ABSTRACT
The future context of agriculture in the United States will differ from the present in ways that cannot be predicted with certainty, but will likely challenge the sustainability of current systems. Research on sustainable agricultural systems must consider this uncertainty, and policy decisions must take uncertainty into account. Uncertainties in predicting the future context of sustainable agriculture in the United States can be illustrated through discussion of potential trends in three key environmental and social variables: human population size, climate, and environmental condition of agricultural landscapes. The size of the human population is the most important factor shaping the future context of agriculture. Population size sets the lower bounds for the levels of food and fiber production that must be sustained by agroecosystems. Many localities have instituted land use planning to reduce farmland loss; however, zoning can be overturned as development pressures mount. For example, Oregon is currently considering legislation to remove millions of acres from exclusive farmland use designation.
