How many animal species do you think go extinct every year? Last week I conducted a highly unscientific polling of around 20 of my Facebook and Google Chat contacts, asking that same question. I’m not trying to brag, but I have some really smart friends, many of them with degrees in biology. Typical answers ranged from about 17 to a seemingly ludicrous 400. They were all wrong though—off by orders of magnitude*. In July, a summary article of nearly 80 papers, published in Science, stated that, “Of a conservatively estimated 5 million to 9 million animal species on the planet, we are likely losing ~11,000 to 58,000 species annually.”
If that finding is true, then every year, between .12% and 1.16% of all the animals on Earth vanish. Rodolfo Dirzo, the lead researcher on the Science study from Stanford University, points out that we’ve already lost 40% of the Earth’s invertebrate species in the last 40 to 50 years.