Costs and benefits of the current protected area network and for future protection scenarios that (a) meet country-level targets for protected area coverage; (b) meet these targets while also achieving 17% protection of each terrestrial ecoregion; (c) meet the targets from scenario a and protect a scaled fraction of the geographic ranges of threatened terrestrial birds, mammals, and amphibians; and (d) achieve the country-level targets for protected area coverage while also achieving five times the level of biodiversity protection relative to scenario a.

<p>*We use all non-Antarctic land areas (132,523,065 km²) as our denominator when calculating proportional protection.</p>†<p>Protection levels exceed 17% globally because some countries have already established protected area networks that exceed this level (Greenland, for instance, has already protected 41% of its land areas).