Reply #44: The problem is that we don't have much time left to implement these solutions

[NickB79]

Between a growing population, Peak Oil, global warming, water depletion, soil degradation, ocean acidification, and increasing resistance to herbicides and pesticides among pest species, food production is going to become very dicey in many parts of the world in the next 20 years. You would need to construct many towers PER DAY, for DECADES, to fend off potential famines as conventional farming fails in various parts of the world.

And the kicker is that the richest nations like the US, Canada, Japan, and Europe aren't the ones that will be paying for these. That burden would fall upon the countries that will be impacted most by the whirlwind of global warming, population growth, and energy depletion: the African and Asian nations that can ill-afford to spend the kind of money required.

The only country I could see putting in such structures on a meaningful level is China.