Earth’s Next Epoch

By Dr. E. Kirsten Peters

I was raised in the Baptist church. As a grade school child, I memorized the books of the Bible. Maybe because of that personal history, when I started to study geology I didn’t resist memorizing the many pieces of the geologic time scale. The next to the last piece of geologic time is the Pleistocene Epoch (known informally by many as the Ice Age). It is followed by the Holocene Epoch (the warm time we are living in now.)

The Holocene Epoch has seen the rise of human civilization. It is the time when people around the world started to shape the surface of the Earth through farming. From the kingdoms of ancient Egypt to the wars of the last century, the history you study in school occurred in the Holocene.

As a geology student I was taught that not only were we in the Holocene, but that we would be for the foreseeable future. But now there’s a move afoot to declare that we are in a new epoch. It’s not just a matter of names, but of our understanding of our place in the world. The new epoch is one in which we humans are taking over the reins from Mother Nature. The proposed new epoch is called the Anthropocene — from “anthro” for people.

Here’s the key: while we humans have been shaping the environment for thousands of years — through farming, early irrigation, and the cutting or burning of forests — our impact on the Earth has been rapidly accelerating.

It’s not easy to see exactly where we should draw the line that marks the start of our biggest impacts. Was it with the Industrial Revolution and the construction of modern cities?

A number of geologists think the line that marks the end of the Holocene should come a bit later.

What’s proposed now is that we declare the Anthropocene Epoch started near the end of World War II. That was the time humans exploded the first nuclear bomb and rival nations started testing nuclear weapons around the world, creating radioactive isotopes that fell to Earth in diverse environments.

This period also saw a new pulse in the increase in global population, as well as the start of industrialization in less developed nations. We poured artificial fertilizer onto fields and produced billions of tons of plastics. The Earth had never seen the like, as a group of scientists called the Anthropocene Working Group recently argued in the journal Quaternary International.

No matter where the line is drawn, the argument is clear that we are entering a new phase of Earth history, one in which we shape more of our own environment. Welcome to the Anthropocene — a time where we are in the driver’s seat. Let’s hope we steer the world as carefully as we can.

Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.