Sixth mass extinction on Earth already underway, scientists say


HONOLULU — A sixth mass extinction event in our planet’s history is already underway, a new study of extinct species reveals. While meteors and natural catastrophes played a role in wiping out life on Earth in the past, researchers in Hawaii say this one is almost entirely man-made.

A team from the University of Hawai‘i at Mānoa and the Muséum National d’Histoire Naturelle in Paris found — when you include snail and slug species to calculations — the Earth has lost up to 13 percent of all known species since the year 1500.

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

Specifically, their study reveals that 7.5 to 13 percent of the two million different living organisms which inhabit the planet are now extinct. That’s between 150,000 and 260,000 species on land, in the sea, or in the air which no longer exist in 2022.

“Drastically increased rates of species extinctions and declining abundances of many animal and plant populations are well documented, yet some deny that these phenomena amount to mass extinction,” says lead author Robert Cowie, a research professor at the UH Mānoa Pacific Biosciences Research Center, in a university release. “This denial is based on a highly biased assessment of the crisis which focuses on mammals and birds and ignores invertebrates, which of course constitute the great majority of biodiversity.”

“Including invertebrates was key to confirming that we are indeed witnessing the onset of the Sixth Mass Extinction in Earth’s history,” Cowie adds.

The study notes that this mass extinction event is affecting life on land at a different rate than in the oceans. On land, the team finds island species are at a higher risk of extinction than those on larger continents. Also, plants seem more resilient to extinction than animals.

Mass extinction denial becoming the new climate denial?

Researchers believe denial of the facts that Earth is already experiencing a mass extinction event is as big of a problem as climate change denial and science denial. Moreover, the team claims that many people will accept this event as the natural course of the planet’s evolution and not attempt to change it. For some people, they view humans as just another species in Earth’s history who have little ability to alter the overall health of the planet — but is this really true?

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

Study authors note that conservation efforts are having some success and saving certain animals. Unfortunately, these efforts can’t save every species on Earth and researchers believe it won’t change the ongoing trend of a sixth mass extinction in history.

Despite facing an uphill battle, researchers say it’s still important to stave off extinction for as many species as possible and document the diversity of the planet before it disappears forever.

“Despite the rhetoric about the gravity of the crisis, and although remedial solutions exist and are brought to the attention of decision-makers, it is clear that political will is lacking,” Cowie concludes. “Denying the crisis, accepting it without reacting, or even encouraging it constitutes an abrogation of humanity’s common responsibility and paves the way for Earth to continue on its sad trajectory towards the Sixth Mass Extinction.”

The findings appear in the journal Biological Reviews.

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