You guys realise we could still invest in building actual train infrastructure and still research and develop hyperloop technology right? Theoretically it would be by far the fastest transport technology, and an airline killer.

Even if it's still decades away, dismissing it completely is like saying 'why are we researching fusion, we should be building renewables which actually work' when we can in fact do both.

In a lot of African countries it's not uncommon to see people living in mud-brick houses they built themselves - but hooked up with a solar panel they've bought, a smartphone that they're using to browse the internet and an incredibly clean and shiny car.

Even in a best-case scenario we'll have to sacrifice substantial areas of land to build dense, sustainable cities. Most of the wildlife and wilderness in that part of West Africa is already gone, most land is deforested and densely populated farmland with some protected areas here and there. The west African mangroves are mostly gone already, for example.

Hopefully Africa does a better job preserving some areas of land for animals while developing others than the West did. Some countries like Tanzania and Namibia are doing OK, others like Nigeria are environmental disasters already with a population density which can only increase.

If Bangladesh can drop it's fertility rate from almost 7 to less than 2 through a well-organised -to-door family planning campaign, any country can.

Is it? The author is clearly well traveled in West Africa, they're surprised because things have seemingly changed so fast.

While I think that population growth will probably decline more than predicted as Africa gets rich, it's worth noting that certain African countries (particularly Nigeria and Uganda) have already hit insanely high population densities before they've become developed, and will see ridiculously fast urbanisation.