“The Anthropocene” – or should it be “the anthropocene”? Some geologists prefer the lower case version but, as it seems to be the biggest thing around these days, I shall stick with the “Anthropocene”.
The period in which human activity might have impacted the planet has been called the Anthropocene. Antecedents for the term can be attributed to early Russian usage for the Quaternary/Holocene (Lewis and Maslin 2018 37) but, in western geological circles, the first mention by Paul Crutzen at a meeting in Mexico in 2000 and published as Crutzen and Stoermer in 2000 (The “Anthropocene”. Global Change IGBP Newsletter, 41) is formally taken as the first published record of its usage. Crutzen later followed this up with a seminal Nature paper (Crutzen, 2002, Geology of Mankind, Nature, 415). So it is fair to say the term is relatively new by geological standards.
Geologist are still conferring on the precise start of this period (or is it era or epoch?). A useful review article by Zalasiewicz et al., was published in the Geological Society of London’s Geoscientist in January 2018, but it wasn’t until the working group of the sub-commission of Quaternary Stratigraphy (http://quaternary.stratigraphy.org/working-groups/anthropocene/) voted in favour of adopting the term, that was it officially recognised by geologists – although this still has to be ratified by higher International geological bodies. Geologists do not accept new stratigraphic terms lightly. The challenge for them is to be able to identify when this period began.
Some would like to go back to when humanity started clearing the forests. Forest fires have always been present in the geological record so perhaps this wouldn’t be uniquely recorded. The release of radio-nucleides through atomic weapon testing in the 1950’s might create a marker that could be ‘fossilised’ (like the one associated with the meteorite impact that is often thought to have wiped out the dinosaurs at the end of the Jurassic). Geologists need to mark the start of a new period with a “Golden Spike”. The problem will be that not enough sediment has been deposited post-1950 to develop a section where a spike can be hammered in. This debate will carry on in geological circles for some time. It seems to be widely accepted that the appearance of humanity will be marked in some way.
Stratigraphic events in the geological column are usually marked by flooding events – when sea is at a high-stand – and we could be heading for one of those, or sequence boundaries where regional erosion and an unconformity occurs. Erosional events are often triggered by earthquakes and resulting tsunamis and, in my poem “Anthropocene”, I speculate that an interesting unconformity and overlying humanity-debris flow will mark the lower boundary. We can all speculate what the debris of humanity might look like in a few million years. I see this as an “event bed” in the geological column with the normal, rather ‘boring’ background sedimentation continuing on past humanity’s peak.
Geologists think in long time frames and clearly the term “Anthropocene” is being used across all disciplines – poetry included – to capture the anthropogenic changes that we are seeing today, at this instant in geological time. Does having a strict geological definition matter? I don’t think we geologists have ownership of the term – even if “we” invented it! I think it is useful that we play our part in providing enlightenment, where we can, on the Earth’s long history of evolution and change
Patrick Corbett, DSc, FGS, FRSE
Professor Emeritus, Heriot-Watt University