Last week, at the 35th International Geologic Conference in South Africa, a group of scientists proposed that the Anthropocene be officially recognized as a new epoch. If the proposal is accepted by the International Union of Geological Sciences, we will officially be living in the Anthropocene or “age of humans.”

What is an epoch? And what evidence exists for a whole new time period dominated by humans?

An epoch is a geologic unit of time typically spanning thousands to millions of years in the history of the Earth. New epochs are defined by a “golden spike,” or a marker that will be recorded in rocks all around the Earth. Currently, we’re living in the Holocene epoch, which began approximately 12,000 years ago at the conclusion of the last ice age. The Holocene is characterized by stable global climate and the flourishing of human society. However, beginning in about 1950, human activity has impacted the Earth so strongly that geologists believe our time should be considered a new epoch. Our impact on the Earth is large enough that it will show in the rock record millions of years from now.

So what have we done to make such a mark on the Earth? Unfortunately, most of our legacy will be negative.

As reported by Damian Carrington in The Guardian, human activity has:

• Increased extinction rates way above the long-term average. If we continue on the current trajectory, 75 percent of the Earth’s species will go extinct in the next few centuries.

• Increased levels of CO2 in the atmosphere at an unprecedented pace.

• Dumped so much plastic in our waterways and oceans that fossil records will contain identifiable plastic for many generations to come.

• Doubled nitrogen and phosphorous content in soils with fertiliser use during the past 100 years, the largest impact on the nitrogen cycle in 2.5 billion years.

• Produced a layer of black carbon through burning fossil fuels that will be permanently recorded in sediment and glacial ice.

For the Anthropocene to be formalized, a definitive golden spike must be chosen to identify the start of the new epoch. Many options exist, including radionuclides from nuclear bomb testing, concrete, nitrates, plastic, carbon, and global temperature increase. Whatever ends up being the formal marker, the acceptance of the Anthropocene will impact human civilization as a whole.

This will be the first new epoch witnessed and caused directly by human beings. If that doesn’t scare you, it should. We’ve caused so much destruction that the Earth may be permanently altered, and we’re far from fully understanding the implications our rash actions. Who knows what kind of world our descendants will inherit? And is the threat of a grim future for our planet enough to wake us up to our self-destructive practices?