Why the 'Great Acceleration' is giving the Anthropocene an identity crisis
Not all geologists agree humans have transformed Earth’s surface in 70 years
*Originally published on April 24, 2023.
Big ideas take years to incubate.
Back in 2000, Dutch chemist Paul Crützen's idea that humans have transformed Earth, pushing it into a new geological age that he dubbed the Anthropocene, sparked interest and controversy in the social sciences — and lots of buzz in the popular media.
For Earth system scientists — those who study how the planet's atmosphere, hydrosphere, rocky crust and biosphere work, in tandem — the idea was immediately compelling.
But some geologists — those who chart Earth's history recorded in hard rock and soft sediments — are more skeptical.
Origins of the Anthropocene
In the coming months, a scientific panel will publicly announce its own proposal for how the Anthropocene should be defined, in strict geologic terms.
Established in 2009, the Anthropocene Working Group (AWG) was assigned three tasks.
Its first task was to identify when the Anthropocene began. Crützen proposed 1780, at the start of the Industrial Revolution.
After a decade of study, the AWG decided it began in the mid-20th century, at the base of something called the 'Great Acceleration'.
American environmental historian John McNeill coined the term 'great acceleration,' inspired by a 1944 work by Austrian economist Karl Polanyi, The Great Transformation: The Political and Economic Origins of Our Time.
The heart of the Great Acceleration is "scale, scope and pace," McNeill told IDEAS. For the first time, beginning just 70 years ago, humans started to "fundamentally affect the governing biogeophysical cycles of the Earth" and the planet's climate system.
McNeill's idea was corroborated by a set of 'Great Acceleration curves,' or graphs, published in 2007 by Crützen, McNeill and Australian Earth system scientist Will Steffen.
There are two sets — one for human drivers of planetary change: population, GDP, energy use and so on. The second set charted Earth system responses to these drivers, such as rising CO2 concentrations, mean global temperature; ocean acidification and tropical forest loss.
Each graph showed sudden, steep increases in the mid-20th century.
Is this the end of the Holocene?
Having decided that the Anthropocene began around 1950, the AWG's second task was to determine how Earth's new age should be ranked. It could simply be a 'stage' — the shortest time unit in the geological time scale, or it could be the start of a brand-new epoch, terminating the one we've been in for the past 12,000 years, the Holocene.
Holocene conditions — temperate and stable — were what made human civilization possible in the first place. If the Holocene is indeed over, humanity may be in deep trouble.
The AWG's third task was the most critical: identifying what geologists call a Global Stratotype Section & Point (GSSP).
More popularly known as a 'Golden Spike,' it would consist of a few centimetres of layered sediments, somewhere on Earth, where human 'signatures' start to be seen, clearly demarcated from underlying Holocene sediments. This would serve as a standard for other sites around the world.
Twelve candidate sites were originally in the running for that Golden Spike, in Japan, China, the U.S., Denmark, Italy, Poland, Australia, the Antarctic — and Canada.
Canada's Crawford Lake
Crawford Lake, about 60 kilometres west of Toronto, is the Canadian candidate.
The lake is deep and conically shaped, so its upper and bottom waters don't mix. Twenty-three metres down, its sediments have been accumulating since before the start of the Holocene, 13,000 years ago. They've been recording human activities for the past 700 years, in three phases.
Pollen grains from corn, bean and squash testify to the presence of Indigenous peoples living along the lake's shores between the late 13th and 16th centuries. Three hundred years after they departed, for unknown reasons, George Crawford purchased the lake. He and his son grew crops and operated a lumber mill, depositing nutrients into the lake that left their mark in lake sediments.
In the 20th century, dust storms, acid rain and Dutch elm disease all left their imprint on the bottom of Crawford Lake. So did the coke ovens at Stelco and Dofasco steelworks, in Hamilton, 30 kilometres away, regional automotive traffic and rising concentrations of atmospheric CO2.
The sudden appearance of Plutonium-239 levels, peaking in 1952, is as distinct a departure from the lake's underlying Holocene sediments as one can imagine.
Political contamination
Still, when higher geological authorities assess the AWG's Golden Spike proposal — be it Crawford Lake or any of the other 12 candidates — those authorities may deep-six the idea.
In a 2016 paper, Stanley Finney, Secretary General of the International Union of Geological Sciences, wrote that the drive to formalize the Anthropocene "may, in fact, be political rather than scientific." He may have changed his mind since then.
But Phil Gibbard hasn't.
Formal designation would confuse or antagonize academics in the social sciences who are already using the term, in a more vague or non-geological sense, said Gibbard, a Cambridge University geologist and the Secretary-General of the International Commission on Stratigraphy.
Humans have been transforming Earth's surface, steadily and gradually, for thousands of years, Gibbard and fellow geologist William Ruddiman have long argued; 1950 is "just yesterday," Gibbard told IDEAS contributor David Kattenburg.
'Geological event'
The Anthropocene may well be a blip — something for archaeologists and anthropologists to study, but not 'hard rock' geologists, said Gibbard.
In a 2022 paper, Gibbard, Finney and others proposed that the Anthropocene be declared a "geological event," rather than a formal epoch — an "event" that's been playing out for tens of thousands of years.
Such a designation would not require formal approval by the geological sciences community. Given these and other objections, chances are even that the AWG's Golden Spike proposal will wither on the geo-bureaucratic vine.
Whatever geologists decide, the scientific basis for the AWG's proposal will stand on its own merits.
And Crützen's idea will continue to incubate — among geologists and other human beings — for many years to come.
Guests in episode:
Colin Waters is an honorary professor at the University of Leicester and the Chair of the Anthropocene Working Group. Among his interests — characterizing human modification of landscapes, and the accumulation of plastic, concrete and other purely human materials.
John McNeill is an environmental historian, author and professor at Georgetown University. His 2000 work, Something New Under the Sun: An Environmental History of the Twentieth-Century World, formed the basis for his 'Great Acceleration' idea, put forward at a conference in Berlin in 2005.
Fridolin Krausmann is a professor at the Institute of Social Ecology, at the University of Natural Resources and Life Sciences, in Vienna. He has written widely on the metabolism of societies and their economies, and is an authority on 'Human Appropriation of Net Primary Production.'
Martin Head is a professor of Earth Sciences at Brock University. He is also the Vice-Chair of the Subcommission on Quaternary Stratigraphy and a voting member of the Anthropocene Working Group. Head was among the first to recognize Crawford Lake sediments as a potential 'Golden Spike' for the Anthropocene.
Thomas Homer-Dixon is the executive director of the Cascade Institute, at Royal Roads University. A 'complexity theorist,' Homer-Dixon has written widely on the relationship between society and the natural world, the roots of conflict, the impacts of technologies and increasing complexity and the potential for turning 'pernicious' cascades into 'virtuous' ones.
Reinhold Leinfelder is professor emeritus of geology and paleontology at the Free University of Berlin, and a voting member of the Anthropocene Working Group. He has studied the geology of 'Devil's Hill,' a mountain of 'technofossils' on the edge of Berlin. Reinhold is the co-author of the scientific comic book Eating Anthropocene.
Francine McCarthy is a professor of Earth Sciences at Brock University, and the scientific coordinator of 'Team Crawford,' putting forward Ontario's Crawford Lake as a potential 'Golden Spike' for the Anthropocene. She is also a voting member of the Anthropocene Working Group, and thankful to be able to vote for her own site.
Eva Horn is a professor of modern German literature and cultural history in the German Department of the University of Vienna, and a member of the Rachel Carson Center for Environment and Society. She is also the founder of the Vienna Anthropocene Network, an interdisciplinary network of social sciences and humanities scholars interested in the Anthropocene idea.
Phil Gibbard is emeritus professor of Quaternary Palaeoenvironments at Cambridge University, and the Scott Polar Institute. He is the Secretary-General of the International Commission on Stratigraphy, and one of the founding members of the Anthropocene Working Group.
Will Steffen was an American-born chemist and Earth system scientist. He was the executive director of the Australian National University Climate Change Institute, and the first director of the Stockholm-based International Geosphere-Biosphere Project. Steffen's name is associated with ideas about planetary 'boundaries,' 'tipping points' and 'Safe Operating Space.' Steffen passed away in January 2023.
Mark Williams is a professor of palaeobiology in the School of Geography, Geology and the Environment at Leicester University. The geology of cities, and the potential for cities to be fossilized, interest him greatly. Williams is a voting member of the Anthropocene Working Group.
*This episode was produced by David Kattenburg, with help from Greg Kelly.
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