The article assesses progress toward protecting 50% of the terrestrial biosphere to address species extinction and conserve global ecological heritage. Using a map of Earth's 846 terrestrial ecoregions, the authors find that 98 ecoregions (12%) exceed the Half Protected target, 313 ecoregions (37%) fall short but have sufficient unaltered habitat to reach the target, and 207 ecoregions (24%) are in peril with only 4% of natural habitat remaining. They propose a Global Deal for Nature to promote increased habitat protection and restoration, national and ecoregion-scale conservation strategies, and empower indigenous peoples to protect their lands. The goal is to protect half the terrestrial realm by 2050 to halt the extinction crisis while sustaining human livelihoods. The article also evaluates the strengths and weaknesses of the Nature Needs Half approach and provides tools and information to chart progress toward this goal.The article assesses progress toward protecting 50% of the terrestrial biosphere to address species extinction and conserve global ecological heritage. Using a map of Earth's 846 terrestrial ecoregions, the authors find that 98 ecoregions (12%) exceed the Half Protected target, 313 ecoregions (37%) fall short but have sufficient unaltered habitat to reach the target, and 207 ecoregions (24%) are in peril with only 4% of natural habitat remaining. They propose a Global Deal for Nature to promote increased habitat protection and restoration, national and ecoregion-scale conservation strategies, and empower indigenous peoples to protect their lands. The goal is to protect half the terrestrial realm by 2050 to halt the extinction crisis while sustaining human livelihoods. The article also evaluates the strengths and weaknesses of the Nature Needs Half approach and provides tools and information to chart progress toward this goal.