Researchers at the Potsdam Institute for Climate Impact Research have found that a global shift to a healthier, more sustainable diet could play a significant role in limiting global warming to 1.5°C. By reducing greenhouse gas emissions related to dietary shifts, particularly methane from ruminant animals raised for meat and milk, the carbon budget compatible with limiting global warming to 1.5°C could be increased, making it easier to achieve the same climate outcome with less carbon dioxide removal and less stringent CO2 emissions reductions in the energy system. This would also lead to reductions in emission prices, energy prices, and food expenditures.
The study, soon to be published in Science Advances, highlights the potential benefits of a more sustainable, flexitarian diet in supporting the goals of the Paris Agreement. By shifting towards a diet that is more plant-based and reduces livestock products, especially in high- and middle-income regions, emissions from the land system could be reduced significantly. This reduction in greenhouse gas emissions from dietary shifts could increase the global CO2 budget by 125 gigatons, allowing for a greater chance of staying within the 1.5°C limit.
The implementation of a price on greenhouse gas emissions in the energy and land system is crucial for staying within the limits of 1.5°C warming. The study shows that a more sustainable diet not only reduces impacts from food production within the land system, such as deforestation and nitrogen losses, but also cuts economy-wide 1.5°C-compatible greenhouse gas prices in 2050 by 43 percent. Additionally, healthy diets could reduce dependency on carbon dioxide removal by 39 percent in 2050, further contributing to the feasibility of the 1.5°C target.
While existing literature had not previously isolated the contribution of dietary shifts alone to the feasibility of the 1.5°C limit, the new study from PIK scientists fills this gap. By using the Integrated Assessment Modelling framework REMIND-MAgPIE, the researchers were able to simulate 1.5°C pathways, with one scenario including dietary shifts towards the EAT-Lancet Planetary Health Diet by 2050 in all world regions. This diet features a variety of plant-based foods, reduced intake of livestock products, and limited added sugars, among other guidelines.
Despite the potential benefits of a flexitarian diet in supporting the 1.5°C target, there are still challenges to be addressed. Decision-making in food policy is often fragmented across different institutions and ministries, hindering the implementation of coherent policies to support healthy diets. Additionally, the authors stress the importance of social inclusion and compensation schemes for a just transition to healthy diets. The results of the study suggest that a shift in global diets could have a significant impact on avoiding exceeding the 1.5°C limit in the next decade, emphasizing the need for coordinated efforts to support the transition towards sustainable healthy diets.
