H-bombs or chicken bones: the race to define the start of the Anthropocene

The mushroom cloud from ‘Ivy Mike’, the first ever hydrogen bomb to be detonated. The test took place on Enewetak, an atoll in the Pacific Ocean, in November 1952. Photograph: Reuters

Exactly where and when did the Anthropocene begin? Scientists are attempting to answer this epochal question in the coming months by choosing a place and time to represent the moment when humanity became a “geological superpower”, overwhelming the natural processes that have governed Earth for billions of years.

They could decide the start is marked with a bang, thanks to the plutonium isotopes rapidly blasted around the planet by the hydrogen bomb tests that began in late 1952, or with a shower of soot particles from the surge in fossil-fuel power plants after the second world war.