How many species really are going extinct this year?

Believing is easier than thinking. Hence so many more believers than thinkers.
~Bruce Calvert

The short answer: no one knows.

The long answer: no one knows, and giving an estimate is like asking to be verbally eviscerated on the internet. In fact, it is asking to be verbally eviscerated on the internet. Someone assaults you because they don’t think that many species are going extinct. Someone else assaults you because they think more species are going extinct.

Now, much of the green movement seems quite content to have the number be anywhere from one to a hundred thousand a year. Of course, no one wants to be the one that actually gives an honest to [insert deity here, if applicable] source for that number, which makes me think it’s all bullshit. More on that later.

Normally for things like this, I go straight to the International Union for the Conservation of Nature, which maintains a database of known species and is generally a good source of information backed by peer-reviewed research. Now, you can extrapolate from the IUCN’s data. But your number would be undoubtedly low. The problem lies in the fact that of all the species on earth, the big high-profile ones are the ones that raise the funding to be researched and surveyed and thus are the ones most likely to end up being listed by the IUCN. This means that a lot of low-profile plant, insect, reptile, fish, and amphibian species go without an IUCN entry. These are also more likely to be the species that go extinct. So you can toss the IUCN’s numbers straight out the window.

The problem with the number the green movement gives is that it’s probably much too high. My gut instinct tells me that 100,000 species are not going extinct this year. Why? Because I know how the green movement and the media like to butcher science. Here’s why I think such a high number is given:

A researcher decides to study the extinction rate in a tropical area, say, Borneo. They do a survey of known species, both extant and extinct, and extrapolate from the data the number of species that may go extinct in Borneo each year. This is more or less a standard mathematical model used often in wildlife biology. Now, Borneo is a tropical rainforest, with a high density of very specialized endemic species that are very much endangered due to habitat loss. Therefore, the number of species going extinct in Borneo is probably pretty high.

The green movement gets a hold of this number, and presents it as not the number of species going extinct each year in Borneo, but simply the number of species going extinct each year. It thus gets passed around and perpetuated, with people dividing it by 365.4 to get the number of species supposedly going extinct each day, etc.

But this mathematical model is only for Borneo. You can’t extrapolate data from a tropical rainforest and apply it to, say, Europe, where biodiversity is much lower and modern humans already more or less naturalized. Not nearly as many species are going extinct this year in Europe as there are going extinct in Borneo. I’d be very impressed with a model that actually looked at extinction rates for various areas and biomes and then extrapolated from that. But I highly doubt that’s what we’re dealing with here.

In short, I have no idea as to what number of species are going extinct this year. But I highly doubt it’s as high as “they” say.

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