Today we are in the middle of the sixth mass extinction. An event of such magnitude that perceiving its consequences is not easy at all. The planet’s current species extinction rate is unimaginable
Many of you may have heard about anthropocene – I have also written about it lately – which is this real geological era in which we live and whose predominant character is given by the telluric action of human activity. Man, for example, through his continuous and unstoppable need to consume is so deeply affecting the characteristics of the planet that he has become the cause of one of the most terrible mass extinctions. In the history of our planet, in order to have catastrophes of a similar magnitude to the one in progress, apocalyptic events such as: asteroids, eruptions, reversals of the Earth’s magnetic field, supernovae, increasing and decreasing the level of the oceans, glaciations and similar catastrophes were necessary. Periodical events that have been estimated to fluctuate between 30 and 62 million years and whose cause has been hypothesized to depend on circumstances such as the fluctuation of the galactic plane or the passage of the Earth through the spiral arms of the Milky Way.
Throughout its history, the Earth has experienced five mass extinctions and a number of minor extinctions. The five major ones, identified by Sepkoski and Raup in a well-known work of 1982, are:
1) the extinction of the Ordovician-Silurian: between 450 and 440 million years ago, two events able to erase between 60% and 70% of all species occurred; they represent the second largest of the five major extinctions in Earth’s history in terms of the percentage of genera that became extinct; 2) the extinction of the late Devonian, which lasted perhaps around twenty million years, during which about 70% of the existing species disappeared; 3) the extinction at the transition between the Permian and the Triassic, 252 million years ago, the most dramatic extinction event that has ever hit the Earth: among 90-96% of all existing species were wiped out; 4) extinction at the transition between Triassic and Jurassic, 201 Ma, during which between 70 and 75% of all species became extinct, and finally 5) extinction during the transition between Cretaceous and Paleogene (in which dinosaurs became extinct), 66 million years ago, in which 75% of living species disappeared.
Today we are in the middle of the sixth mass extinction. An event of such magnitude that perceiving its consequences is not easy at all. The planet’s current species extinction rate is unimaginable. In 2014, a research team coordinated by Stuart Pimm of Duke University estimated the normal extinction rate on Earth, before the man’s appearance, to be 0,1 extinct species per million species per year (0,1 E / MSY). Today’s rate would be 1,000 times higher, while models for the near future would indicate an extinction rate of up to 10,000 times higher than normal. These are the numbers of an apocalypse. Never in the history of the planet, even during the most catastrophic mass extinctions, have the extinction rates been so high and, most of all, compressed into such an imperceptible lapse of time. The past mass extinctions we know, although fast, have always manifested themselves over a span of millions of years. Human activity, on the other hand, is concentrating its lethal influence on other living species in a few years. The entire history of Homo sapiens began only 300,000 years ago, less than a blink for the three billion eight hundred million years of life.