Teaching at UEA

For many years I taught a six week module (12 lectures) to first-year undergraduates at UEA upon ‘Earth Surface Processes’ (a subject referred to as ‘Physical Geography’ in other venues). It was a companion module to one presented by my friend and colleague Neil Chroston that covered Igneous and Metamorphic Processes (although he stole my rights to talk about volcanoes). He was a wonderful and natural lecturer whom students loved. I watched him teach and observed just how good he was. At one time he would take a plastic bucket, into which he would theatrically place large specimens of feldspar, quartz and mica (large specimens needed because it was a large 150-seater lecture hall and those sitting at the back needed to see). He would lower the bucket behind the bench at the front of the hall, out of the sight of students, and then raise an identical bucket with an even larger specimen of granite (actually a granite pegmatite with very large crystals of the three minerals). Neil would claim he had combined the minerals into an igneous rock. The students went nuts, screaming that he must have had two buckets. What they didn’t realise was that gently, and irretrievably, they had been taught the difference between minerals and rocks and they would never forget it. I couldn’t match such skill, but I tried my best.

I had already given up trying to cover all the material in the recommended textbook and resolved that my task was to interest the students sufficiently that they would wish to read their beautiful and well-written book for themselves. Later I gave students transcripts of my lectures in the classes so they could just annotate and this would allow them to think about what I was trying to teach rather than just copy. This gave me a great deal of freedom in what I taught and how I taught it. Perhaps the discussion topic that benefited most from such freedom of approach proved to be the importance of human agency.

Humans changing the land surface

I came across a short paper written by R. LeB Hooke in 1994 that I seized upon and transformed into a summary lecture that became one of my and my students’ favourites. Entitled “On the efficacy of humans as geomorphological agents” the paper compared the rates of change caused by natural agents ranging from rivers, glaciers and other surface processes to mountain building. Rates were determined by how much material was transported by each of the geomorphological agencies. This formed a beautiful end-stop to my lecture series reviewing each earth surface process and quantitatively comparing them. Hooke reached the conclusion that mankind had become the most effective agent transforming the Earth’s surface. The methods he used to estimate these changes themselves became an interesting side issue (think about how you might estimate the amount of material shifted by mountain building processes, per year). Unlike most geomorphological agents that move Earth materials around in directions imposed by or controlled by gravity, humans move material commonly against the dictates of gravity in directions that they desire.

In 2000 Hooke wrote, what was to me, another seminal short paper which showed how humans had become more and more effective geomorphological agents over time, starting with an estimate of how effective we were at the time of pyramid building in Egypt, then building roads under Roman rule, and on until recent times. Hooke also recognised that agriculture caused the efficacy of rain, drainage and wind to increase significantly, and so calculated another term to account for human unintended interference (originally much larger than direct purposeful movement of material by humans).

The amount and speed with which humans have modified the Earth’s solid surface is simply staggering. Price et al (2011) estimated that inhabitants of the United Kingdom have, over the past 200 years and by themselves, excavated, moved and built the equivalent of a volume equivalent to six mountains the size of Ben Nevis. The latest estimates were then that, worldwide, humans annually move 57,000 million tonnes of earth and rock, and this compares with only 22,000 million tonnes of sediment annually moved to oceans by rivers (previously the most effective natural agency changing the Earth’s surface).

Link between human geomorphological change and the Anthropocene concept

Only very recently have I found that Hooke’s two short papers have been used to partly justify the highly contentious period of time that some wish to recognise – the Anthropocene, an interval formerly considered as the most recent part of the Holocene. Surprisingly Hooke’s papers go unmentioned in the Wikipedia entry upon The Anthropocene, an entry which is otherwise very good. This short time period is supposedly distinct because, during it, humans have become the most important agents of geomorphic change (including changes to the composition of the atmosphere). This, it is argued, can be recognised in the sediments laid down in this time period, hence justifying its recognition as a separate period of geologic time. This is highly contentious with some international groups of geologists rejecting the concept of the Anthropocene, while other groups vigorously support it, not least those determined to recognise human impact on the climate and climate change. So the Anthropocene is a concept ignored or rejected by most climate change sceptics (if they think about it at all). 

I am ambivalent about its fate. I was taught geology by professors and lecturers of the ‘old school’ who had fought in World War II, and they even considered the whole of the Holocene to be a manufactured sliver of a time carved out from the Pleistocene just because modern humans lived during it. (I don’t believe those people were impressed by modern humans, but they didn’t really want to talk about it). The Holocene, in my teachers’ views, had no more reason to be separately recognised as a geologic epoch than previous interglacials like the last one: the Eemian within the Pleistocene. To them the Holocene was another name for a Flandrian Interglacial, the youngest part of the Pleistocene. I even heard murmurings that the Pleistocene itself was an upstart, being merely a rather cold episode at the end of the Pliocene.  Much earlier and longer ice ages weren’t given separate recognition as stages. To those iconoclasts the Quaternary (Pleistocene + Holocene) was unnecessary.

Then there are other well-known divisions of Recent time that are not standard geological but climate based, for example the Holocene Climate Optimum, the Roman, Medieval and Present Warm Periods and the Little Ice Age with which we in Europe are familiar. Then again there is the Blythe-Sernander scheme, for those into peat bogs, where other recognisably named subdivisions (also climate based) are employed – the pre-Boreal, Boreal, Atlantic, Subboreal and Subatlantic. Today there are three officially recognised (by the International Commission on Stratigraphy) subdivisions of the Holocene announced as late as 2018, the Greenlandian, Northgrippian and Meghalayan with completely different boundaries to subdivisions in other schemes. The youngest officially recognised division – the Meghalayan- began 4.2k years ago with a widespread 200 year long drought that caused major cultural shifts in human civilisations from the Eastern Mediterranean, across the Middle East, the Indus River and to the Yangtze River basin. Such a plethora of names; do we need yet another and possibly one only spanning my lifetime? And yet I haven’t mentioned countless other divisions and subdivisions that have been proposed. North America has different names for some European divisions and goodness knows what they use in deepest darkest Peru. It was bad enough when I was an undergraduate (I dreaded having to answer a question on the Pleistocene or Holocene on my stratigraphy paper, having to remember seemingly countless names, who used them, what they were equivalent to and what they all meant): it must be so much worse for students now.

So what am I to think about the Anthropocene?  

If we should recognise the Anthropocene as a quite separate period of time, identifiable as the time during which humans became dominant earth sculptors and perhaps changed our climate, we need to be able to do the following:

1) Identify the sediments (or other materials such as ice or speleothems) that were laid down in this time period.

2) Agree an accepted date at which the Anthropocene began.

3) Agree upon a location where materials at the junction of the Holocene and Anthropocene are exposed and where a commonly agreed “golden spike” can be driven that constitutes a common reference point that specialists can visit and take samples.

To my knowledge none of the above points has yet been fully agreed.

There is no agreement on when the Anthropocene began. Suggestions range from 12,000 to 15,000 years ago (during the Neolithic agricultural revolution) to as late as 1965. If we are to incorporate biodiversity loss as one of the criteria, then the Anthropocene began even earlier, during the time all humans were hunter-gatherers. For most geologists the difference between a few tens of years and a few tens of thousands of years is inconsequential and scarcely identifiable. Much of this decision is based upon necessity – the need to be able to identify Anthropocene sediments and materials. Here, the contained particles of human origin, such as microplastics, heavy metals or radioactive components from thermonuclear tests, would act as identifiers. In fact the 1945 Trinity test has been formally proposed as beginning the Anthropocene.

Others (the non-geologists) like the Dutch atmospheric chemist Paul Crutzen got involved in the Anthropocene promotion game arguing that humans have significantly changed the Earth’s atmosphere, causing everything from ozone holes to global warming, and sufficiently to identify this episode as a distinct geological epoch. How this is to be done by geologists is left to them. It should be of considerable interest to climate sceptics that there is a considerable groundswell of opinion that the Anthropocene should begin sometime in the mid Twentieth century, when human geomorpholocal activities began to surpass in terms of transported mass those of natural geomorphological agents and we began to significantly increase atmospheric CO2. Is this deliberate or just a coincidence?

Decisions about the Anthropocene are due this year (2021) but I have heard nothing; perhaps they are delayed by the pandemic, or will be announced just before COP26. Whenever they come, if they are favourable and identify the mid Twentieth century as a starting point, then anticipate yet another arrow for the alarmist bow.

If we do finally acknowledge the Anthropocene as a separate period of time, then I’m going to begin canvassing for the time period between 1943 (the year of my birth) and the present day as the Kendallocene. After all, from my POV, the world revolves around me. I think you will find that this would make the Anthropocene redundant. 

Bibliography

I start with the two papers that introduced me to the idea that humans had outstripped natural geomorphological agencies in modifying the Earth’s surface, and which I used in my UEA teaching.

Terms are rigorously defined, methodology discussed and estimates defended. Wonderful material for undergraduates (and others): 

Hooke, R.LeB., 1994, On the efficacy of humans as geomorphological agents.  GSA Today, 4 (9) 224-225.

Hooke, R.LeB., 2000, On the history of humans as geomorphological agents,  Geology, 28, 845-846.

A more recent evaluation, with special emphasis on the U.K. and a link to the Anthropocene concept (mankind becomes the predominant modifying force. Requires a separate geological time period to emphasise that:

Price, S.J., Ford, J.R., Cooper,A.H. & Neal., C., 2011, Humans as major geological and geomorphological agents in the Anthropocene, the significance of artificial ground in Great Britain. Phil. Trans. Royal Soc A369, 1056-1084.

Finally, of the many, many articles and papers written supporting or opposing the Anthropocene, I have found the following both well-written and illuminating:

Peter Brennan, 2019, The Anthropocene is a joke. On geological timescales human civilization is an event, not an epoch. The Atlantic.

Sam Perrin, 2019, If the Anthropocene is a joke, it’s a useful one. Ecology for the Masses.

via Climate Scepticism

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July 15, 2021