NEW YORK ( ETF Expert) -- According to the U.S. Census Bureau and a variety of institutions that study human population growth, the world will need to feed roughly 70 million new mouths every year. That is the current "net" projection when births are offset by deaths.Pundits from Marc Faber to Jim Rogers have talked about the demographic changes. Their solution? Invest in agriculture. Faber tends to talk more about investing directly in farmland as a hedge against social unrest. Rogers tends to discuss the benefits of owning all commodities, though often raises awareness about the benefits of farmland and the agricultural grains produced there. Yet, prior to this year's epic summer drought, agricultural commodities had not been kind to exchange-traded enthusiasts. In fact, owning PowerShares DB Agriculture ( DBA) seemed like an exercise in futility.