If Half of All Species Go Extinct, Will One of Them Be Us?

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 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. Almost half the animals without skeletons have gone extinct within half a human lifetime. The wide range of these estimates reflects our own uncertainty on this subject, but even our low-end assessments are alarming.