Modelling the drivers of a widespread shift to sustainable diets

Abstract

A reduction in global meat consumption can significantly reduce the adverse environmental effects of the food system, but it would require widespread dietary changes. Such shifts to sustainable diets depend on several behavioural factors, which have not yet been addressed in relation to the food system. This study links a behavioural diet shift model to an integrated assessment model to identify the main drivers of global diet change and its implications for the food system. The results show that the social norm effectfor instance the extent of vegetarianism in the population that accelerates a further switch to a vegetarian dietand selfefficacy are the main drivers of widespread dietary changes. These findings stress the importance of value-driven actions motivated either by intrinsic identity or by group dynamics over health and climate risk perception in steering diet change dynamics. Main Lifestyle change is considered an important demand-side measure to mitigate climate change 1, 2. Lowering energy demand and the greenhouse gas (GHG) emissions of food consumption with climate-friendly lifestyle choices can be key to achieving 1.5°C pathways 3, 4. Besides issues related to land use and GHG emissions, the food system damages natural ecosystems 5 and pushes the Earth towards the planetary boundaries for freshwater use, deforestation, and ocean acidification 6, 7. Several studies have demonstrated that lowering global meat consumption can significantly mitigate the adverse environmental effects of the global food system 8, 9, 10, 11, 12. Diet change scenarios explored in previous studies, which are based on stylized diets or average consumption values, are promising to alleviate environmental degradation. Yet, they are difficult to achieve due to the scale of behavioural change required. For instance, if the world's average diet became flexitarian by 2050, meaning that red meat consumption is limited to one serving per week and white meat to half a portion per day, the GHG emissions of the agriculture sector would be reduced by around 50% 12. Currently, 1.8% of daily calories are obtained from red meat (beef and lamb) in the world's average diet 13. In a flexitarian diet, one serving of red meat per week constitutes only 0.5% of daily caloric intake. The difference is small, but it would require billions of consumers to change their diets for a global change.

Green Light for Climate-friendly Food Transitions? Communicating Legal Innovation Increases Consumer Support for Meat Curtailment Policies

“…It could also prove fruitful to assess if communication signaling successful implementation of MCPs could increase personal support for specific MCPs in practice. These hypotheses are especially relevant in light of recent findings that norms-based approaches may be particularly effective for promoting reduced meat consumption (Eker, Reese, & Obersteiner, 2019;Sparkman & Walton, 2017;Stea & Pickering, 2019). In other words, it is plausible that reconfiguring perceived norms with regard to meat consumption and plant-based eating may be effective not only to help shape eating habits, but also to shape attitudes toward MCPs.…”

Improving Climate Change Mitigation Analysis: A Framework for Examining Feasibility

“…Some efforts are underway to incorporate explicit psychological models of consumer behavior into modeling. 39,40 As the IPCC moves forward to incorporate a richer treatment of initiative-related processes, including those of both governments and non-governmental actors and a broader set of actors that can be change agents and targets of initiatives, it will be helpful to have a framework for explicitly assessing and analyzing social, cultural, behavioral, organizational, and political aspects of policy and decision making.…”

“…And the requirements of modeling in the service of decision making would provide feedback that encourages theory to engage with decisions of great consequence and urgency. 40,130 A special challenge will be to build cumulative knowledge by better integration of insights from public and elite surveys, survey-based experiments, quantitative and qualitative analysis of previous successes and failures in promoting and implementing initiatives, and theoretical analyses. For example, surveys and survey-based experiments can provide substantial insights into public acceptability of various types of initiatives and thus help guide initiative design.…”

Forbidden knowledge in machine learning reflections on the limits of research and publication

“…However, it fails for several reasons. First, many studies show that moral behavior is "contagious", meaning that the morally desirable as well as the unacceptable behavior swiftly finds imitators and spreads (Bollinger and Gillingham 2012;Eker et al 2019;Kraft-Todd et al 2018). Applied to the field of ethics of science, this means that abstaining from pursuing certain research questions can be seen as an example and is imitated, while an "if we do not do research on X or develop X, others will do it" attitude leads to a general lack of accountability and disregard for ethical concerns.…”