Anthropocene: This lake in Canada could prove we’ve entered a new chapter in Earth’s history

Scientists believe that human activity has altered the geology, atmosphere and biology of Earth so much that it has now entered its newest epoch: the Anthropocene.

On Tuesday (11 July) the Anthropocene Working Group (AWG) released evidence that they believe shows the start of this new geological time period in the planet’s 4.5 billion year history.

Though climate change, pollution and biodiversity loss have all made an indelible impact on the world, it is a lake just outside of Toronto, Canada, that they say is the location which marks this geological break.

Crawford Lake is a 29 metre deep body of water and it is this depth that makes it ideal for studying distinct historical environmental markers. Humanity’s effect on Earth’s atmosphere, soil and biology are all preserved in the sediment that lays at its bottom.

“The sediments found at the bottom of Crawford Lake provide an exquisite record of recent environmental change over the last millennia,” says Dr Simon Turner, secretary of the AWG from University College London.

Scientists believe they can pinpoint the exact start of the Anthropocene epoch by documenting what they call the “golden spike” in these layers of sediment. This is a sudden and dramatic - at least in geological terms - change in the conditions.

Part of this “spike” is the presence of plutonium at the bottom of the lake. The element only occurs naturally in trace amounts and so experts from the AWG concluded that it must have come from nuclear testing in the 1950s.

“The presence of plutonium gives us a stark indicator of when humanity became such a dominant force that it could leave a unique global ‘fingerprint’ on our planet,” says Professor Andrew Cundy from the University of Southampton, another member of