I’ve made mention of daily extinctions in many different places, always qualifying it as an estimate. If “as many as 200 species” become extinct every day, this may mean that 55 species became extinct yesterday and that 178 became extinct today.
I’ve asked conservation biologist Dr. Alan D. Thornhill if he knows the origin of the original 200 estimate. He said he was certainly familiar with it but could not point to a particular source for it (though it seemed to him not an unreasonable estimate).
In May, 2007 Ahmed Djoghlaf, head of the U.N. Convention on Biological Diversity, said that “Extinction rates are rising by a factor of up to 1,000 above natural rates. Every hour, three species disappear. Every day, up to 150 species are lost.” So at last we have a pretty authoritative estimate—but of course it IS just an estimate. There is no exact way to keep track of the surviving populations of millions of species.
updated: 24 Jun 2005