The end of my blogging era...

It is with regret that after 4 months of blogging, many ranting posts, some interesting debates, and lots of new thoughts, the very sad time has come for this blog to end (for now, at least...). Expressing my views, finding my unique perspective on things, and conveying the literature to you all on this platform has been an incredible experience, so much so that I hope to continue blogging in the future (when I get some spare time outside of the impending dissertation and exam season!). Looking over the entirety of my university career, this has definitely been the most challenging, yet rewarding experience! I've found myself trawling through the internet with a pair of 'blogging-goggles' on. Where ever I search, be that the darkest depths of YouTube, or the endless pages of journal articles, there seems to be endless topics to blog to you about. I really hope you've enjoyed this blog as much as I've loved running it, and have found it as educational as I have. Now, all emotions aside, it is time for a quick debrief...

In retrospect, it appears my opinion on the Anthropocene Epoch being formalised was dubious from day one. In October, I questioned the impact of human activity on an epochal scale, and postulated that a much clearer stratigraphic signal might emerge in the decades or centuries to come. I still agree that we could be jumping the gun with making the Anthropocene an epoch now, and might benefit in waiting until a clearer signal becomes available for the start of this interval of time (e.g. Wolff 2014). Essentially, if the key environmental changes still lie ahead, then it is too early to conclude the base position of the Anthropocene now, even if current scientific evidence suggests stratigraphic evidence is significant (Waters et al 2014; Wolff 2014). Though I can see the use of the Anthropocene as a unit of time in human history, we must objectively question its utility for other disciplines ranging from stratigraphy to philosophy.

Onto the title of this blog: are we in the dawn or dusk of this unit of time? Wolff (2014) would likely argue we are in the dawn, living through a transition into this new epoch. Others might argue we are also in the dawn, but instead because the Anthropocene only began very recently (e.g. 1945 Alamogordo atomic test, 1950s Great Acceleration, 1960s radionuclide fallout spike). You might ask, 'how can we be in the dusk of an epoch that has only really just begun?', and I would say, what if it began at the same time of the Holocene, 11,700 years ago, or perhaps during early Neolithic agricultural expansion? I might also respond by saying we are at its dusk, because the Anthropocene could fade into non-existence before it ever really took off the ground. However, as of the new article on 8th January (Waters et al 2016; see here), it appears the AWG are leaning towards the opinion that we are in the dawn of this new epoch of time, with it beginning mid-20th century. If it becomes formalised later this year, consequently, we will have reached the end of the (very short) Holocene Epoch...

Main topics and key words to take away from my blog! Clearly 'Anthropocene' stands out as most common, but others including 'human', 'Earth', 'time' and 'future' signify the diverse debates I have covered.

Despite sitting here now (no longer a rookie at this whole blogging thing), the debates of the Anthropocene are still as complex as they were when I first set out to explore them. I set out with a vague idea of what I wanted to cover and followed a loose agenda of topics, which allowed the literature and areas of interest to guide me. This framework was definitely beneficial, and I have surprised myself by what interested me the most. For example, I found myself getting more involved in the philosophical debates (e.g. human vs Earth history, nature vs humans, are we jumping the gun?) than I once imagined I would. As a physical geographer, I pictured myself diving off into literature about chemostratigraphical signatures and CO2 peaks, but instead it was really eye-opening and rewarding to postulate on some more human-focused debates around the topic.

Momentum is building for the Anthropocene, and a decision is set to be made this year. Will the Anthropocene join other epochs on the Geologic Time Scale, will it be downscaled to an Age in the Holocene, or will it be refused formalisation all together and remain an informal term? Regardless of the outcome later this year, the concept of the Anthropocene is undoubtedly here to stay and has made a phenomenal impact. There have been various new peer-reviewed journals set up in its name (e.g. 'Anthropocene' and 'The Anthropocene Review'), and over 1,080,000 search results on Google (this was actually ~700,000 when I looked yesterday, so mainstream interest is growing rapidly - perhaps due to the release of Waters et al (2016) paper). 

I've realised the Anthropocene not only represents a paramount point in human and Earth history whereby humanity has become a global geologic force, but a point of change in the way we envisage our impacts on the planet. Unique in history, humans have become a central characteristic of the Anthropocene, but also the deciders of its fate. The decision of the AWG and ICS will not be easy, but it deserves every ounce of brain power, logic, and humility to make. Regardless of whether the Anthropocene is kept as an informal term or becomes formalised, the concept has opened up a vast new area of valuable research, shining a light on human impacts on our planet, and this research doesn't seem to be slowing down any time soon. 

On a final note, I just want to say thank you to everyone who contributed to my blog by commenting and critically challenging my ideas week after week! This has been a truly wonderful experience which I shall look back upon fondly for a very long time. Farewell, my loyal readers.

Katy

Your views: poll results

The results are in from those of you who voted in my poll (thank you!), and they are quite divided:

The majority (39%) of you were under the impression that we had entered the Anthropocene, but only in the last few decades. This opinion aligns with the growing general consensus in academia and the AWG, arguing that the Great Acceleration period of the mid-20th century, encompassing huge societal, technological, and environmental changes, is the most likely date of onset (Waters et al 2016). 

23% of you believed that we have been in the Anthropocene for centuries i.e. Ruddiman's early anthropogenic hypothesis (Ruddiman 2003; Ruddiman 2013), or maybe even as far back as megafaunal extinctions (Doughty et al 2010)! Those of you who voted 'Other' (23%) commented that it depends on the ways in which we define the Anthropocene. Does it mean a time of great human impact and dominance, and if so, how do we measure human impact objectively? Or, does it mean a time of vast changes to Earth Systems, noted from the first instance of change, or the largest change? Some of you also commented that it depends whether the Anthropocene is defined as an epoch or age. 

Finally, 15% of the votes argued that we are still in the Holocene. This either means that these people disagree with the Anthropocene concept entirely and think we should remain in the Holocene Epoch which already encompasses human impact, or can see its merits for research but believe it should remain an informal term. 

The division of opinions in my one small poll almost represent a small-scale version of the spread of voices in academia which have been explored over the last 4 months! Even if Waters et al (2016) represent a large majority of the AWG's opinion, the remaining members of the group and other academics are either completely against formalisation, or argue a different onset should be chosen instead of mid-20th century. Has your opinion changed since your vote in this initial poll and after reading the debates on my blog? Please let me know in the comments below!

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.

Plastiglomerate takeover!

In the search for a golden spike, ranging from SCPs and atomic bomb radionuclides, to anthropogenic soils and industrial CO₂ peaks, could a new type of "plastic stone" signal the start of the Anthropocene? This "stone" aka "plastiglomerate" is a hybrid mix of melted plastics, beach sediment, basaltic lava, and organic debris (Corcoran et al 2014). How does plastic become merged with rock, you ask? Well, the bits of plastic debris are essentially melted onto rocks mostly through beach campfires, but possibly also lava flows and forest fires (Herreria 2014). As a result, this relatively dense plastiglomerate is not easily transported by wind or water, and therefore has the potential to be buried and preserved, unlike plastic floating around in the oceans (Corcoran et al 2014). Could this partially plastic rock become a global stratigraphic marker for the Anthropocene?

This poor oystercatcher died from starvation when its beak
became stuck in a plastic cap (Source) 

Plastics are a completely human-made material used for consumer and non-consumer goods (Barnes et al 2009). Unless you've been living in a cave with your eyes and ears taped shut, I'm sure you will be aware that these durable, lightweight plastics are becoming quite the environmental problem (e.g. recent BBC article discussing the thousands of pink Vanish bottles washing up on the Cornish coast). With inefficient waste disposal steadily increasing, plastic debris washing up along shorelines and water catchments have caused fatal consequences for freshwater and marine species (Derraik 2002). Plastics are literally choking our planet. But it isn't just the sheer volume of plastics in the environment which make them a concern, it is the fact they do not degrade. Over long periods of time, plastics just break down into smaller and smaller pieces. Though awful news for the wildlife who ingest or get tangled up in debris, and more generally for the environment, this is good news for a potential Anthropocene golden spike as preservation is a key feature of a GSSP.

The Great Pacific Garbage Patch - the oceanic source of much
plastic debris washed up on shores worldwide (Source).

A recent study by Patricia Corcoran et al (2014) discovered these plastiglomerates on one of the world's dirtiest beaches - Kamilo Beach in Hawaii. Despite being distant from the nearest town and miles away from other land, the pristine looking sea is washing up a seemingly endless supply of our planet's plastic waste (tyres, hats, bottles, fishing gear, pellets). Most of this material comes from the North Pacific Subtropical Gyre aka the "Great Pacific Garbage Patch" (Herreria 2014) due to anticyclonic surface ocean currents. If you took a stroll along this beach (though I don't recommend it), over 50% of the material underneath your feet would be tiny plastic debris, with an appearance of multi-coloured sand particles. Even if you started digging up the material (maybe you're trying to build a plastic sandcastle?), you would see nothing but vast depths of plastic. It seems this Hawaiian beach is slowly becoming entirely plastic.

An example of a plastiglomerate containing plastic pellets
and wood chips (Source: Patricia Corcoran)

I mentioned earlier that a potential facilitator of plastiglomerates on Kamilo Beach is molten lava flow. However, this has been dismissed by Corcoran et al (2014) as recorded locations of flowing lava do not coincide with the position of the beach. Therefore, it seems this "plastic rock" is of pure anthropogenic formation (Corcoran et al 2014), making it a distinct marker for human pollution, and a suitable match for the Anthropocene concept. Even if plastiglomerates are formed elsewhere through non-anthropogenic sources (e.g. lava flows and forest fires), the artificial plastics still signify an important identifier of human activity. I also personally think the plastiglomerates act as a cultural signifier of the Anthropocene, demonstrating that humans are literally morphing their way into nature.

The burning question with the use of these plastiglomerates as a geological marker is whether they will preserve long enough into the future to be easily detected. In a recent interview in Science (Chen 2014), geophysicist Douglas Jerolmack agrees the new rocks would make a good marker for the Anthropocene, but doubts their endurance in the fossil record with extreme temperatures in Earth's depths. In the same article, Zalasiewicz, head of the AWG, gives the nod of approval for plastiglomerates as a potential Anthropocene marker, providing they preserve well enough in the geologic record. However, Gibbard (who we've met briefly in my other blog posts e.g. here) sets a seed of doubt in plastiglomerate use, as he is concerned the plastics could revert back to oil depending on burial conditions (Chen 2014). Zalasiewicz and Corcoran disagree with Gibbard, arguing the plastiglomerates may instead be preserved as a "thin carbon film", similar to fossil preservation, that could even leave an imprint of a flattened plastic bottle (Chen 2014)! Lots of important questions about the utility of this "plastic rock" as a marker for the Anthropocene are in the process of being answered by Patricia Corcoran. Corcoran is (as we speak) undertaking experiments testing the heat and pressure that plastiglomerates can withstand (Jazvac, in Valentine 2015).

(Source)

Though much more research is needed into these newly discovered stones of the Anthropocene, for now they are an interesting finding which highlights a fascinating, yet worrying signature of human pollution on the planet. In regards to a date these plastiglomerates would be globally detectable and thus a date of onset for the Anthropocene, I highly suspect it will be another case of a diachronous signal.

A question of rank...

One of the great things about a blog is being able to express your honest opinion about stuff and not be judged for it (well, maybe a little judged). Does something anger you? Does something excite you? Does something upset you? Does something frustrate you to the point that you have to vent it on the internet? On the topic of the Anthropocene, there is one aspect that has really bothered me whilst trawling the web over the course of the last 3 months. This is the misuse of the terms 'age', 'epoch', and 'era' (which I define here) in the mass media. For example, this BBC article asks 'Have humans created a new geological age?', but then continues to refer to the Anthropocene as an epoch throughout the article. Another example, in Nature refers to the Anthropocene as the new 'human age' in its title. Furthermore, an article in The Independent discusses the 'Anthropocene era of man's dominance', only to call it an epoch throughout the bulk of the news article. This constant switching between different terminology is not only confusing, as each rank of geological time is vastly different to the other in terms of length and scale, but also misleading in what the Anthropocene represents. If it is an 'era', then we have waved goodbye to our long-term friend, the Cenozoic Era of the last 65 million years. If it is an 'epoch', then the familiar Holocene Epoch of the last 11,700 years is over, but we remain within the Quaternary Period of the last 2.8 million years. If it is an 'age' then the Anthropocene is a new smaller unit of time within the Holocene epoch and thus a smaller subdivision of geochronological time. 

Or is it an age?! So. Much. Confusion. (Source)

When proposed in 2000 (Crutzen and Stoermer) to denote this current time interval, the Anthropocene implied by name (due to ending in the suffix '-cene') that it had Epoch status (Gibbard and Walker 2013; Waters et al 2014). If the Anthropocene was meant to be of a smaller magnitude, i.e. a Stage/Age within the Holocene, the suffix would be expected to end with '-ian' based on geological standards (Waters et al 2014). Whether this is accidental or intentional, I cannot say. Gibbard and Walker (2013) make it crystal clear they do not support the formalisation of the Anthropocene as an Epoch status in the international Geological Time Scale. This is due to the belief that geological evidence does not support a change of this magnitude which would end the Holocene, already characterised by human influence on natural Earth Systems, and that the Anthropocene is too young at present with too many varying and diachronous global stratigraphic signals (Gibbard and Walker 2013).

I really want people to think about the Anthropocene. Not just its name, human facets, or environmental characteristics, but whether it really, honestly, hand-on-heart truly deserves to be of Epoch ranking. Has human impact had the same magnitude of impact on the Earth as the change between the end of the Pleistocene Last Glacial and the start of the Holocene interglacial and human influence? Maybe it has, maybe it hasn't, or maybe it will in the future. But this confusion and flitting between different terms in various popular media platforms detracts from the importance of the Anthropocene's status. The greater the rank is of the Anthropocene, the more disparate the conditions on the planet must be within the present unit of time and the prior division of equal status. Perhaps this is one of the reasons we cannot come to an honest consensus on the Anthropocene's existence and formalisation - because we cannot agree if the Anthropocene should be of Epoch status, or of a lower division. Yes, academic articles all seem to call the Anthropocene an epoch, but to me there almost feels like a lack of belief that it is an epoch, as questions continue to arise about its rank in various papers (e.g. Waters et al 2014; Gibbard and Walker 2013). Due to this confusion, journalists picking up academic papers and translating them to popular media could be mislead and thus fail to see the significance of terminology. I might be wrong, but I believe if we all (be that students, academics, journalists, radio and TV presenters, and the general public) sing from the same hymn sheet, we might be able to think more critically and seriously about other facets of the Anthropocene, of which there are many.

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.

The clue is in the carbon...

Ever heard of spheroidal carbonaceous particles (SCPs for short)? Well, unless you're really into environmental change research or atmospheric pollutants (which I hope you might be if you've stumbled across my blog), I doubt you have - and if I'm honest, neither had I until I started researching potential stratigraphic markers for the Anthropocene. SCPs are a very distinctive type of black carbon ash particle, which form only as a by-product from the incomplete high temperature (>1000°C) combustion of fossil fuels (Rose 2015; Swindles et al 2015). In other words, these are real physical carbon by-products of human activity from the burning of coal and oil. As a unique and purely anthropogenic particle, detected and preserved with high resolution in marine sediments, lake sediments, peat, and ice cores (Rose 2015), it seems SCPs could be the "golden spike" geologists and stratigraphers need to pinpoint the start of the Anthropocene!

A scanning electron microscopy (SEM)
image of an SCP. Their morphology,
shape, and colour are completely distinctive
(Source: Rose 2015) 

The presence of SCPs have been discovered synchronously on a global scale (even in remote locations such as Greenland and Antarctica), with a rapid increase in the accumulation of particles starting around the year 1950, coincidently the same time of the Great Acceleration (Rose 2015; Swindles et al 2015; Steffen et al 2007; Steffen et al 2011; Steffen et al 2015). The Great Acceleration, aka the "Atomic Age" is characterised by a signal of dramatically increasing and widespread global human impacts on the planet, e.g. increased fossil fuel combustion, rapid atmospheric CO2 increase, use of nuclear bombs, exponential growth in human population, alteration of nitrogen cycles etc (see any of the Steffen et al 2007, 2011, or 2015 papers for more detail). The stratigraphic marker chosen must characterise the nature of the Anthropocene in a range of global archives, and reflect the global pressing impact of humanity on the planet (Swindles et al 2015). Therefore it would seem SCPs, as completely non-natural markers and unambiguous signals of industrial human pollution, could be entirely suitable for an Anthropocene golden spike in the Great Acceleration (Rose 2015).

A recent study by Neil Rose (2015) represents a culmination of over two decades of research undertaken at UCL's Environmental Change Research Centre (ECRC). Rose (2015) looks at sediment cores from 71 lakes across the globe, comparing the timing and accumulation of fly ash SCPs from atmospheric deposition. Though observed start dates for the appearance of SCPs in records varies around the mid-19th century, a considerable increase is detectable in all the lakes around 1950 (Rose 2015). The increased deposition of SCPs represents the sharp rise in energy demand from post-WWII introductions of cheap fossil fuels (Rose 2015). Though deposition has generally declined in recent decades for various reasons such as cleaner fuel technologies, less heavy industry, and cleaner air legislation, the mid-20th century peak is a robust and clear signal of human impact.

Figure from Rose (2015), showing the SCP sediment profile from different lakes across the world. Solid black lines are the mean data, and the red bar is the mid-20th century mark (~1950). The rapid increase in SCPs after 1950 are clearly globally synchronous.

Why SCPs over other markers?

Other indicators of a mid-20th century Anthropocene start, such as trace metals, are prone to degradation and alteration to concentrations from changes in weathering over time (Rose 2015). A popular suggestion is the use of radionuclide fallout from nuclear weapons testing (Zalasiewicz et al 2015), however as Rose (2015) points out, half-lives of these radionuclides prevent them from being a long-term stratigraphic signal. SCPs, on the other hand, have no half-life and thus are expected to preserve well in the long-term (Rose 2015). Furthermore, SCPs are a robust signal at the same time of the Great Acceleration and are temporally close to the Alamagordo nuclear testing of 1945, unlike some proposed radionuclide fallout peaks of the early 1960s (Lewis and Maslin 2015), which occur nearly 20 years after the nuclear testing and a decade after the SCP record peak. As argued by Swindles et al (2015), radionuclides and anthropogenic soil horizons (Certini and Scalenghe 2011) fall out of favour as markers because signals can be diachronous and globally inconsistent.

Thoughts...

Though Rose's study is a fantastic piece of research into a potential marker, and illuminates the permanence of human impact in sediment records, more evidence is required from other natural archives (ice cores, peat, and marine sediments) to confirm the globally synchronous signal. It is essential that the AWG come to an agreement on a suitable GSSP or GSSA for the Anthropocene epoch's lower boundary. SCPs, with their globally synchronous, robust and crystal-clear anthropogenic signal, could be just what the group has been searching for to define the onset of the Anthropocene.