Alaska is 424,000,000 acres. To fit 7.8 billion people at 1 acre each would take 18.4 Alaskas. Or about 4 times the entire acreage of the United states including Alaska. Since the arable land is about 5% of earth's surface, that means we only have about 1 acre of food producing land per person on ... View MoreAlaska is 424,000,000 acres. To fit 7.8 billion people at 1 acre each would take 18.4 Alaskas. Or about 4 times the entire acreage of the United states including Alaska. Since the arable land is about 5% of earth's surface, that means we only have about 1 acre of food producing land per person on earth. Thats about double what it would take to feed everyone on earth (assuming 0% waste), so we have room to grow, but not unlimited room. The earth can support about one more doubling of the population before it'll be impossible to feed everyone. At which point there will be inevitable and massive famines. It's unknown at this point if it's possible to provide the necessary fertilizer and fresh water to maintain that food production indefinitely.