sixth mass extinction

Sixth mass extinction is here, researcher declares

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There is no longer any doubt: We are entering a mass extinction that threatens humanity’s existence.

That is the bad news at the center of a new study by a group of scientists including Paul Ehrlich, the Bing Professor of Population Studies in biology and a senior fellow at the Stanford Woods Institute for the Environment. Ehrlich and his co-authors call for fast action to conserve threatened , populations and habitat, but warn that the window of opportunity is rapidly closing.

“[The study] shows without any significant doubt that we are now entering the sixth great ,” Ehrlich said.

Although most well known for his positions on human population, Ehrlich has done extensive work on extinctions going back to his 1981 book, Extinction: The Causes and Consequences of the Disappearance of Species. He has long tied his work on coevolution, on racial, gender and economic justice, and on nuclear winter with the issue of wildlife populations and .

There is general agreement among scientists that rates have reached levels unparalleled since the dinosaurs died out 66 million years ago. However, some have challenged the theory, believing earlier estimates rested on assumptions that overestimated the crisis.

The new study, published in the journal Science Advances, shows that even with extremely conservative estimates, species are disappearing up to about 100 times faster than the normal rate between mass extinctions, known as the background rate.

“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 Autónoma de México.

Conservative approach

Using fossil records and extinction counts from a range of records, the researchers compared a highly conservative estimate of current extinctions with a background rate estimate twice as high as those widely used in previous analyses. This way, they brought the two estimates – current extinction rate and average background or going-on-all-the-time extinction rate – as close to each other as possible.

Focusing on vertebrates, the group for which the most reliable modern and fossil data exist, the researchers asked whether even the lowest estimates of the difference between background and contemporary still justify the conclusion that people are precipitating “a global spasm of biodiversity loss.” The answer: a definitive yes.

“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 researchers write.

To history’s steady drumbeat, a human population growing in numbers, per capita consumption and economic inequity has altered or destroyed natural habitats. The long list of impacts includes:

  • Land clearing for farming, logging and settlement
  • Introduction of invasive species
  • Carbon emissions that drive climate change and ocean acidification
  • Toxins that alter and poison ecosystems

Now, the specter of extinction hangs over about 41 percent of all amphibian species and 26 percent of all mammals, according to the International Union for Conservation of Nature, which maintains an authoritative list of threatened and extinct species.

“There are examples of species all over the world that are essentially the walking dead,” Ehrlich said.

As species disappear, so do crucial ecosystem services such as honeybees’ crop pollination and wetlands’ water purification. At the current rate of species loss, people will lose many biodiversity benefits within three generations, the study’s authors write. “We are sawing off the limb that we are sitting on,” Ehrlich said.

Hope for the future

Despite the gloomy outlook, there is a meaningful way forward, according to Ehrlich and his colleagues. “Avoiding a true sixth will require rapid, greatly intensified efforts to conserve already , and to alleviate pressures on their populations – notably habitat loss, over-exploitation for economic gain and climate change,” the study’s authors write.

In the meantime, the researchers hope their work will inform conservation efforts, the maintenance of ecosystem services and public policy.

The Sixth Mass Extinction of Fauna and Flora is Imminent, Duke University Study Reveals | Inhabitat – Sustainable Design Innovation, Eco Architecture, Green Building

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A new study has revealed that extinction rates for plants and animals are currently 1,000 times higher than they were before humans arrived. The rate is so high, in fact, that the planet hasn’t seen anything like it since the dinosaurs were wiped out in a mass extinction event 65 million years ago. If we don’t take measures to address the situation, the lead scientist for the project, biologist Stuart Pimm of Duke University, says that we are heading for a sixth mass extinction.

The study was published in the journal Science by a team of seven scientists. It focuses on the annual rate of extinctions per one million species rather than the number of species lost each year. This allows scientist to compare extinction rates from different periods in the earth’s history with the aid of fossil records and DNA evidence.

Revisiting a report that Dr Pimm worked on in 1995, the team discovered new data which showed that past figures were incorrect and the prehuman extinction rate was actually only 0.1 species per million per year, not one per year as previously believed. Currently, the extinction rate is between 100 and 1,000 species per million per year. The team points the finger at climate change, habitat destruction, invasive species and overfishing as the primary causes of such an elevated rate.

Knowing the causes gives us hope, claims Pimm. With the aid of modern technology and as an interim measure, we can identify and monitor at-risk species and work to protect them, either through habitat protection, modifying our behavior in cases of overharvesting, and working on captive breeding programs. These won’t halt the larger issue of climate changethough, and without action on that front, we may just end up joining the queue for mass extinction along with everything else.

watch the video.URL:https://youtu.be/j3inFXgO_k8

Earth is headed for its sixth mass extinction.

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The rapid depletion of Earth’s biodiversity indicates that the planet is in the early stages of its sixth mass extinction of life since becoming habitable 3.5 billion years ago, according to a new study published in Science.

Human activity, including a doubling of its population in the past 35 years, has driven the decline of animal life on Earth, the researchers concluded.

AFP Photo / NASA

There has been a 25 percent average decline rate of remaining terrestrial vertebrates, and a 45 percent decline rate in the abundance of invertebrates. These losses will continue to have innumerable impacts on species that depend on the delicate balance of life on Earth for their own survival.

“We tend to think about extinction as loss of a species from the face of Earth, and that’s very important, but there’s a loss of critical ecosystem functioning in which animals play a central role that we need to pay attention to as well,” said Rodolfo Dirzo, lead author of the study and a biology professor at Stanford University.

“Ironically, we have long considered that defaunation is a cryptic phenomenon, but I think we will end up with a situation that is non-cryptic because of the increasingly obvious consequences to the planet and to human wellbeing.”

The “Anthropocene defaunation,” as some researchers have dubbed this era, is hitting large animals such as elephants, polar bears, and rhinoceroses the hardest, as these megafauna are the subject of some of the highest rates of decline on Earth. This trend matches previous mass die-offs of the Big Five extinction periods.

Megafauna usually have lower population growth rates that need larger habitat areas to maintain their populations, thus they are particularly affected by human growth and desire for their meat mass. Losses among these animals often mean dire impacts for other species that depend on them within an ecosystem.

Past studies have found that the loss of larger animals means a spike in rodents, as grass and shrubs proliferate and soil compaction decreases, all while the risk of predation also declines, Futurity.org notes. As rodent populations increase, so do the disease-transporting ectoparasites that come with them.

“Where human density is high, you get high rates of defaunation, high incidence of rodents, and thus high levels of pathogens, which increases the risks of disease transmission,” said Dirzo.

“Who would have thought that just defaunation would have all these dramatic consequences? But it can be a vicious circle.”

About 16 to 33 percent of all vertebrate species are considered threatened or endangered, the review found.

Invertebrate loss also has far-reaching ripple effects on other species. For example, the continued disappearance of vital honeybee populations across the globe will have bleak consequences for plant pollination, and thus on the world’s food production, as RT has previously reported.

Insects pollinate about 75 percent of the world’s food crops, according to Futurity.

Overall, of the world’s more than 71,000 species, 30 percent of them are threatened, according to the International Union for Conservation of Nature. Based on this assessment – and without drastic economic and political measures to address the current die-off – the sixth mass extinction could be cemented by 2400 A.D., University of California, Berkeley geologist Anthony Barnosky told Harper’s magazine.

Solutions to the die-off are complicated, the study posits, as reducing rates of habitat change and overexploitation of lands must come through regional and situational strategies.

“Prevention of further declines will require us to better understand what species are winning and losing in the fight for survival and from studying the winners, apply what we learn to improve conservation projects,” said Ben Collen, a lecturer at the University College of London and a co-author of the study.“We also need to develop predictive tools for modelling the impact of changes to the ecosystem so we can prioritize conservation efforts, working with governments globally to create supportive policy to reverse the worrying trends we are seeing.”

Researchers from University of California, Santa Barbara; Universidade Estadual Paulista in Brazil; Universidad Nacional Autonoma de Mexico; the Natural Environment Research Council Centre for Ecology and Hydrology in England; and University College London are coauthors of the new study.