The Anthropocene refers to the idea that human behaviours have changed the earth’s ecosystems, but it hasn’t been formalised scientifically. Recent work has shed light on our impact on the planet, and raises some profound questions around the future of humanity.
Though the concept of the Anthropocene is becoming both more mainstream while remaining disputed, Professor of Palaeobiology at the University of Leicester, Jan Zalasiewicz, tells me that the idea’s antecedent can be traced back to the 18th Century, ‘the first reference which you could say is an ancestor in the first ever scientific earth history, something called the Epochs of Nature, written by Comte du Buffon in 1778.’
Professor Zalasiewicz explains that du Buffon divided earth history into seven epochs, the final one du Buffon argues, is one where human beings are ‘assisting’ the power of nature. ‘The idea that humans have changed the earth has been around a long time,’ says Professor Zalasiewicz, ‘but most of that time geologists have usually thought it was nonsense.’
However, Professor Zalasiewicz and his colleague Mark Williams, also a Professor of Palaeobiology at the University of Leicester, have made significant contributions to a research study (co-authored with 24 others) just published in the journal ‘Earth’s Future’. It makes the case that human beings have changed the Earth’s ecosystems and evidence is increasingly geologically visible.
Inventing the Anthropocene
The term Anthropocene was popularized in 2000, by atmospheric chemist Paul Crutzen and biologist Eugene Stoermer in a piece they wrote in the newsletter of the International Geosphere-Biosphere Programme. Crutzen had won a Nobel Prize in 1995 for his work on the ozone layer.
‘When I was studying [at university] or when Mark was studying,’ says Professor Zalasiewicz, ‘geologists would have said that the changes you get with volcanoes and the mountain belts is far greater. It’s really only the last couple of decades that scientists, particularly those working on the Earth’s system as a whole, have realised that humans can in fact impact very greatly on the earth.’
So when the term Anthropocene was first used by Crutzen, ‘he was working in a very active high-profile group of scientists,’ explains Professor Zalasiewicz. ‘The term spread among them and beyond them, and began to be used in serious literature without any sense of irony or inverted commas, as if it was real and formal.’ Though it hadn’t been scientifically formalised at the time, the term Anthropocene crystallised a sense that human beings were changing the earth in a significant way.
The stratigraphic Anthropocene
Looking back, Professor Zalasiewicz reflects that while geologists like himself and Professor Williams came a little in a little bit late onto that, over the last decade the concept has gone way beyond the Earth Sciences into the humanities, the social sciences and art. ‘We have to try and keep track of all that, not all of it is directly relevant to our specific work, what we call the stratigraphic Anthropocene. But the huge explosion of interest is certainly something we have to be aware of. It’s relevant because humans are the driving force, geologists are not the best people to try and understand humans and human behaviour.’
They wrote their initial paper in 2008 arguing that the term might make geological sense. Consequently Professor Zalasiewicz and Professor Williams were invited to form an official international working group to examine the evidence for whether the Anthropocene might become geologically real. ‘We have a eclectic group,’ says Professor Zalasiewicz, ‘we have geologists, we include people working on icecaps and oceans and modern ecologies and even international lawyers looking at the utility of the term.’
Professor Williams explains that looking at the fossil record and the evolution of life over four billion years, ‘we see the evolution of some major innovations which effectively remodel all the biosphere. Perhaps the most significant Deep Time one that you find would be about two and a half billion years ago, when we can see evidence in the fossil record for the evolution of photosynthetic organisms that are actually producing oxygen as by product of that metabolism.’
The Future of Humanity
What he and Professor Zalasiewicz have been trying to do is quantify the current rate of change to the biosphere, ‘trying to find out how significant the human influence is on remodelling of the biosphere, and it seems to be very, very substantial indeed. In fact it seems to be completely unique and it might be that we are approaching one of these huge changes in the organisation of the biosphere that would presage a completely different trajectory of the biosphere in the future.’
Professor Williams suggests there are a variety of different possible directions for the biosphere. So for example one line of thinking is that due to consumption behaviours the human impact is so great that it is not sustainable over a long time frame, and may significantly alter the biosphere. ‘It might mean that human civilisation and human society actually collapses,’ he says, and, ‘that would leave a signal we think in the stratigraphic record that would be recognisable by future geologists as perhaps as epoch level – like perhaps between the Pleistocene Epoch [2,588,000 to 11,700 years ago, the era of the most recent Ice Age, the evolution of Homo Sapiens] and the Holocene Epoch [11,700 years ago to now].’
They are also considering that the degree of change might have such a significant impact on the biosphere there may be a mass extinction event, equivalent to period change on the level of the Cretaceous mass extinction, known for the death of the dinosaurs but also many other organisms and life forms. This would reset the biosphere.
‘There is another potential trajectory which is perhaps bordering on science fiction,’ suggests Professor Williams, ‘but one that is very reasonable we think, to actually moot. That is possibly the evolution of the biosphere in conjunction with technology which might actually produce a kind of synergy that becomes sustainable over a long timeframe.’ This would be where geology and technology become integrated, ‘hopefully to the benefit of both the biosphere and technology – the earth evolving into a completely new state. It would be like that transition between the Proterozoic and the Phanerozoic [the transition to the emergence of complex life forms] or between Archean and the Protozoic, that fundamental.’
In terms of the next steps of the Anthropocene working group, they will deliver their findings by the middle of the year delivering a preliminary résumé of evidence, interim recommendations – for and against. While Professor Zalasiewicz believes that most of the group will lean towards confirming that the Anthropocene is geologically real and can be formalised, it’s unlikely to be the end of the story.
They will need to provide some visible evidence of a unit of geological time, what’s called a ‘golden spike.’ Professor Zalasiewicz explains that this is, ‘a global reference section of rock or sediment which is the best physical reference for other scientists to use, to define the beginning of the Anthropocene.’
Alongside that there will be continuing collaboration with other scientists in geology within Earth Systems Science and in other disciplines entirely. ‘We are working with the social sciences, with the likes of Bruno Latour and the historian Dipesh Chakrabarty and others, looking at what it might mean, learning from each other,’ says Professor Zalasiewicz. ‘Scary it might be in some ways, but in another ways it’s been a superb concept for quite naturally forming interdisciplinary links between different people, between different groups of people, it has happened quite spontaneously.’