extinction Intelligent Design

Is the Sixth Great Extinction a big myth?

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Recently, I was astonished when I came across an article titled, Are We in a ‘Sixth Great Extinction’? Maybe Not, by Ross Pomeroy, an editor of RealClearScience and a zoologist and conservation biologist by training. The author’s candor and intellectual honesty are refreshing:

The notion that humans are erasing species off the face of the Earth at near unprecedented levels is a perennial story that has been blared in the media for more than two decades. In the year 2000, the United Nations’ Millennium Ecosystem Assessment estimated that species are going extinct 1,000 times faster than they naturally do, and that this rate could increase to 10,000 times. These rates translate to between 17,000 and 140,000 species going extinct each year by some estimates…

…[M]y acceptance of those estimates was recently shaken when I came across a simple fact. Over the last five hundred years, there have been just 875 confirmed extinctions. Why so few, when some scientists have insisted there should have been millions?

There’s no doubt that humans have caused and are causing animals to go extinct, but to compare the current situation to previous mass extinctions is misleading. As Sarah Kaplan reported in the Washington Post last year:

The losses of the past century account for only about 1 percent of the roughly 40,000 known vertebrate species — a statistic that pales in comparison to the level of destruction seen during previous mass extinction events. Even in the least of them, between 60 and 70 percent of species were killed off. During the end-Permian event about 250 million years ago, known as “the Great Dying,” that number was more than 90 percent.

In her recent book Resurrection Science, journalist M.R. O’Connor offered a reason why the hyped notion of a sixth mass extinction persists.

“The field of conservation biology is a crisis discipline,” she wrote, suggesting that the field is inclined to forecast doom and gloom in order to promote needed environmental protections.

“Conservationists themselves have said that the field breeds a culture of despair,” she continued. “And at times, their pessimism threatens to undermine the cause. ‘A society that is habituated to the urgency of environmental destruction by a constant stream of dire messages from scientists and the media will require bigger and bigger hits of catastrophe to be spurred into action,’ wrote biologists Ronald Swaisgood and James Sheppard in 2010.”

Ross Pomeroy’s honesty is commendable. It is rare to find a science writer who is willing to admit that he/she may have been wrong on an issue relating to public policy.

Pomeroy’s article confirms suspicions which I voiced last year, in a post on Uncommon Descent:

Studies propagating the myth of the Sixth Great Extinction continues to be breathlessly repeated in the media. Just last week, a Live Science report by Laura Geggel, titled, Here’s More Proof Earth Is in Its 6th Mass Extinction [June 19, 2015], was posted on Yahoo. The report trumpeted the findings of a new study purporting to clinch the case and silence the doubters once and for all…

Curious about the study, I dug up … the abstract of the study, which is titled, Accelerated modern human-induced species losses: Entering the sixth mass extinction (Science Advances 19 Jun 2015: Vol. 1, no. 5, e1400253) and is co-authored by Gerardo Ceballos, Paul R. Ehrlich, Anthony D. Barnosky, Andrés García, Robert M. Pringle and Todd M. Palmer…

The full text of the study is available here. However, as soon as I read the abstract, I could see immediately that there were some major flaws in the study’s reasoning.

Flaws in the 2015 study by Ceballos et al.

FLAW #1: The study fails to mention that scientific estimates of the current rate of species extinctions are wildly divergent, varying by a factor of 100

The first point I’d like to make is that scientists have a very poor idea how rapidly species are actually dying out as a result of human activity. Ronald Bailey, a science correspondent for Reason magazine, has pointed out that many estimates of the rate at which species are becoming extinct are highly inflated, in a carefully documented article titled, Predictions of a Man-Made Sixth Mass Extinction May Be Exaggerated (Reason, August 1, 2014). For instance, a recent study by Rodolfo Dirzo et al. (Science 345, pp. 401-406, 2014) claimed that the world is “likely losing 11,000 to 58,000 species annually.” At the higher rate, something like 40 percent of all animal species will be gone by 2050. However, according to the most recent and authoritative estimate by Stuart Pimm et al. (Science 30 May 2014: Vol. 344 no. 6187), the current extinction rate of species is actually 100 out of every million species, per year – which means that if there are five to ten million species on Earth, about 500 to 1,000 species are going extinct every year. That’s about 20 to 100 times lower than Dirzo’s extravagant estimate. What’s more, very few (if any) of these extinctions can be linked to global warming.

Note the high level of variation here: Pimm estimates that the number of species going extinct each year may be as low as 500, while Dirzo claims it may be as high as 58,000. That’s a ridiculous level of scientific uncertainty…

FLAW #2: If we exclude one-off extinctions occurring on islands between 1500 and 1980, the rate of extinctions caused by human activities drops to only about 5 times higher than the background rate, not 114 times as claimed by Ceballos et al.

In their study, Ceballos et al. chose to focus on vertebrates, the best-studied group of animals, and they deliberately counted only those species of animals that were officially listed as being extinct, or that were likely to have become extinct, but not yet officially verified. Methodologically, their procedure was commendably cautious. What they overlooked, however, was that nearly all of the officially recorded extinctions during the last 500 years took place on islands (including the geographically isolated “island continent” of Australia), as a result of the introduction of alien predators and uncontrolled hunting. … If we leave out island extinctions, then the rate of man-made extinctions in the past 500 years drops dramatically to less than ten times the background rate.

FLAW #3: Even if the figures cited by Ceballos et al. were correct, it would be absurd to infer that a sixth great extinction was underway

But let’s suppose that Ceballos et al. are right after all in their estimate of the rate of man-made extinctions. They claim that it is about 100 times the natural background rate of two out of every 10,000 species per century. That would mean that 200 out of every 10,000 species, or 2% of all species on Earth, are becoming extinct every century. But at that rate, it would take more than two millennia for half of the Earth’s species to die off, in a sixth great extinction. That’s over 2,000 years.

Now, any scientist will tell you that 2,000 years is a mere eye-blink in geological terms, and that many of the previous five great extinctions took place over a considerably longer period. That may be so, but in human technological terms, 2,000 years is an eternity. (Think of how we lived 2,000 years ago: paper had only just been invented, the average lifespan was about 35 years, and our scientific knowledge was virtually nil.) My point is that even if we are killing off 2% of the Earth’s species every century, it’s highly likely that we’ll have figured out how to halt this ecological destruction by the year 2100 or 2200. After all, think of how far we’ve come in the last century: radio (1900), the airplane (1903), television (1925), the computer (1936), satellites (1957), the Internet (1969), the personal computer (1982) and the World Wide Web (1989), to name just a few inventions that have shaped our lives. What the proponents of a sixth great extinction are really saying is that 2,000 years from now, we still won’t have figured out a way to halt the environmental destruction that we are causing now. That’s absurdly pessimistic.

In other news, the global warming Website Watts Up With That? (WUWT) has recently exposed three more eco-myths that continue to be widely circulated on the Internet.

Myth #1: Polar bear numbers are declining dangerously

The first myth relates to polar bears, whose populations (it turns out) are not crashing after all. Here’s a brief excerpt from a WUWT post titled, Ten dire polar bear predictions that have failed as global population hits 20-31k (February 25, 2016) by Dr. Susan Crockford:

While polar bears may be negatively affected by declines in sea ice sometime in the future, so far there is no convincing evidence that any unnatural harm has come to them. Indeed, global population size (described by officials as a “tentative guess“) appears to have grown slightly over this time, as the maximum estimated number was 28,370 in 1993 (Wiig and colleagues 1995; range 21,470-28,370) but rose to 31,000 in 2015 (Wiig and colleagues 2015, [pdf here] aka 2015 IUCN Red List assessment; range 20,000-31,000)…

Polar bears are not fragile canaries in an Arctic climate-change coal mine but resilient and adaptable predators remarkably suited to their highly variable habitat.

Myth #2: The destruction of Easter Island was caused by the islanders chopping down all the trees

The second myth is the eco-fable that deforestation by the local inhabitants of Easter Island caused habitat destruction and led to the depopulation of the island. This eco-myth was popularized in Easter Island, Earth Island by Paul Bahn and John Flenley (1992), and in Jared Diamond’s Collapse: How Societies Choose to Fail or Succeed (2005). Here’s an excerpt from a WUWT post titled, Science debunks the fable of Easter Island, which quotes from an article by Larry Kummer, from the Fabius Maximus website:

Summary: The fast Polynesian expansion across the Pacific from Samoa to South America is one history’s greatest achievements of exploration. Conducted with primitive technology, they colonized almost every suitable island in the Pacific. Equally remarkable in a different way is how the sad story of the last and least-suitable of their settlements has been twisted into an eco-fable. Here is that story and the long effort of a few scientists to bring the truth to light…

One of the more complete tellings of the full story is The Statues that Walked: Unraveling the Mystery of Easter Island by Terry Hunt and Carl Lipo (2011). From the publisher’s summary:

“… Far from irresponsible environmental destroyers, they show, the Easter Islanders were remarkably inventive environmental stewards, devising ingenious methods to enhance the island’s agricultural capacity. They did not devastate the palm forest, and the culture did not descend into brutal violence.“Perhaps most surprising of all, the making and moving of their enormous statutes did not require a bloated population or tax their precious resources; their statue building was actually integral to their ability to achieve a delicate balance of sustainability. The Easter Islanders, it turns out, offer us an impressive record of masterful environmental management rich with lessons for confronting the daunting environmental challenges of our own time.”

The people of Easter Island, like so many others, were wrecked by the West: we gave them pandemic diseases, then depopulating slave raids and ecological devastation (conversion of the island to a sheep range, for which it was poorly suited). This eco-fable is an outrageous example of blaming the victim.

Myth #3: Ocean acidification is endangering the planet

Finally, a new post on WUWT exposes the myth that ocean acidification poses a danger to the planet:

A new paper published in the ICES Journal of Marine Science puts the issue of “ocean acidification” to the test, and finds that there has been significant exaggeration in the issue…

From an article in The Times:

An “inherent bias” in scientific journals in favour of more calamitous predictions has excluded research showing that marine creatures are not damaged by ocean acidification, which is caused by the sea absorbing carbon dioxide from the atmosphere.It has been dubbed the “evil twin of climate change” and hundreds of studies have claimed to show that it destroys coral reefs and other marine life by making it harder for them to develop shells or skeletons.

The review found that many studies had used flawed methods, subjecting marine creatures to sudden increases in carbon dioxide that would never be experienced in real life.

“In some cases it was levels far beyond what would ever be reached even if we burnt every molecule of carbon on the planet,” Howard Browman, the editor of ICES Journal of Marine Science, who oversaw the review, said. He added that this had distracted attention from more urgent threats to reefs such as agricultural pollution, overfishing and tourism…

Dr Browman invited scientists around the world to contribute studies on ocean acidification for a special edition of his journal. More than half of the 44 studies selected for publication found that raised levels of CO2 had little or no impact on marine life, including crabs, limpets, sea urchins and sponges…

In the article from the Times, the lead author [Howard Browman] also has this to say:

…He said that a handful of influential scientific journals and lobbying by international organisations had turned ocean acidification into a major issue. The bias in favour of doom-laden articles was partly the result of pressure on scientists to produce eye-catching work, he added.

Doom-and-gloom bias in the publicity-hungry science media? Who would have thought it?

Comments are welcome.

10 Replies to “Is the Sixth Great Extinction a big myth?

  1. 1
    News says:

    Most likely, most of what you read about polar bears is motivated nonsense. First, they are a subgroup of the grizzlies and are known to hybridize with other bears (when lonely).
    http://www.polarbearsinternati.....ly-hybrids

    Recent restrictions on trophy hunting probably result in increased adult numbers, which means they range more widely for food, apart from any environment factor.

    The bear is omnivorous and in time will likely adapt to any diet, including stale donuts. His biggest concern is bigger bears, as he has no natural enemies.

    In any event, bears are sighted more often now by people:

    http://churchillpolarbears.org/

    Polar bear jail:
    https://www.youtube.com/watch?v=CS17gL2_lYI

    http://kenmaxwell.com/2011/11/.....-manitoba/

  2. 2
    Roy says:

    Note the high level of variation here: Pimm estimates that the number of species going extinct each year may be as low as 500, while Dirzo claims it may be as high as 58,000. That’s a ridiculous level of scientific uncertainty…

    …when compared with the uncertainty in IDers’ estimates for the age of the Earth.

  3. 3
    Algorithm Eh says:

    I agree that the extinction numbers are often blown way out of proportion, and that doesn’t help the scientists who are studying this. Part of the problem is in how we define “extinct”. The general public view extinction as the complete loss of a species (e.g., trilobites and dinosaurs). Biologists often use the same word (erroneously) to describe species that are no longer found in the wild, or in a certain area in which they were once found. For example, it is often stated that cougars are “extinct” in eastern Canada.

    If global warming is true (which I doubt), and the arctic ice pack melts, polar bears as we know them will become “extinct”. But that does not mean that their genetic lie will not persist through interbreeding with other bears, specifically grizzlies.

  4. 4
    Eric Anderson says:

    Ah, yes. The old vast extinctions claim. Not much observational evidence for the wildly high claims of current extinction rates. But surely someone has generated a “model” somewhere that shows such high extinction rates: “We got a computer model. We don’t need no stinkin’ evidence.”

    Reminds me of the lack of evidence for the wildly high claims of past extinction numbers. Asked someone on UD recently for some evidence for the “99% of all species have gone extinct” meme, but all I got in return was an insult about how foolish I was to even ask such a question. 🙂

    Some “facts” dare not be questioned . . .

  5. 5
    markf says:

    VJ

    I do so wish you were right in downplaying the threat of species extinction but I am afraid the warnings of a 6th great extinction are reasonable.

    You included the quote:

    Over the last five hundred years, there have been just 875 confirmed extinctions. Why so few, when some scientists have insisted there should have been millions?

    But you omitted the answer to this rhetorical question,  which is partly supplied by Pomeroy in the next paragraph:

    A large reason for the disparity is that we almost certainly have not come close to identifying all of the species alive on Earth. Between one and 1.5 million species have been discovered, but there may be five to 14 million in total, perhaps more. And so, conservationists assume that many of these undescribed species face similar extinction risks as a result of human activity.

    Much of Pomeroy’s article is about the validity of models that extrapolate from confirmed extinctions to total extinctions. He quotes a single paper (Fangliang and Hubbell) that suggests the commonly used models are overestimating by 160% i.e. the extinction rate is actually about a third of what is estimated – still a massive rate and far above normal. And Pomeroy appears to agree with Fangliang and Hubbell that species extinction is a serious issue that must be addressed.

    The other source he quotes is the Sarah Kaplan article.

    The losses of the past century account for only about 1 percent of the roughly 40,000 known vertebrate species — a statistic that pales in comparison to the level of destruction seen during previous mass extinction events. Even in the least of them, between 60 and 70 percent of species were killed off. During the end-Permian event about 250 million years ago, known as “the Great Dying,” that number was more than 90 percent.

    This is a fairly blatant example of quote mining and a misunderstanding of what conservation biologists are saying. The Kaplan article supports the case of most biologists which is that the current rate of extinction is way above normal and that some of the changes we are making to the environment will accelerate that rate of extinction so if we don’t do anything about it there will be a sixth mass extinction within a few hundred years (a geological instant). In the quoted paragraph Kaplan points out that the total extinctions are not yet comparable to the mass extinctions of the past which occurred over hundreds of thousands of years. But we are causing species to go extinct at a rate that will lead to something comparable if don’t address it. Which is all that responsible conservationists are saying.

  6. 6
    Me_Think says:

    There is a serious misunderstanding. Extinctions are on geological time scale. The Holocene extinction (Sixth extinction)is ongoing extinction of species during the present Holocene epoch – since around 10,000 BCE

  7. 7
    vjtorley says:

    markf and Me_Think,

    Thank you for your posts. I’ll keep this brief, and reply at further length later. First, I’m well aware that the Permian extinction took place over geological time – about 60,000 years, in fact. My point was, however, that it would be absurd to assume that present rates of human-caused extinctions will continue for hundreds of years, which is totally unrealistic. As I stated in my article:

    “My point is that even if we are killing off 2% of the Earth’s species every century, it’s highly likely that we’ll have figured out how to halt this ecological destruction by the year 2100 or 2200. After all, think of how far we’ve come in the last century: radio (1900), the airplane (1903), television (1925), the computer (1936), satellites (1957), the Internet (1969), the personal computer (1982) and the World Wide Web (1989), to name just a few inventions that have shaped our lives. What the proponents of a sixth great extinction are really saying is that 2,000 years from now, we still won’t have figured out a way to halt the environmental destruction that we are causing now. That’s absurdly pessimistic.”

    Second, re markf’s charge that the quote from Sarah Kaplan is “a fairly blatant example of quote mining and a misunderstanding of what conservation biologists are saying”: may I remind you that the quote from Kaplan is Pomeroy’s, not mine. Pomeroy is a conservation biologist. For you, a non-scientist, to accuse a conservation biologist of “misunderstanding … what conservation biologists are saying” is just a little impertinent.

    Third, markf quotes Pomeroy as stating: “between one and 1.5 million species have been discovered, but there may be five to 14 million in total, perhaps more.” Yes, I’m aware of that, but that would only raise the number of extinctions by a factor of ten at the most, from 875 (the observed number) to 8,750 – over a period of 500 years. Yet according to experts, the number of extinctions is supposed to be somewhere between 500 and 50,000 species PER YEAR. Clearly something very fishy is going on in the world of conservation biology.

  8. 8
    markf says:

    VJ

    “My point is that even if we are killing off 2% of the Earth’s species every century, it’s highly likely that we’ll have figured out how to halt this ecological destruction by the year 2100 or 2200.”

    I am sorry I didn’t read the whole of your OP. Although a lot shorter than many of your OPs it was too long for me to read it all. However, now I have read what you said, I think you are confusing technological progress with social and political progress. One is blindingly fast. The other is barely detectable. We already have the technology to halt ecological destruction. What we don’t have is the political and social structures to make it happen. We most unlikely to develop such structures if we don’t recognise that there is a major problem.

    “For you, a non-scientist, to accuse a conservation biologist of “misunderstanding … what conservation biologists are saying” is just a little impertinent.”

    I confirm that it is Pomeroy, not you, that I accuse of quote mining. I will rephrase my statement slightly. The quote promotes a misunderstanding of what conversation biologists are saying – I suspect Pomeroy understands the issues perfectly but was excercising a bit of poetic license to make a good article.

    I would like to add:

    * Pomeroy trained as a conservation biologist. That doesn’t mean he is a conservation biologist. His writings seem to be very widespread.

    * I can’t help smiling at a UD regular saying it is impertinent to challenge the authority of an expert in the field.

    “Yes, I’m aware of that, but that would only raise the number of extinctions by a factor of ten at the most, from 875 (the observed number) to 8,750 – over a period of 500 years. Yet according to experts, the number of extinctions is supposed to be somewhere between 500 and 50,000 species PER YEAR.”

    Extrapolation from confirmed extinctions to estimated actual extinctions is not a straightforward multipication of unobserved by observed species. The best model of course is a matter of debate but here are some considerations:

    There is good reason to suppose that extinction rates are much higher among unobserved species which are either very small (which frequently correlates with local and vulnerable to habitat loss) or rare and therefore vulnerable period.

    A species is not generally confirmed as extinct unless “there is no reasonable doubt that the last individual has died”. Most species that go extinct will not be confirmed as extinct for a long time afterwards. It is only the larger and more dramatic species that we are likely to monitor the last living member of the species.

    Although the 875 confirmed extinct species is over the last 500 years I am willing to bet the vast majority actually went extinct in the last 50. Which immediately increases the rate by a factor of 10.

    However, a much lower rate than 500 species a year is quite sufficient to justify the claim of entering a 6th mass extinction. The point is not so much the actual number of species but how much greater is the current rate than the normal background rate and what are the prospects for the fture.

  9. 9
    vjtorley says:

    markf,

    You write:

    “Although the 875 confirmed extinct species is over the last 500 years I am willing to bet the vast majority actually went extinct in the last 50. Which immediately increases the rate by a factor of 10.”

    In fact, extinction rates have been going down this century, as far as we can tell, for mammals and birds, for whom reliable statistics exist. See Willis Eschenbach’s article, Where are all the corpses? and see Dr. Craig Loehle and Willis Eschenbach’s article, Historical bird and terrestrial mammal
    extinction rates and causes
    in Diversity and Distributions, (Diversity Distrib.) (2011) 1–8.

    Results: Only six continental birds and three continental mammals were recorded in standard databases as going extinct since 1500 compared to 123 bird species and 58 mammal species on islands. Of the extinctions, 95% were on islands. On a per unit area basis, the extinction rate on islands was 177 times higher for mammals and 187 times higher for birds than on continents. The continental mammal extinction rate was between 0.89 and 7.4 times the background rate, whereas the island mammal extinction rate was between 82 and 702 times background. The continental bird extinction rate was between 0.69 and 5.9 times the background rate, whereas for islands it was between 98 and 844 times the background rate. Undocumented prehistoric extinctions, particularly on islands, amplify these trends. Island extinction rates are much higher than continental rates largely because of introductions of alien predators (including man) and diseases.

    You add:

    However, a much lower rate than 500 species a year is quite sufficient to justify the claim of entering a 6th mass extinction. The point is not so much the actual number of species but how much greater is the current rate than the normal background rate and what are the prospects for the future.

    By that logic, we could speak of a Sixth Great Extinction if the rate of extinction soared to 100 times the background rate for just ONE year, before returning to the normal rate.

  10. 10
    markf says:

    “By that logic, we could speak of a Sixth Great Extinction if the rate of extinction soared to 100 times the background rate for just ONE year, before returning to the normal rate.”

    And clearly we don’t have to wait 2000 years before deciding the rate has been sustained long enough to justify calling this a sixth mass extinction. It is a case of noting the causes of the extinction (habitat loss above all) and assessing whether they are long term or not. Do you see Madagascar which has about 10% of its rainforest left being returned to rainforest or even retaining what remains?

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