Out of thin air: the threat of massive species extinction

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Out of thin air: the threat of massive species extinction

The often quoted figure that 40,000 species are lost every year comes from a 1979 article by Norman Myers, an ecologist at Oxford University. This figure was not based on any evidence, just on Myers's speculation that one million species might be lost from 1975 to 2000. In 1981 it was increased by arch-doomsayer Paul Ehrlich to 250,000 species per year. (Ehrlich also predicted that half the planet's species would be extinct by 2000.)

The International Union for the Conservation of Nature, which maintains the Red Book of endangered species, concluded in 1992 that the extinction figures for mammals and birds were "very small" and that the total extinction rate, assuming 30 million species, was probably 2,300 species a year.

Nonetheless, Myers repeated his estimate in 1999 with a warning that we are into the opening stages of a human-caused biotic holocaust. He explained that the 40,000 figure was an illustration used to make his argument clear and that he gave figures only when I am speaking to a political leader or policy maker who says that in order to sell his message, he absolutely must have some number.

As the theory goes if you cut down 90% of a forest, you lose 50% of the species it contains. But that doesn't seem to be confirmed if you look at specific examples. The Brazilian Atlantic rainforest was almost entirely cut down, mainly in the 19th century. By now, many of its species should be extinct. [Lomborg] But not one mammal, bird or plant has been found to become extinct there. Zero extinction. Still, United Nations figures predict a loss of 0.1-1% of all species for all of the next 50 years (notice the uncertainty inherent in that range). This forecast includes beetles, ants, flies, worms, bacteria and fungi, which make up 99 percent of all species, plus a small but unknown number of mammals and birds.

Finally, let us remember that extinction is a completely natural event — a simple aspect of evolution at work in the past, present and future. The only real issue at hand should be whether mankind is increasing the selective pressure on existing species in an unusual way, and what the consequences might be for mankind and life on Earth. Death and extinction have been natural phenomena for billions of years past and will remain so for billions of years to come.