The sixth mass extinction is underway: about 10% of known species have become extinct in the last 500 years. This is the new estimate that comes from a new study coordinated by the University of Hawaii and the Natural History Museum in Paris and published in the journal Biological Reviews, which analyzed in particular the biodiversity loss of molluscs.
"The drastic increase in species extinction rates and the decline in the abundance of many animal and plant populations are well documented, yet some deny that these phenomena amount to mass extinction," noted Robert Cowie, first author of the study. .
To support these theses, the researchers note, is a partial vision of the problem. In other words, we tend to observe only what is happening among the more easily 'visible' species, such as mammals and birds, which however constitute only a small part of the world's biodiversity. Focusing instead on the world of invertebrates, a particularly dramatic picture emerges: starting from 1500 it is estimated that of the almost 2 million known living species, between 150 thousand and 260 thousand have disappeared (between 7.5 and 13% of the total).
"The inclusion of invertebrates is the key to confirming that we are indeed witnessing the beginning of the sixth mass extinction in Earth's history," Cowie said. Obviously the extinction rate is not the same in the various ecosystems and in the various groups of living beings, for example in the seas the disappearance of species seems to be much more reduced than on land.
Unfortunately, there are many 'deniers' on the subject - the researchers add - or theses that argue that the change underway should be interpreted as a sort of 'correction' of ecosystems by man.
"Denying the crisis, accepting it without reacting, or even encouraging it - concludes Cowie - constitutes an abrogation of the common responsibility of humanity and opens the way to continue on this sad trajectory towards a sixth mass extinction".
