goldstone, good morning to you, sir. >> good morning, craig. >> give us a sense of the size and the ratet is our world population growing? >> what's amazing is world population is growing faster than ever. we added 1 billion people in just the last 12 years. it looks like we're going to add another 2 billion by mid-century, and then another billion after that. now, it's a good thing. it's because people are living longer and more children are surviving, but the numbers do add up quickly. >> well, it's a good thing for some of us. for others, maybe not so much. i want to talk about that in just a moment. let's talk about the population boom. where are these boom centers? which continents and areas are going to be seeing the largest numbers of people? >> the biggest boom is going to be in africa. africa is expected to grow from about 1 billion people today to over 3 billion by the end of this century. at that point, well over one out of three people in the world will be someone living in sub-saharan africa. that's a huge change from today, when it's about one in six, one in seven. >> what