Above: Photo via economist.com
By contributor Dallas Bezaire
Our Earth is said to be 4.5 billion years old. Its age has been calculated in a number of ways, one being through the use of stratigraphic layers—layers of sediment left by millions of years’ worth of silt and soil.
The largest divisions are called eras, the current one being the Cenozoic Era which started with the extinction of the dinosaurs by a large meteor. Eras are further divided into periods; the current is the Quaternary which is marked by the frequent glaciation periods triggered in part by the fusing of North and South America at the end of the last period.
Finally, periods are further divided into epochs. The epoch we are living in is known as the Holocene. It began about 11,000 years ago at the end of the last glaciation period and was only recognized in 2008. Before the ink was even dry on that decision, groups from various areas of science were already pushing for the recognition of a new epoch that they claim we are already living in, the Anthropocene.
The Anthropocene is the age of the Earth dominated and dictated by the activities of humans. The idea isn’t exactly new either; a similar proposal for the “Anthropozoic” was proposed back in the 1870s, but it never really took off until it was proposed by Paul Crutzen, the Dutch chemist and Nobel Prize winner for discovering ozone depletion.
Since then the term has grown more and more popular among several fields of science, much to the ire of actual geologists. Many geologists see the term as assumptive, as the last 100 years of human activity would barely form a millimeter of ocean floor sediment and the geological epochs are meant to label past periods, not current and future ones. However, the popularity and the evidence has pushed the term into prominence and it appears that it is here to stay.
From clearing forests and swamps to make farm land, to the cultivation and domestication of crops and animals, humans have been altering the planet in dramatic ways for thousands of years now. Between 1570 and 1620 the death of approximately 50 million Native Americans from epidemics led to a massive regrowth of forests that left a measurable impact on global CO2 levels. The start of the industrial revolution also left a visible black soot line in soil and silt deposits around the world. Some have put forward the possibility that the Anthropocene started 5000 years ago, while others claim its beginning was during the Industrial Revolution in the 1600s. However, the majority of the scientific community is pushing towards the 1950s, also known as the Great Acceleration.
It was at this point that human impact on Earth suddenly accelerated. The expulsion of CO2 into the atmosphere, the fixation of nitrogen from the atmosphere into soils and ecosystems in the form of fertilizer, the alteration of erosion and soil deposits through large dams and roads, the extraction of ground water from aquifers, methane production, environmental lead, atmospheric sulfates levels, tropical deforestation, fish stock depletion, ocean acidification, and human population have all gone up almost exponentially since the 1950s.
The mid-20th century also saw the peak of ozone depletion, the first introduction of man-made satellites into our planet’s orbit, and the first use of atomic weaponry. The atomic bombs have left an especially permanent mark on our planet by introducing radioactive elements into nearly everything that has been and will be created after July 16, 1945. This radioactive signature has been proposed as the golden signal that would officially mark the start of the Anthropocene and be measurable down to the day by geologists thousands of years into the future.
We have also introduced a large number of archeological signatures since the start of the 20th century including concrete, plastics, glass, and elemental aluminum. Large-scale terrestrial alterations like the Hoover Dam or the Panama Canal will be as visible to future archeologists and civilizations as the Grand Canyon.
Our impact on the biosphere will also be just as visible as the extinction of the dinosaurs. Homo sapiens have been causing extinctions of mega fauna, such as the giant sloth and the cave bear, since we first left Africa as a species. Since the 1500s, extinction rates have been far above background rates and have only risen to the point at which it can now be classified as a mass extinction event, the severity of which is still to be determined.
Combined with the translocation of animal species across the globe (often invasively but also of our own domesticated plants and animals) and the alteration of earth ecosystems through fertilizers, deforestation, land alterations, and climate changes, our impact on the biosphere will be marked and severe. The entire future of biological evolution on this planet will feel the mark left by humans.
Now, all of this seems rather scary, doesn’t it? We are causing climate, biosphere, and archeological impacts comparable to the shifting of continents and orbital cycles, the evolution of cellulose and photosynthesis, or massive extinction events like giant meteors and super-volcanoes. We as a human species have taken up the mantle of makers and movers. We now directly control the future of every single organism on this planet in some way or another, most importantly being ourselves.
Yet, there is hope. Despite our clumsiness and resistance to change, we are able to pivot as a species and move ourselves and the planet we live on down a different path. Ozone depletion in the upper atmosphere from CFCs, environmental lead from leaded gasoline, and acid rain from atmospheric sulfates and nitrous oxides have all been countered and are returning to healthy and preferable levels.
It seems that when we put effort into something as a species, we can have considerable power to change and direct the outcome. We, and the other life on this planet, are resilient and adaptive. Already bacteria and fungi are adapting to the new plastic and oil food sources we have put into their environment and animals are adapting to the new concrete ecosystems we have created. Our own species has made it through an uncountable number of extinction events and climate shifts, although the same can’t be said of our civilization and societies. Eventually we will need to make a change.
While many people like to call us passengers on a cosmic space ship, I see it a little differently. The world is not a dead mechanical thing to be piloted. It is an organism with complex and dynamic systems that are constantly operating to find their equilibrium against external and internal changes.
In the words of Agent Smith of The Matrix, we are like a virus, a retrovirus of sorts. We have overgrown our natural roles and become a global infection disrupting natural systems and creating scars across the land. It is a very good thing that we are quickly adapting and the Earth is resilient; with time, we may achieve what most viruses do best—become symbiotic with our host.
If we do that, we can make our host stronger than it was before, augmenting it much like we hope to do to ourselves with retroviral gene therapy, by creating buffers against environmental or climate catastrophe and preventing or mitigating major extinction events such as meteors hitting Earth.
One day Earth may very well be a utopia made all the stronger and richer by the life that inhabits it and maybe this Anthropocene will extend beyond an epoch and become a true era of Earth’s history. First we must survive this fever we have created, let the Earth’s systems return to some form of equilibrium, and learn to protect our home.