Hot off the press!

So just as I was beginning to wrap things up in my mind about this blog, I stumbled across this brand new paper published in Science TODAY! It is seriously hot off the press, so don't burn yourself. The article, written by a large portion of the AWG, concludes that the Anthropocene is "functionally and stratigraphically distinct from the Holocene". In other words, it seems the AWG are fairly certain the Anthropocene deserves its own unit of time, separate from the Holocene. Whether that unit of time is formal or informal, however, is yet to be determined.

Summarising the key markers of change for the Anthropocene.
The top graph (A) illustrates novel markers , and the bottom graph
(B) indicates long-ranging signals which rapidly rise
during the mid-20th century, eventually exceeding Holocene ranges.
(Source: Waters et al 2016).

Waters et al (2016) recognise that previous forcings used in other Quaternary stratigraphic units (e.g. orbital variations and volcanic eruptions) are also present with the Anthropocene, but that human modification of Earth Systems at unprecedented rates is a key additional driver. This human driver has produced a large range of anthropogenic signals, such as atmospheric ¹⁴C concentration, concrete production, surface temperature anomalies, carbon dioxide (ppm), black carbon (e.g. SCPs), and plastic production (see previous post) (Waters et al 2016). Though these signals clearly vary in their development, and thus their uses, most could probably be used to stratigraphically characterise the lower boundary of a formalised Anthropocene epoch possibly in the mid-20th century (Waters et al 2016). Furthermore, these stratigraphic signatures are either completely novel compared to other epoch signals, or outside the range of variation of suggested Holocene subdivisions (Waters et al 2016).

Whilst an exciting new release for Anthropocene-lovers like myself, it is important to remember this paper is NOT the final statement on the topic, rather more of an update on the position of the AWG regarding the decision to be made later this year. Waters told the BBC today that within the group there still remains discussion as to whether the Anthropocene should be a formal or informal unit. Despite this continued open question of formalisation, the start date appears to be moving gradually towards a mid-20th Century boundary. This onset encompasses the Great Acceleration period of rapid changes both in Earth Systems and the environment, but also in the way our global society functions and the socio-economic changes which occur synchronously (Steffen et al 2015). It is a rather difficult and mind-boggling concept to realise that one single species (humanity) has been able to profoundly change a 4.5 billion year old planet in such a short blip of geological time. Yet, the evidence is mounting all around us.

Waters et al (2016) admit that further work is needed before formalisation can be achieved. This work involves deciding whether to define the Anthropocene by GSSA or GSSP...or even a mix of the two. If the mid-20th century is proposed as the beginning of the epoch, what exact date should be chosen? 1945, with the Trinity atomic bomb detonation? Or 1964, with a peak in radiocarbon? Last but not least, the AWG must decide whether the Anthropocene is better as a formal or informal term. Waters et al (2016) argue that if the term remains informal, it will still be a robust geological term, with use similar to that of the Precambrian. The reason formalisation has become such a difficult debate to settle is because the implications extend beyond just the realms of geology and Earth sciences (Waters et al 2016). The Anthropocene, if formalised, would be completely unique in its present recognition by humans, but also because humans are both the cause and defining feature of it.