The Complete Menu: Creating a Sustainable Food Future (Synthesis)
The Complete Menu: Creating a Sustainable Food Future (Synthesis)
The individual menu items presented in Courses 1–5 can each contribute to meeting global targets for increasing food production, minimizing expansion of agricultural land area, and reducing GHG emissions. In this section, we use the GlobAgri-WRR model to examine some plausible (or at least possible) combinations of menu items and analyze how they could close the three gaps and achieve a sustainable food future.
To assess the potential of the full menu to close the food, land, and GHG mitigation gaps, we constructed three combination scenarios that reflect ascending levels of ambition (Table 3). They are guided by the following criteria:
- Coordinated Effort Scenario. Menu items involve measures we are confident the world could achieve with a strong, coordinated, global commitment to action. The economic costs would be limited or even positive. No fundamental breakthroughs in technology would be required.
- Highly Ambitious Scenario. Menu items involve measures at the outer range of what might be technically achieved either with existing technology or with realistic improvements to existing technology. Costs would likely be higher.
- Breakthrough Technologies Scenario. Measures from the Highly Ambitious scenario plus those that could be achieved with technological breakthroughs in fields where science has shown significant progress.
The size of the gap closure contributed by each menu item does not necessarily reflect the return per unit of effort. It is more a measure of the definitional scope of each menu item. For example, large reductions in food loss and waste (affecting 24 percent of global calorie production) will, by definition, contribute more than improving productivity of aquaculture, which only affects 1 percent of global calorie consumption.
The GlobAgri-WRR 2050 baseline projection and three combination scenarios
Quantitative results of the three combination scenarios are presented in Table 4. The contributions of specific menu items are shown in Figures 21–23 for the Breakthrough Technologies scenario only. For each menu item, its contribution in the combined scenarios is smaller than its “standalone” contribution due to interaction between menu items (e.g., land “savings” attributed to food waste reductions are smaller if those reductions happen simultaneously with additional crop yield growth).
All three scenarios substantially reduce the food gap by reducing the rate of growth in demand for food. The challenge of increasing crop production by 56 percent between 2010 and 2050 (baseline) is reduced to 43 percent, 35 percent, and 29 percent in the three scenarios, respectively.
The Coordinated Effort scenario reduces agricultural land expansion between 2010 and 2050 by 78 percent. The Highly Ambitious and Breakthrough Technologies scenarios completely close the land gap and create the opportunity for significant reforestation on liberated agricultural land.
The hardest gap to close is the GHG mitigation gap because it is difficult to reduce annual agricultural production emissions to the 4 Gt CO2e target while feeding everyone in 2050. Annual production emissions remain at 4.4 Gt even in our Breakthrough Technologies scenario (Figure 23). Reaching the 4 Gt goal would require major technological advances as well as full reforestation on at least 80 Mha of liberated agricultural land.
Furthermore, other analyses have suggested that to meet the more ambitious 1.5°C warming target in the Paris Agreement,98 CO2e the world will need to use large quantities of land to offset other sources of emissions. In our Breakthrough Technologies scenario, it might be possible to liberate 585 Mha of agricultural land—after accounting for some expansion of timber plantations and human settlements—which, if fully reforested, could offset around 4 Gt of emissions per year for many years.
Plausible pathways toward a sustainable food future exist, but they will require strong and almost universal political and social effort. Achieving even our Coordinated Effort scenario requires reversing a wide range of current trends. Truly realizing the environmental benefits from food demand reductions and crop and livestock yield gains also depends on policies that greatly reduce agricultural land-shifting and protect forests and other natural areas.
Global effects of 2050 combination scenarios on the three gaps, agricultural land use, and greenhouse gas emissions
Numbers may not sum correctly due to rounding. Under the Highly Ambitious and Breakthrough Technologies scenarios, 0.3 Gt CO2e of ongoing peatland emissions remain, but total agricultural area declines between 2010 and 2050. We discuss the need to reforest “liberated” agricultural lands to offset agricultural production emissions on page 59.
We conclude that three categories of menu items are particularly important at the global level:
- Boosting productivity. The Coordinated Effort scenario requires faster rates of crop yield growth than historical rates since the 1960s. Recent yield trend lines (since the 1980s) are actually slower than those in our baseline, and far from the additional yield gains required. Ruminant meat and milk yield gains in the Coordinated Effort scenario require massive increases in output per hectare of pastureland—far greater than the output gains projected by extending a linear trend from the 1960s.
- Shifting diets to reduce demand for ruminant meat. A reduction in ruminant meat consumption by 30 percent relative to our 2050 baseline—which still results in a 32 percent increase above 2010 levels—plays a major role in closing the land and GHG mitigation gaps. We consider it eminently practicable, but the cultural and behavioral changes required will be challenging.
- Reducing food loss and waste. Globally reducing the rate of food loss and waste by 10, 25, or 50 percent would significantly close all three gaps. However, there is little precedent for achieving such large-scale reductions—particularly because as countries’ economies develop, food waste near the consumption side of the food supply chain tends to grow even as food loss near the production side decreases.
Under the Breakthrough Technologies scenario, the amount of additional food needed to feed the world in 2050 could be cut by half
Includes all crops intended for direct human consumption, animal feed, industrial uses, seeds, and biofuels.
Under the Breakthrough Technologies scenario, the area of land needed for agriculture could shrink by 800 million hectares, which would be liberated for reforestation
Under the Breakthrough Technologies scenario, agricultural greenhouse gas emissions would fall dramatically but reforestation and peatland restoration would be necessary to meet the target of 4 gigatons per year
Solid areas represent agricultural production emissions. Hatched areas represent emissions from land-use change.
- 98Lowder et al. (2016).