A polar bear stands on an ice floe near Manitoba, Canada, in 2012. Polar bears depend on sea ice, which is forming later in the fall and disappearing earlier in the spring. (photo: Paul Souders/Corbis)
20 June 15
readersupportednews.orgStudy reveals rate of extinction for species in the 20th century has been up to 100 times higher than would have been normal without human impact
he
modern world is experiencing a “sixth great extinction” of animal
species even when the lowest estimates of extinction rates are
considered, scientists have warned.
The rate of extinction for species in the 20th century
was up to 100 times higher than it would have been without man’s
impact, they said.
Many conservationists have been warning for years that a mass extinction event akin to the one that wiped out the dinosaurs is occurring as humans degrade and destroy habitats.
But the authors of a study published on Friday said that even when they analysed the most conservative extinction rates, the rate at which vertebrates were being lost forever was far higher than in the last five mass extinctions.
“We were very surprised to see how bad it is,” said Dr Gerardo Ceballos of the National Autonomous University of Mexico. “This is very depressing because we used the most conservative rates, and even then they are much higher than the normal extinction rate, really indicating we are having a massive loss of the species.”
Previous studies have warned that the impact of humans taking land for buildings, farming and timber has been to make species extinct at speeds unprecedented in Earth’s 4.5bn-year history.
Ceballos said that his study, co-authored by Paul R Ehrlich who famously warned of the impact of humanity’s “population bomb”, employed better knowledge of natural or so-called background extinction rates. He said it was conservative because it looked only at species that had been declared extinct, which due to stringent rules can sometimes take many years after a species has actually gone extinct.
Under a “natural” rate of extinction, the study said that two species go extinct per 10,000 species per 100 years, rather than the one species that previous work has assumed.
Modern rates of extinction were eight to 100 times higher , the authors found. For example, 477 vertebrates have gone extinct since 1900, rather than the nine that would be expected at natural rates.
“It’s really signalling we’ve entered a sixth extinction and it’s driven by man,” said Ceballos.
Many conservationists have been warning for years that a mass extinction event akin to the one that wiped out the dinosaurs is occurring as humans degrade and destroy habitats.
But the authors of a study published on Friday said that even when they analysed the most conservative extinction rates, the rate at which vertebrates were being lost forever was far higher than in the last five mass extinctions.
“We were very surprised to see how bad it is,” said Dr Gerardo Ceballos of the National Autonomous University of Mexico. “This is very depressing because we used the most conservative rates, and even then they are much higher than the normal extinction rate, really indicating we are having a massive loss of the species.”
Previous studies have warned that the impact of humans taking land for buildings, farming and timber has been to make species extinct at speeds unprecedented in Earth’s 4.5bn-year history.
Ceballos said that his study, co-authored by Paul R Ehrlich who famously warned of the impact of humanity’s “population bomb”, employed better knowledge of natural or so-called background extinction rates. He said it was conservative because it looked only at species that had been declared extinct, which due to stringent rules can sometimes take many years after a species has actually gone extinct.
Under a “natural” rate of extinction, the study said that two species go extinct per 10,000 species per 100 years, rather than the one species that previous work has assumed.
Modern rates of extinction were eight to 100 times higher , the authors found. For example, 477 vertebrates have gone extinct since 1900, rather than the nine that would be expected at natural rates.
“It’s really signalling we’ve entered a sixth extinction and it’s driven by man,” said Ceballos.
However, Prof Henrique Miguel Pereira, the chair of the Group on Earth Observations Biodiversity Observation Network, said that the new paper did not add anything revolutionarily new.
“They argue that recent extinction rates are up to 100 times higher than in the past. I think it improves our documentation of the process but it does not yet confirm a sixth mass extinction. I tend to think we have a major biodiversity crisis, but it would take either a fast acceleration of current extinction rates or a couple of centuries at current extinction rates, for the current process to become a sixth mass extinction.”
The team behind the new analysis said “rapid, greatly intensified efforts” would be needed to stop or slow the extinctions currently underway.
Ceballos pointed to the Pope Francis’s encyclical on the environment, which was published on Thursday and lamented the loss of the world’s biodiversity, and interventions by Barack Obama, as signs of hope. “These important figures are starting to really grasp the problem,” he said.
On why people should be worried about the rate of extinctions, he said: “People say that’s really sad, but why does it affect me? There are many reasons we should care. We are the species that are causing the loss of all these other species.”
But the most important reason, he said, was that by losing species humanity was losing what enabled us to have a “good standard of living”.
The paper, Accelerated modern human–induced species losses: Entering the sixth mass extinction, was published in the journal Science Advances.
Comments
+9
#
2015-06-20 10:31
Here's to all the
species that have quietly disappeared, the scientists who warn us and
the activists who inspire change. Thanks to Pope Francis for spreading
the word. But simply put, I'm not betting on this pony.
+6
#
2015-06-20 12:40
Erhlich's Population
Bomb is more relevant today as it was in the 1970s. Probably the most
painless way of reducing stresses on the planet leading to continual
warfare, chronic poverty, resource depletion, environmental pollution,
and species extinction is for people to practice family planning (aka
birth control). It is not that difficult to do and certainly saves a lot
of pain, expense, and trouble in the long run.
Pope Francis seems to be heading in the right direction by speaking out on climate change. If he would also work toward changing church doctrine on human reproductive choice, immense progress might become possible in meeting many of the challenges we are currently facing.
Pope Francis seems to be heading in the right direction by speaking out on climate change. If he would also work toward changing church doctrine on human reproductive choice, immense progress might become possible in meeting many of the challenges we are currently facing.
+7
#
2015-06-20 14:33
Population is not
quite yet the key factor: Resource/energy use per capita is the question
here; & the 3d World countries rank low on that scale...as well as
producing most of their own food.
+1
#
2015-06-20 19:38
Thank you. Indeed, based on your facts, the U.S. is the country that should be cutting its population the most drastically.
+12
#
2015-06-20 13:17
And in addition to
the rapid extinction of entire species, the loss of members of species
is even higher. The populations of many surviving species have dropped
by 50% or more in the past few decades.
This is an inevitable result of capitalism. The system MUST exploit every "resource" completely. Band-aids in the form of environmental laws and anti-trust or bank regulations make some Liberals feel that they're controlling Frankenstein, but they are not and never will.
The monster simply mutates and remains many steps ahead of the Reformers.
To fix Clinton's 1992 campaign slogan: It's the Economic System, Stupid.
This is an inevitable result of capitalism. The system MUST exploit every "resource" completely. Band-aids in the form of environmental laws and anti-trust or bank regulations make some Liberals feel that they're controlling Frankenstein, but they are not and never will.
The monster simply mutates and remains many steps ahead of the Reformers.
To fix Clinton's 1992 campaign slogan: It's the Economic System, Stupid.
