Should The Anthropocene Be Added To The Geological Time Scale?

The Anthropocene is the idea that humans have pushed Earth into a new geological epoch. In March 2024, geologists voted to reject it as a formal unit of the geological time scale, so the Anthropocene remains an informal term rather than an official epoch. Many scientists still use it to describe the scale of human impact on the planet.

The Geological time scale helps us to understand the Earth’s past and the events that have shaped its evolution. It is like a history book that documents the Earth’s past and the various stages of its evolution. It provides a timeline that allows scientists to understand how the Earth has changed over billions of years, from its earliest eras to the present day.

Think of the Geological time scale as a giant puzzle that scientists are piecing together using clues from rock formations, fossils, and other forms of geological evidence.

You’ve probably heard of the term Anthropocene, which refers to the current geological epoch, in which humans are the primary drivers of changes in Earth’s ecosystems.

However, it should be noted that the Anthropocene has not been officially added to the Geological time scale. In fact, in March 2024 the world’s geologists voted to reject it as a formal epoch, a decision we’ll come back to shortly.

There are two schools of thought on whether the Anthropocene should be included, and it’s worth understanding both before we look at how that vote turned out.

What Is The Anthropocene?

The Anthropocene is our current geological epoch, defined by the impact of human activities on Earth’s ecosystems. Agriculture, deforestation, industrialization, and the use of fossil fuels have all resulted in significant changes in the composition of the Earth’s atmosphere, oceans, and land.

In 2000, Nobel Laureate Paul Crutzen coined the term “Anthropocene.” He contended that the Earth had entered a new geological epoch that was fundamentally different from the previous one, the Holocene. Since then, the term has gained popularity and has sparked a great deal of scientific and public debate.

Consider the Earth as a canvas, and humans as artists.

The Anthropocene can be thought of as a time when humans began to paint with new colors and materials that had never been seen before, resulting in a radically different image (on the canvas) than what had previously been seen.

The use of fossil fuels, for example, has had a significant impact on the Earth’s climate and atmosphere, much like a new color can drastically alter the appearance of a painting.

Why Should The Anthropocene Be Added To The Geological Time Scale?

There are several reasons to include the Anthropocene on the Geological Time Scale. The most prominent argument is that the Anthropocene marks a significant and unprecedented shift in the Earth’s ecosystem as a result of human activity.

Human activities have had such a significant impact that they have altered the Earth’s geology, distinguishing it from any previous epoch. By including the Anthropocene on the Geological Time Scale, we acknowledge the impact of humans on Earth’s ecosystems and the need for long-term solutions to mitigate the damage.

The scale and pace of human activity are now so great that they are altering our planet’s natural systems. For instance, the level of carbon dioxide in the atmosphere has increased by more than 50% since the beginning of the Industrial Revolution (from about 280 to over 420 parts per million), and the global average temperature has risen by roughly 1.1–1.3°C.

The Anthropocene’s impact can be seen in ozone layer depletion, climate change, and biodiversity loss. These changes are not only significant, but also irreversible, and long-term solutions are required to mitigate their effects.

Why Should The Anthropocene Not Be Added To The Geological Time Scale?

One of the main arguments against including the Anthropocene is that the Anthropocene is not yet a well-defined concept.

The start of a geological epoch is typically marked by a significant geological event, but there is no clear event that can be attributed to the start of the Anthropocene.

Another reason for not including the Anthropocene on the Geological Time Scale is that it may be premature. Only after several years of research and analysis, geological epochs are typically added to the Geological Time Scale. The Anthropocene, on the other hand, is a relatively new concept, and more research is needed to fully understand its long-term effects on the Earth’s ecosystems.

Even the Anthropocene’s beginning is hotly debated. Some think it started when humans first began farming, others say it didn’t begin until the Industrial Revolution, and another camp points to the mid-20th century.

The International Commission on Stratigraphy (ICS), the body with the power to modify the Geological time scale, requires a “golden spike” before it will add a new epoch. Formally called a Global Boundary Stratotype Section and Point (GSSP), it is a single physical location in the rock or sediment record where a clear, worldwide signal marks the boundary. To define the Anthropocene, the Anthropocene Working Group spent years searching for that marker.

So, Was The Anthropocene Added To The Geological Time Scale?

For a while, it looked like it might be. In 2023, the Anthropocene Working Group settled on its golden spike: the muddy bottom of Crawford Lake, a small, deep lake in Ontario, Canada. The lake’s sediments form neat annual layers, like tree rings, and the layer corresponding to 1952 contains a spike in plutonium from hydrogen-bomb tests, along with fly ash and nitrates from burning fossil fuels and spreading fertilizers. The group proposed this mid-20th-century layer as the start of a formal Anthropocene epoch.

Then came the vote. In March 2024, the Subcommission on Quaternary Stratigraphy, the panel of experts responsible for this part of the time scale, rejected the proposal by a wide margin (roughly 12 votes to 4). The International Commission on Stratigraphy and the International Union of Geological Sciences (IUGS) both upheld that decision later the same month, making it official: the Anthropocene is not a formal geological epoch.

The main objections were the ones the skeptics had raised all along. A few decades of lake mud is a vanishingly thin sliver of the geological record, and pinning a global epoch to a single moment in the 1950s struck many geologists as too narrow a definition for something as sprawling as humanity’s footprint. Officially, then, we are still living in the Holocene, the epoch that began about 11,700 years ago.

That isn’t quite the end of the story, though. In its statement, the IUGS noted that the Anthropocene will keep being used by Earth scientists, social scientists, and the public as a powerful way to describe how profoundly humans have reshaped the planet, just not as an official tick on the geological time scale.

A Final Word

For now, the geologists have spoken: the Anthropocene will not appear as a formal epoch on the Geological time scale. Yet the debate it sparked is far from settled, and the term itself is going nowhere. Supporters still feel that naming the Anthropocene is a way of acknowledging the human impact on Earth’s ecosystems and the need for long-term solutions to mitigate this damage. Skeptics counter that the rock record is simply too young to justify carving out a new epoch just yet. Both sides, tellingly, agree on the underlying point: human activity has changed the planet on a scale that is impossible to ignore.

We must consider how our actions will impact the Earth in the future. It is up to us to reduce the damage we are causing and to develop more sustainable ways of living. The Anthropocene should serve as a reminder of the importance of being responsible and sustainable. We must act now to ensure that future generations inherit a healthy and sustainable planet.