Today, Africa’s population is 1.2 billion, or 16 percent of the world. The UN projects that will double by 2050. By the end of the century, Africans will have contributed 3.2 billion of an anticipated 3.8 billion increase in population. Increased life expectancy will make them 39 percent of the world’s people. I traveled from Senegal in the west to Kenya in the east to meet some of the Africans who are laying the foundations of a better future for those new billions of people.