Subtracting this uninhabitable 57% (32,665,981 mi2) from the total land area leaves 24,642,757 square miles or 15.77 billion acres of habitable land. Divide this figure by the current human population of 7 billion (that's 7,000 million people!) and you get just under one hectare (2.3 acres) per person.Terrible Truths About Global Warming & World Domination! (2015)