Options For Keeping The Food System Within Environmental Limits
Over the next few decades, the world will continue to see increases in both population and income levels. This growth will inevitably be accompanied by changes in the global food system, which will, in turn, impact the global environment. Unfortunately, according to current projections, environmental impacts from the food system are expected to increase 50-90% between 2010 and 2050. This is problematic, because if those impacts exceed “safe operating boundaries”, ecosystems may become destabilized and may lose the ability to self-regulate and remain sustainable in the long term.
This study looked at five environmental systems that are impacted by the global food system—climate change, land use, freshwater resource depletion, nitrogen pollution, and phosphorus pollution—and examined how effectively three types of intervention can mitigate those negative environmental effects. The three interventions studied were dietary change, reductions in food loss and waste, and technological improvements.
As a starting point, the study estimates that, in 2010, the food system emitted approximately 5.2 billion tons of carbon dioxide, occupied 12.6 million square kilometers of cropland, used 1810 cubic kilometers of freshwater, and applied 104 teragrams of nitrogen and 18 teragrams of phosphorus in the form of fertilizers. By 2050, the authors anticipate that the global population will grow by one-third, and that global incomes will triple. This will increase demand on each of the earth systems studied by 50-92%, with the greatest pressures on greenhouse gas emissions followed by use of croplands, freshwater, phosphorous, and nitrogen, respectively.
Though these expected environmental demands are significant, the authors are optimistic about the potential for aggressive mitigation efforts to keep the food system within safe operating boundaries. Current estimates suggest that one-third of food produced annually is wasted, but that 50-75% of this wastage could be eliminated. Additionally, technological change and stronger management of food production and transport processes could greatly increase the efficiency of the global food system. This might include interventions such as: rebalancing nitrogen and phosphorus application between high-use and low-use regions, recycling phosphorus, increasing crop yields, developing and building better infrastructure for food storage and transport, etc. Finally, moving toward healthier, more plant-based diets across the globe could have significant sustainability impacts, particularly regarding greenhouse gas emissions. Indeed, moving globally to a flexitarian diet that is largely plant-based could reduce greenhouse gas emissions by 56%, and reduce impacts on the other four studied systems by 6-22%.
The authors looked at each of these three mitigation methods through both “medium ambition” and “high ambition” degrees of change. They found that if humans pursued “high ambition” interventions in all three areas, we could actually end up with environmental impacts that are 20-55% lower than current impacts. These “high ambition” steps would require us to reduce food waste by 75%, move to plant-based flexitarian diets globally, and make significant technological improvements, including closing the gap between actual and potential crop yields, rebalancing nitrogen and phosphorus application, improving water management, greatly decreasing food-related greenhouse gas emissions, and recycling phosphorus, among others. If all strategies are pursued at “medium ambition”, we could see environmental impacts that are within 15% above or below current levels.
Although there is uncertainty about the projected safe operating boundaries for these different Earth systems, the authors expect that we are currently on a path to exceeding those boundaries in all five systems. Using today’s baseline rates of consumption and the expected population and income changes, we would likely surpass the boundary for greenhouse gas emissions by 110%, the boundary for cropland use by 70%, the boundary for freshwater consumption by 50%, the boundary for nitrogen use by 125%, and the boundary for phosphorus utilization by 75%, by 2050. The studied interventions offer practical options for avoiding these impacts, though successful implementation will require significant dietary change, investing in public infrastructure, creating better regulations and incentive schemes for farming, and engaging in massive public education campaigns.
If successfully deployed, the suggested technology improvements would be responsible for the bulk of reductions in cropland use, freshwater use, nitrogen application, and phosphorous application. Dietary change would be responsible for the bulk of reductions in greenhouse gas emissions, since environmentally-intensive animal product consumption would greatly decrease and be replaced by more environmentally sustainable plant foods. When combined, these interventions could help us avoid the negative environmental impacts that are currently projected to occur by 2050.