Land Versus Sea: Do the Oceans Offer the Most Sustainable Way To Feed the World?

The global demand for protein is projected to increase dramatically in the coming decades due to increases in the number of people and increases in their average wealth. This growth in demand occurs disproportionately in the developing world. Meeting this surge in demand is challenging, and recent syntheses suggest that the available options pose significant threats to other issues (e.g., biodiversity loss, climate change, nutrient loading of watersheds). Analyses of these options, however, largely focus on food production from the land and ignore the potential contributions from the sea – both through capture fisheries and aquaculture. Here we compare the costs (economic, biodiversity loss, green house gas emissions, and nutrient enrichment) of different pathways for meeting the global demand. The results suggest that the sea can provide solutions at potentially far lower costs for each of these measures of cost. The least expensive options for meeting the initial part of the increased demand comes from fixing the management of capture fisheries. Fortunately, some of the largest potential gains are projected for the areas of the planet where the growth in demand is likely to be greatest. But this clear option can only meet a fraction of the projected increase in global demand. Aquaculture, using best practices, is the least costly option economically and environmentally to meet the remaining shortfall.