One scarce item in the future will be water. If you could think of an inexpensive way to get water from places of abundance to places where it is needed for drinking, farming, and other uses, such as fracking, you could become a wealthy marketing intermediary. Pipelines are an alternative, but could you also freeze the water and ship it by train or truck? Could you use ships to tow icebergs to warmer climates? What other means of transporting water might there be?