PALO ALTO, Calif., June 19 (UPI) -- Animal and plant species are disappearing at alarming rates, scientists say -- faster than at any time since the disappearance of the dinosaurs.
According to Stanford researcher Paul Ehrlich, a new mass extinction event has arrived on planet Earth, and in the balance is humanity itself.
"[The study] shows without any significant doubt that we are now entering the sixth great mass extinction event," Ehrlich said in a press release.
The study relies on a range of fossil records, which researchers used to calculate both the current extinction rate and the background rate. The background rate is the rate at which species can be expected to regularly expire -- the unavoidable costs of a competitive biological world.
The current extinction rate -- like the rate of previous mass extinctions -- is a divergent rise in the number of extinctions, as a result of external factors like habitat loss and climate change.
Researchers mostly agree that extinction rates have risen -- but to what degree? In order to prove the arrival of the sixth mass extinction, Ehrlich and his colleagues compared the most conservative of the current extinction rate estimates to the most aggressive background rate.
Even in doing so, the calculations show an accelerating current extinction rate in line with past mass extinctions.
"We emphasize that our calculations very likely underestimate the severity of the extinction crisis, because our aim was to place a realistic lower bound on humanity's impact on biodiversity," the researchers write in their new study, published this week in the journal Science Advances.
The scientists blame habitat loss, invasive species, climate change and pollution for the mass extinction's arrival.
But they say it's not too late to put the environment back on the right path.
"Avoiding a true sixth mass extinction will require rapid, greatly intensified efforts to conserve already threatened species," the authors write, "and to alleviate pressures on their populations -- notably habitat loss, over-exploitation for economic gain and climate change."