Since the 1950s, increased agricultural productivity has allowed food supply growth to outpace demand on a global scale, resulting in a downward trend in world prices. Investments into agricultural research and development (R&D) have been the foundation for this achievement, but there is a long lag in agricultural productivity response to the investments. The optimal path of R&D spending depends on future population, income and climate change, all of which are highly uncertain. This study offers a dynamic framework for analyzing optimal agricultural R&D spending in the 21st century factoring in uncertainties in these drivers, as well as lagged pay offs on investments into improvements of agricultural productivity.