These excellent videos from Small Circles Forward gives us a visual understanding of world population and the aging population. I don't think these videos answer the why but they helps us to see the trends over time. - Andy
Video from Small Circles Forward
Visualizing the World's Fertility Rate over 200 years
"Starting in the 20th century, the fertility rates of the world went crashing down. In just one or two generations nations went from 7 or 8 babies per woman on average to 1 or 2. In this video we visualize that change, look at differences between regions and predict what the future holds and what that means for the future of the human population. Many factors come into play when fertility rates go down. Women's access to education, the labour market and health care. The gender power balance in politics, communities and families. How cultural and religious aspects affect the community as well as the economic opportunities of the individual. To name a few. Fertility rates are, alongside the death rate, the driving factor in the demographic transition and the reason why the population of nations stagnate and eventually fall. 00:00 Intro 00:16 Fertility map 1900-2022 03:56 Causes: Intro 05:13 Causes: Wealth and labour 07:15 Causes: Education 09:29 Causes: Culture and religion 12:21 Fertility map projections 2022-2100 13:24 Outro Small Circles Forward by Daniel Karlsson Lönnö 2022." from video introduction.
The Worlds Aging Population
Video from Small Circles Forward
"The share of the world's population older than 75 years will go up to 14 % in the coming 80 years from 4 % today and 1 % in 1950. In this video I visualize the world's aging population, the geographical distribution, population pyramids and how this trend can affect society. Small Circles Forward by Daniel Karlsson Lönnö 2021." from video introduction.