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The questionable age of man

By Oskar Swartling


The study of Earth, rocks and how they change and are created is an old, although still important scientific field. Geology does not only provide information of historical importance, but also helps us understand the world we live in and the world we will live in. Like the field of medical sciences, the advancement of geology has widespread impact on our society. By studying the continental drift, the layers of the Earth and past climates, geology delivers useful and necessary information about natural hazards and climate change, to name a few. The impact of humanity on the Earth is one of our time’s major topics, but is not limited to climate change, the rise of the sea levels or the deforestation of rainforests. The idea of a geological time that recognizes our impact on the planet is gaining ground and more voices are being raised to let the present epoch Holocene give room for the Anthropocene: the age of man.

Geology uses periods, epochs and ages as units of time to make sense of all the rocks, fossils and sediments that are found around the world. By doing this, it is possible to give all these materials an absolute age and to determine the geologic history of the Earth. This discipline is called geochronology and uses radioactive isotopes and other techniques to date the material. It is therefore possible to divide the geologic history in the units of time named earlier. The body controlling this is the International Commission on Stratigraphy (ICS) by defining strata criteria. In short, they are responsible for the geological time scale, making the sciences of geology, palaeontology and geobiology working on a global scale. We are right now living in the Quaternary period and the Holocene epoch, starting 11,700 years ago after the last ice age. Although that might change, the ICS has started the Anthropocene Working Group, evaluating the proposed new epoch. It is, however, necessary to understand just how important the geological time scale is. Some describe it as so fundamental for geology that it can be compared to the periodic table for chemists. With this in mind, it is not hard to understand that although popular, the Anthropocene is not warmly accepted in all corners of the scientific field.

Geology delivers useful and necessary information about natural hazards and climate change


The proposed epoch Anthropocene is becoming widely popular, not just within geology. The epoch is thought to have started when human activities started to have an impact on the ecosystems of the Earth. The next question is, however, when did this happen? The early start of the Anthropocene is when humans first started changing the land by farming and herding. To be an adequate unit of time, the start has to be clearly defined. For example the start of the current epoch, the Holocene, is a chemical reflection of the end of the last ice age in an ice core found 1,492.45 metres down in Greenland. Due to this need of specificity, just the start of the Anthropocene is a big debate. The early start of the Anthropocene could be seen in the rise of methane in the atmosphere, indicating a higher frequency of farming and herding activities. Another possible start of the epoch is what is known as the Great Acceleration, a time starting in the beginning of the twentieth century. During this time, the marks of humanity on the environment increased exponentially. A third proposed start is the records we can find all over the world after the nuclear bomb tests in the 1950s. Another, somewhat terrifying start of the epoch is a drop in carbon dioxide levels in the atmosphere between 1570 and 1620. A paper published in Nature linked this drop to the death of 50 million indigenous people after the ‘discovery’ of America. According to the paper, millions and millions of hectares of agricultural land became overgrown by forest, thus the drop of the carbon dioxide concentration. Despite the different candidates for the start of the Anthropocene, there are other reasons besides pure scientific reasons that the proposed epoch is so popular.

Usability is the main reason the Anthropocene has become so popular. A geological time defined by a starting point from when humanity started to destroy the ecosystems of the Earth is a useful tool. What started as a geological concern became something many disciplines can use as a way of getting heard. It is beyond doubt that humanity has a major impact on the Earth and that this is recorded in material all over the world, but since the geological time scale is immensely large, many question the significance of this impact on the rocks and sediments that are studied today. Many environmental researches, media and politicians embrace the proposed epoch to push for legislations and to get the public’s attention. The Anthropocene is no longer just a name for a unit of time, a new element in the periodic table of geology; it is a way of changing the route we have embarked on. The geologists concerned with the idea of an age of man do certainly not question the evidence for climate change. They are, however, sceptical of letting politics and public opinions affect their science.

The epoch is thought to have started when human activities started to have an impact on the ecosystems of the Earth


The dividing line seems to be the question of whether it is too premature or due to non-geological reasons the new epoch would be introduced. Humanity is affecting our planet and we are leaving well-defined marks suitable for a definition of a new epoch. But from a pure scientific point of view, it is not totally clear if it is necessary. If the start of the Anthropocene would be the beginning of the twentieth century, e.g. the Great Acceleration, the sedimentation on the bottom of the sea from this period would be thinner than one millimetre. Given this, some geologists recommend that the evaluation of the new epoch should happen in some thousand years.

The Anthropocene has become a political statement. The need to formalise the age of humanity’s impact on Earth is more than geology. The new epoch could be used as a, albeit good, argument in many relevant and important decisions. With this epoch and its definition, it might be easier to raise the question of climate change even more, to really reach out to the public. One can imagine the incitement and strive to globally end the Anthropocene, the modern equivalent of the Dark Ages. But the Anthropocene is a formal geological time scale; the Dark Ages is not. The word Anthropocene is already in use in the geological society, although informally. Still, the message is clear even from an informal definition.

What started as a geological concern became something many disciplines can use as a way of getting heard

For an outsider it is difficult to recognize the importance and status of the geological time scale, but it has undoubtedly a high place in geology and other sciences. Like in many other disciplines, there is a debate on scientific grounds whether the Anthropocene should be honoured with a formalisation. It is clear, however, that other aspects are influencing the pure scientific debate. Keeping in mind that an age of man could be used as a good weapon in the tiring and slow debate on climate change, maybe a formalisation is a good thing. Or do we want science to be independent, a place where one can extract information and use it for the advancement of our society? The questionable age of man raises important questions for all the scientific disciplines and it is hardly the last time these hard questions have to be asked. We have on one hand a geological time scale used to date and relate geological materials and to describe our world. But on the other hand, climate change debates are crumbling and new inputs and arguments are certainly needed. The Anthropocene Working Group will publish its recommendations by 2016. After that follows discussions and a decent time of voting before the epoch finally could be formalised. The importance of this can be argued. The real problem is not whether the Anthropocene should join Cambrian, Jurassic and the Holocene as a unit of time. The real problem is that we can actually define the geological history of our planet by the impact we are having on it.

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