The levers for a sustainable food system

(Press-News.org) A large-scale model study now shows how the global food system can contribute to the fight against global heating. It identifies 23 levers, calculates their effectiveness and concludes: a decisive transformation of this sector alone, without the indispensable energy transition, can limit the global temperature increase to 1.85°C above pre-industrial levels by 2050. In addition, food will become healthier and cheaper, and agriculture will be more compatible with biodiversity conservation. The study was led by the Potsdam Institute for Climate Impact Research (PIK) and published in Nature Food.

The study is based on three possible pathways for the future: the standard “SSP2” scenario commonly used to model the continuation of current trends; a scenario of rapid transformation in the food system; and an expanded scenario with greater sustainability in other economic sectors as well. A powerful analytical framework developed at PIK, with PIK’s agri-food system model MAgPIE at its core, and comprising several models from other institutes as well, determines not only the effects on climate, but also on human health, the environment, social justice and economic output.

“Our study shows the great importance of the food system,” explains Benjamin Bodirsky, PIK researcher and lead author of the study. “If we resolutely transform this sector towards sustainability, we will not only significantly slow down global heating, but also move towards many other desirable goals. Life expectancy will increase, nitrogen pollution will decrease, and global poverty will also decline slightly. What’s more, if we also make changes in other sectors, we can even limit climate change to well below 2°C.” (A short video with lead author Benjamin Bodirsky can be found here).

From diets to agriculture and international trade

The research team modelled the transformation of the food system in very concrete terms and analysed the impact of 23 levers. Some relate to the Planetary Health Diet co-developed by PIK in 2019, which improves both human and planetary health: less sugar, meat and dairy products, more legumes, vegetables, fruits, nuts and whole grains. The study also examines how levers related to reducing hunger, overeating and food waste affect global production systems and the environment. Other levers deal with changes towards environmental conservation and sustainable agriculture. Finally, the study investigates the effects of lower trade barriers, living wages in agriculture in low-income countries, and less capital-intensive production in high-income economies.

On the one hand, the study specifies how the transformation of the food system alone helps to attain the various goals from climate mitigation to healthy and affordable food. Activating each individual lever has advantages and disadvantages, but in combination they lead to a clearly positive result. On the other hand, the study shows what happens if the transformation is embedded in an even broader change. To this end, the team is considering five additional levers outside the food system: lower population growth, more sustainable socio-economic development, a faster shift away from fossil fuels, more bioplastics instead of fossil-based materials, and more timber for construction instead of steel and concrete.

Study helps to assess the level of policy ambition

In this expanded sustainability scenario, the model study finds that there is a 38 percent probability that the 1.5°C limit will be met in 2050, and a 91 percent probability that the 2.0°C mark will be met. Diet-related health risks such as diabetes and cardiovascular diseases decline, and economic output is significantly higher than in the baseline scenario. The number of people living in extreme poverty is not just slightly reduced, but three-quarters lower than in the baseline scenario. At the same time, damage to the biosphere comes to a halt – a decisive success for nature conservation.

“The food system transformation is crucial for the conservation of biodiversity,” explains Alexander Popp, head of the PIK Land Use Transition Lab and co-author of the study: “By combining measures – from protecting biodiversity hotspots, to plant-based diets, to more variation in crop rotations and better structured landscapes – the pressure on biodiversity can be significantly reduced.”

Hermann Lotze-Campen, head of the PIK Climate Resilience research department and co-author of the study, clarifies: “This study deliberately eschews the policy instruments that can modify all these levers, and how these can be communicated and implemented. Rather, this work creates a positive vision for the future, quantifies the interdependencies and thus helps to assess the level of policy ambition. With this holistic view, which considers climate and human health outcomes and the environment as well as social justice, we are contributing to the increasingly intense social and political discourse on the future of our food.”

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