Attaining the twin goals of food and environmental security in the coming decades poses a significant sustainability challenge. This paper examines the food and environmental security implications of a range of policies affecting the global food economy and terrestrial ecosystems, first in the context of historically segmented markets, and secondly in a hypothetical future world of fully integrated crop commodity markets. We begin by revisiting history, considering how food production and global land use would have evolved over the period: 1961–2006 in the presence of greater market integration. We find that there would have been greater disparities in regional crop output growth, with regions experiencing higher productivity growth tending to expand more rapidly under this counterfactual experiment. Going forward, greater market integration can be expected to reshape the way we think about future food and environmental security. In the presence of continued market segmentation, strong population growth, accompanied by robust overall income projections, results in exceptionally high demand growth, rising prices and increased non-farm undernutrition in Sub-Saharan Africa (SSA) by 2050. On the other hand, if markets are fully integrated, relative rates of productivity growth become key to the regional composition of world crop output and agricultural production and cropland grow much more slowly in SSA. We explore the implications of four policy initiatives aimed at improving food security and environmental outcomes, including enhanced on-farm productivity and reductions in post-harvest losses in SSA, reductions in food waste in the wealthy economies, and a global terrestrial carbon policy. We also evaluate the potential impacts of climate change under these two trade regimes. Our results suggest that, in some cases, the food and terrestrial implications will be radically different in a more integrated global economy.