Humans have contributed to the extinction of more than 300 mammalian species, according to a new study, equivalent to 2.5 billion years of evolutionary history. The development of a sufficient number of new species can take millions of years, and, most likely, by that time not a single person will remain on Earth.
Scientists estimate that it could take 5 to 7 million years for diversity to recover to levels that were before the arrival of modern humans, assuming humans are completely free of poaching, pollution and habitat destruction in the next 50 years.
Experts agree that the world is currently at the center of the sixth mass extinction, also known as the Anthropocene. According to the head of the new study, Matt Davis of the University of Aarhus in Denmark, the current human influence on the animal kingdom can be compared to the asteroid that killed the dinosaurs.
Davis and his colleagues focused not only on the number of extinct species, but also on the length of their evolutionary history, that is, how long each species took to evolve before being destroyed. The study found that from the beginning of the spread of modern humans until the 16th century, two billion years of evolutionary history of mammals disappeared. An additional 500 million years have been lost since then, and 1.8 billion years could be lost over the next five decades if mammalian extinction rates remain high.
The research is published in Proceedings of the National Academy of Sciences.