The number of people which the world must feed is expected to increase by another 2 billion people by 2050. When coupled with significant nutritional improvements for the 2.1 billion people currently living on less than $2/day, this translates into a very substantial rise in the demand for agricultural production. Most past growth in the demand for food has been met by improvements in productivity, but there is evidence of declining growth rates for agricultural yields; climate-change is likely to have important impacts on productivity through changes in temperature and precipitation; land-based climate mitigation policies are also projected to lead to increasing pressure on agricultural lands. Meanwhile supplies of water for irrigation are under pressure, urban land use is on the rise, and demands for setting aside land for environmental purposes continue to increase. Clearly, an enormous amount of additional research on ways to deal with this potential “perfect storm” is needed. This paper highlights the explores the roles of biophysical and economic uncertainty in these projections of long run land use change, using this to suggest a future research agenda.