A group of scientists say human activity has fundamentally altered the Earth’s geology, atmosphere and biology.
Scientists say human activity has so fundamentally altered Earth’s geology, atmosphere, and biology that it has ushered in a new geological epoch known as the Anthropocene.
On Tuesday, members of the Anthropocene Working Group (AWG) presented evidence of this shift from a lake in Ontario, Canada — evidence they believe may help define the beginning of the new man-made era.
“It is very clear that the magnitude of the changes has increased incredibly and that it has to be human impact,” said University of Leicester geologist Colin Waters, who chaired the AWG.
He explained that human activities “no longer just affect the sphere of the earth, but actually control it”.
Tuesday’s announcement focused on discoveries at Lake Crawford, about 60 km (37 miles) west of Toronto.
Sediments deposited at the bottom of lakes can provide scientists with a geological record of changing environmental conditions.
While the team of scientists collected core samples from 11 other sites, Lake Crawford’s exceptional depth allowed sediments to float down relatively undisturbed, creating strata that can capture unique environmental markers.
Scientists were therefore able to document a “golden spike” between its sedimentary layers: a dramatic and, at least from a geological point of view, sudden change in Earth’s conditions.
Part of this “spike” was evidenced by the presence of plutonium in the lake sediment. Plutonium is rare in nature, leading scientists to conclude it came from nuclear tests in the 1950s.
Geologist Waters said it was a “clear marker” for the transition to the Anthropocene, the Age of Man. He and the other members of the AWG have suggested naming the start of the new epoch between 1950 and 1954.
If accepted, the Anthropocene – derived from “anthropo-“, meaning “man” – would mark the conclusion of the Holocene, the epoch spanning the last 11,700 years.
“Obviously, the biology of the planet has changed abruptly,” Waters added. “We cannot go back to a Holocene state now.”
However, the idea of an Anthropocene epoch has yet to be officially recognized. First proposed by Nobel laureate Paul Crutzen some 20 years ago, the Anthropocene has been hotly debated: scientists disagree on when it might have started or how to define it.
The AWG plans to submit its evidence to the International Commission on Stratigraphy, whose job it is to name geologic epochs in Earth’s history. Several scientific bodies have yet to vote in favor of recognizing the Anthropocene before it is widely accepted.
John Holdren, a former United States White House Science Advisor, is among those who advocate for a much earlier beginning of the Anthropocene. While not a member of the AWG, he still agrees that human behavior is changing the earth in unexpected ways.
“The hubris is imagining that we’re in control,” Holdren told The Associated Press. “The reality is that our ability to change the environment far exceeds our understanding of the consequences and our ability to change course.”