Thanks a lot :)
You are probably aware of the debate which was sparked about the quality of the used data, especially when it comes to extrapolation and following assumptions. Therefore, I even if current trends seem to indicate a decrease in growth/fertility, these will not necessarily continue. But as far as I'm concerned, it's at least one possibility which might not be too far from the truth.

this could be different for proper water soon or later. I actually see more water as the seed of the next world war, to be honest.

Hm. Yeah, that's the fear of many people. Personally, I think it's more likely we will find more efficient ways to transform water sources like oceans in a way humans can actually drink it. As far as I know, this process is currently quite expensive - if we manage to make it cheaper and find ways to transport it over large distances, conflicts could be avoided.