Secondary Geography

Kit Marie Rackley

Secondary Geography Subject Specialist

Are humans having such an impact on the Earth that we are impacting the geological record? A timeline of rock and sediment that could be read millions into the future? While the debate whether we could recognise a new geological epoch, dubbed the ‘Anthropocene’, has been going on for decades, recent news suggests a growing body of scientists think we should make it official.

Back in October 2020 I wrote and performed a presentation for a ‘jovial’ kind of TED talk. Here, on the back of recent news, I share this with you. You can watch the presentation over at GEOGRAMBLINGS, or you can read the text below. Either way, enjoy!

The Anthropocene: Does arrogance outlast decay?

The ‘Anthropocene’ – a unique period of Earth’s history in which humans are one of the dominant forces of nature. But the debate is still feverish whether we should be formally designating the current period of history with this term. And perhaps one of arrogance, too. Are we having such a profound impact on our planet that when, not if, decay sets in, our mark will be forever present?

The concept of the ‘Anthropocene’ has been around amongst scholars for over 150 years, but it was Soviet mineralogist and geochemist Vladimir Vernadsky who, in the 1920’s, first pioneered the thought that living organisms could reshape the planets as “surely” as any physical force. He was a man who was so dedicated and passionate to the synergetic, transcendent and collaborative nature of science despite the dramatic historical events of the early 20th century that impacted his everyday life. On top of this, his work was largely dismissed by the West until decades later, but it is now recognised that Vernadsky was a pioneer for many concepts that make up what we know today as ‘Environmental Sciences’. Scientific controversy over out impact on the Earth was true then as it is now.

Fast forward to 2011, and this quote: “It’s a pity we’re still officially living in an age called the Holocene…” said a Nobel Prize for Chemistry winner “…The Anthropocene – human dominance of biological, chemical and geological processes on Earth – is already an undeniable reality.” This quote to me, is academic in nature, but does have a tone of arrogance to it. This Nobel laureate had a rather fiery outburst at colleagues during a meeting in 2000 – the constant use of the word ‘Holocene’ was apparently making his blood boil!

This passion and ‘arrogance’ came from Dutch chemist Paul J. Crutzen. Months later, Crutzen teamed up with American biologist, Eugene Stoermer, and expanded on the idea – the popularisation of the concept began.

But let’s leave the origin story and turn to context. We’ll use a human arm for scale. If Earth’s lifespan, all 4.5 billion years of it, was the length of an arm and Earth was born at his armpit, then it’s not until you get to the knuckles that the Phanerozoic Eon (542ma) began with the Cambrian explosion and trilobites! Dinosaurs roamed the Earth on the upper index finger, ending in the infamous meteor 65ma that saw their demise. This is the Cretaceous–Paleogene (K-Pg) extinction event. Humans have only been around for the distal (free-edge) of the fingernail, and us trolling the Earth in epic arrogant scale has been microscopic in terms of time. So, the ‘Anthropocene’ could be seen as a very arrogant claim in terms of deep time. Has our impact already been so profound? Bear in mind that the next time you bite your nails (as I do too often), you’ve just erased all of human history!

Ok, I’m a huge sci-fi and fantasy fan. So, indulge me on a thought experiment here popularised by the 2009 book “The World Without Us” by Alan Weismann. First (SPOILER ALERT for Avengers: Infinity War), let’s say Thanos decided to use the infinity stones to rid the Earth of all human life instead of half of it, leave all else untouched. Then what of our arrogance might endure? What might take longest to decay?

The Channel Tunnel, or “Chunnel” which connects England and France is built within the rock under the English Channel. It may remain passable for a while to allow migrating animals, until sea level rise floods the French end. Continental movements after millions of years would be the death knell for it. It tickles me to think that it would grate Nigel Farage, Brexit stalwart, to learn that this physical legacy of joining Britain to Europe will long outlast his efforts to separate the UK from the EU.

Everyday stainless-steel items, such as… nunchucks… odor bars to get rid of that pesky sulphur… and chainmail gloves… would last millions of years if they ended up buried and fossilised.

Mount Rushmore in South Dakota is carved out of granite with intrusions of pegmatite, exceptionally resistant to weathering, eroding only one inch every 10,000 years. Noses disappear within 2.5 million years. Heads lose their definition around 7,000,000 years. Typical, and the epitome of privilege, that a monument to a bunch of white, cisgender, old dudes would last for so long. But an attempt to ‘decolonise’ that would be the monument to Crazy Horse, also made out of pegmatite granite. Being larger and more defined than Rushmore, let’s get Crazy Horse finished before Thanos snaps his fingers, so it would outlast the colonials.

And I know, I’m cheating here. But the human artefact that is most likely to last into the billions of years is within an environment lacking the agents of weathering and erosion. Our activity on the moon will last except in the unlucky event of a direct meteor strike!

I haven’t covered the ‘usual subjects’ of human artefacts that will be contained in a geological record. Atmospheric carbon, petrochemicals, and mass extinction get enough coverage as it is, so let’s focus on the root of these; human arrogance.

Flipping the title of this talk, let’s ask does arrogance cause decay, and look at the Anthropocene not as a geological era itself, but more like an event, like the meteor that caused the extinction of the dinosaurs and the K-Pg geological boundary. That event has its fallout showing up as a slither of small layer of deposits.

Sticking with scale, here we are, trolling the Earth on a Crazy Horse distal. But how does the ‘Anthropocene’ compare in terms of timescale to say the K-Pg boundary? If I make those lines representing these events a certain thickness to match their timescale, then this is what they look like. Various start dates for the Anthropocene have been proposed; let’s be generous and go from the earliest estimate of the Agricultural Revolution of 15,000 years. And for the K-Pg boundary, we’ll use deposits in the Denver Basin that shows that the interval between the extinction of the dinosaurs and the appearance of earliest Cenozoic mammals was around 185,000 years. In other words, the last extinction event lasted roughly 12 times longer than our current influence on this planet.

The K-Pg event caused ¾ of life of plant and animal species on Earth to go extinct, but like extinction events before it, life recovered and led to an explosion in ‘evolution’ and diversity, filling niches left by the dead. 90% of mammal species were snuffed out by the asteroid, but they recovered and then some within just a few 100,000’s of years, they went on to evolve into horses, whales, bats and our primate ancestors. So, what might life look like after the decay brought on by our trolling activity?

Well, there will be life, but to quote Spock from 1987’s pop song Star Trekkin’!, “It’s life, Jim, but not as we know it!” Now of course we have no way to know for sure, but some educated guesses based on science, formed part of a wonderful 2019 BBC Future article. So, get your head around these possibilities…

If hotter, drier conditions persist in the future due to climate change, then “Larger animals might evolve things like extended sails or skin flaps that they could extend out in the early morning to try to capture moisture.” to quote Patricia Brennan, an evolutionary biologist   “The frilly collars of some lizards, for example, could become very large and exaggerated to gather water in this way.” The frilled-necked lizard from New Guinea & Australia, plus fog harvesting nets in Peru equals… the fog-net-necked lizard!?

You may, or may not, have heard of the 19th century hoax of the Madagascar ‘man-eating tree’ or the myth of the Yateveo, the latter being a carnivorous tree with huge poisonous spines? Today, the ‘walking palm tree’, native to Central and South America already exists, and so does the more well-known venus fly-trap. Who knows with a million or so years of evolution?

Indulge me one more time… With potential long-term disruption to habitats, there may be a necessity for species to ‘habitat switch’. “Consider a toad whose gullet swells outward as a large gasbag used to make mating calls”. Now what if that toad evolved to be able to fill its gasbag with hydrogen, taken from water allowing it to hop further or even float? So there’s no longer a need for legs, they become tentacles over time. And through natural selection, the toads become bigger to survive predators. A Zeppelinoid! suggests Peter Ward, a palaeontologist at the University of Washington. Zeppelinoids become predators themselves, ensnaring their prey in their tentacles.

I began with a quote from Crutzen, which, on behalf of humanity, has a tone of arrogance. But to end I will return to Vladimir Vernadsky who in 1945, the year of his death, said: “The whole of mankind put together represents an insignificant mass of the planet’s matter. Its strength is derived not from its matter, but from its brain. If man understands this, and does not use his brain and his work for self-destruction, an immense future is open before him in the geological history of biosphere.” A warning to humanity, of their arrogance.

Life will go on after decay, whether it be mass-extinctions from geological upheaval, asteroid strikes, or sheer bloody arrogance. And so, I would like to give us a little ‘hope’ with a toast. And that is we may feel like the events of ‘today’ is causing decay in some form or another, and what comes next may be inconceivable or uncertain. But what appears to be inevitable is that from decay comes rebirth, and an explosion of diversity and evolution. Here’s to what comes next. Cheers.

Visit GEOGRAMBLINGS for the video presentation of this talk, plus a list of references and links.

Visit the Secondary Geography resources

Kit Marie Rackley, 14 July 2023

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