Animals

Published on July 14th, 2017 | by Stephen Hanley

Is The World On The Verge Of A Sixth Mass Extinction? Scientists Say Yes

Most of us do not spend our waking hours reading the Proceedings of the National Academy of Sciences of the United States. Certainly no one in the #FakeTrump administration does, as they are too busy lining their own pockets at public expense and practicing the art of self aggrandizement. But if we did, we might have come across an item entitled “Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines.”  Sounds like a real page turner, doesn’t it?

The Sixth Extinction Study

Articles written by scientists rarely evoke much passion and can be deathly dull and difficult to plow through. But this one merits your attention. Spend a moment reading the executive summary.

“The population extinction pulse we describe here shows, from a quantitative viewpoint, that Earth’s sixth mass extinction is more severe than perceived when looking exclusively at species extinctions. Therefore, humanity needs to address anthropogenic population extirpation and decimation immediately.

“That conclusion is based on analyses of the numbers and degrees of range contraction (indicative of population shrinkage and/or population extinctions according to the International Union for Conservation of Nature) using a sample of 27,600 vertebrate species, and on a more detailed analysis documenting the population extinctions between 1900 and 2015 in 177 mammal species.

“We find that the rate of population loss in terrestrial vertebrates is extremely high — even in “species of low concern.” In our sample, comprising nearly half of known vertebrate species, 32% (8,851/27,600) are decreasing; that is, they have decreased in population size and range. In the 177 mammals for which we have detailed data, all have lost 30% or more of their geographic ranges and more than 40% of the species have experienced severe population declines (>80% range shrinkage).

“Our data indicate that beyond global species extinctions Earth is experiencing a huge episode of population declines and extirpations, which will have negative cascading consequences on ecosystem functioning and services vital to sustaining civilization (emphasis added). We describe this as a ‘biological annihilation’ to highlight the current magnitude of Earth’s ongoing sixth major extinction event. A ‘biological annihilation’ of wildlife in recent decades means a sixth mass extinction in Earth’s history is under way and is more severe than previously feared, according to research.

Time is a curious thing. We think because a weather event is classified as a “100 year storm,” that means if we had one yesterday, we won’t have another until one hundred years from now. That impression is false. The odds of a 100 year storm are exactly the same the day after the storm as they were before it.

Similarly, when we hear about mass extinctions that happened millions of years ago, we assume another one can’t be happening today because the odds of one taking place during the little wink of time when we happen to be alive seem impossibly small. But if the authors of this report are correct, that is precisely what is happening.

Five Previous Mass Extinction Periods

Let’s take a little trip back in time to identify the five prior mass extinctions that scientists say happened. Of course, none of this will be comprehensible to those who hold with the notion that the world was created just 7,000 years ago and that humans once rode to work on the backs of dinosaurs. For them, all science is just a theory, in the same way that apples fall from trees because of gravity is a theory and the notion that the earth revolves around the sun is a theory.

End Ordovician, c. 443 million years ago

A severe ice age caused sea levels to fall 350  feet, wiping out up to 70% of all species, most of whom lived in the ocean. The ice melted soon afterwards (in geological terms), which left the restored oceans critically short of oxygen.

Late Devonian, c. 360 million years ago

A prolonged climate change event hit life in shallow areas of the oceans very hard and killed 70% of species including almost all coral reefs.

Permian-Triassic, c. 250 million years ago

95% of all species on earth perished during this event, including trilobites and giant insects. Scientists believe this extinction was brought about because of massive volcanic eruptions in Siberia that caused extreme global warming.

Triassic-Jurassic, c 200 million years ago

Once again, 75% of all species were killed off as the result of volcanic activity. As we all know from Jurassic Park, the dinosaurs ruled the earth afterwards.

Cretaceous-Tertiary, 65 million years ago

A combination of a giant asteroid impact on Mexico and large volcanic eruptions in what is now India brought about the end of dinosaurs and ammonites. Mammals appeared and eventually human beings appeared.

The Sixth Mass Extinction Report Findings

So here we are 65 million years later and the research shows another period of mass extinctions is upon us. Just our luck to be born at the wrong time, huh? The scientists found that a third of the thousands of species losing populations are not currently considered endangered and that up to 50% of all individual animals have been lost in recent decades. Detailed data is available for land mammals, and almost half of these have lost 80% of their range in the last century. Prof Gerardo Ceballos, at the Universidad Nacional Autónoma de México, who led the research study, says, “The situation has become so bad it would not be ethical not to use strong language.”

The scientists found billions of populations of mammals, birds, reptiles and amphibians have been lost all over the planet, leading them to say a sixth mass extinction has already progressed further than was thought. Their report concludes, “The resulting biological annihilation obviously will have serious ecological, economic and social consequences. Humanity will eventually pay a very high price for the decimation of the only assemblage of life that we know of in the universe.”

While all is not lost — yet — the prospects for a good outcome are dim. “All signs point to ever more powerful assaults on biodiversity in the next two decades, painting a dismal picture of the future of life, including human life.”

What Causes A Mass Extinction?

Wildlife is dying out due to habitat destruction, over hunting, toxic pollution, invasion by alien species, and climate change. Ultimately, the primary cause, according to the authors, is “human overpopulation and continued population growth, and overconsumption, especially by the rich.” One of the authors of the report is Stanford professor Paul Ehrlich. His book, The Population Bomb published in 1968, is a seminal, if highly controversial, work.

“The serious warning in our paper needs to be heeded because civilization depends utterly on the plants, animals, and microorganisms of Earth that supply it with essential ecosystem services ranging from crop pollination and protection to supplying food from the sea and maintaining a livable climate,” Ehrlich tells The Guardian. “The time to act is very short,” he says. “It will, sadly, take a long time to humanely begin the population shrinkage required if civilization is to long survive, but much could be done on the consumption front and with ‘band aids’ — wildlife reserves, diversity protection laws — in the meantime.”

The research analysed data on 27,500 species of land vertebrates from the IUCN and found the ranges of a third have shrunk in recent decades. Many of these are common species and Ceballos gave an example from close to home: “We used to have swallows nesting every year in my home near Mexico city – but for the last 10 years, there are none.”

The researchers also highlight the case of the lion. “The lion was historically distributed over most of Africa, southern Europe, and the Middle East, all the way to northwestern India. [Now] the vast majority of lion populations are gone.” Historically lions lived across Africa, southern Europe, the Middle East, all the way up to Northwestern India. Today their habitat has been reduced to a few tiny pockets of the original area.

Other Voices

Not all scientists agree with this latest study. Professor Stuart Pimn of Duke University disputes that a sixth extinction is already underway but is otherwise in agreement with the research. “It is something that hasn’t happened yet – we are on the edge of it,” he says. Pimm was not involved in the research or writing of the study.

He goes on to say, “Should we be concerned about the loss of species across large areas? Absolutely, but this is a fairly crude way of showing that. There are parts of the world where there are massive losses, but equally there are parts of the world where there is remarkable progress. [The report] is pretty harsh on countries like South Africa which is doing a good job of protecting lions.”

Robin Freeman of the Zoological Society of London says, “While looking at things on aggregate is interesting, the real interesting nitty gritty comes in the details. What are the drivers that cause the declines in particular areas?” He adds, “We need people to be aware of the catastrophic declines we are seeing. I do think there is a place for that within the [new] paper, although it’s a fine line to draw.”

Ehlich’s book predicted hundreds of millions of people would die of starvation in the 1970’s due to overpopulation, an event that obviously did not come to pass. Many factors combined to undercut his conclusions, including the introduction of new crops with higher yields. Nevertheless, he says his theory has been successful at alerting people to the dangers of global climate change, particularly as a result of overpopulation. “Show me a scientist who claims there is no population problem and I’ll show you an idiot,” he says.

Political Considerations

The report’s focus on wealth and income inequality is bound to raise the hackles of some readers, but the current political situation in the United States, which has turned the country into little more than a kleptocracy in which feckless politicians hasten to do the bidding of wealthy donors, has to be addressed at some point in the climate change discussion. Ultimately, capitalism is a negative sum game. More and higher profits in perpetuity is simply an unsustainable model, which should be intuitively obvious to the most casual observer by now.

Let’s assume the report is off by a few decades or even a few centuries. Is that reason enough to continue with a business as usual mentality? Ultimately, don’t we owe it to our heirs to leave them a world that is still capable of sustaining human life as well as an abundance of other species? Or is it okay to grab for everything we can get now and let future generations worry about the future? Many of us could benefit from re-reading The Three Little Pigs. The wolf is at the door. What do we intend to do about it?

Source and homepage graphic credit: The Guardian


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About the Author

writes about the interface between technology and sustainability from his home in Rhode Island. You can follow him on Google + and on Twitter.



  • news bytes

    humans have survied a lot and will do a lot. any way great article

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