Earth has entered new Anthropocene epoch, scientists vote

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29 August 2016 • 2:06pm

 

The rapid industrialisation of the last century has caused the Earth to enter its first new geological epoch in more than 11,500 years, scientists believe.

An international team of researchers say the worldwide spread of plastics, new metals and concrete, combined with manmade climate change, has pushed the planet into a new Anthropocene epoch.

While human activity has left visible traces on the Earth since before the current Holocene epoch, which begun around 9,700 BC, the scientists argue that the recent changes to global systems are sufficiently simultaneous and significant to justify the adoption of a new geological time unit characterised by human domination.

The concept of the Anthropocene manages to pull all these ideas of environmental change togetherProfessor Colin Waters, British Geological Survey

The Working Group on the Anthropocene (AWG), which is meeting in Cape Town this week, is proposing that the starting date for the new epoch should be set for around 1950.

The group’s committee of 35 members voted by a majority of 20 to recognise the new time division as an epoch, rather than the lower ranked age, such as a subdivision of the Holocene, or a higher ranked period like the Jurassic or Cretaceous.

The search is now on to find what geologists call a “golden spike”, a physical reference point that can be dated and taken as a representative starting point for the Anthropocene epoch.

A river bed in Scotland, for example, is taken to be the representative starting point for the Holocene epoch.

Professor Jan Zalasiewicz, a palaeobiologist at the University of Leicester and a member of the working group, said carbon and nitrogen levels in the atmosphere had remained reasonably steady before the “great acceleration” of the 20^th Century.

“Human action has certainly left traces on the earth for thousands of years, if you know where to look,” he said.

“The difference between that and what has happened in the last century or so is that the impact is global and taking place at pretty much the same time across the whole Earth.

“It is affecting the functioning of the whole earth system.”

The concept of an Anthropocene epoch was first proposed by Nobel-prize winning chemist Paul Crutzen and colleague Eugene Stoermer in 2000.

This week’s AWG vote is scientific endorsement that the epoch is geologically real and of a sufficient scale to be considered for formal adoption as part of the International Chronostratigraphic Chart.

Professor Colin Waters, principal geologist at the British Geological Survey and WGA secretary, said: “Being able to pinpoint an interval of time is saying something about how we have had an incredible impact on the environment of our planet.

“The concept of the Anthropocene manages to pull all these ideas of environmental change together.”

Changes to the Earth system which characterise the potential Anthropocene Epoch include the presence of plastic and aluminium particles and high levels of nitrogen and phosphates in soils, as well as “large-scale chemical perturbations to the cycles of carbon and nitrogen,” according to the AWG.

Professor Zalasiewicz said that there has traditionally been an element of national competition when putting forward geological “golden spike” candidates for the beginning of an epoch.

He added, however, that countries may be more reluctant to put forward locations representative as the beginning of the new Anthropocene epoch because of its negative associations.

Once one or more candidate sites have been selected, a formal proposal for the formal recognition of an Anthropocene epoch will be made to a series of commissions, culminating in the Executive Committee of the International Union of Geological Sciences.

The process is likely to take at least three years.

 

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Welcome to the Anthropocene.

 

Thanks to all our plastic pollution and nuclear testing, humans have cut short a 11,700-year-old geological epoch known as the Holocene, and have initiated a new, human-influenced epoch called the Anthropocene, experts say.

 

An international team of researchers recommended to the International Geological Congress in Cape Town, South Africa on Monday that the Anthropocene be officially declared, suggesting that its starting date should be 1950 - when nuclear tests created a new layer (or stratum) in Earth’s surface.

 

The group of 35 experts, known as the Working Group on the Anthropocene, took a vote on whether we should officially call it quits on the Holocene, and 30 voted in favour of declaring a new geological era, while three voted against, and two were absent.

 

"The significance of the Anthropocene is that it sets a different trajectory for the Earth system, of which we of course are part," working group chair, Jan Zalasiewicz, a geologist from the University of Leicester in the UK, told the media.

 

"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."

 

If you want to define a new human-influenced geological epoch, it’s not as simple as just listing all the ways that humans have irrevocably changed the experience of life on Earth. 

 

Sure, we’re directly causing species to go extinct, and warming the planet so much that Antarctica is crumbling - oh and let's not forget how scientists predicted that by 2050, there'll be more plastic than fish in the ocean. But in order to declare a new geological epoch, we have to have made, well, a geological impact. A big one.

 

As Damian Carrington explains for The Guardian, that geological impact must be global, and has to be significant enough to be clearly defined in the future geological record.  

 

For example, you might assume that the end of the Cretaceous epoch 66 million years ago was marked by the mass death of all non-avian dinosaurs, but it’s actually defined by a 'golden spike' in metal iridium sediments that can be seen in Earth’s strata. 

 

When that meteorite collided with Earth to initiate the rapid demise of the dinosaurs, massive amounts of metal iridium sediment blanketed the entire globe, creating a distinct geological signal for an event that would change the world forever. 

 

Fast-forward to now, and our insistence on messing around with nuclear weapons over the past 70-odd years has already seen enough radioactive sediments settle into a new stratum in Earth’s geological record, the Anthropocene working group argues.

 

"The radionuclides are probably the sharpest - they really come on with a bang. But we are spoiled for choice. There are so many signals," Zalasiewicz said, adding that micro-plastics are also components of sediment around the world, both on land and in the oceans.

 

The announcement backs previous research from a team of geologists at University College London in the UK who last year published a paper arguing that the Anthropocene is here, and we need to make it official.

 

As Fiona MacDonald reported for us in March 2015, rather than arguing that the start of the Anthropocene was as recent as 1950, they said it’s been going on for much longer:

 

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"[A]fter studying the environmental impact of humans over the past 50,000 years, researchers ... have now not only confirmed that the new epoch is definitely here, they've also pinpointed that it started all the way back in 1610 - most likely as a result of Europeans colonising the Americas."

 

Regardless of when experts think it started, there's a definite movement towards making the Anthropocene official. So how does that happen?

 

Well, now that the group has voted on it, they'll begin investigations to make sure the start of the Anthropocene is scientifically valid. This will involve up to three years of site sampling and analysis to identify the most convincing Global Standard Stratigraphic Age (GSSA) for the beginning of the epoch - for example, 1950 or 1610 - which will be submitted as a formal proposal to the International Commission on Stratigraphy (ICS).

 

If approved by the ICS, it will need to be ratified by the Executive Committee of the International Union of Geological Sciences (IUGS) to make it official. So the working group is going to be busy in the coming years, but they're confident this is going to happen.

 

"Our stratigraphic colleagues are very protective of the geological time scale. They see it very rightly as the backbone of geology and they do not amend it lightly," Zalasiewicz told The Guardian. "But I think we can prepare a pretty good case."

 

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or it could be called run humans run the end is nigh