World popolation is around 7.8 billion, and is projected to peak around 11 billion. Given that of all agricultural land only 23% is used for non-feed crops (producing 82% of global calorie supply) that doesn't sound like an existential problem, even if you assume that climate change makes much more land unarable than it makes arable.

Not solving it unless you solve the other problems such as where the energy comes from how do you deal with waste where do you get the water from.

Farmland utilization is on the downtrend everywhere except Africa though.

doubtful, as little far back as a decade there was considered to be over 2.7 billion hectares of land available that would was considered usable, this is mostly in areas like South America, sub-Saharan Africa, and Central America.

Global Warming may actually open areas previously unsuited for certain crops; evidence pointed to much warmer climates in Europe with grapes further North in mans short existence, and the impact on existing uses is not fully understood.

The simple fact is, every time someone suggest were are running out of food or have too many people or water is not wet anymore we find out that it simply is because we don't look further than we are standing.

The biggest reason people starve today is repressive governments that respect neither the person or private property. that one percent, the ruling elite of the world, loses its grip in highly informed, rights driven parts of the world but they sure do fight to keep the pie to themselves even there.

but isn't aquafarming vastly superior to vertical farming for that problem statement?