Even if the recent claim by the WWF, that the world’s animal population has declined by 52% since 1970s, were true, it would be a misleading statistic to report. Masters at fund-raising propaganda, the WWF turned out a gem of quotable nonsense.
If there was a performance bonus for most-improved propaganda, surely the spin doctors at the Worldwide Fund for Nature (WWF) deserve the accolade. They issue The Living Planet Report every two years, and this year, they out-performed the 2012 report by a massive 86%. They produced stunner headlines: WWF: World has lost more than half its wildlife in 40 years.
As the Cape Times put it before reading the report, “We killed 52% animals in 44 years.” (You can tell they didn’t read it, because the data period is still 1970 to 2010, as it was in 2012, and that isn’t “44 years”. In case you noticed this, it is explained in the FAQs on page 140.)
In 2012, the WWF found that the average population size of animal species had only declined by 28% since 1970s. Either we went on an unprecedented slaughter spree in the last two years, or they found a way to make the numbers look almost twice as bad.
Let me stipulate from the outset that the idea that some animal and plant populations have declined, and some precipitously so, is uncontroversial. Human development historically came at a cost to the environment. It stands to reason that a doubling in the world’s population since 1970, from 3.7 billion to 7.2 billion, would have an impact on nature, even if economic development today is far less environmentally harmful than it was in the past.
That we need to be concerned about some species and ecosystems is not in dispute. The question is whether the sensational 52% headline can be supported, and if so, what it is supposed to achieve.
The first worry is that it is easily misinterpreted. For example, 702 Talk Radioreported the news ambiguously: “The 2014 #LivingPlanetReport shows a decline of 52% in our wildlife species in the last 4 decades.”
Its sister station, Cape Talk helpfully resolved the ambiguity: “The World has lost half the total wildlife species since 1970.”
Surely, if so many species had gone extinct, someone would have noticed? Why, then, can the wisdom of crowds not come up with more than 25 actual examples during that time, out of 1.9 million described species? (Forgive my resorting to Wikipedia in this case. The IUCN Red List has no means of searching extinctions by the year in which they were declared.)
The problem is that the WWF report didn’t say anything about species numbers, because the world has lost surprisingly few species. That we “lost half the total wildlife species” was, at best, a hurried misquote.
That nobody did a double-take at the claim that half of all species have disappeared shows the effectiveness of decades of propaganda. We’ve long been told that thousands of species go extinct every year, and some accounts number them in the millions. I rebutted this fear in detail last year. [….]
I’m not the only one expressing skepticism. Scientists and green activists are raising eyebrows too.
National Geographic coyly phrased the headline as a question: “Has Half of World’s Wildlife Been Lost in Past 40 Years?”
It goes on to quote Stuart Pimm, a conservation ecologist at Duke University who is certainly not prone to underestimating extinction threats.
“I’m not a fan of this planetary index because it mixes a lot of different numbers together in an essentially arbitrary way,” Pimm told them. “Therefore, it’s hard to know what exactly is meant by a 50 percent loss of vertebrates over the last 40 years. … It’s an apples and oranges and pears and grapes and cookies index that lumps a whole bunch of things together in a way that requires a lot of effort to dissect all the different pieces. It’s not ‘we lost half of all vertebrates’ – it’s more complex than that.”
The WWF’s factoid makes for sensational headline copy, but it offers little clarity, even to the people who study these things.
The BBC quoted Stephen Buckland, a director of the National Centre for Statistical Ecology, who also cast doubt on the numbers. “[There] is the question in the Living PIanet Index of why some populations are monitored when others are not. Those in decline are perhaps of greater interest, and hence more likely to be monitored, than those that are stable or increasing. For practical reasons, populations that are more impacted by man are more easily monitored.”
So we have selection bias in the underlying data, long before anyone even touched it with the statistical manipulation weapons of weightings, suppositions, adjustments and extrapolations.
“Further,” Buckland continued, “the quality of the data is highly variable from one population to another, and some population trends are likely to be biased. So is there a decline? Certainly. Are animal numbers around 52% lower than 40 years ago? Probably not.”
Remember, these are ecologists speaking. If even they can’t swallow the WWF’s propaganda, why should we?