I remember seeing somewhere that the Population of Europe in 1700 was 3 times that of Africa (don't think they had any citations), but now Europe is 50% that of Africa.
Why? Europe developed modern medicine earlier - so more babies lived and people lived longer and more productive lives. As that increased, less people had 12 babies and more lived to 80
That's happening now in Africa and as that happens, the number of kids they have reduces
Is it a problem? I don't have enough knowledge to state anything factually but I can state what I think based on the limited knowledge I have
To me, this is not a problem - we had a population of 1 billion in 1700 and we're not going to go down to that level again - or at least in this century.
the World's population looks to peak at 10 billion, but NOTE
The population increase peaked in 1968 - since then the growth in population is because people live longer
When you look at "Karate Kid" vs "Cobra Kai" it will tell you
Pat Morita in the movies was the same age that Ralph Macchio is today in Cobra Kai
But Ralph looks younger - and it is not just actors - 60 year olds today are healthy and more active and productive than 60 year olds in the 1980s
Today's kids could quite easily live to their 80s or be centenarians - and be productive for much of that time period