Sixth mass extinction has begun and humans could be among victims

Researchers have declared that we are entering a mass extinction that threatens humanity's existence.

Scientists call for fast action to conserve threatened species, populations and habitat, but warn that the window of opportunity is rapidly closing.

The Stanford University study shows that even with extremely conservative estimates, species are disappearing up to about 100 times faster than the normal rate between mass extinctions, known as the background rate.

Lead author Gerardo Ceballos said that if it is allowed to continue, life would take many millions of years to recover, and our species itself would likely disappear early on.

Using fossil records and extinction counts from a range of records, the researchers compared a highly conservative estimate of current extinctions with a background rate estimate twice as high as those widely used in previous analyses. This way, they brought the two estimates, current extinction rate and average background or going-on-all-the-time extinction rate, as close to each other as possible.

Researchers wrote that their calculations very likely underestimate the severity of the extinction crisis, because their aim was to place a realistic lower bound on humanity's impact on biodiversity.

The long list of impacts includes: Land clearing for farming, logging and settlement; Introduction of invasive species; Carbon emissions that drive climate change and ocean acidification; Toxins that alter and poison ecosystems; Now, the specter of extinction hangs over about 41 percent of all amphibian species and 26 percent of all mammals, according to the International Union for Conservation of Nature, which maintains an authoritative list of threatened and extinct species.

The study is published in the journal Science Advances.