Actually this is far sighted of someone of your experience Sean.
Scientists have frequently documented the exponential growth in the world's human population.
7 Billion Minds, 7 Billion Hearts « SkeptEco
I too have been concerned with the overall food supply, especially when we begin considering using food to provide energy for our car's engines.
There was recently an article written about this problem and I cannot find it. The article was about how the world crop production has always outpaced the population growth by about 4% until recently. The increase in crop production was due to increasing yield per acre of farm land. This was achieved with super fertilizers that rely on potassium and other minerals. The crop yields are shrinking due to lack of potassium. They are still outpacing population growth by about 2%.
The premise was that if we do not figure out a way for our world crop yields to continue to exceed the population growth, then we are one disaster away from massive food shortages. Lot's of scholarly journals have been written about potassium and other minerals needed for crop production.
potassium shortage and crop yields - Google Scholar
I do agree that we will probably have to use more land to produce the same crops but that costs more resources and will drive the cost of food up.
The thing about this is that if and when we figure out there is a problem it will be too late. It takes time for the food to grow.
Soylent Green aynone?
Soylent Green - Wikipedia, the free encyclopedia
Looks like the money is going to be in controlling the minerals and water sources needed for crop production.