Are we living in the Anthropocene? - Part 1

As an Earth Science student I have spent countless hours during lectures and out in the field trying to decipher what a certain rock sample or outcrop can tell us about the climate, atmosphere and environment at the time of deposition. So what happens during the next 100 million years when the rocks of our time become upthrust, eroded and exposed to the Earth’s surface? What will they say about our time on planet Earth? One thing is for sure; we have made a huge impact to the conditions on our planet, and these impacts are likely to be reflected in the future landscape of Earth. Whether these impacts will be great enough to distinguish rocks created before the evolution of humans to those being created today sparks debate over the Anthropocene.

Looking at a current geological timeline the Holocene is the present epoch which stretches back 10,000 years, but there is a growing scientific movement proposing we have entered the Anthropocene – a time characterised by human impacts to the Earth. This suggestion was first put forward in 2002 by Paul Crutzen, a Nobel Prize-winning atmospheric chemist. The term has since taken off, receiving support from The Geological Society of London Stratigraphy Commission and Jan Zalasiewicz. The Anthropocene could soon be made a formal unit of geological time, and be the first to be done so live.

Geological times are recognised by specific rock sequences, characteristic of Earth’s atmosphere, biodiversity and ocean acidity. Anthropological impacts will therefore be recorded in the rock record if humans have an influence on these factors. Arguably, human activity has already impacted every corner of the globe, from deep ocean environments to atmospheric composition.

Even at first glance, numerous examples of human impacts on biodiversity spring to mind. The expansion of the human race demands widespread agriculture which reduces numbers of native plants in preference to large expanses of single crops. The removal of forest for this purpose has knock-on effects of increased erosion. Fertilisers used for food production rinse into rivers, lakes and the ocean where they promote algal plumes. Human activity introduces invasive species which can eradicate native species. Ocean acidification is causing loss of coral species which will change the future of ocean rocks.

We are even more familiar with climate change. We constantly hear about carbon emissions in the media, and atmospheric carbon is now a third higher than in pre-industrial times, which links to global rises in temperature, in turn causing glacial retreat and further losses in biodiversity. Other processes of urbanisation such as construction and the damming of rivers, coupled with deforestation, as mentioned, are eroding excessive amounts of sediment to add to stratigraphy. Not to forget the legacy of plastic waste we are leaving behind us.

By briefly touching on the variety of human interactions with natural cycles you can see why the idea of the Anthropocene is becoming more widely supported. As each one of these changes is recorded by Earth they will create unique rock sequences that will, if we truly are in the Anthropocene, point towards a definitive changing point in Earth stratigraphy.

-Video source