- Many refer to it as the Sixth Mass Extinction, but it isn’t. It’s different.
- We are not simply in the sixth round of a continuing series of events that have devastated life on Earth. We are in the midst of the first of a new type of event, unlike the earlier mass extinction events.
- The five mass extinctions were naturally occurring cataclysmic events that completely changed the course of evolution and life on Earth. The current event is a ‘biotacide,’ an unnatural cataclysmic event that is changing the course of life on Earth.
- This post is a commentary. The views expressed are those of the author, not necessarily Mongabay.
Many refer to it as the Sixth Mass Extinction, but it isn’t. It’s different.
We are not simply in the sixth round of a continuing series of events that have devastated life on Earth. We are in the the midst of the first of a new type of event, unlike the earlier mass extinction events. The five mass extinctions were naturally occurring cataclysmic events that completely changed the course of evolution and life on Earth. The current event is a ‘biotacide,’ an unnatural cataclysmic event that is changing the course of life on Earth. We are wiping out various forms of life at an unprecedented rate by willfully destroying landscapes, sending toxic chemicals into the atmosphere, and polluting water sources, not to mention killing and overexploiting wildlife.
This destruction of Earth’s flora and fauna is biotacide — the killing of life. The massive acceleration of the pace of eradication has been called an ‘extinction tsunami’ and a ‘biological annihilation.’
To understand why this is not a Sixth Mass Extinction, consider the Big Five. The first occurred during the Ordovician/Silurian transition, about 440 million years ago, and lasted for up to thirty million years.
The Late Devonian Extinction began around 360 million years ago, wiped out about 75 percent of life on Earth, and persisted for up to 20 million years.
The third mass extinction, at the Permian/Triassic Boundary, was the deadliest: Scientists estimate that, 250 million years ago, over 90 percent of marine species, along with some 75 percent of terrestrial species, went extinct during this event, which probably took at least 15 million years from ‘start’ to ‘stop.’
About 200 million years ago, a series of extinction pulses permeated the planet for approximately 18 million years and are collectively known as the Triassic/Jurassic Extinction. The time period between these two extinctions was marked by massive changes in the Earth, with Pangea subdividing into Gondwanaland and Laurasia.
Finally, the most famous, and last of the mass extinctions, saw the disappearance of the dinosaurs and the explosion of mammals and birds. This Cretaceous/Tertiary event occurred about 65 to 66 million years ago and seems to have been the shortest of the Big Five, because it might have lasted for about one million years.
These five mass extinctions share two features that distinguish them from the current state of affairs:
First, all were triggered by unpredictable and catastrophic — yet natural — events. They all brought havoc to the planet following changes in the Earth’s atmosphere due to regularly occurring events: asteroid impacts, volcanic eruptions, continental movements, modifications in oceanic currents, and the Earth’s wobble, or shift in the axis of rotation. The pivotal event of the Cretaceous/Tertiary extinction was an asteroid or comet smashing into the Yucatan peninsula region and leaving us with the Chicxulub Crater. Combined with extensive volcanic eruptions in the Deccan Traps in modern-day India, the atmospheric conditions resulted in substantial changes to both flora and fauna. The Permian Extinction was probably a result of volcanic eruptions that pumped carbon dioxide into the atmosphere, along with blanketing extensive coal regions in Siberia with molten lava, which then burned the carbon captured in the coal, yielding a natural situation not unlike the present day use of fossil fuel that feeds carbon dioxide into the atmosphere.
Second, they all lasted for at least a million years. Determining the precise length of time of an ‘event’ that lasts for so long is quite difficult and relies upon estimates of the onset and termination based upon geochemical analyses of key features found in layers of rock and ice in Earth’s crust, along with paleontological analyses. The Big Five all had durations longer than the amount of time that modern human beings have been on the planet. A million years ago was before the time of the Neanderthals; Homo erectus was still wandering about.
As opposed to the five mass extinctions, the present biotacide is not a consequence of an unusual confluence of natural events. Modern human beings came on the scene no more than 200,000 years ago, and for nearly all of that time, until we began to exterminate species during the Pleistocene Extinction at 20,000 to 10,000 years ago, we were part of the economy of nature.
The dodo bird was first described in 1598 and last seen in 1662, but the world record for rapidity of extinction is held by Stellar’s sea cow. This huge relative of the dugong and manatee was discovered by Europeans in the Bering Sea in 1741, hunted extensively by Russian fur traders, and shot into non-existence by 1768! Twenty-seven years from description to disappearance.
More than 500 species have been driven to extinction in North America since the Pilgrims arrived at Plymouth Rock. Within the last few hundred years, human beings have erased from the planet not only dodo birds and Stellar’s sea cows, but also passenger pigeons, Great Auks, lesser bilbies, thylacines, moas, bluebucks (or blue antelopes), Javan tigers, Caspian tigers, golden toads, Baji River dolphins, bubal hartebeests, Spix’s macaws, Caribbean monk seals, Pyrenean ibexes, quaggas, and many more. Several more species are threatened today. In the last 30 years or so, for instance, the number of giraffes roaming the African continent has plunged by 40 percent.
In The Origin of Species (1859), Charles Darwin explained how evolution and extinction are two sides of the same coin. He also reasoned that, “Though Nature grants long periods of time for the work of natural selection, she does not grant an indefinite period; for as all organic beings are striving to seize on each place in the economy of nature, if any one species does not become modified and improved in a corresponding degree with its competitors it will be exterminated.”
When we disrupt the ‘economy of nature,’ some species, such as mosquitoes carrying deadly diseases, adjust quite readily and spread, whereas others, such as the giraffe, have much more difficulty. Darwin also commented: “Rarity precedes extinction; and we know that this has been the progress of events with those animals which have been exterminated, either locally or wholly, through man’s agency.” He was quite aware that people were responsible for some extinctions.
We are not really in a Sixth Great Extinction. Let’s not deceive ourselves into thinking that this is another in a series of catastrophes that have hit the planet. It is something never before experienced. This is a premeditated holocaust against our fellow residents of the planet as she makes her annual trip around the sun. As we decimate the planet, the canary in the coal mine finds it more difficult to sing; it is gasping for air.
We are not witnessing a Sixth Mass Extinction; we are causing the World’s First Biotacide.
CITATIONS
-
- Ceballos, G., Ehrlich, P. R., & Dirzo, R. (2017). Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines. Proceedings of the National Academy of Sciences, 114(30), E6089-E6096. doi:10.1073/pnas.1704949114
- Lovejoy, T. E. (2017). Extinction tsunami can be avoided. Proceedings of the National Academy of Sciences, 201711074. doi:10.1073/pnas.1711074114
- Muller, Z., Bercovitch, F., Brand, R., Brown, D., Brown, M., Bolger, D., Carter, K., Deacon, F., Doherty, J.B., Fennessy, J., Fennessy, S., Hussein, A.A., Lee, D., Marais, A., Strauss, M., Tutchings, A. & Wube, T. 2016. Giraffa camelopardalis. (errata version published in 2017) The IUCN Red List of Threatened Species 2016: e.T9194A109326950. Downloaded on 22 August 2017.
Fred Bercovitch, Ph.D., is Executive Director, Save the Giraffes; Adjunct Professor, Wildlife Research Center, Kyoto University, Japan; and Adjunct Professor, Department of Animal, Wildlife, and Grassland Sciences, University of the Free State, Bloemfontein, South Africa.
