Population Sizes Around the World in 75 Years, So Different

For decades the scenario of world population has been known quite well. World population will keep growing for several decades. Eventually it will peak and then began to drop. In the U.S. we will have a growing population for more years than many wealthy countries. It is almost staggering how much we yet will grow even though our birth rate is below replacement. We are growing because of immigration. 

Around the world, huge differences will have taken place in 75 years. China will have become a much smaller population than it is now. It's population is plummeting. The largest populations in 75 years will be in counties we today seldom talk about.  

Korea's birth rate is so low its population is expected to fall by half be 2100 from its current of about 60 million to about 30 million. Turkey, Brazil and Vietnam will rise for a couple of decades and they plumet.

Nigeria, India and Pakistan are countries with the age distribution to see rising populations. India will  replace China as the largest population and Nigeria will be second.  

During all of this is a general aging of the populations around the world. We can all wonder how this will change day to day life. As the money of supporting old people comes from a smaller and smaller pool of people young and middle-aged cohorts will that be sustainable with retirements in the decade of people's 60's. tt doesn't seem like it be we don't yet know. It doesn't seem like the current high standard of living in the U.S. and other prosperous countries can be maintained. 

Then there are the thorny medical questions that are raised by developments in the science of medicine. Will we want as much life extending measures as we have today?

For the earth's environment and extending the time humans can survive on earth, however, smaller populations will surely be a good thing. Fewer humans, less damage. That is the good news of smaller populations.