By Luke Farnish
What time is it?
The answer may seem simple, just look over at your clock for the time, your calendar for the date and year. But for geologists, things are not so easy. The Earth’s geological history is split into segments of varying length, from aeons which can last five hundred million years or more to epochs and ages that can last just a few thousand. Pick up any off the shelf text book on geology and it should proudly claim that we currently live in the Holocene epoch, an epoch that began somewhere around ten to twelve thousand years ago. But now this view has begun to change.
Originally coined in the 80s by E. F. Stoermer, the phrase Anthropocene began to be used more commonly after 2000 when P Crutzen published a paper suggesting that our atmosphere is now so heavily tainted by pollutants (most notably by greenhouse gasses) and that we have altered the climate and ecology of the earth so heavily that a layer that will be visible to geologists in the future.
What is the Anthropocene and when did it start?
Anthropocene’s Greek meaning is simply ‘man epoch’, an apt name for the age. Like all geological periods, the Anthropocene is a period that will appear as a different rock layer to surrounding rocks. Previous periods can be noted for obvious features such as certain fossils being present/missing, layers of fossil fuels or simply the rock type. The Anthropocene is no different. The layer will show a rapid loss in the diversity of fossils (although an increase in fossil chicken bones has been suggested as a potential marker), combined with radioactive isotopes, general rubbish from human habitation (notably plastics and concrete) as well as showing evidence of rapid climatic changes.
A paper published in science in January this year (Waters et al., 2016) cemented many of the theories associated with the Anthropocene. One of the many conclusions was that the epoch likely began in the early 1950s. Even since 1954, radiocarbon daters have used the date of January 1st 1950 as a time known as ‘the present’ because the level of radioactivity after this time is enough to disrupt readings. (Note that these levels are not dangerous, just detectable.) There are, however, still strong arguments that the epoch began around 1800 as the industrial revolution altered the face of the planet forever.
In the wake of the paper, major efforts are being made to get the Anthropocene officially recognised. The Subcommission on Quaternary Stratigraphy (SQS) have set up a working group on the Anthropocene (WGA), with the aim of getting the period officially recognised by the end of the year. It is they who presented the facts outlined above to the International Geological Congress on Monday 29th August. However, they need to formally identify a global universal marker that proves layers belong to the Anthropocene, not the Holocene. The hope is that this will be a reminder to governments of the world of our impact on the world and need to reduce this impact.
Relevance at UEA and further reading
The recent developments on the idea of the Anthropocene will have an impact on the careers of Ecology, DEV, ENV and NAT students as further research is needed to verify findings and finding ways to minimise human impact. It is already a term that students and staff of these areas are familiar with. Anthropocene based projects are also now becoming more popular among PhD students. It is clear we still have a long way to go in our understanding of this rapidly developing period and UEA is likely to be at the cutting edge of much of the research.
Check out: http://www.anthropocene.info or http://www.quaternary.stratigraphy.org/workinggroups/anthropocene/ for more information about the Anthropocene.
Geological time periods (Aeon, Epoch, Age): The study of geological time periods is called geochronology. Within this, 5 main levels of division of the earth’s geological past are defined. These are, in order of size; Aeons (US spelling; Eon) of which there are four and they last at least half a billion years. Eras which last for a few hundred million years. Periods which last several tens of millions of years. Epochs which last a few tens of millions of years. And ages which last a few million years or less. These periods can be used a little like an address, focusing on narrower and narrower lengths of time e.g. the point when the dinosaurs became extinct was: Phanerozoic aeon, Mesozoic era, Cretaceous period, Late Cretaceous epoch, Maastrichtian age.
Quaternary: (Name meaning: fourth.) The current period (see above).
The Subcommission on Quaternary Stratigraphy (SQS): (from their own website) ‘The Subcommission on Quaternary Stratigraphy is a constituent body of the International Commission on Stratigraphy (ICS), the largest scientific organisation within the International Union of Geological Sciences (IUGS).
It is also the only body concerned with stratigraphy on a global scale for the whole geological column. Its most important major objective is the establishment of a standard, globally-applicable stratigraphical scale, which it seeks to achieve through the co-ordinated contributions of a network of Subcommissions and Working Groups with a specific, limited mandate.’
Image from NASA