Image by Matt Palmer on Unsplash
By Matt Goodey
Humans have had a devastating impact upon the planet. There is no doubt to be had about this. CO2 levels have risen at an unprecedented rate in the last 100 years. And that does not look to be changing in any significant manner in the near future, as the underwhelming COP26 deal shows. What is more, the human population is projected to reach 11 billion by 2100. So, even though we already consume around double the amount of resources that the Earth can produce each year, it seems, paying no heed to this disturbing fact, we are bound to become ever more unsustainable. And make no mistake, in this we are unique: even bacteria know when to stop dividing as their population reaches a maximum.
In light of the recent catastrophic human impact upon the planet, it has been suggested that the earth has entered a new era in its history: the Anthropocene. But is there any definite evidence for this?
First of all, if we are going to pin the emergence (or lack thereof) of the Anthropocene down to a point in Earth’s history, we need to be able to picture it in light of Earth’s more general history.
That said, Earth’s is 4.567 billion years old. Most of its history has been relatively poorly recorded. Indeed, only the last ~500 million years (Ma) are sufficiently detailed for geologists to examine, and attempt to understand, events. The geological column is composed of eons (i.e. Phanerozoic or Archean) which in turn are formed from Eras (the Phanerozoic is split into Cenozoic meaning young life, Mesozoic meaning middle life and Paleozoic meaning old life) which are composed of Periods, split into Epochs. Usually, the transition into different periods is defined by a notable change in the fossil recorded. The most significant five major mass extinctions, where there was catastrophic loss of biodiversity, mark the transition into different periods, respectively. The appearance/disappearance of other globally distributed species mark the transition into different Epochs (this is known as biostratigraphy). The last epoch on the geological column is the Holocene, which describes the last 11,700 years.
So, the Anthropocene (which stems from Greek meaning new man) defines a new Epoch: a point in Earth’s history where human activities can be seen within the geological record. It could also be referred to as the sixth extinction, for species are disappearing around 100 times faster than they would without anthropogenic activities.
So, there is no doubt that the Anthropocene has begun; the question is when.
Many would argue that it began with the start of the industrial revolution (~1800 AC), as this is when the burning of fossil fuels began changing the content of Earth’s atmosphere. Others would suggest that it began with the testing of the first atomic bomb, which occurred in the mid 1940s. Earlier dates have also been proposed, such as the start of the deforestation of Britain’s ancient woodlands, which now only occupies 2.5% of Britain’s total land mass. If we went with the last suggestion, then we would be suggesting that the Anthropocene began around the time that humans transitioned from Hunter-gatherers to cultivating livestock and crops some 10,000 years ago.
For a geologist, the physical appearance or disappearance of fossils or other such features in the rock recorded dictates the transition into a new period or epoch. Now, Plastic debris has been known to be melted and incorporated into lava flows which then solidify forming new igneous material. Sedimentary rocks are composed of fragments of pre-existing rocks cemented together in a process known as lithification. Sediment is carried into the ocean through various different processes, and microplastics have been shown to be present across the entire ocean floor. Sedimentary rocks containing plastic are known as “plastiglomerates” and have been recorded on beaches on Hawaii. So, from a geological perspective, the appearance of plastics, first produced in the 1950s, in the rock record is a logical way to mark the beginning of the Anthropocene.
I do not mean this suggestion to be definitive across the board. Rather, I stress it because, beyond being simply sensible, it effectively bars us from passing the Anthropocene off as something that began in distant history. It makes it a recent reality: our reality. Being so unique in nature in our destructive capacities, it reminds us that we must become unique in our capacities to regenerate, rejuvenate, and restore the only Earth that we have, now. The other option is a catastrophic worsening of the reality we have made: for ourselves and all life on Earth.