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.

New year, new epoch?

First things first, HAPPY NEW YEAR to you all! Hopefully the somewhat inevitable hangover from last night's celebrating isn't causing you too much discomfort on the first day of 2016. I may be being a bit ambitious in trying to write a post today, so I'll keep it short and sweet.

(Source)

What is in store for you this year? For myself, 2016 is the year I will graduate from UCL with a BSc in Geography, having had the most incredible whirlwind 3 years of my life. 2016 is the year I will hopefully join either a Master's programme or get my first full-time real-life-adult job (terrifying thought!). Failing that, 2016 will be the year I save some money and explore the world, broadening my horizons (I know, how cliché...). For the Anthropocene, its fate has yet to be decided.

2016 marks the year that the AWG are set to meet and make a formal proposal to the ICS (International Commission on Stratigraphy), deciding whether to formalise the Anthropocene as an official epoch of the Geological Time Scale. If formalised as an epoch, this will ultimately bring an end to the Holocene. There have also been suggestions that the Anthropocene may instead be considered at a lower hierarchial level (i.e. an age/stage), thus becoming a subdivision of our existing Holocene Epoch.

As it stands, there is no firm consensus. Though in January 2015, 26 members of the AWG argued mid-20th century markers were "stratigraphically optimal" and the Trinity atomic bomb blast of 1945 would be a good start date (Zalasiewicz et al 2015), the remaining half of the AWG were not on board with the idea (Monastersky 2015). One member of the AWG, Erle Ellis, proposed that the working group should hold off for ~1000 years to avoid making a premature decision (Monastersky 2015). Those who have come to disagree with the idea entirely and feel they have nothing left to add, such as Michael Walker, have left the working group (Monastersky 2015). Walker was part of a great achievement just a few years ago, covered in an earlier blog post - finding and deciding on the GSSP which formally marks the start date of the Holocene (Walker et al 2009). Gibbard, a member of the AWG and a voting member of the Quaternary subcommission, admits he has not been convinced by arguments in favour of the Anthropocene, mostly because this new epoch will not actually help geologists who study the Holocene or Pleistocene (Monastersky 2015). Gibbard doesn't want to "ruin the party", and admits a great deal of useful thoughts and conclusions are arising from thinking about the world through Anthropocene-lenses (Monastersky 2015). Gibbard and Walker (2013) argue the current view of the Earth Science community is that the Anthropocene should remain an informal term. But what about other, broader academic circles?

Even if the working group make a robust proposal, it needs to get past a long line of hurdles first. A recent Nature article demonstrates that the proposal needs at least 60% support by Quaternary subcommission members to proceed to the next stage, where the same minimum level of support is required by leaders of the ICS. The final hoop to jump through is persuading the executive committee of the IUGS to approve the proposal. It is a gruelling process that sees many proposals completely revised, and some even scrapped entirely. Whatever the outcome, 2016 is likely to be a momentous year for the Anthropocene, and thus both Earth and human history.