> Over-population would be a much more difficult problem to manage, I am not sure about the optimal human population for this planet, but I am fairly certain th

> Over-population would be a much more difficult problem to manage, I am not sure about the optimal human population for this planet, but I am fairly certain that a stable population is much better than a quickly growing one. The environment isn't affected by "over-population" it's affected by environmental destruction and carbon emissions. A lot of the developed countries where the populations are stabilizing or decreasing are already causing disproportionate environmental destruction and carbon emissions, especially if you factor in the effects in other countries caused by producing products that people in the developed countries are consuming. > Quick decline can also be an issue at some point, but in my opinion there is a tight relationship between population density and the housing market, the latter acting as a bottleneck, and if I am right the whole thing should be self-correcting. It may be counterintuitive, but having people concentrated in denser urban areas actually reduces the environmental impact overall. If the housing market leads to more people moving out of cities, that will actually increase the environmental damage.