Anthropocene: Have humans created a new geological age?

By Howard Falcon-Lang Royal Holloway, University of London
Auckland skyline Cities will leave an unmistakeable mark in the geological record of our planet

Human civilisation developed in a cosy cradle.

Over the last 11,700 years - an epoch that geologists call the Holocene - climate has remained remarkably stable.

This allowed humans to plan ahead, inventing agriculture, cities, communication networks and new forms of energy.

Some geologists now believe that human activity has so irrevocably altered our planet that we have entered a new geological age.
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   Simply put, our planet no longer functions in the way that it once did”

Jan Zalasiewicz University of Leicester

This proposed new epoch - dubbed the Anthropocene - is discussed at a major conference held at the Geological Society in London on Wednesday. Yet some experts say that defining this "human age" is much more than about understanding our place in history. Instead, our whole future may depend on it.

The term, the Anthropocene, was coined over a decade ago by Nobel Laureate chemist, Paul Crutzen.

Professor Crutzen recalls: "I was at a conference where someone said something about the Holocene. I suddenly thought this was wrong. The world has changed too much. No, we are in the Anthropocene. I just made up the word on the spur of the moment. Everyone was shocked. But it seems to have stuck."

But is Professor Crutzen correct? Has the Earth really flipped into a new geological epoch - and if so, why is this important?

Back to the beginning

Dr Jan Zalasiewicz of the University of Leicester is one of the leading proponents of the Anthropocene theory. He told BBC News: "Simply put, our planet no longer functions in the way that it once did. Atmosphere, climate, oceans, ecosystems… they're all now operating outside Holocene norms. This strongly suggests we've crossed an epoch boundary."
Atomic weapons test DOE Early atomic bomb tests have left a tell-tale signature in soil

Dr Zalasiewicz added: "There are three ideas about when the Anthropocene began. Some people think it kicked off thousands of years ago with the rise of agriculture, but really those first farmers didn't change the planet much.

"Others put the boundary around 1800. That was the year that human population hit one billion and carbon dioxide started to significantly rise due to the burning of fossil fuels in the Industrial Revolution," he explained.

"However, the really big changes didn't get going until the end of the Second World War - and that's another candidate for the boundary."

To formally define a new epoch, geologists must show how it can be recognised in the layers of mud that will eventually form rocks. As it turns out, there is enormous practical advantage in fixing 1945 as the beginning of the Anthropocene.

"1945 was the dawn of the nuclear age," explained Dr Zalasiewicz. "Sediments deposited worldwide that year contain a tell-tale radioactive signature from the first atom bomb tests in the States".

So, thousands of years from now, geologists (if any still exist) will be able to place their finger on that very layer of mud.
Extraordinary times?

Nonetheless, the choice of 1945 for start of the Anthropocene is much more than just convenient. It coincides with an event that Professor Will Steffen of the Australian National University describes as the "Great Acceleration".

Professor Steffen told the BBC: "A few years ago, I plotted graphs to track the growth of human society from 1800 to the present day. What I saw was quite unexpected - a remarkable speeding up after the Second World War".

In that time, the human population has more than doubled to an astounding 6.9 billion. However, much more significantly, Professor Steffen believes, the global economy has increased ten-fold over the same period.

"Population growth is not the big issue here. The real problem is that we're becoming wealthier and consuming exponentially more resources," he explained.

gizmo_2655 wrote on May 12^th, 2011 at 2:30pm:


It matters a lot Gizmo.
It means that we are at the end of the warm period & anytime now
we could re-enter the cold period.
Why? - because we've had about 10,000 years of warm weather
which has allowed the human population to explode &
the cold weather would be devastating.
Also - it would mean that more CO2 emissions wouldn't matter.

There is some theory  that the solar system orbits in & out of a
spiral arm in the Milky Way.
We spend 10,000 years outside the arm & 100,000 years inside.
That means because of the dust inside the arm that we get
10,000  warm years &  100,000 cold years in
a never ending cycle.

I am not sure if I can find the proof.

Bobby. wrote on May 13^th, 2011 at 5:57pm:



You are a wooly thinker Mr Bat.

The Solar System encounters a spiral arm of the Milky Way Galaxy on the order of about once every 100,000,000 years, and spends about 10,000,000 years crossing the main part of the arm and the order of 1,000,000 years in the dust compression lane.

Bobby. wrote on May 15^th, 2011 at 11:00am:


That's the wooly bit. It isn't implied by the theory at all.