Plutonium, aluminium, plastic - How humans changed the face of the Earth

Scientists debate the place that best sums up the rise of Homo sapiens and dawn of the Anthropocene era

- Robin McKie

This month, geologists will select a site that demonstrates most vividly how humans have changed the structure of our planet’s surface. They will choose a place they believe best illustrates when a new epoch – which they have dubbed the Anthropocene – was born and its predecessor, the Holocene, came to an end.

The Holocene began at the conclusion of the last ice age 11,700 years ago as the great glaciers that had previously covered the Earth began to retreat. In their wake, modern humans spread inexorably across the planet.

Homo sapiens flowered during the Holocene but our expansion had geological consequences. The minerals we mined, the gases we released by burning fossil fuels and the radioactive material we have produced have begun to make fundamental changes to Earth’s geology.

Many scientists believe the Holocene is over and they have given the name Anthropocene to its replacement, a move that recognises humans as planetary influencers for the first time. As to the date of this event, most point to the years that followed the second world war when countries worldwide embarked on a massive economic and industrial expansion. This triggered the Anthropocene, it is argued.

But exactly where this transformation should be commemorated has yet to be decided. A list of nine sites – including coral reefs in Australia, layers of silt from Canada and ice cores from Antarctica – was created last year by the Anthropocene Working Group as the best candidates in providing markers, in their sediments, that demonstrate the changes that led to the new epoch.