Strong evidence shows sixth mass extinction of global biodiversity is in progress

Shells of land snails from Rurutu (Austral Islands, French Polynesia) – recently extinct before they were collected and scientifically described. Credit: O. Gargominy, A. Sartori.

Five times the history of life on Earth has been marked by mass biodiversity extinction events caused by extreme natural phenomena. Today, many experts warn that the sixth mass extinction crisis is underway, this time being caused entirely by human activities.

A comprehensive assessment of the evidence for this ongoing extinction event was recently published in the journal Biological Reviews by biologists from the University of Hawaii at Manoa and the National Museum of Natural History in Paris, France.

Said Robert Coy, lead author of the study and research professor at the UH Mānoa Pacific Biosciences Research Center in the School of Earth and Ocean Science and Technology (SOEST). “This denial is based on a biased view of the crisis that focuses on mammals and birds and ignores invertebrates, which of course make up the vast majority of biodiversity.”

Extrapolating from estimates obtained from land snails and mollusks, Coy and co-authors estimated that since 1500, Earth could have already lost between 7.5 and 13% of the two million known species on Earth—a staggering number ranging from 150,000 and 260,000 species.

“The inclusion of invertebrates was key to confirming that we were indeed witnessing the beginning of the sixth mass extinction in Earth’s history,” Coy said.

Strong evidence shows sixth mass extinction of global biodiversity is in progress

The native Hawaiian snail’s habitat is in Pu’u Kukui, Maui. Credit: Robert Coy

However, the situation is not the same everywhere. Although marine species face significant threats, there is no evidence that the crisis is affecting the oceans as much as land. On land, island types, such as those on the Hawaiian Islands, are affected more than continental ones. The rate of plant extinction appears to be lower than the rate of wild animal extinction.

Unfortunately, along with denying science is taking a foothold in modern society on a range of issues, the new study suggests that some people also deny that the Sixth Extinction began. In addition, others accept it as a new and natural evolutionary path, since humans are just another species that plays its natural role in Earth’s history. Some even consider that biodiversity should only be manipulated for the benefit of humanity – but the benefit is determined by whom?

“Humans are the only species capable of manipulating the biosphere on a large scale,” Cui emphasized. “We are not just another species that evolves in the face of external influences. In contrast, we are the only species that has a conscious choice regarding our future and the future of Earth’s biodiversity.”

To combat the crisis, several conservation initiatives for some charismatic animals have succeeded. But these initiatives cannot target all species, nor can they reverse the general trend of species extinction. However, it is essential to continue these efforts, to continue cultivating the wonders of nature, and to document biodiversity before it disappears.

“Despite the rhetoric about the seriousness of the crisis, despite the existence of remedial solutions and drawing the attention of decision-makers, it is clear that the political will is lacking,” Coe said. “Denying the crisis, accepting it without reacting, or even encouraging it negates humanity’s shared responsibility and sets the stage for the Earth to continue its sad path toward the sixth mass extinction.”

Humans are driving animals and plants to the brink, but are we really headed for mass extinction?

more information:
Robert H. Coy et al., The Sixth Mass Extinction: Fact, Fiction, or Conjecture?, Biological Reviews (2022). DOI: 10.1111 / br.12816

Presented by the University of Hawaii at Manoa

the quote: Strong Evidence Showing the Sixth Mass Extinction of Global Biodiversity in Progress (2022, January 14) Retrieved on January 14, 2022 from

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