Sixth mass extinction picks up pace, threatening to wipe out over 500 species in next 20 years
Human-induced actions such as climate change, wildlife trade, pollution, habitat loss and the use of toxic substances have brought many species to the brink of extinction
The sixth mass extinction event is dramatically accelerating now, threatening to wipe out over 500 species in the next 20 years. If it goes unchecked, it could set off a chain reaction, ultimately challenging human existence, warn scientists in their new analysis.
For all of this, we have ourselves to blame, they add. Human-induced actions such as climate change, wildlife trade, pollution, habitat loss, and the use of toxic substances have brought these species to the brink of extinction. In fact, the Covid-19 pandemic is the result of wildlife trade, the researchers point out. Citing an example, the team says, hundreds of species of frogs and toads are suffering population declines and extinctions. Though a parasite named chytrid fungus is directly responsible, humans have indirectly helped the infectious agent spread from place to place.
"When humanity exterminates populations and species of other creatures, it is sawing off the limb on which it is sitting, destroying working parts of our own life-support system," Stanford biologist Paul Ehrlich, and the co-author of the study says. "The conservation of endangered species should be elevated to a national and global emergency for governments and institutions, equal to climate disruption to which it is linked."
A loss of about 75% of all existing species across the entire Earth characterizes mass extinction. The planet has already witnessed five extinction events, of which the third --occurring around 250 million years ago -- was by far the worst, as it wiped out 95% species. "Life has now entered a sixth mass extinction. This is probably the most serious environmental problem because the loss of a species is permanent," the authors wrote in their study.
In the last 100 years, more than 400 vertebrate species went extinct, which would have taken up to 10,000 years without human disruptions. And more recently, between 2001 and 2014, we lost 173 species. "173 species is 25 times more extinct species than you would expect under the normal, background, extinction rate," Gerardo Ceballos González, a professor of ecology at the National Autonomous University of Mexico and one of the authors of the study, tells CNN.
Currently, extinction rates are hundreds or thousands of times faster than the “normal” rates recorded in the last tens of millions of years, the researchers explain.
Domino effect: 'Extinction breeds extinction'
When the planet loses one species, it could erode the ecosystem, making life impossible for other species. The vast majority -- 84% -- of species with populations under 5,000 live in the same areas as species with populations under 1,000. Such conditions provide the perfect platform for a chain reaction.
"Extinction breeds extinction," the study authors write. Given the threats, the team has a proposal: list populations under 5,000 as critically endangered on the International Union for Conservation of Nature Red List, an international database used to inform conservation action on a global scale.
"What we do to deal with the current extinction crisis in the next two decades will define the fate of millions of species. We are facing our final opportunity to ensure that the many services nature provides us do not get irretrievably sabotaged," Ceballos notes.
"It's up to us to decide what kind of a world we want to leave to coming generations -- a sustainable one or a desolate one in which the civilization we have built disintegrates rather than builds on past successes," said study co-author Peter Raven, president emeritus of the Missouri Botanical Garden.