The World’s Population May Peak in Your Lifetime. What Happens Next? The global human population has been climbing for the past two centuries. But what is normal for all of us alive today — growing up while the world is growing rapidly — may be a blip in human history. A baby born this year will be 60 in the 2080s, when demographers at the U.N. expect the size of humanity to peak. The Wittgenste..