Human impact on Earth is so great that a new epoch has started, scientists said yesterday.
They claim that everything from nuclear bomb tests to the domesticity of chickens have left such an indelible mark on the planet that we are entering a new phase of geological time.
The Anthropocene, or ‘new age of man’, will actually be given a starting date of around 1950, if the proposal from a working group led by a Leicester University scientist is agreed.
That is when scientists decided the world had changed sufficiently to be given a new name. Since then, more of the effects of Mankind, including pollution cause by plastic, have emphasised the change.
An epoch is one of the shorter chunks of time used by geologists. The current epoch, the Holocene, started 12,000 years ago, after the last ice age.
But yesterday an international working group of scientists unanimously voted in favour of calling an end to that epoch and declaring a new one under way.
They say that millions of years from now geologists would be able to see profound changes in the make-up of the Earth’s rocks in much the same way that we can see the imprint of dinosaurs from the Jurassic period today. It is argued that climate change, deforestation and population explosion heralded the end of the Holocene.
The Anthropocene will be defined geologically by phenomena as diverse as the effects of nuclear bomb tests, plastic pollution, concrete and soot from power stations. Even the bones left by the global domestication of chickens could be a marker of the new age.
Professor Jan Zalasiewicz, a Leicester University geologist and chairman of the Working Group on the Anthropocene (WGA), said: ‘We are spoilt for choice. There’s a whole array of potential signals out there.
‘The significance of the Anthropocene is that it sets a different trajectory for the Earth system, of which we of course are part.’
The professor, who made his proposal to the International Geological Congress in Cape Town, South Africa, said: ‘If our recommendation is accepted, the Anthropocene will have started just a little before I was born.
‘We have lived most of our lives in something called the Anthropocene and are just realising the scale and permanence of the change.’
Although not a member of the WGA, Professor Chris Rapley, a climate scientist at University College London, told the Guardian: ‘The Anthropocene marks a new period in which our collective activities dominate the planetary machinery.’
The recommendation has been seven years in the making. However, approval could take a further two years and the proposal is not without its critics. The word anthropocene – first proposed for use in 2002 by Nobel chemistry laureate Paul Crutzen – has been adopted by environmentalists as a rallying cry, and is viewed by some as a stalking horse for what they see as aggressive, economy-choking policies to combat climate change.
Other scientists say it is too soon to make a decision and it will be centuries before we know what lasting impact humans have had on the planet.
If the Anthropocene is voted into existence, scientists will have to decide on a ‘golden spike’ – a physical point in the geological record that shows where one epoch changed to the next.
The working group is divided on what that essential signal might be, but traces left by the explosions of nuclear bombs are a favourite.