Explaining the Anthropocene

The term “anthropocene” has been getting thrown around recently to help understand humanity’s impact on the earth. But what does it mean? In this podcast, I break down the term and why people use it at a level appropriate for a middle schooler interested in the environment.

Podcast transcription:

I want to talk about my favorite stream. It’s called Four Mile Run, and it’s right near where I live in Arlington, Virginia. When I was a kid, I’d bike up and down the trail there, whizzing past old couples and birdwatchers and moms with strollers. It’s a really pretty place, with running water lined with trees, and it feels (quite literally!) like a breath of fresh air. It was, for me, my little piece of nature.

But lately, I’ve been thinking more and more about what it means to call something “nature.” After all, can a stream just a few miles from a big city, crisscrossed by concrete paths and asphalt roads, really be called natural?

Hi everyone, welcome back to Science Words with Sam, the show where we break down tough concepts in simple ways. Today, we’re going a little off the beaten path: the word of the day is Anthropocene. 

Before we get started, I wanted to welcome all our listeners, new and old, young and… old back to the podcast. We’ve got a really fun show on our hands today. We’re gonna be talking about nature and how people affect it. That’s what our word of the day, Anthropocene, is all about. To help us get into the nitty-gritty details, I want to talk more about my stream.  

There used to be a railroad that ran down Four Mile Run. It started way out in farm country and brought fruits and vegetables and animal products down to the port in Alexandria. But eventually the railroad ran out of money, and the community decided to rip up the train tracks and put in a bike trail. Trees that had been cut down when they built the railroad were replaced with new growth, parts of the stream that had been put in tunnels were dug back up and exposed to air, and the ecosystem started to rebuild itself. 

When I bike down Four Mile Run, what I’m seeing isn’t untouched nature. The lovely landscape that I think of as natural is different in practically every way than the ecosystem that came before the railroad. Everywhere, we can see the impact of human life. 

Let’s think even bigger: is there any part of the world where you can find an ecosystem that’s totally and completely natural? It’s harder than you might think. Even in the farthest reaches of the Amazon Rainforest, life is affected by increased carbon dioxide in the atmosphere, chemicals in the air and water, and so much else. Even in the darkest depths of the Mariana’s Trench, 7 miles down, there’s plastic floating around!

It’s a sign of the times: everything in our world has been changed by human activity. Some scientists say we need a whole new word to describe the era we’re living in. This is what they’re calling the “Anthropocene.” 

It sounds confusing — scientists do that sometimes — so let’s break it down. “Anthropo” comes from an ancient Greek word meaning “human.” “-cene” comes from geology. Geologists name eras things like the “pleistocene” or “holocene,” so “anthropocene” is just the next one in line.

Now, you might be asking yourself, how long has this “anthropocene” thing been going on? As it turns out, that’s a question at the heart of the anthropocene debate. Some scientists say we should look all the way back to the birth of agriculture over 10,000 years ago. Others think a better start date is more recent, something like the start of the Industrial Revolution a few hundred years ago. Still others pick nuclear weapons or colonization as good starting points.

In 1610, the amount of CO2 in the atmosphere reached a historic low. When Europeans came to the Americas, many Native Americans — as many as 50 million — were killed. Without people tending croplands and forests for their own use, these ecosystems started sucking up carbon from the atmosphere like a sponge. Simon Lewis and Mark Maslin, authors of an important paper about the date debate, call this the Orbis Spike, from a Latin word meaning “world.” They say the Orbis spike is one of the two best dates to use to start the anthropocene.

The other date comes not from colonization, but from nuclear weapons. In 1964, the amount of atmospheric Carbon-14, a radioactive type of carbon that comes from nuclear bombs, reached an all-timee high. We can measure the impact of both colonization and nuclear weapons consistently around the world, unlike the more wishy-washy measures that come with industrialization or agriculture, so both work as start dates. Picking between the two is, at least in part, a question of what you care about.

Lewis and Maslin say that “the Orbis spike implies that colonialism, global trade and coal brought about the Anthropocene.” On the other hand, “choosing the bomb spike tells a story of an elite-driven technological development that threatens planet-wide destruction.” Two different stories, both very scary, and both suggesting different ways to think. 

This issue is big! The anthropocene is important not just because it is different than before, but because it affects people in different ways. It’s good to know about the anthropocene, but why bother defining it if we’re not going to do anything about it? Starting the anthropocene with either colonization or nuclear weapons gives us the chance to have real, meaningful conversations about these issues.

In all honesty, you and I probably don’t have to worry about specific terms and details like Carbon-14 or the Orbis Spike or any of that. But we do have to worry about the ecosystems, natural and man-made, that we interact with. And, we have to worry about the people whose lives are impacted by the environment, whether that comes in the form of rising sea levels, deforestation, or anything else. It means recognizing the beauty of a bike ride down Four Mile Run, and recognizing the humanity of people hurt by environmental changes. 

Alright, that’s all we have for the show today. Thanks for tuning in, and I’ll see you all next week. 

[Featured Image by Malte Wingen on Unsplash]

Written by Sam Libberton