Ruth Graham explores the world of conservation science, where a precise tally on the number of extinct species is hotly debated:
Actual documented extinctions are vanishingly rare. “If you ask any member of the public to name 10 species that have gone extinct in the last century, most would really really struggle,” [conservation scientist Richard] Ladle said. “Then you’ve got the world’s most famous conservationists telling you that 27,000 are going extinct every year. The two don’t tally up.” The International Union for Conservation of Nature, which keeps the most definitive list of extinct and threatened species, has counted just over 800 total confirmed animal extinctions since the year 1600.
The huge numbers of extinctions being thrown around may be overstated, or they may be understated. They may also, some say, be the wrong thing entirely to focus on. “It bothers me, and you can quote me on this, that we are still talking about species-level extinction,” said Ross MacPhee, a paleontologist at the American Museum of Natural History who studies extinction. There are other vital questions: Is there a wild population diverse enough to be healthy? Does the animal exist only in zoos? Is a threatened species a linchpin in a large ecosystem? Is it particularly unusual genetically? As Ladle pointed out in a 2010 paper, “extinction” isn’t as binary as it seems: There’s local extinction, extinction in the wild, extinction of subspecies, theoretical extinction of unknown species, and so on—each of which can grab headlines, depending on the fame of the animal.