PARIS: Scientists on Tuesday designated a small body of water near Toronto, Canada as ground-zero for the Anthropocene, the proposed geological epoch defined by humanity’s massive and destabilising impact on the planet.

Layered sediment at the bottom of Lake Crawford — laced with microplastics, fly-ash spread by burning oil and coal, and the detritus of nuclear bomb explosions — is the single best repository of evidence that a new, and challenging, chapter in Earth’s history has begun, members of the Anthropocene Working Group concluded.

“The data show a clear shift from the mid-20th century, taking Earth’s system beyond the normal bounds of the Holocene”, the epoch that began 11,700 years ago as the last ice age ended, working group member Andy Cundy, a professor at the University of Southampton, said.

After years of deliberation, the Canadian lake was selected from among 12 candidate sites around the world — including another lake, coral reefs, ice cores and an ocean bay in Japan — as the Anthropocene’s so-called golden spike.

“The sediment found at the bottom of the Crawford Lake provides an exquisite record of recent environmental change over the last millennia,” said working group chair Simon Turner, a professor at University College London.

“It is this ability to precisely record and store this information as a geological archive that can be matched to historical global environmental changes.” Those changes are currently on dramatic display: last week was the hottest globally on record.