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Dietary changes could compensate for potential yield reductions upon global river flow protection
- Johanna Braun, Fabian Stenzel, Benjamin Leon Bodirsky, Mika Jalava, Dieter Gerten
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- Journal:
- Global Sustainability / Volume 5 / 2022
- Published online by Cambridge University Press:
- 11 July 2022, e14
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Non-technical summary
Globally, freshwater systems are degrading due to excessive water withdrawals. We estimate that if rivers’ environmental flow requirements were protected, the associated decrease in irrigation water availability would reduce global yields by ~5%. As one option to increase food supply within limited water resources, we show that dietary changes toward less livestock products could compensate for this effect. If all currently grown edible feed was directly consumed by humans, we estimate that global food supply would even increase by 19%. We thus provide evidence that dietary changes are an important strategy to harmonize river flow protection with sustained food supply.
Technical summaryTo protect global freshwater ecosystems and restore their integrity, freshwater withdrawals could be restricted to maintain rivers' environmental flow requirements (EFRs). However, without further measures, reduced irrigation water availability would decrease crop yields and put additional pressure on global food provision. By comparing the quantitative effects of both global EFR protection and dietary changes on regional and global food supply in a spatially explicit modeling framework, we show that dietary changes toward less livestock products could effectively contribute to solving this trade-off. Results indicate that protection of EFRs would almost halve current global irrigation water withdrawals and reduce global crop yields by 5%. Limiting animal protein share to 25, 12.5 and 0% of total protein supply and shifting released crop feed to direct human consumption could however increase global food supply by 4, 11 and 19%, respectively. The effects are geographically decoupled: water-scarce regions such as the Middle East, or South and Central Asia would be most affected by EFR protection, whereas dietary changes are most effective in North America and Europe. This underpins the disproportionally high responsibilities of countries with resource-intensive diets and the need for regionally adapted and diverse strategies to transform the global food system toward sustainability.
Social media summaryCombining dietary changes and global river flow protection could contribute to a more sustainable food system.
Food futures: Storylines of dietary megatrends along the Shared Socioeconomic Pathways (SSPs)
- Roberta Alessandrini, Benjamin Leon Bodirsky
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- Journal:
- Proceedings of the Nutrition Society / Volume 79 / Issue OCE2 / 2020
- Published online by Cambridge University Press:
- 10 June 2020, E327
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Under- and over-nutrition are among the most important global health determinants, and the agro-food system is the main interface between human society and the natural world and thereby responsible for land cover change, water withdrawals, greenhouse gases, biodiversity loss and nutrient pollution.
We formulated five qualitative storylines of future dietary developments using the Shared Socioeconomic Pathways (SSPs), a tool widely used in the climate change research community. Our storylines diverge in respect to the main actors in the food system, the policy framework, the food supply chain organisation, consumer context, dietary composition, health systems and health outcomes in respect to under- and over-nutrition. We titled each storyline with combinations of iconic foods that would be representative of each future.
SSP1 = Minestrone and Enjera (sustainable diets). The civil society is the main actor in shaping the food system and diets are mainly unprocessed and plant-based. The health burden from under- and overnutrition is drastically reduced in societies all over the world.
SSP2 = Pizza Hawaii with a side salad and banana (middle of the plate). This is a continuation of the current trends. The food industry is the main actor of the food system providing highly marketed processed food. Undernutrition slowly declines in the least developed countries, but obesity and NCDs increase drastically in both LMIC and HIC.
SSP3 = Kohlroulade and instant noodles (rocky road). Populistic and monopolistic governments are the main actors in shaping the food system. Diets are made of traditional and unhealthy dishes. Obesity and micronutrient deficiencies coexist and the nutrition-related burden of disease is high.
SSP4 = Kaviar and beans (inequality). A small and wealthy elite is the key actor shaping the political and the global food system. Diets are luxurious, highly customised and marketed for wealthy, and consisting of cheap and simple ingredients for the vast majority. While the elite enjoys healthy and long lives, malnutrition and stunting remain widespread in LMICs; obesity and diet-related NCDs decline everywhere.
SSP5 = Artificial meat burger with a skinny milkshake (fossil fuel). A few large tech companies are the main actors shaping the food system. Algorithms based on big-data provide customised diets consisting of superfoods and new foods. Under-nutrition disappears, BMI converges to normal levels, while diet-related NCDs remain prevalent.
The existing storylines in the literature do not focus on the agro-food system and on health and nutrition outcomes. Our work contributes to the ongoing conversation on food futures.