It’s happening right now and we’re causing it. It’s as big as Chicxulub, which wiped out the dinosaurs. It may even attain end-Permian proportions, when 95% of all species disappeared. If we were to stop now and undo what damage we could, the geological record would still mark our depredations.
That’s what I got from Richard Leakey’s book. It’s hard to gainsay him although I’m sure some would. The figures by themselves are compelling though. Here’s a few of ‘em. Normal background rate of extinction: one species every four years. Current rate of progress? Hard to say because we haven’t even counted all existing species yet but four every hour seems to be in the ballpark.
Take birds alone, which should be going extinct at about one a century. The back of my New Zealand bird guide lists five in that one small country during the 1900s. Europe has probably already lost the slender-billed curlew for this century’s quota. Plenty more on the continent are lined up to follow this decade: Balearic shearwater; Siberian crane; sociable lapwing; and, probably irretrievable, Azores bullfinch.
It’s motivation enough to give up the day job and go birding like mad. Or beetling. Or treeing. Or whatever taxonomic class floats your boat. Species will disappear in your lifetime.