The
world is embarking on its sixth mass extinction with animals
disappearing about 100 times faster than they used to, scientists
warned, and humans could be among the first victims
The world
is embarking on its sixth mass extinction with animals disappearing
about 100 times faster than they used to, scientists warned Friday, and
humans could be among the first victims.
Not since the
age of the dinosaurs ended 66 million years ago has the planet been
losing species at this rapid a rate, said a study led by experts at
Stanford University, Princeton University and the University of
California, Berkeley.
The study "shows without any
significant doubt that we are now entering the sixth great mass
extinction event," said co-author Paul Ehrlich, a Stanford University
professor of biology.
And
humans are likely to be among the species lost, said the study -- which
its authors described as "conservative" -- published in the journal
Science Advances.
"If it is
allowed to continue, life would take many millions of years to recover
and our species itself would likely disappear early on," said lead
author Gerardo Ceballos of the Universidad Autonoma de Mexico.
The
analysis is based on documented extinctions of vertebrates, or animals
with internal skeletons such as frogs, reptiles and tigers, from fossil
records and other historical data.
The modern rate of species loss was compared to the "natural rates of species disappearance before human activity dominated."
It can be difficult to estimate
this rate, also known as the background rate, since humans don't know
exactly what happened throughout the course of Earth's 4.5 billion year
history.
For the study, researchers used a past extinction rate that was twice as high as widely used estimates.
If
the past rate was two mammal extinctions per 10,000 species per 100
years, then the "average rate of vertebrate species loss over the last
century is up to 114 times higher than it would be without human
activity, even when relying on the most conservative estimates of
species extinction," said the study.
"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 causes of species loss range from climate change to pollution to deforestation and more.
According
to the International Union for Conservation of Nature, about 41 percent
of all amphibian species and 26 percent of all mammals are threatened
with extinction.
"There are examples of species all over the world that are essentially the walking dead," Ehrlich said.
The
study called for "rapid, greatly intensified efforts to conserve
already threatened species, and to alleviate pressures on their
populations -- notably habitat loss, over-exploitation for economic gain
and climate change."
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