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The five countries with the most endangered species 1:13
(CNN) - The sixth mass extinction is not a concern for the future. It's happening now, much faster than expected, and it's entirely our fault, according to a study published Monday.
Humans have already wiped out hundreds of species and brought many more to the brink of extinction through wildlife trade, pollution, habitat loss, and the use of toxic substances. But the findings published in the scientific journal Proceedings of the National Academy of Sciences (PNAS) show that the extinction rate of species has accelerated in recent decades.
Gerardo Ceballos González, professor of ecology at the National Autonomous University of Mexico and one of the study's authors, said that approximately 173 species became extinct between 2001 and 2014.
"173 species is 25 times more extinct species than would be expected under the normal extinction rate," he told CNN in an email. He and his team discovered that in the past 100 years, more than 400 vertebrate species became extinct. In the normal course of evolution, such extinctions would have taken up to 10,000 years, they said.
Orangutans are being exterminated as their habitat continues to disappear.
Mass extinctions are as severe as the name suggests. There have been five mass extinction events in Earth's history, each eliminating between 70% and 95% of plant, animal and microorganism species. The most recent, 66 million years ago, saw dinosaurs disappear.
READ : The asteroid that wiped out the dinosaurs hit at the "deadliest possible" angle
Past events were caused by catastrophic disturbances in the environment, including massive volcanic eruptions or an asteroid collision. The sixth mass extinction, the one occurring now, is different: Scientists say it is caused by humans.
"It is entirely our fault," said Ceballos González.
Extinction breeds extinctions
While life on Earth has recovered after each of these events, it took millions of years to restore the number of species.
"Although it is only estimated that 2% of all species that ever lived are alive today, the absolute number of species is greater now than ever before," the scientists said. "It was in a world so biologically diverse that we evolved, and it is that world that we are destroying."
Ceballos González and his colleagues said that many of the species that are on the verge of extinction are concentrated in the same regions decimated by human impact.
Amur leopards are critically endangered.
When one species in the ecosystem disappears, it erodes the entire ecosystem and pushes other species toward annihilation. The researchers use amphibians as an example of this phenomenon. Hundreds of frog and toad species are experiencing population declines and extinctions due to chytrid fungal disease, which is sometimes spread to new areas by humans. Climate change probably worsens the problem.
This interdependence of different species is also bad news for humans.
"When humanity exterminates populations and species of other creatures, it is sawing off the branch it is sitting on, destroying functional parts of our own life support system," said Paul Ehrlich, a well-known Stanford professor who wrote the controversial 1968 book. "The Population Bomb" and is co-author of the new study.
The researchers also said that the current coronavirus crisis shows how recklessness with which people treat the natural world can backfire. Many of the endangered or on the brink of extinction species are being decimated by the wildlife trade.
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"We believe that the recent coronavirus outbreak is related to wildlife trade and consumption in China," they said. "The Chinese government's wildlife trade ban could be an important conservation measure for many species on the brink of extinction, if it is enforced correctly."
The researchers said these data highlight the urgency with which the world needs to act.
Later this year, the United Nations Convention on Biological Diversity is expected to set new global goals to combat the current biodiversity crisis in the coming decades.
At a 2010 summit in Japan, the United Nations set similar goals. But the world failed to meet most of those goals by 2020 and is now facing unprecedented extinction rates, threatened ecosystems, and dire consequences for human survival.
Sixth extinction