The signs are increasingly visible: climate change threatens coastal regions and biodiversity in several places; carbon dioxide emissions have already changed the composition of Earth’s atmosphere; traces of plastic, aluminium, concrete and other materials leave their signature over landscapes in all continents. We are witnesses of the birth of a new geological epoch. At least this is the idea that many geologists and researchers want to propose to the international community. One of the branches of the International Commission on Stratigraphy (and, by consequence, of the International Union of Geological Sciences), the Anthropocene Working Group (AWG) argues that human action has become a geological force, comparable to volcanoes -- mainly from the 1950s onwards. 

To British scientist Colin Waters, AWG Secretary, “we have already changed the planet, and these changes will be permanently expressed in the rocks of the future”. In a phone interview to the Museum of Tomorrow, Waters advocated that we entered the Anthropocene about 70 years ago -- the term stems from “Anthropos” (man) and “cenos” (new). He is speaking as a member of the group that says we are no longer living in the Holocene, the current official geological epoch that started a little less than 12 thousand years ago. 

Honorary Professor at Leicester University, in the East of England, the researcher emphasized that the formalization of the “human epoch” is important as it “shows the extent that we have had an impact on the planet to the point that we are leaving a permanent legacy of our existence”. The formalization of the term is an object of intense debate within the scientific community and brings political and economic implications with it. It was one of the themes discussed during the 35th International Geological Congress which takes place every four years -- the latest occurring in Cape Town, South Africa, between the end of August and beginning of September 2016.

Museum of Tomorrow - What is the Anthropocene, after all?

Colin Waters - There have been many interpretations of what it is. As geologists, we’ve been looking at environmental changes that happened intermittently over the last 4,5 billion years – expressed in the rocks. Since the start of the Holocene, about 11,700 years ago, there has been a fairly stable environment. There has been a very amicable climate; it’s the time interval during which we’ve prospered as a species and we’ve occupied a dominant niche across the planet.

But something else happened subsequently, notably towards the mid-20th century, when the whole scale of our influence on the planet changed radically. And we see that in a whole host of different signals, whether that be just novel materials such as plastic, concrete, fuel ash from power stations or new chemicals. We have produced new pollutants, such as DDT, insecticides, but at the same time we have pumped huge amounts of greenhouse gases into the atmosphere through our consumption of hydrocarbons – it has all changed the Earth very dramatically over a very short period of time.

To us, that’s what the Anthropocene really represents - a physical change to the planet, one through which we are living and at the same time the cause of - and many of these changes will be permanently written in the rocks that will record the history of our time on the planet. That record includes the way we have modified the abundance and distribution of other life forms on the planet as well.

Why can’t we decide about a starting point?

Reading the geological record isn’t like a scientific experiment in which you have a hypothesis, test it in the laboratory and use the results to come up with a unique solution. Examining the possible start of the Anthropocene requires interpretation of multiple options of many different changing environmental signals and potential start dates - in the end, aiming to pick the optimal solution - or what looks the best marker for allowing global correlation of the sum of these environmental changes.

We’re able to change the world on a much larger scale than we were a few centuries ago. We live a lot longer now than in previous times and consume more; we use huge machinery that can move vast amounts of earth. All these changes focus on a ‘Great Acceleration’ in our global impact during the second half of the 20th century and have become a very significant marker to the way we’re able to modify the planet for our own benefit.

I think because this all happened quickly, the boundary we’ll see in sediments or in glacial ice coinciding with the mid-20th century will be marked by a large number of environmental signatures which will appear to have changed in an instant when compared with geological time scales. Some geologists argue against the definition of the Anthropocene because it is such a short interval of time compared with the millions of years typical for other geological epochs. However, the duration is not necessarily the most important thing - it’s the size and rapidity in the change of the signatures that started in the mid-20th century, which makes it acceptable that we’re only 70 years into what we consider as the Anthropocene. I think we can say no matter what happens in the future, we’ve already changed the planet to the point that a fundamental change in the planet will be expressed permanently in rocks –  that will be visible forever as an abrupt signal in the geology.

The meaning of 'Anthropocene' is 'the epoch of humans'. But are we really talking about a 'human epoch'? Wouldn’t it be the epoch of a certain socio-economic development model?

As a species, we’re able to make a decision to “take as much coal as we wish from the ground, but at the cost of increasing greenhouse gases”, but at the same time we can decide not to do that, we can decide to keep coal in the ground and to use more renewable energy. So I think that perhaps the logic in using this term, “new humans”, reflects the new human way of controlling aspects of the planet’s environment rather than just influencing it the way our species did during the Holocene.

Is the Anthropocene associated with a development model?  In some aspects you can say “yes it is”. Because there is this interval after World War II when we developed globalization of the world economies so that we’re able to grow crops or extract minerals in one country and transport them across the planet to be consumed in vast quantities. And that is very much indicative of socio-economic development within this 70-year period which is occurring at an unprecedented scale. It is this story of greatly expanded consumption at this time that has left (and continues to leave) its legacy in the geological record.

So it’s not only about depth but also about the extent of the human impact.

It’s a matter of not just the extent but also of magnitude of change. For example, carbon dioxide in the atmosphere at the end of the last ice age was at about 250 parts per million (to every one million molecules of air, 250 were carbon dioxide). It has considerably increased since the Industrial Revolution, but especially over the last century and is now in excess of 400 parts per million. The magnitude of this change is so dramatic, currently increasing at a rate more than 100 times faster than at the start of the Holocene, back 11,700 years ago, that we think that the significant state of change for this gas is comparable or greater than we’ve seen in the geological past -- and that’s what makes it important to be able to make case for this new geological time interval.

By the way, do you think we can conciliate capitalism and sustainable development?

This is a question that goes outside my expertise as a geologist. Our work regarding the Anthropocene is at the end of the day concentrating on signals found in sediments and glacial ice and how they can be correlated from one part of the planet to another.  It is not necessary to know how the signals were created for them to have importance as a geological marker.  But it’s still interesting to understand the process by which they’re formed.

I suppose the key cause of the Anthropocene has been globalization of economies and increased consumption of materials and goods such as fossil fuels, minerals, food, and to an extent we can say that had a capitalist drive. 
 

The term was proposed by ecologist Eugene Stoermer in the 80s and popularized by Paul Crutzen in the 2000s. What does this debate around the Anthropocene mean, being done right now? Why now?

I think to a certain extent, we can consider the impact we have on the planet has only really become significant in the last 60 to 70 years. When I started as a geologist, we were told that humans had no significant impact on the planet - the planet was so big and geological processes were so vast that anything we did had a very small imprint.
But it probably wasn’t until the 1970s when we first had satellites circling the planet and carrying out monitoring of the environment and we started getting real time data that we were able to measure climatic change, changes in the ozone layer, rates of deforestation and ice sheet melting. We started to understand that the planet as a whole behaved holistically as a single system. So it’s become obvious that if we start pumping out more greenhouse gases into the atmosphere, there will be repercussions not just to the atmospheric chemistry, but also rising temperatures and sea levels and acidification of the oceans.

I think that the popularity of the Anthropocene concept is it’s come at the right time as a term because it coincides with our recognition of climate change, large scale environmental pollution and species loss, for example. The Anthropocene actually encompasses them all together. We’re very interested in the loss of species, the changing abundance and distribution of domesticated animals and cultivated plants,  in evidence for climate change, in the evidence for contamination of the planet, the generation of new minerals and materials like plastic and concrete - all of these things are relevant to the science of the Anthropocene.

What the term is doing is synthesizing all this environmental information, from many different scientific fields, and summarizing it in one simple concept. It allows people to understand that everything we do has some degree of impact on the planet. Whether those impacts are positive or negative, that’s not really the important aspect of the research, but it’s important that people understand that what we do does have an impact, and the repercussions are greater than what we perhaps perceive around us. That we could actually, by increasing the amount of fertilizers we are putting on our fields, cause algal blooms in the oceans that starve the water of oxygen and end up causing dead zones in the oceans – a repercussion which is not initially obvious and has only been known over recent years. But now we can actually quantify the scale of these impacts through the science that is being carried out globally. I think all in all, it has maybe been only the last 20 years or so that we have had the information available to start to understand the Anthropocene fully, and new information that helps refine our understanding arrives continually. That’s why, in my belief, the term has become so popular.

The term is not formal yet but has been widely used. Why, then, fight for a formalization? What changes in the lives of people if this new epoch is formalized?

At present, scientific journals will allow publications to refer to an ‘Anthropocene’ of maybe 10,000 years ago – a very different concept from an Anthropocene of only 70 years ago that the working group as a majority prefers. Science requires rigorous definition - we have to have a standard definition of what a centimeter or a kilogram is… because if we don’t, chaos will result as people will lack a means of describing absolute measurements consistently. So, similarly, we feel we have to be equally rigorous in our use of the term, and by appearing on the geological time scale, people will understand “this is the definition of the unit, this is when it started” we will share a common language. And, if people use the term the way they wish, it will lose its rigorousness or perhaps will no longer be used, because it will have become a meaningless term to talk about human impact on the planet. 

The Anthropocene is more about that understanding that it gives you that we as a species are leaving a lasting legacy on the planet. It’s about our impact on the consumption of fossil fuels, minerals, the greater and greater demand for products. Many people associate the Anthropocene with change for the worse. But we’ve never lived longer, or economically prospered as a species. But that comes at a cost -- the change we make to the planet itself. So the Anthropocene as a term encapsulates that impact. To many people that’s an important thing to understand because, in many different aspects, not just climate change, we’ve had an impact upon the animals and plants of the planet as well and how we’re changing the atmosphere and oceans dramatically. And these are things that everybody is developing an interest in, and this term allows us to understand how this is all interrelated.

Interview: Meghie Rodrigues e Davi Bonela - Pesquisadores do Observatório do Amanhã

Edition:  Emanuel Alencar - Editor de Conteúdo do Museu do Amanhã