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This @PeterBrannen1 piece appears to have been written so the over-privileged have something to talk while the world slides in environmental breakdown. It is also *staggeringly* incorrect. A (slightly grumpy) thread on the #Anthropocene from narrow geological viewpoint:
If you fail to explain what the Geologic Time Scale is, you fail your reader in ever hoping to understand if the Anthropocene is a geological joke or not.
The Geologic Time Scale is a product of the human mind, to break Earth's history into intelligible chunks, to help navigate Earth's history. Investigating the Anthropocene, as a geological discussion, is to ask the question: are human's having impacts on geological timescales.
The Geologic Time Scale is constructed by classifying time using long-dead living creatures in rock, which we all know as fossils (think demise of the dinosaurs, rise of the mammals). In essence, the appearance of new life-forms = new chunk of geological time.
The Anthropocene question is then even narrower, it is: are humans producing a new chunk of geological time because we have changed life on Earth resulting in the evolution of new life-forms to be captured in the rocks of the future. The answer is an unequivocal yes.
Since the Pangea super-continent began to break up, life has spent the past nearly 200 million years becoming more isolated and evolving separately on different continents and ocean basins. This ended with trans-continental shipping in the late 1400s.
Ships, planes and people have created a globally interconnected New Pangea, which is irreversible, and evolution will forever work its magic on the genetic material available on each continent and ocean basin, regardless of what happens to human civilisation in the future.
Added to this, the end-Pleistocene mass extinctions of the large mammals on land and the later near extinction of many species in the oceans, which based on extinctions from the geological past, it will take millions of years for evolution to produce a new Earth of giants.
The evolutionary results of both the homogenisation of Earth's biota and the loss of almost all the large mammals will be clear in the geological record millions of years in the future. We certainly live in a new geological time-unit, the Anthropocene.
So, to re-cap, if we apply the normal rules of defining geological time, and analyse what we have already done to life on Earth and how those change will pan out, it is clear we're living in a new geological time. The rest of it is secondary importance.
What Bannen is first focusing on is the ephemera of human impacts, rather than our impact on the future of life on Earth. But in nearly all cases geologists define time for the Geologic Time Scale via changes to life, so is irrelevant to the argument made by Bannen.
It's worth being clear that new geological time-units are spans of rock and time, so need a beginning, so there is a debate to be had about when to start it, but that's secondary debate, contingent upon first agreeing we're in a new geological time.
Brannen second focus on events, confuses events, potential markers of events and potential Anthropocene start dates, and comparisons of these with the geological past, rather than the outcomes of those events on life on Earth.
These big events can drive changes to life, so even in Brannens view, if the Anthropocene is merely a big event of geological-scale importance, it is actually more evidence that the Anthropocene is not a joke, as the event will drive changes to life that define geological time!
Lastly, Anthopocene debates in geology and the vastly more important wider debates are a mess, the Brannen article is symptomatic of the confusion. I wrote a book, with @ProfMarkMaslin, to get it straight in my own mind. its called #TheHumanPlanet. Thanks for reading this far!
