[YorkshireSeason]

   desirable land, land that can 
   support populations is very much 
   a constrained resource.

I'm afraid I don't agree.

We only loose land to development were we don't push density. Desertification is not a major problem, since -- due to global warming -- we win more new land in previously uninhabitable areas (e.g. Siberia). From a sustainability POV, it is desirable to increase density of human dwelling: the more density, the less transport is needed, the more public transport makes sense, the more heating / cooling, electricity production etc can be centralised, which means more efficient usage of resources.

[ryanmercer]

Research water rights, research where water comes from for large cities (sometimes hundreds of miles away, look at Tokyo/Miami/London/Cairo/Beijing/Bangalore/Las Vegas/Mexico City/New York City), look at water scarcity for Africa as a continent, look at the insane groundwater depletion going on for several decades now. As it stands now 14%, and growing, of the world's population suffers from water scarcity. Anything less than 1,700 cubic meters (for referenced an Olympic pool is 2,500) per person of freshwater is considered water scarcity.

Just because there is land, does not mean it's usable or should be used.

Functional real estate remains an extremely finite resource. Land prices will continue to rise, debt amassed for purchasing said land will continue to rise and will sooner or later hit a wall where land is largely only exchanging hands when the owner dies for large parts of the world.