MONTREAL - For the last 11,700 years, mankind has lived in what geologists refer to as the Holocene epoch.
This interglacial period has been defined by its stable warm climatic conditions that have allowed Homo sapiens to populate the Earth and become its dominant species.
Many scientists now believe that over the last 200 years, mankind’s impact on the Earth has become so powerful that we have ushered in a whole new geological age, which they call the Anthropocene, or Age of Man.
British geologist Jan Zalasiewicz says there is a “widespread realization among Earth and environmental scientists” that man-made changes to the Earth now rival some of the great forces of nature that have changed the planet’s environment and caused mass extinctions in the 4.56 billion years since the planet was created.
In other words, mankind has become a sort of in-house asteroid that has struck the planet from within and set it on a new and irrevocable course in geological time. It has upset the stability of the Holocene and launched us into a more insecure future that threatens the life-support systems that have so successfully nurtured our species.
Even scientists who are skeptical about man-made climate change believe that mankind has in so many other ways launched an entirely new epoch in geological time.
One of those is geologist Andrew Miall, a professor at the University of Toronto: “Deforestation, agriculture, increase in erosion, the pumping of all kinds of artificial things into the hydrosphere; all these phosphates and nitrates going into the river systems (so that) we now have this huge dead zone in the middle of the Gulf of Mexico because of all the agricultural chemicals that have gone down there. These are all undeniable effects. There is no point in trying to evade it. To call this now the Anthropocene epoch would certainly crystallize that concept.”
Zalasiewicz said the term is already widely used in the scientific community and is producing new scientific perspectives. He said it should be formalized to assure that it has a precise definition. “If current global changes are comparable with those associated with great geological transitions of the past, that should be recognized formally,” he said.
Scientists say the principal agents of this change are the machinery of the industrial age and its chemical toxins. Modern mining, urbanization, forestry, agriculture and fishing practices have refashioned both the terrestrial landscape and continental shelves. Toxic pollutants are changing weather patterns, warming oceans, increasing their acidity and raising sea levels.
Distinct geological markers of this human impact are now fully evident in the atmosphere and sedimentary rock as well as weather patterns, scientists say.
The result has been “great changes to the biosphere, not just (species) extinctions but also species invasions,” Zalasiewicz said. “The CO2 increase associated with global warming and ocean acidification – this is large in scale and probably unprecedented in its speed.”
The notion of a geological age of our own making, first termed the Anthropozoic Age, has been hanging around the scientific community for more than a century. The current move to formalize this new age began in 2002 at the suggestion of Paul Crutzen, who in 1995 received the Nobel Prize for Chemistry for his work on atmospheric ozone.
“The Anthropocene is here treated as a geological phenomenon, comparable to some of the great events of the Earth’s deep past,” one paper published by the Royal Society last year states. “But, the driving force for the component global changes is firmly centred in human behaviour, particularly in social, political and economic spheres.”
Zalasiewicz, who is a major campaigner for official recognition of the Anthropocene, said he can’t say when the scientific community will attempt to formalize the new age. A working group is aiming for some kind of formal proposal to be made at the 2016 international Geological Congress.
Meanwhile, there is still a lot of work to be done, he said. The Anthropocene is multi-faceted and scientists have to determine its scale, when it officially began and the interrelation of each of its components.
Numerous papers have been published on the topic and a Google search of the term “Anthropocene” produces more than 400,000 hits.
A key question for scientists is deciding when the Anthropocene began.
Some argue it began in 1800 when the Industrial Revolution took a firm hold in England and began a rapid transformation of that country away from the traditional rural society. It then spread to Europe and North America.
During this time, the concentration of carbon dioxide in the atmosphere began steadily to increase beyond the 278 parts per million that had helped stabilized climates throughout the Holocene. By 1900, CO2 content was nearing 300 ppm.
Other scientists think the Anthropocene took hold after the Second World War in the post-1945 period that has been labelled the Great Acceleration.
During this time, the human population doubled to more than 6 billion, the number of motor vehicles rose to 700 million, from 40 million, people abandoned farming for life in the cities, use of fertilizers grew to 300 million tonnes a year, from about 50 million, and CO2 concentrations in the atmosphere increased to 390 ppm, from 311.
While the Great Acceleration of the 20th century was driven by western countries, a new acceleration in the 21st century is being driven by the emerging economies of China, India, Indonesia, Brazil and South Africa.
Emissions have grown exponentially. China and India, for example, are responsible for 90 per cent of the growth in coal use.
Some scientists believe that a formal recognition that mankind is now the most powerful force of nature on the planet will help draw the world’s attention to the damage mankind is causing to the Earth’s life support systems.
Another Royal Society paper on the Anthropocene last year suggested that a formalization could instill a negative relation akin to the reaction that greeted Darwin’s theories on the origins of species and the evolution of man.
The authors point out, however, that while Darwin’s theories provoked fury in parts of society, they had no impact on its well-being.
“The ultimate drivers of the Anthropocene, on the other hand, if they continue unabated through this century, may well threaten the viability of contemporary civilization and perhaps even the future existence of Homo sapiens,” the authors state.
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