Franky I'm of the opinion that most of our problems could be solved by having fewer people. The earth is not getting any larger, there is no new land left to discover, and most people desire to live in a small handful of particularly nice areas. Resources are also limited and the more people there are, the thinner the resources get spread. If the population stopped growing housing would catch up.
Oh, don't worry...population will certainly decrease when the environmental situation really hits the fan. I suspect a significant fraction of the world population will be lost in the next 100 years.
In 100 years, 99.99% of those alive today will be dead, unless we get a lot better at living past age 100. So you are probably correct.
Actually, most of the worlds land is unpopulated, the problem with lack of space is down to amenities outside large cities. If there is no employment, utilities, roads, support facilities, in a given area, it cannot populate. And the only way those issues can be addressed is through a governments political will. Even here in the UK, a small island country, the capital, London is the place that gets all the attention. As you move out, even as close as 30-50 miles away, opportunities fall away dramatically with some areas being virtual ghost towns with high crime, drugs and alcohol abuse problems. However, because of insane property prices, fewer and fewer people can afford to live there, so if you work in London you have to commute from as far away as 100 miles!!! Utterly crazy and a complete waste of resources that other parts of the country could provide, which would massively improve growth and prosperity.
Also, I recall reading somewhere, that the entire world population could be accommodated in Texas, with room to spare!! Not surprising really when great areas of land mass have no population at all, a lot of it in America, even more in Russia, Africa, South America etc, etc. Ok, some places are uninhabitable, but even here in the UK we have massive areas of land that could be developed for human habitation. That has to be better than cities like London, New York, Tokyo, etc, that are just bursting at the seams, causing all sorts of problems.