emission can be no greater than the rate at which that pollutant can be recycled, absorbed, or rendered harmless in its sink.

Timescales

Adding the Anthropocene

How fast are perturbations "overwritten"?

Relatively short residence time

Longer residence time

Even longer residence time

Perturbed atmospheric CO2 concentration

Are we facing a single perturbation though?

Still, in the end,
time heals all
(anthropegenic)
wounds

Traces from the past in the present

"Now that our industrial civilization has truly gone global, humanity’s collective activity is laying down a variety of traces that will be detectable by scientists 100 million years in the future."

Nitrogen
Rare earth minerals
Synthetic steroids
Plastic
Carbon isotopes of fossil fuel

Interesting paradox:

Civilizations that do not find a sustainable way of relating to the planet leave few traces (by the virtue of their quick demise).
Civilizations that do find a sustainable way of relating to the planet leave few traces (by the virtue of the absence of any planetary modifications).

Or how Schmidt & Frank are describing this:

"There is an interesting paradox in considering the Anthropogenic footprint on a geological timescale. The longer human civilization lasts, the larger the signal one would expect in the record. However, the longer a civilization lasts, the more sustainable its practices would need to have become in order to survive."

Schmidt, G. A., & Frank, A. (2019). The Silurian hypothesis: would it be possible to detect an industrial civilization in the geological record?. International Journal of Astrobiology, 18(2), 142-150.

https://archive.is/Y7znE

Traces from the present in the future

The past as the key to the future #1

The (west of) the Netherlands will be given up

Link to coastal risk screening tool (same as slide, but focused on the Gulf of Fragile Masculinity).

From: https://nos.nl/artikel/2271163-kustlijn-opgeven-en-het-hogerop-zoeken-dat-is-een-plan-b-bij-zeespiegelstijging

"Eén meter, of twee, dat lukt nog met een combinatie van zandsuppleties, dijken en natuurlijke opslibbing", zegt de Utrechts hoogleraar fysische geografie Maarten Kleinhans. "Dus als regeringen zich daadwerkelijk aan Parijs zouden houden, dan is dit het scenario." Maar als 'Parijs' niet lukt, dan is er volgens hem een groot probleem. "Ik ben het helemaal eens met de inschatting dat als de zeespiegel meer dan anderhalf à twee meter gaat stijgen, we het niet meer gaan redden met dit land."

Translation:

"If it's just one or two meter, we'll probably manage, with suppletion of sand and overall strengthening of coastal protection", says the Utrecht professor of physical geography Maarten Kleinhans. So if governments actually adhere to Paris, then this would be the scenario. But if 'Paris' does not succeed, then there will be a big problem, according to him. "I totally agree with the estimate that if the sea level starts to rise more than one and a half to two meters, this country won't make it."

"Als we zo doorgaan, zal een groot deel van Nederland opgegeven moeten worden. Verhuizen naar Duitsland zou een onderwerp van gesprek moeten zijn."

Translation:

"If we continue like this, a large part of the Netherlands will have to be given up. Moving to Germany should be a topic of conversation."

Becoming one with the sediment

Brannen: "Only a handful of spots on earth will count themselves lucky enough to get covered in sediment and then subside into the earth, where they’ll remain shielded from erosion and endure the ages unmolested by plate tectonics. These are the fragments of our modern world that have even the slightest chance of leaving any trace in the rocks in the far, far future of geological time. It’s heartening to know that, though its prospects for short-term survival are grim, New Orleans—sitting as it does on the business end of a subsiding sedimentary basin—has perhaps the world’s greatest potential for long-term preservation. If, in 100 million years, a geologist from somewhere on the tree of life discovers the flattened strata of the Crescent City in the side of a canyon, I can think of worse ways to be represented in the fossil record than by this one data point about humanity."

Not so fast. Don't forget the AUC dorms.