The Convention on Biological Diversity claims that up to 150 species of animals and plants become extinct each day. Yet the International Union for the Conservation of Nature only has a list of 801 species that have been lost in the last 500 years.
A great piece on this weeks More or Less explains why questions such as counting how many species are going extinct (or even how many species there are) can prove very difficult to come up with even vaguely accurate answers to.
