The climate change convinced dared to dream a dream: that human beings, single-handedly, uniquely, in the 4.2 billion year geological history of planet Earth, had, some time within the last few hundred years, initiated a new geological epoch they dubbed the Anthropocene. They have lovingly nurtured their dream for nearly two decades now, eagerly anticipating the day when it would finally be officially accepted as the most recent geological epoch, the one which ended the (natural) Holocene, replacing it with the decidedly unnatural, man-made Anthropocene. Alas, ’twas not to be.
It already wasn’t looking that good for the Anthropocene to be honest. It had many critics among geologists especially, then along came this excoriating article recently by Mark Sagoff of George Mason University who renamed it, rather aptly and somewhat amusingly, the Narcisscene. As Sagoff points out pertinently in his article:
Geologic epochs typically last around three million years. In establishing them, the ICS has historically proceeded by first identifying a stratum or “chronostratigraphic unit,” which is usually categorized in terms of the fossils it contains. By figuring out how long fossil layers took to accumulate, geologists date them and derive the geologic time scale, which is used to estimate the age of the Earth.
By contrast, in convening the AWG to determine the onset of the Anthropocene, the ICS apparently abandoned this practice, instead presuming that the new epoch had already begun and then casting about for a fossil record or other stratigraphic evidence of the existence of the Anthropocene and of when exactly it began.
This has been the main bone of contention among opponents of the Anthropocene; the fact that it cannot be defined conventionally according to evidence dug up from the past, i.e. a clearly defined stratigraphic layer of fossilised remains and mineral deposits combined with the palaeo-climatological evidence of the changing climate and the abrupt increase in CO2 from ice cores. Anthropoceenies have countered with various arguments re. the onset of farming, mass tree felling/land clearance, nuclear tests and most recently the widespread problem of plastic rubbish floating around in our oceans. These things, they contest, will demarcate the beginning of the Anthropocene once they’ve been squished down into a thin layer by Mother Nature and buried beneath more recent deposits. But Anthropoceenies can’t wait that long so they ask us to suspend our scepticism and basically imagine that in several millennia from now, the incontrovertible evidence for a new geological epoch will be there, in the hard geological record; a globally identifiable, well-defined, stratigraphic layer. Meanwhile, they can flaunt their new epoch to politicians and policy-makers as ‘evidence’ that humans are indeed profoundly affecting the planet and that we must do something about it.
Anthropoceenies got their very own working group at the ICS (International Commission on Stratigraphy) and it was all going swingingly until another group of scientists at the ICS announced earlier this month that the most recent unit of the Geologic Time Scale is now officially the Late Holocene Meghalayan Age. Not a new geological epoch, just a most recent subdivision of the Holocene, starting around 4200 years ago, precipitated by a natural climatic event which coincided with the collapse of civilisations across the globe.
The Late Holocene Meghalayan Age, newly-ratified as the most recent unit of the Geologic Time Scale, began at the time when agricultural societies around the world experienced an abrupt and critical mega-drought and cooling 4,200 years ago. This key decision follows many years of research by Quaternary scientists, scrutinized and tested by the subcommissions of the International Commission on Stratigraphy under the chairmanship of Professor David Harper, Durham University, UK.
Agricultural-based societies that developed in several regions after the end of the last Ice Age were impacted severely by the 200-year climatic event that resulted in the collapse of civilizations and human migrations in Egypt, Greece, Syria, Palestine, Mesopotamia, the Indus Valley, and the Yangtze River Valley. Evidence of the 4.2 kiloyear climatic event has been found on all seven continents.
The 4.2kyr climatic event was one of a series of North Atlantic Cold Events which affected climate and circulation patterns across the globe and involved the slowing of the Atlantic Meridional Overturning Circulation (AMOC), at least some of which also coincided with a marked downturn in solar activity. The Little Ice Age Maunder Minimum marked the culmination of the last Holocene North Atlantic Cold Event. The 4.2kyr event resulted in cooling and intense aridification across many regions of the globe, including North Africa, Spain, the Arabian Peninsula, south central Asia and India, Mesopotamia and China.
Afterwards, the global climate continued to gradually cool and stayed dry, unlike in the early Holocene when the ‘norm’ was hot and humid. Quite obviously then, the beginning of the latest geological subdivision of the Holocene coincided with natural climate change (a transition to cooler and drier). It remains to be seen if the modest warming we’ve seen since 1850, the early phase of which consisted of a recovery from the LIA, will reverse that cooling and drying trend. There is little convincing evidence thus far that modern climate change is highly unusual in that it exceeds the bounds of past natural Holocene climate variability.
Prof Mark Maslin, of University College London, has invested considerable time and energy in researching and promoting the Anthropocene, along with his colleague Simon Lewis, and as such is considerably peeved by it being effectively sidelined by this new official ratification from the ICS:
I doubt this will mark the end of efforts to try and get the Anthropocene officially recognised, but it deals a severe blow to that endeavour and to the concept that humans drive global environmental change. Quite the opposite in fact, it affirms that the most recent subdivision of geological time involved human civilisation being severely affected by natural global climate change.
NASA climatologist Gavin Schmidt wasn’t too happy about Judith Curry effectively dissing the Anthropocene by quoting Sagoff’s excellent article above either. Bizarrely, he posted this tweet in response as somehow providing ‘proof’ that the signal of the current warming episode and the accompanying increase in atmospheric CO2 is comparable to the signal of the PETM warming episode 56 million years ago! (Hint: just look at the chronological scales of both ‘events’ and note also that most of the ‘signal’ in the modern event consists of model projections).
Not really a very convincing argument for adopting the Anthropocene I think!