How much species' biodiversity could area targets protect globally?

Protection targets for addressing biodiversity loss include protecting at least 30% of the land and ocean in ecologically representative areas, but do not specify how many or what proportion of species should be protected from extinction. Here, a systematic analysis of 77 880 marine, freshwater and terrestrial species indicates that all species could be protected in 50% of the planet; 69% in 30%; and 58% in 10%. These percentages only apply if the optimal areas for these species are protected. Thus, the ‘at least 30% by 2030' international target cannot protect more than about two‐thirds of all species even in these optimal places, but 50% could. However, over 80% of the species most endangered by extinction could be protected in 10% of the area. Furthermore, 39% of the optimal areas are in places with minimal human impact. Thus, focusing on these optimal places, in a network of protected areas selected to collectively include as many species as possible, would be a better target for conservation than a simple indicator of area protected.