The World's Population Density
This is how many people that can live sustainably per square kilometre, depending on latitude. There are also other local variables like the terrain, altitude, climate and ocean currents that need to be considered.
Map of the world showing population density per kilometre depending on latitude. This work is based on public domain data. https://commons.wikimedia.org/w/index.php?curid=1361680 and https://commons.wikimedia.org/w/index.php?curid=868126
Converting the 50-60 million square kilometres of land that is currently in use into sustainable communities would sustain 5-6 billion people. Making marginal land arable with water catchments, 7 billion people is sustainable. And with reforesting the grasslands and deserts, 10 billion people is possible.

​Once we secure the future our population will find its balance. Overpopulation is caused by fear. Fear of the future and fear of the other. Any attempt at population control will inevitably backfire.
Back to 'The Thousand Year Plan'
This work is based on public domain data.
A graphic representation of light that looks like 216 happy faces.
Kane J Fielding CC 2018 @kainuititirangi - Link to Creative Commons website.