16 July 1945 opened a new age. When the Manhattan Project detonated the first nuclear bomb at the Los Alamos test range in New Mexico, the scientists involved knew that human history had changed. ‘I am become Death, the destroyer of worlds,’ famously said lead atomic scientist Robert Oppenheimer, using a quote taken from the Hindu scripture the Bhagavad-Gita.
An international working group on the Anthropocene thinks the nuclear tests opened more than a perilous era in international relations. The Anthropocene is a proposed new geological age in which humans have become the dominant influence on the Earth’s climate and the environment. Opinions differ as to when this new age began. Some scientists argue for the industrial revolution, others for the agricultural revolution and some for even earlier points in human history.
‘As in all geology we need to find a boundary somewhere,’ says Dr Jan Zalasiewicz from the University of Leicester, who chairs a geological the working group on the Anthropocene. ‘It’s sometimes not obvious where to put it though.’ Twenty-six of the working group’s members agree that the Anthropocene should be dated to the first atomic bomb detonations.
“In the mid-20th century a whole lot of things become more intense”
‘All the proposed start dates for the Anthropocene are geologically important, but the trouble is they give different signals in different parts of the world,’ says Zalasiewicz. ‘In the mid-20th century a whole lot of things start, or become more intense. There’s the CO2 signal. Most of that is post-1950 with the bulk from the mid-20th century. The change in nitrogen is readable and shows a clear lift off in the mid-20th century. So do more prosaic markers, like plastics and aluminum.’
According to Zalasiewicz, there’s also evidence like cities destroyed in the Second World War. In places like Berlin there are in effect small mountains of rubble that can be taken as specific, well-marked and defined geological layers. ‘The nuclear age is a marker. It’s by no means the most significant, but it’s something new that is distributed all around the Earth. We all have little bits of plutonium in us from that time. It’s not perfect because the detectable increase happened a few years later,’ he adds.
The working group will release alternative time frames for the Anthropocene this year, and in 2016 expects to make recommendations on whether the Anthropocene should be formalized as new geological time unit.