Making up extinction numbers
On the advice of a regular reader, and because I’ve been delinquent in posting recently, I thought I’d post a snippet I sent to a mailing list in response to someone who declared: “We’ve caused thousands of species to go exctint!” or “We’re facing a mass extinction!” or some such hysterical catastrophist trope.
They asked, “Do scientists just make this stuff up, you think?”
The answer, of course, is: “Yes, they do.”
To illustrate, I put together this summary, extracted from Bjørn Lomborg’s classic 2001 book, The Skeptical Environmentalist, about whether species are going extinct hand-over-fist, and if not, why some people might think so.
First, the data (sources given at the end):
#species #ext* % ext #p/a % p/a* Vertebrates 47000 321 0.683 0.8 0.00171 Mollusks 100000 235 0.235 0.6 0.00059 Crustaceans 4000 9 0.225 0.0 0.00056 Insects >1000000 98 0.010 0.2 0.00002 Vasc. plants 250000 396 0.158 1.0 0.00040 Total ~1600000 1033 0.065 2.6 0.00016 Excl. insects 401000 961 0.240 2.4 0.00060 * Total documented extinctions since 1600AD
These are known species, and documented extinctions. The latter certainly under-report reality, though it isn’t possible to say by how much. That most obviously appears to be the case with insects, an outlier in the data above, so I built a second totals line excluding insects. To give some idea of scale, the 0.24% of all non-insect species to have gone extinct in the last 400 years doesn’t even compare with previous extinctions. The famous dinosaur extinction claimed over 40% of all species. In some 50 separately identified extinction periods, more than 10% of species were wiped out. So losing 1 in 400 is pretty mild, as extinctions go.
One might expect that with mammals, whose extinction rate is the highest by a large margin, the documented extinction rate is much closer to reality. Not many mammals escape our attention.
For mammals (a subcategory of vertebrates in the table above) we have 4500 species, 110 extinctions, which is 2.444% of the total, and 0.00611% per annum.
The total number of species, as well as the actual extinction rates among them, are pure speculation. Now it’s not exactly reasonable to extrapolate from mammals, but let’s do so, to develop a worst-case scenario for all species. Then we get an extinction rate of 0.006% per annum for all species. It is possible that some non-mammal species go extinct at a higher rate, but I don’t have any data either to confirm or deny this, so let’s work with 0.006% per annum.
This is high, but certainly not catastrophic. (Whether it is too high, getting worse, or what, if anything, we should do about it, is beyond the scope of this post.)
Al Gore, in his 1993 book Earth in the Balance, says “40,000 species go extinct per year”. Problem is, he is exaggerating by at least a factor of four. Even if he weren’t exaggerating, he performs a trick well known to those who lie with statistics: he fails to mention the denominator of that fraction. 40,000 of 100,000 is a lot. 40,000 of a million is not a lot. 40,000 of 10 million is negligible. So if our estimate of 1.6 million total known species is correct, even Al Gore’s exaggeration is somewhere between not a lot and negligible.
But if that number is wrong, where did he get it? The answer is that he got it from a British ecologist, Norman Myers. And where did Norman Myers get it? He made it up.
No, really, he made it up! Pulled it out of thin air.
Here’s how. As long ago as 1979, he wrote that until 1900, one species went extinct every four years; since 1900, one species per year went extinct. So far so good.
He then referenced a conference from five years earlier, which had “hazarded a guess” of an extinction rate of 100 per year at present, as the “overall extinction rate among all species, whether known to science or not”.
That hazardous guess seems way out of proportion to the rate Myers accepted for the period 1900-1974, being suddenly 100 times higher with only global cooling and the oil crisis to blame. Even if it includes species not known to science, that’s a rather dramatic jump.
But not to Myers. He is underwhelmed and undaunted, and goes on: “Yet even this figure seems low. Let us suppose that, as a consequence of this man-handling of natural environments, the final one-quarter of this century witnesses the elimination of 1 million species — a far from unlikely prospect. This would work out, during the course of 25 years, at an average extinction rate of 40,000 species per year, or rather over 100 species per day.”
That’s it. That’s the totality of his argument. The lot. There’s no data, no citations, no research, no extrapolation from known facts, nothing. Just an assumption, pulled out of thin air, of a million extinctions in 25 years, which he then in wonderful circular fashion divides up to get an extinction rate 40,000 times higher than he himself says occurred in the first three-quarters of our century.
See the problem? That 40,000 number, which almost thirty years later seems to be “common knowledge”, because scientists and activists have stated it as fact, is an invention. Complete fiction. No bearing on reality whatsoever. But it’s scary! Woooo!
If we know about 1.6 million species, don’t you think we’d have noticed a million extinctions by now? I’ll bet most people can’t even cite, off the top of their heads, just a few examples of actual extinctions; let alone dig up a list of the tens or hundreds of thousands that would be indisputably on record if Al Gore and Norman Myers hadn’t been dead wrong. The irony of the newspaper headline above, 25 years after Norman Myers made up his million-in-25-years number, is the stuff a sub-editor lives for.
So when someone raises extinctions as this major catastrophe, I say, “people make this stuff up”. Not because I’m being argumentative, or because I’m being controversial, but because they really do make this stuff up.
(Source: Lomborg 2001, p250ff, citing among others Bailie and Groombridge, 1997, Walter and Gillett 1998, May et al, 1995:11, Reid 1992:56 and, of course, Myers 1979:5.)
trying to make up some page impressions again eh
Pitiful. You can’t call me oil-company funded, but by Gaia, you’ll impugn my motives anyway. Nice try.
Guess it really burns you when I publish inconvenient truths or annoying facts about the green religion’s high priests.
Now now, Ivo, why would we let “facts” get in the way of our great and noble agenda..? ;)
Well thats OK then. Climate change is a non-event, oil will last forever, the worlds fisheries are in great shape, the worlds rain forests are just fine and the human population and its economy can at least double, maybe triple.
From Wikipedia:
The Holocene extinction event is the widespread, ongoing mass extinction of species during the modern Holocene epoch. The large number of extinctions span numerous families of plants and animals including mammals, birds, amphibians, reptiles and arthropods; a sizeable fraction of these extinctions are occurring in the rainforests. This extinction event is sometimes referred to as the sixth extinction following the previous five extinction events. Since 1500 CE/AD, 784 extinctions have been documented by the International Union for Conservation of Nature and Natural Resources.[1] However, since most extinctions are likely to go undocumented, scientists estimate that during the last century, between 20,000 and two million species have become extinct, but the precise total cannot be determined more accurately within the limits of present knowledge. Up to 140,000 species per year (based on Species-area theory)[2] may be the present rate of extinction based upon upper bound estimating.
In broad usage, the Holocene extinction event includes the notable disappearance of large mammals, known as megafauna, by the end of the last glacial period 9,000 to 13,000 years ago. Such disappearances have been considered as either a response to climate change, a result of the proliferation of modern humans, or both. These extinctions, occurring near the Pleistocene–Holocene boundary, are sometimes referred to as the Quaternary extinction event or Ice Age extinction event. However the Holocene extinction event continues through the events of the past several millennia and includes the present time.
The observed rate of extinction has accelerated dramatically in the last 50 years. There is no general agreement on whether to consider more recent extinctions as a distinct event or merely part of a single escalating process. Only during these most recent parts of the extinction have plants also suffered large losses. Overall, the Holocene extinction event is most significantly characterised by the presence of human-made driving factors and its very short geological timescale (tens to thousands of years) compared to most other extinction events.
If you want to argue with any credibility, it helps not to put words in my mouth.
It is unsubtle and pathetic nonsense to suggests anyone who disputes the world is going to hell in a handbasket must therefore think everything is hunky-dory. It is idiotic rhetoric to suggest that someone who thinks government bureacracy isn’t the best way to deal with the world’s problems must therefore think the problems don’t exist, or don’t need dealing with. It is simply childish to claim the only alternative to believing in critical resource depletion is to claim resources are infinite.
Saying these things makes you look like a fool, but then, I didn’t expect an environmentalists to grasp the dreary normalcy of basic arithmetic or elementary logic.
If you insist:
Nowhere do you dispute the simple fact I’m raising here, namely that current and past extinction rates, whatever they really are, have been dramatically overstated by the alarmists. They have been exaggerated by orders of magnitude, and in fact, the stuff you read in the media — not even that global warming could cause extinctions, but how it will cause a million of them — has been made up. Fiction. Horror-show fantasy. Hitchcock and Poe were more subtle about it.
In plain English, they’ve been lying to you. They’re making up the numbers. And they use those numbers to promote the cause du jour of the environmental movement. They use them to scare you not only into giving them money, but also into agreeing to their fascist rules and costly regulations.
And just as your simplistic exaggerations and lies about what you think I’m saying undermines the credibility of your own arguments, this alarmist hysteria and blatant propaganda seriously undermines the credibility of the environmental alarmists’ causal attribution, their policy recommendations, and their doom-laden predictions for the future.
If you’re going to ask me to spend R10 on your potatoes, I want to be sure I really need them. “You’ll starve if you don’t eat,” won’t cut it. I also want to be sure how many I’ll get. “Perhaps as many as a million,” or, “up to 40,000 a year,” doesn’t cut it either, and will show you up as a swindler and a fraud if I have even a vague idea what the going price per kilo might really be. In short, no sale. And you’ll be whining about how unfair it is that I don’t have to buy from you.
“[…]a gargantuan house of cards rested on models, assumptions, and values that were, for the most part, baseless. It was hard for the man on the street to know this, of course, because thoroughly-conflicted insiders, clueless academics, corrupt politicians, toothless regulators and various industry shills were running around claiming that they knew what was going on[…]”
Spooky because the author wasn’t speaking about global warming, though. Rather, Wall Street :)
http://www.istockanalyst.com/article/viewarticle+articleid_2536488.html