Sixth mass extinction 'already underway': Study

Monday, June 22, 2015, 6:30 AM - You've heard it before, but now there's more proof: A sixth great mass extinction is underway, and we're running out of time to stop it.

That's the conclusion of a new study published in the journal Science Advances, and if it keeps up at the current pace, our own species will be affected.

"If it is allowed to continue, life would take many millions of years to recover, and our species itself would likely disappear early on," lead author Gerardo Ceballos of the Universidad Autónoma de México told Stanford News.

Specifically, the researchers say the average rate of vertebrate species loss over the last hundred years is 114 times higher than the normal or "background" rate of loss.

That's taking a non-mass extinction rate of two mammal extinctions per 10,000 species per 100 years. The researchers say at that rate, the extinction of the number of species we've lost over the last century would normally have taken 800 to 10,000 years, depending on the species.

It sounds drastic, but the researchers say they deliberately based their research on conservative estimates of mammal and vertebrate extinctions, which they say is low because a species has to meet certain stringent criteria in order to be declared extinct.

"Earlier estimates of extinction rates have been criticized for using assumptions that might overestimate the severity of the extinction crisis," the researchers write.

As mentioned, the new study isn't remotely the first to suggest a major extinction is underway.

The last major study, published in Nature, suggested 41 per cent of all amphibians face extinction, along with 26 per cent of mammal species and 13 per cent of birds.

The researchers say growing human population growth, increased consumption and "economic inequality" has damaged or destroyed natural habitats, accelerating the extinction.

That will come back to humans eventually, since ecosystems like crop-pollinating honeybees and water purifying wetlands are also at risk. Many such benefits to humans could be lost within three generations, the studies authors write.

"Avoiding a true sixth mass extinction will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations—notably habitat loss, overexploitation for economic gain, and climate change," they say. "However, the window of opportunity is rapidly closing."

SOURCES: Science Advances | Stanford University

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