I'm confused. There are about 40,000 known species of vertebrate. There were 18,000 NEW species of life in general discovered in 2016 alone (http://www.latimes.

I'm confused. There are about 40,000 known species of vertebrate. There were 18,000 NEW species of life in general discovered in 2016 alone (http://www.latimes.com/science/sciencenow/la-sci-sn-new-species-top-10-20170522-htmlstory.html http://www.latimes.com/science/sciencenow/la-sci-sn-new-spec...). It's estimated there are more than 8 million species of plant, animal and insect life on the earth. Population decline doesn't equal extinction. So how, pray tell, do we find ourselves in a mass extinction event when less than half of vertebrate species are in decline, less than 1% of species in general are in decline, and when we're still discovering new species and adaptations by existing species every year?