Are we in a 6th mass extinction?

Robert Cowie, a research professor at the University of Hawaii, told Live Science that, strictly speaking, you can't declare a mass extinction until it's actually happened — once 75% of species are gone.

Some researchers have estimated that we'll reach the 75% threshold within 10,000 years, while other studies have concluded that we could be at this grim milestone in just a few centuries — with the potential for an even shorter time frame if things get worse.

Mass extinctions occur within a short geological time period of less than 2.8 million years, according to the Natural History Museum in London.

"We are witnessing the sixth mass extinction in real time," Anthony Barnosky, a professor emeritus of integrative biology at the University of California, Berkeley, told Live Science in an email.

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.

For instance, a 2015 study co-authored by Cowie and published in the journal Conservation Biology highlighted the decline of Hawaii's Amastridae snails due to invasive species and habitat loss.