While the absolute numbers of humans on Earth will continue to rise for another generation at least, birth rates around the world are sinking, particularly in the developed countries. In the coming decades many emerging countries — currently boosting the rise in absolute population numbers — will themselves make the transition to lower birth rates. While most estimates see the global population of Earth peaking around 2040-50, what none of them show is what happens afterward. Unless some unknown counterforce arises, what happens after the peak is that the world's birth rate steadily sinks below replacement level. Increasing people's longevity can only slightly postpone this population fizzle.
The main reason this is unreported is that it will be decades before it will happen and until it does, the population boomers are correct: our numbers swell exponentially. But the story is worth reporting for three reasons:
1) Long before the world's population fizzles, it will age. As it already is. The average age of a human on earth has been increasing since 1972. The developing countries are aimed to be Geezer Countries in another twenty years or less. This will affect culture, politics, and business.
2) There is currently no cultural force in the modern societies to maintain human population levels over the long term. Population robustness these days comes primarily from undeveloped countries, and from cultural practices that are disappearing in developed countries. Once the developing countries become developed, there will be little at work to maintain an average of one offspring per person, with millions have more to balance the millions with few or no children. How many future readers will be willing to have three or more kids?
3) There is no evidence in history of declining population and increasing prosperity. In the past rising prosperity has always accompanied rising populations. Prosperity riding upon of declining population *may* be possible through some wisdom or technology that we don't possess now, but it would require developing an entirely new skill set for society.
This story could be reported by asking the non-obvious questions of the usual population pundits: what happens afterwards? What happens in China with a continually declining birth rate? What would happen to the US without immigration? Who is going to work in Europe?