Book of Life

Dour predictions that extinctions will outpace efforts to name Earth’s species are unfounded, scientists argue. With the help of amateurs and online tools, they say, researchers could catalogue most of the planet’s flora and fauna within a century.

Biologists worry that millions of species still haven’t been documented and the number of taxonomists qualified to do so is declining. But the picture may not be not as glum as people assume. In a review article in Science, researchers estimate that Earth houses 2 to 8 million species, and 1.5 million have been described. Other studies have suggested a species count of 30 to 100 million, but such estimates “seem highly unlikely,” the authors write.

Taxonomists also are not as rare as people think. In fact, there are two to three times more taxonomists now than there were about 50 years ago, the team says. While the percentage of papers about new species from North America has dropped since the 1980s, the percentage from Asia and South America has risen. And amateurs are describing about half of the new animal species in Europe, the authors say.

So how long will it take to complete Earth’s catalogue? If there are 2 to 5 million species and people continue describing them at the same rate seen over the last decade, the bulk of the job would be done between 2040 and 2220. Assuming less than 1 percent of species go extinct per decade, “the rate of species description greatly outpaces extinction rates whether there are 2 or 10 million species on Earth,” the authors write. Roberta Kwok | 24 January 2013

Source: Costello, M.J., R.M. May, and N.E. Stork. 2013. Can we name Earth’s species before they go extinct? Science doi: 10.1126/science.1230318.

Image © Brenda Carson |