Are we about to disappear? “We are witnessing the sixth mass extinction”

Scientists have documented five major mass extinction events in the history of the Earth, during which at least three-quarters of life became extinct. But with humans destroying habitats, exterminating species and changing the climate, Are we now in a sixth mass extinction?

The sixth mass extinction

Robert Cowie a research professor at the University of Hawaii, told LiveScience that, strictly speaking, you can’t declare a mass extinction until it actually occurs, once 75 percent of the species are gone.

A 2022 study conducted by Cowie and published in the journal Biological Reviews estimated that up to 13% of known species have gone extinct since 1500, well below the 75% mass extinction threshold.

“It hasn’t happened yet“, he said.

Is it time we go extinct?

Some researchers have estimated that we will reach the 75% threshold within 10,000 yearswhile other studies have concluded that we could reach this grim milestone in a few centuries , with the possibility of an even shorter period of time if things get worse.

According to Natural History Museum, London, mass extinctions occur in a short geological period of less than 2.8 million years. The centuries or millennia it might take to reach the mass extinction threshold are well within that time frame. Thus, if such estimates are considered predictive, researchers can argue that the event has already begun.

“We are witnessing the sixth mass extinction in real time“he told LiveScience in an email Anthony Barnosky professor emeritus of integrative biology at the University of California, Berkeley.

The acceleration of extinction

Studies have estimated that species are currently going extinct between 100 and 1,000 times faster than normal background extinction rate, calculated based on when species evolve and go extinct in the fossil record. “I think the rate will increase as we destroy more of the planet“, he said Cowie.

“We have killed almost 70% of the planet’s wild animals since I was born“, he said Barnosky. “Obviously this cannot go on much longer without the sixth mass extinction becoming a reality.”

A 2022 WWF report found that monitored vertebrate populations of mammals, birds, amphibians, reptiles and fish declined by an average of 69% between 1970 and 2018. This figure is a global average; Latin America had the highest regional decline, at 94%. Furthermore, that number does not include the most numerous invertebrate species.

Data on invertebrate declines is lacking, but some groups have suffered staggering losses. For example, a 2015 study written by Cowie and published in the journal Conservation Biology highlighted the decline of Hawaiian Amastridae snails due to invasive species and habitat loss. Of the 282 species that historically inhabited Hawaii, researchers could only confirm that 15 were still alive. “This is a mass extinction,” Cowie said.

Barnosky described the decimation of biodiversity and increasing mass extinction as “the bad news”. But he said it is not too late to save most of the endangered species and thus prevent us from reaching the sixth mass extinction threshold.

“Even though we are wiping out populations and species astonishingly quickly, we haven’t finished the job yet“Barnosky said. “We still have the chance to change things, but the window of opportunity to do so is closing fast.”