A recent report by a UN organisation stated that one million species are under threat of extinction, and the rate of extinctions is accelerating.
But an Auckland University scientist says that estimation is wrong, that it's far fewer, and for a simple reason - many names for species may be synonyms.
Marine Biologist Mark Costello has had a letter published in the journal Science, out this week, arguing that overestimating these figures isn't helpful to conservation. He explains his work.
