Global Extinction Rates Have Likely Been Exaggerated


A new study in Science finds that global extinction rates of species has likely been exaggerated. As LiveScience reports:

Concerns that many animals are becoming extinct, before scientists even have time to identify them, are greatly overstated, according Griffith University researcher, Professor Nigel Stork. Professor Stork has taken part in an international study, the findings of which have been detailed in "Can we name Earth's species before they go extinct?" published in the journal Science.

Deputy Head of the Griffith School of Environment, Professor Stork said a number of misconceptions have fueled these fears, and there is no evidence that extinction rates are as high as some have feared.

"Surprisingly, few species have gone extinct, to our knowledge. Of course, there will have been some species which have disappeared without being recorded, but not many we think," Professor Stork said.

Professor Stork said part of the problem is that there is an inflated sense of just how many animals exist and therefore how big the task to record them.

"Modern estimates of the number of eukaryotic species have ranged up to 100 million, but we have estimated that there are around 5 million species on the planet (plus or minus 3 million)."

Good news indeed. Some years ago I testified at an oversight hearing before the House Subcommittee on Energy and Mineral Resources. The topic of the hearing was on the impact of science on public policy. I focused on various failed apocalyptic environmentalist predictions, one of which was the allegedly imminent extinction of a huge percentage of the Earth's species. Specifically I reviewed a number of earlier such predictions:

Let me close with a brief tour of past predictions about species extinctions. Again the predictions by concerned scientists were way off the mark. In 1970, Dr. S. Dillon Ripley, secretary of the Smithsonian Institute, predicted that in 25 years, somewhere between 75 and 80 percent of all the species of living animals will be extinct. That is 75 and 80 percent of all species of living animals would be extinct by 1995. In 1975, Paul Ehrlich and his biologist wife, Anne Ehrlich, predicted that "since more than nine-tenths of the original tropical rainforests will be removed in most areas within the next 30 years or so, it is expected that half of the organisms in these areas will vanish with it." It's now 29 years later and nowhere near 90 percent of the rainforests have been cut.

In 1979, Oxford University biologist Norman Myers suggested in his book The Sinking Ark that 40,000 species per year were going extinct and that 1 million species would be gone by the year 2000. Myers suggested that the world could "lose one-quarter of all species by the year 2000." At a 1979 symposium at Brigham Young University, Thomas Lovejoy, who is now the president of The H. John Heinz III Center for Science, Economics, and the Environment announced that he had made "an estimate of extinctions that will take place between now and the end of the century. Attempting to be conservative wherever possible, I still came up with a reduction of global diversity between one-seventh and one-fifth." Lovejoy drew up the first projections of global extinction rates for the Global 2000 Report to the President in 1980. If Lovejoy had been right, between 15 and 20 percent of all species alive in 1980 would be extinct right now. No one believes that extinctions of this magnitude have occurred over the last three decades.

What did happen?

Most species that were alive in 1970 are still around today. "Documented animal extinctions peaked in the 1930s, and the number of extinctions has been declining since then," according to Stephen Edwards, an ecologist with the World Conservation Union, a leading international conservation organization whose members are non-governmental organizations, international agencies, and national conservation agencies. Edwards notes that a 1994 World Conservation Union report found known extinctions since 1600 encompassed 258 animal species, 368 insect species, and 384 vascular plants. Most of these species were "island endemics" like the Dodo. They are particularly vulnerable to habitat disruption, hunting, and competition from invading species. Since the establishment of an endangered species list only seven species have been declared extinct in the United States. Four are freshwater fish: the Tecopa pupfish (1982), the Amistad gambusia (1987), the Cisco longjaw (1983), the blue pike (1983); a freshwater clam, the Sampson's pearlymussel (1984), and two small birds, the dusky seaside sparrow (1990) and the Santa Barbara song sparrow (1983).

Let me say clearly from a personal perspective that species extinction is undesirable and should be avoided when reasonably possible. Extinction really is forever. But to put it in perspective, Science magazine just published an article called "Prospects for Biodiversity" by Martin Jenkins, who works for the United Nations Environment Programme-World Conservation Monitoring Center that bears on this topic. Jenkins points out that even if the dire projections of extinction rates being made by conservation advocates are correct they "will not, in themselves, threaten the survival of humans as a species." The Science article notes, "In truth, ecologists and conservationists have struggled to demonstrate the increased material benefits to humans of 'intact' wild systems over largely anthropogenic ones [like farms]….Where increased benefits of natural systems have been shown, they are usually marginal and local."

I am very happy to report that there is now even more data suggesting that the extinction apocalypse has been greatly exaggerated.