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With more species at risk of extinction, study warns of "biological annihilation"

Species extinctions accelerating, study warns
Time running out to save biodiversity as species go extinct, leading scientists say 06:47

In recent months, the global pandemic has illuminated how mismanagement of wild animals and natural ecosystems can threaten human health and even the stability of society. Now, a new study from Stanford University issues a dire warning, concluding the extinction rate is likely much greater than previously thought and that if we don't reverse course, the consequences for mankind could be "unimaginable."

The new study, titled "Vertebrates on the brink as indicators of biological annihilation and the sixth mass extinction," was published Monday in the Proceedings of the National Academy of Sciences. It highlights how human pressures such as population growth, habitat destruction, the wildlife trade, pollution and climate change have combined to wipe out hundreds of species and are critically threatening thousands more around the world at an unprecedented rate. This, the authors say, is eroding nature's ability to provide vital sustenance to people.

This research is an update of a 2015 paper from the same lead authors, which famously declared we have now entered the era of Earth's sixth mass extinction. That study concluded the current extinction rate is more than 100 times normal, meaning that the world is now losing the same number of species in one year that we used to lose in 100 years. And while past mass extinctions were caused by natural events — like the impact of a massive asteroid that may have doomed the dinosaurs — the current one is exclusively caused by human activity.

This study backs up the findings of an alarming United Nations report on species extinction released last year. That report, assembled by 400 experts from 50 nations, put the world on notice that one in every four species on Earth — one million total — could be at risk of extinction, many within decades.

For this new study, the authors examined thousands of species and found that 515 species of terrestrial vertebrates are on the brink of extinction, each with fewer than 1,000 individuals remaining. About half had fewer than 250 individuals left.

Left: Sumatran rhino; approximately 80 remain. Right: Española giant tortoise, Galapagos Islands; approximately 200 remain. Rhino: Rhett Buttler/Mongabay; Tortoise: Gerardo Ceballos

The authors estimate that nearly the same number of species are likely to go extinct in just the next 20 years. 

In addition, they found that more than 237,000 distinct populations of those 515 species have been extinguished since 1900. Most of these highly endangered species are concentrated in tropical and subtropical regions that are affected by human encroachment.

Extinction rates are rising so fast that co-author Gerardo Ceballos, a senior researcher at the National Autonomous University of Mexico, warned that without expansion of conservation efforts, "Most likely they will become extinct in the next decade."
Ceballos stresses that extinction is truly irreversible, since once a species is gone there is no way to bring it back. He put it bluntly: "This is our final opportunity, we are running out of time. What we do in the next 10 [to] 15 years will define the future of biodiversity and the future of our species."
The authors remind us that while these exotic species can seem distant and unrelated to our everyday lives, humans everywhere depend on the health of the natural world.
"Our results show that the extinction crisis is even worse than previously assessed. And that the consequences for biological diversity and mankind are unimaginable," Ceballos said.

The key takeaway is that "we cannot separate ourselves from the natural world — we are part of it and depend on it for food, water, air, and so on. We continue to destroy it at our peril," legendary animal behavior expert and conservationist Jane Goodall told CBS News. 

"We are treating the natural resources of the planet as though they were infinite and putting economic development before the protection of the environment for future generations. And as increasing numbers of plant and animal species become extinct, the health of ecosystems are compromised since all species have a role to play in the complex tapestry of life," said Goodall, founder of the Jane Goodall Institute and a U.N.  Messenger of Peace.
Rebecca Shaw, chief scientist at World Wildlife Fund (WWF) who was not involved in the research, says the paper delivers a credible and vital message for humanity, "telling us with scientific certainty that the survival of these species is linked to our own survival."
"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," said Dr. Paul Ehrlich, professor of biology and population studies at Stanford University.

One vivid example of how sensitive ecosystems are to change is illustrated by the decimation of kelp forests in the northern Pacific in the 1990s. Because of overfishing, killer whales began attacking sea otters, a natural predator of the sea urchin (prickly creatures known as the porcupines of the sea). As a result of the decline in sea otters, populations of sea urchins exploded. This overwhelmed kelp forests, upsetting the natural balance, wiping out these thriving underwater kelp cities and the species which inhabited them.

Sea urchin population explodes off West Coast 04:25

Ecosystems ranging from kelp forests to coral reefs to mangrove forests to jungles and deserts depend on long-evolved relationships between species to maintain their functions. "Every time we lose a species, we erode the capability of Earth to maintain life in general and human life in particular," said Ceballos. 
That's because with thinner populations, species are unable to serve their function in an ecosystem. The ramifications cascade through the environment, not only weakening the biosphere itself, but also the vital services they provide to humans like maintaining water quality, pollination of crops and protection against diseases.

The authors say this trend is leading to an intensification of health threats to humans, with the coronavirus pandemic being one timely example of the interplay between wild species, changing ecosystems and human health. "We have destroyed more than 50% of all-natural ecosystems. And we trade millions of wild species every year. We have broken the barriers that biodiversity and ecosystems provide us against natural diseases," Ceballos explains.
The novel coronavirus, which experts believe originated in bats and may have been transmitted to humans through another creature, perhaps in a live animal market, is an example of how the wildlife trade can hurt humans.

Ceballos says the current pandemic, and more than 30 to 50 other outbreaks of disease affecting humans in the last 3 decades, such as SARS, MERS and Ebola, have arisen  from the same issues: habitat destruction and illegal trade.  
"We have the vaccine against all these emerging diseases: maintaining the natural ecosystems, stopping the illegal wildlife trade, and rethinking the legal wildlife trade," contends Ceballos.

While there are many factors which contribute to the extinction of species — including habitat destruction; hunting wild animals for food, traditional medicine and pets; the illegal wildlife trade; and climate change — some factors are easier to deal with than others. 

Ehrlich suggests that a global agreement to stop the illegal trade of wildlife would be one solution that could make a big impact quickly. The research team also calls for all species with populations under 5,000 to be listed as critically endangered.

Climate change, on the other hand, is a much tougher and longer term challenge.  Ehrlich says climate disruption is already a factor in species extinction and "will become a gigantic factor."
"If you garden or raise tropical fish you know that every species is evolved into and adapted to a very ideal climate — they are extremely sensitive to changes in their environments especially temperature and humidity," explains Ehrlich. "When you change the climate you are automatically wiping stuff out because they can't adapt or move to a different climate."
Ceballos warns that if we continue to lose biodiversity at this scale, little else will matter. "This is not an option: this is the struggle for the survival of all living things and humanity." 

While the consequences of inaction are seemingly dystopian, Rebecca Shaw of WWF underscores that transformation is possible through creativity and cooperation. "The creative drive that we brought to once unimaginable technological innovations that we take for granted should now be focused squarely on reconfiguring our relationship with nature to achieve yet another set of unimaginable outcomes — a sustainable planet for nature and people."
Jane Goodall puts it in personal terms: "Please remember that your life matters in the scheme of things. Every day you make some impact on the planet, and you can choose what sort of impact you make. What you buy, eat, and wear, how you interact with people and nature, does truly make a difference when millions of people all make ethical decisions."

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