Extreme makeover: are humans reshaping Earth?

A A A

If alien geologists were to visit our planet 10 million years from now, would they discern a distinct human fingerprint in Earth's accumulating layers of rock and sediment?

Will homo sapiens, in other words, define a geological period in the way dinosaurs - and their vanishing act - helped mark the Jurassic and the Cretaceous?

A growing number of scientists, some gathered at a one-day symposium this past week at the British Geological Society in London, say "yes".

One among them, chemistry Nobel laureate Paul Crutzen, has even suggested a new name: the Anthropocene.

Whether this "age of man" will be short or long is unknown. But one thing is clear, says Crutzen, who shared his Nobel for unmasking the man-made chemicals eating away at the atmosphere's protective ozone layer.

For the first time in Earth's 4.7 billion year history, a single species has not only radically changed Earth's morphology, chemistry and biology, it is now aware of having done so.

"We broke it, we bought it, we own it," is how Erle Ellis, a professor of geography and ecology at the University of Maryland at Baltimore, put it.

"We don't know what is going to happen in the Anthropocene - it could be good, even better," he said. "But we need to think differently and globally, to take ownership of the planet."

Dinosaurs were most likely wiped out by a giant meteor that cooled Earth's temperatures below their threshold for survival.

An analogous fate could await humans if temperatures climb by five or six degrees Celsius, which climate scientists say could happen within a century.

But dinosaurs thrived for more than 150 million years before a cosmic pebble ended their extraordinary run, while modern humans have only been around for about 200,000 years, a snap of the fingers by comparison.

Another key difference: dinosaurs didn't know what hit them, and played no role in their own demise.

Humans, by contrast, have been the main architects of the enormous changes that are threatening to throw what scientists now call the Earth System out of whack.

Since Crutzen coined the term a decade ago, the Anthropocene has been eagerly adopted by scientists across a broad spectrum of disciplines.

"It triggered the realisation that we were in an entirely new era of planet Earth," said Will Steffen, head of Australian National University's Climate Change Institute.

It also triggered fierce debate.

At one level, the issues are narrow to the point of pedantry - rock experts quibbling over whether mankind's present and future geological imprint merits recognition by the International Commission on Stratigraphy.

At the same time, however, the concept forces us to ponder whether humanity's outsized impact on the planet could lead to undesired, possibly uncontrollable, outcomes, and what, if anything, humanity should do about it.

That leaves scientists who may be more comfortable classifying rocks than rocking the boat in a tricky position.

- 'Sculpting the Earth' -

--------------

For now, the man in the hot seat is University of Leicester professor Jan Zalasiewicz, who heads the group of geologists tasked with recommending whether the Anthropocene should be added to the 150-odd eons, eras, periods, epochs and ages into which the last 3.6 billion years of Earth's history has been officially divided.

"Jan must recognise the implications for society if his own tribe decides, using classical criteria, that there is not yet enough evidence to formally recognise a new boundary in the geological record," said Bryan Lovell, president of the British Geological Society and a professor at Cambridge.

Evidence of abrupt change - on a geological time scale - wrought by human hands would seem to be overwhelming.

The burning of fossil fuels has altered the composition of the atmosphere, pushing the concentration of carbon dioxide to levels unseen at least for 800,000 years, perhaps for three million.

The resulting global warming has itself set in motion other planetary-scale changes: massive melting of the parts of Earth normally covered by ice and snow (aka the cryosphere), and the acidification of the oceans.

Past shifts in the biosphere - the realm of the living - show up in sediment and rock, especially mass extinctions that have seen up to 90 percent of all lifeforms disappear within the geological blink of an eye.

There have been five such wipeouts over the last half billion years, and most scientists agree that we have now entered the sixth, with species disappearing at 100 to 1,000 times the so-called "background" rate.

Another key index is the rise of invasive species travelling in a globalised world via ship ballasts, air travel and old-fashioned smuggling.

"The mass homogenisation event" - finding the same species everywhere - "will be quite a clear signal in the archaeological record a million years from now," said Zalasiewicz.

Even the planet's outer skin, or lithosphere, has been transformed.

"We are sculpting the surface of the Earth," said James Syvitski, a professor at the University of Colorado, pointing to two centuries of industrial-scale mining, damming, deforestation and agriculture.

Thousands of dams built since the mid-19th century have "completely altered the planet's terrestrial plumbing," he said.

To validate the Anthropocene, all these changes will be measured against the range of variation in our current geological period - the Holocene epoch - which began some 12,000 years ago as Earth emerged from the last ice age.

"Human influence on the global environment must push the Earth system well beyond the Holocene envelope of variability," said Steffen.

By one key measure, at least, we already have: the concentration of CO2 in the atmosphere - measured in parts per million - remained in a narrow range of 260 to 285 for nearly 12,000 years. Today is stands at 390 ppm, and is sure to rise considerably higher in coming decades.

- The 'golden spike' -

------------

If the hugely complex web of chemical and biological interactions that sustains most life does tip seriously out of kilter, the planet will find a new equilibrium, as it has in the past.

Earth, in other words, will do fine. Humans, on the other hand, may find the transition more than difficult.

"It is a planet that will be much warmer, much stormier, much less biodiverse," said Steffen. "We will need to be very resilient as a species."

In nailing down the Anthropocene, there is also a question of timing. Some scholars favour dating it to the start of agriculture, some 8,000 years ago.

Most, however, favour hammering the "golden spike" in the middle of the 19th century when the steam engine and then fossil fuels kicked off an exponential explosion in population and consumption that is still gathering pace.

Starting around 1950, the "Great Acceleration" has seen dozens of key indicators, plotted on a graph, take off like a rocket: population, damming of rivers, water and fertiliser use, paper consumption, tourism, and vehicles, to name a few.

These, in turn, have sparked correspondingly sharp rises in greenhouse gas concentrations, ozone depletion, great floods, depletion of fisheries, loss of forests, species loss.

The dramatic transformation we have seen so far has been driven mainly by the 20 percent of the world's population living in rich nations.

Crutzen said he hopes that putting a name - the Anthropocene - to these changes may help focus humanity's mind on the challenges ahead.

"It could well be a paradigm shift in scientific thinking," he said at the London meeting.

"But it will probably take another 20 years before it is formally accepted."

PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment
glastonbury
News
i100
Arts and Entertainment
Shock of the news: Jake Gyllenhaal in ‘Nightcrawler’
filmReview: Gyllenhaal, in one of his finest performances, is funny, engaging and sinister all at once
Arts and Entertainment
Shelley Duvall stars in Stanley Kubrick's The Shining
filmCritic Kaleem Aftab picks his favourites for Halloween
News
people
Arts and Entertainment
Kit Harington has been given a huge pay rise to extend his contract as Jon Snow in Game of Thrones
tv
Life and Style
Taste the difference: Nell Frizzell tucks into a fry-up in Jesse's cafe in east London
food + drinkHow a bike accident left one woman living in a distorted world in which spices smell of old socks and muesli tastes like pork fat
Sport
Luke Shaw’s performance in the derby will be key to how his Manchester United side get on
footballBeating City is vital part of life at United. This is first major test for Shaw, Di Maria and Falcao – it’s not a game to lose
Life and Style
Google's doodle celebrating Halloween 2014
tech
Arts and Entertainment
Don’t send in the clowns: masks and make-up conceal true facial expressions, thwarting our instinct to read people’s minds through their faces, as seen in ‘It’
filmThis Halloween, we ask what makes Ouija boards, demon dolls, and evil clowns so frightening?
News
peopleFarage challenges 'liberally biased' comedians to 'call him a narcissist'
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Senior IP Opportunity at Major Firm

vary Attractive Salary: Austen Lloyd: MANCHESTER - AN OPENING AT A VERY HIGH Q...

Nursery Manager

£100 - £110 per day: Randstad Education Ilford: Nursery Manager Long term Ran...

Sales Consultant – Permanent – West Sussex – £24-£25k plus commission and other benefits

£24000 - £25000 Per Annum plus company car and commission: Clearwater People S...

SEN Teaching Assistant

£45 - £65 per day: Randstad Education Bristol: Supply SEN Support Jobs in Bris...

Day In a Page

The drugs revolution starts now as MPs agree its high time for change

The drugs revolution starts now as MPs agree its high time for change

Commons debate highlights growing cross-party consensus on softening UK drugs legislation, unchanged for 43 years
The camera is turned on tabloid editors in Richard Peppiatt's 'One Rogue Reporter'

Gotcha! The camera is turned on tabloid editors

Hugh Grant says Richard Peppiatt's 'One Rogue Reporter' documentary will highlight issues raised by Leveson
Fall of the Berlin Wall: It was thanks to Mikhail Gorbachev that this symbol of division fell

Fall of the Berlin Wall

It was thanks to Gorbachev that this symbol of division fell
Halloween 2014: What makes Ouija boards, demon dolls, and evil clowns so frightening?

What makes ouija boards and demon dolls scary?

Ouija boards, demon dolls, evil children and clowns are all classic tropes of horror, and this year’s Halloween releases feature them all. What makes them so frightening, decade after decade?
A safari in modern Britain: Rose Rouse reveals how her four-year tour of Harlesden taught her as much about the UK as it did about NW10

Rose Rouse's safari in modern Britain

Rouse decided to walk and talk with as many different people as possible in her neighbourhood of Harlesden and her experiences have been published in a new book
Welcome to my world of no smell and odd tastes: How a bike accident left one woman living with unwanted food mash-ups

'My world of no smell and odd tastes'

A head injury from a bicycle accident had the surprising effect of robbing Nell Frizzell of two of her senses

Matt Parker is proud of his square roots

The "stand-up mathematician" is using comedy nights to preach maths to big audiences
Paul Scholes column: Beating Manchester City is vital part of life at Manchester United. This is first major test for Luke Shaw, Angel Di Maria and Radamel Falcao – it’s not a game to lose

Paul Scholes column

Beating City is vital part of life at United. This is first major test for Shaw, Di Maria and Falcao – it’s not a game to lose
Frank Warren: Call me an old git, but I just can't see that there's a place for women’s boxing

Frank Warren column

Call me an old git, but I just can't see that there's a place for women’s boxing
Adrian Heath interview: Former Everton striker prepares his Orlando City side for the MLS - and having Kaka in the dressing room

Adrian Heath's American dream...

Former Everton striker prepares his Orlando City side for the MLS - and having Kaka in the dressing room
Simon Hart: Manchester City will rise again but they need to change their attitude

Manchester City will rise again but they need to change their attitude

Manuel Pellegrini’s side are too good to fail and derby allows them to start again, says Simon Hart
Isis in Syria: A general reveals the lack of communication with the US - and his country's awkward relationship with their allies-by-default

A Syrian general speaks

A senior officer of Bashar al-Assad’s regime talks to Robert Fisk about his army’s brutal struggle with Isis, in a dirty war whose challenges include widespread atrocities
‘A bit of a shock...’ Cambridge economist with Glasgow roots becomes Zambia’s acting President

‘A bit of a shock...’ Economist with Glasgow roots becomes Zambia’s acting President

Guy Scott's predecessor, Michael Sata, died in a London hospital this week after a lengthy illness
Fall of the Berlin Wall: History catches up with Erich Honecker - the East German leader who praised the Iron Curtain and claimed it prevented a Third World War

Fall of the Berlin Wall

History catches up with Erich Honecker - the East German leader who praised the Iron Curtain and claimed it prevented a Third World War
How to turn your mobile phone into easy money

Turn your mobile phone into easy money

There are 90 million unused mobiles in the UK, which would be worth £7bn if we cashed them in, says David Crookes