All five previous mass extinction events in our planet’s history were caused by dramatic natural events. But the authors of a new study say a sixth major extinction is currently underway, and this time humans are to blame.
Researchers writing in the journal Biological Reviews estimate that 13 percent of all invertebrate species may have gone extinct in the last 500 years and warn that it is now our responsibility to act to avoid a catastrophic decline in biodiversity.
The true extent of the current stalemate is somewhat masked by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, which gives the impression that the current rate of species loss remains in line with the background rate, the authors say. “However, the Red List is largely biased,” the researchers write. and he concludes that we may indeed witness the beginning of the Sixth Mass Extinction.”
The study authors cite a 2015 study on mollusks that, in support of their claims, concluded that about seven percent of land snail species have gone extinct since 1,500 years ago. Assuming that this number represents extinction rates for all marine invertebrates, and that such species is about one-third more than marine invertebrates, the researchers calculate that between 7.5 and 13 percent of the two million known mollusc species are now extinct.
In absolute numbers, this equates to the extinction of between 150,000 and 260,000 species, significantly higher than the 882 species of mollusks listed as extinct by the Red List. Of course, this finding is based on “an assumption” and has not been conclusively verified. Still, the researchers conclude that a sixth mass extinction event “definitely started and was caused by human activity.”
While this explanation is alarming, the authors continue to explain that there is no evidence to suggest that marine species are affected in the same way as terrestrial invertebrates, while plants do not appear to be affected by the current crisis.
Research author Robert Cowie stated that humanity needs to take responsibility to prevent this impending disaster, stating that “humans are the only species with the ability to manipulate the biosphere on a large scale, we are the only species that can make conscious choices about our future and Earth’s biodiversity. ” he says.
Researchers therefore reject the argument that our actions and their consequences are part of the natural evolution of life on Earth. On the contrary, Cowie warns, “to deny, unresponsively accept, and even encourage crises is a removal of humanity’s collective responsibility and paves the way for Earth to continue on its sad trajectory towards the Sixth Mass Extinction.”
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