Let’s call it an epochal step in the right direction.
We’re talking here about the Anthropocene, generally, and the Anthropocene Working Group, specifically, and the recent discovery of physical, chemical and biological markers that underscore the very notion of the phenomenon as a new unit of the geological time scale.
According to Jan Zalasiewicz, professor of inaugural lectures and paleobiology at the University of Leicester, a strong proponent of the Anthropocene and a member of the team, the recent work is promising.
“It is new information when organized as context for a potential Anthropocene ‘golden spike,’ though it is based upon data collected in many previous studies (almost all of them collected without the Anthropocene in mind at all). And perhaps not a breakthrough, but very useful in showing where and how our future efforts should be channeled,” he said.
Zalasiewicz and his group recently published a study in the journal Earth-Science Reviews detailing their research.
He wants to emphasize that this doesn’t settle the debate – for there are still detractors out there – but does “ … provide a very great deal of information regarding the technical issues of formalizing the Anthropocene.”
Specifically, based on current knowledge, approximately 70 years into this proposed new time interval, the new research indicates that the Holocene-Anthropocene transition is a good deal more sharply definable than most epochal boundaries, using a range of information, and in this respect rivals the Cretaceous-Paleogene boundary.
“It does have novel signals such as those of the techno-fossil record and of artificial radionuclides, as well signals (e.g. the change in carbon isotope values) of the kind that have been used to help characterize or define other epochal boundaries (e.g. the Paleocene-Eocene boundary is defined by its carbon isotope signal),” Zalasiewicz explained.
The practical effect will help future research locate and specify future “golden spike sections,” he added.
The term “Anthropocene” was first coined, almost improvisationally, by Paul Crutzen, a Nobel Prize-winning atmospheric chemist, at a conference in 2000 in Mexico City. Literally meaning “the Age of Man,” its origins, according to proponents like Crutzen, began around the middle of the 20th century and rests on the assumption that humans are altering the planet, including long-term global geologic processes, at such an accelerated pace that a new epoch is upon us in the geological time scale.
(The late biologist Eugene Stoermer, who had been using the term informally for years, was quoted in The New York Times back in 2011 as saying he never formalized the term until Crutzen contacted him.)
Zalasiewicz said the term started off organically, then became semi-formal, through the Stratigraphy Commission of the Geological Society of London (a formal body, but with no direct power over the time scale) – and then became formal with the Anthropocene Working Group of the International Commission on Stratigraphy.
It has been, Zalasiewicz said, “a kind of evolution of interest,” including disciplines beyond the scientific community, including environmental, anthropological, political, and social.
The immediate question for the AWG is whether “Anthropocene” should be added to the International Chronostratigraphic Chart.
Fundamentally, the debate centers on whether humans have changed the figurative and literal landscape to such an extent that recent and currently forming geological deposits include a signature that is distinct from those of the Holocene and earlier epochs.
Zalasiewicz thinks it has, even before the latest research, which, he believes, is reason enough for the term to be recognized.
“One of the advantages would be stabilizing the meaning within geology, and therefore helping precise communication,” he said.
“Whether the Anthropocene becomes formal or not, it’s a very real and distinct phenomenon stratigraphically,” he said, adding that the work and research will continue regardless of an official recognition.
The criticism of the Anthropocene comes from those who, for starters, think the term is arrogant in the thinking that human beings are a geologic force on par with nature, in fact superseding it. By proof, critics point to the named epochs covering the last 145 million years and how none are named for the cause of the changes to the planet – until now.
More substantive is this criticism, best described in a 2013 Smithsonian Magazine article by Joseph Stromberg, “What is the Anthropocene and Are We in It?”:
“Many stratigraphers (scientists who study rock layers) criticize the idea, saying clear-cut evidence for a new epoch simply isn’t there. ‘When you start naming geologic-time terms, you need to define what exactly the boundary is, where it appears in the rock strata,’ said Whitney Autin, a stratigrapher at the SUNY College of Brockport, who suggests Anthropocene is more about pop culture than hard science. The crucial question, he said, is specifying exactly when human beings began to leave their mark on the planet: The atomic era, for instance, has left traces of radiation in soils around the globe, while deeper down in the rock strata, agriculture’s signature in Europe can be detected as far back as A.D. 900. The Anthropocene, Autin said, ‘provides eye-catching jargon, but from the geologic side, I need the bare bones facts that fit the code.’”
For his part, Zalasiewicz welcomes the criticism and thinks the debate is healthy.
“It is an essential part of the testing of this concept – for the Anthropocene to be taken seriously, the science behind it must be robust and based on sound evidence,” he said.
Navigating the Controvery
He believes the research indicates that the Anthropocene is not, in fact, just a difference in epochal interpretation or degree of the Holocene Epoch of the Quaternary Period, but a change in kind, pointing to distinctive changes to the Earth due to the introduction of artificial radionuclides, plastics, fly ash, metals such as aluminum, pesticides and concrete.
Those in the Anthropocene camp believe that humans have made epoch-scale changes to the Earth’s geology, changes substantial and dramatic enough to have ushered in this new era and should be recognized as such.
As to the charge of political tinkering, Zalasiewicz believes that an examination of the Anthropocene Working Group’s research should dispel any doubts as to the group’s motivations, and he does not believe the work is pitting scientists against politicians against environmentalists.
“On the whole, I don’t think so – though there have been many different opinions on the Anthropocene from many communities (and indeed a number of different interpretations of the Anthropocene, which is why we on the AWG are cleaving closely to the ‘stratigraphical Anthropocene’). The various proxy signals of the Anthropocene might be considered part of the evidence for global environmental change, though on the AWG we are considering them impartially, as geological signals to compare with those of the geological past,” he explained.
He is careful about editorializing too much on the subject.
“There are wide ranges of opinion from proponents of the ‘good Anthropocene’ to those who consider that the changes associated with this putative epoch are largely deleterious (to the biosphere, and ultimately to humans). Again, our task is to examine the stratigraphic evidence as best we can,” said Zalasiewicz.
The What Versus the When
These epochal moments are not like elections – they don’t have specific start and end dates. In fact, some epochal moments have lasted thousands of years. The actual start date of the Anthropocene, Zalasiewicz said, is less important than the fact of it.
“If we are using chronostratigraphic criteria, then it is probably best to consider it as the start of a very long unit of time, in which Earth history might evolve in a number of ways. In the same way, the Eocene epoch did not terminate after the carbon release/global warming event that triggered it had died down, after 0.1-0.2 million years of perturbed climate – this was sufficient to set the Earth on a new trajectory, with the next epoch (the Oligocene) not defined until another major change, 20 million years later. This is an imperfect comparison, but perhaps demonstrates the kind of temporal measure that one might make,” he said.
As for what happens now, in light of the new findings, Zalasiewicz said, “We hope to have a formal proposal based on a good deal of detailed and focused analytical work ready by 2020, but this may well be optimistic (it would be a good deal faster than most geological boundary work, and there is still a great deal of organizational work to do). We will do the best we can. As regards a decision, I have no reliable crystal ball here – we simply wish to do the science as well and honestly as we can.”