The global body tasked with naming geological eras, the International Commission on Stratigraphy, has rejected the proposed Anthropocene epoch, the controversial ‘geological’ epoch in which mankind allegedly dominates natural processes. The international commission has now rejected the proposal and has instead split the Holocene Epoch into three different geological ages, all of which were primarily shaped by natural, not human factors.
Will Steffen’s paper gets scientists hot under the collar
Will Steffen’s “Hothouse Earth” paper has gone viral since its publication this week. Amounting to a call to arms, the paper’s key message is that society needs to be radically reordered if we are to prevent the runaway impacts of human-induced climate change.
Behind the scenes is a smaller story of thwarted ambition over whether or not human impact on the planet should define a new geological age.
The paper by Steffen and his 15 co-authors, published in Proceedings of the National Academy of Sciences of the United States of America, a leading science journal, was titled “Trajectories of the Earth System in the Anthropocene”. Anthropocene is the name proposed for a new geological epoch defined by human impact on Earth.
All going well, the naming of this new era might have coincided with the release of the paper by Steffen, a member of Australia’s Climate Council. However, the global body tasked with naming geological eras, the International Commission on Stratigraphy, had other ideas. Last month, rather than announce a new Anthropocene Epoch, it declared it would split the Holocene Epoch, in which we have been living for the past 12,000 years, into three ages.
The decision has unleashed rancour, with claims of ethical lapses, scientific misrepresentation and unseemly publicity-seeking among those determined to declare the age of human planetary impact is upon us.
The ICS says we are living in the Meghalayan Epoch, the third of the three new ages that started about 4250 years ago. The epoch is defined by a mega-drought that caused the collapse of a number of civilisations in Egypt, the Middle East, India and China, about 2250 years BCE. The name comes from the northeastern Indian state of Meghalaya where a stalagmite recovered from a cave provided chemical evidence of the drought.
Defining a geological epoch around human impact has become highly politicised and the decision is considered a blow to those pushing hardest for tough action on climate change.
ICS’s decision is clearly a blow to those pushing hardest for tough action on climate change. The decision is something Mark Maslin, Professor of Earth System Science at University College London, says “has profound philosophical, social, economic and political implications”.
“There is a huge difference to the story of humanity if we are living in the Meghalayan Age that makes no mention of the human impact on the environment — or in the Anthropocene Epoch, which says human actions constitute a new force of nature,” he writes in the UK equivalent of The Conversation this week. “The Meghalayan Age says the present is just more of the same as the past. The Anthropocene rewrites the human story, highlighting the need for planetary stewardship.”
The scientific community is divided. In an interview with The Atlantic magazine, the chairman of the ICS Anthropocene working group, British academic Jan Zalasiewicz, accuses his colleagues of “committing ethical lapses and of courting an unseemly amount of press coverage”.
“They have an incredible press campaign that has misrepresented the science and history of the units of stratigraphy,” he is quoted as saying. The Anthropocene working group had fixated on finding a “golden spike” in time to start the new epoch, but failed to find “a stratigraphic unit”, a rock layer that associates with the Anthropocene, he says.
Climate scientists and geologists had been debating whether the Anthropocene should be dated to the first atomic bomb blast, the start of the industrial revolution or as early as 6000 years ago when farmers began to remake the land surface.
Geological critics of a formalised Anthropocene alleged the idea did not arise from geology; that there is simply not enough physical evidence for it as a strata; that it is based more on the future than on the past; that it is more a part of human history than the immensely long history of Earth; and that it is a political statement, rather than a scientific one.
Steffen’s latest paper says regardless of the stratigraphic committee decision it is becoming apparent that Anthropocene conditions transgress Holocene conditions in several respects.
The article says crossing the “Hothouse Earth” threshold would lead to a much higher global average temperature than any interglacial in the past 1.2m years and to sea level rises of tens of metres. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies.
However, doubters have questioned the paper’s foundations, claiming there is no real evidence that a rise of global temperatures of 2 degrees C above pre-industrial levels will be a tipping point.
“There is no new science that this is a threshold after which global warming will become unstoppable. No new science, no new scenario and consequently no new cause for panic,” Global Warming Policy Foundation science editor Dr David Whitehouse said this week.