The Washington Post, using data from the UN population fund, posted a map and related article that I found highly telling of the global population trends.
“Countries need to grow in order to stay healthy and successful, but not too quickly or they risk problems like political instability.”
‘Blue countries have growing populations; red countries are shrinking. Purple are growing slowly or not at all. Data source: United Nations Population Fund.’ The numbers include data both births, deaths, and migration. The estimates naturally do not account for wars, natural disasters, etc.
What this article is quick to point out is that the most important region here is Sub-Saharan Africa, which you can see is noticeably darker than the rest of the map. What the Post also points out is that a high number of the births in Sub-Saharan countries are from mothers between the age of 9 and 15, which proves often to be too young an age to support a child because of the health risks, and the mother is usually giving up an education.
For some reference to where these population changes may lead, particularly in that very blue continent, check out this post on The African Spring. Then see below the info-graphic on trends by continent (mostly predictions).