The Long Game: Reducing Meat Consumption By 2100

There is strong evidence that cutting global meat consumption is essential to preventing climate-related destruction, but it’s no simple feat to inspire billions of meat-eaters to change their eating patterns. Factors like culture, social pressures, and personality can all play a role in whether a person decides to give up meat. How do all these variables interact on a larger scale, and which should animal advocates prioritize?

This study used a predictive model to forecast global trends in vegetarianism and agricultural emissions, up until 2100. Researchers also analyzed which factors have the most potential to influence the percentage of vegetarians over time. The model drew from theories of human psychology and research on human behavior related to climate change. 

Researchers considered multiple scenarios, based on four possible shifts in the population’s diet by 2050:

Scenario 0 — Reference: There are no changes to either the meat-eaters’ diets or vegetarians’ diets. 

Scenario 1 — Healthy + Reference Scenario: All meat-eaters reduce their meat consumption by following healthy eating guidelines, and all vegetarians’ diets remain unchanged. 

Scenario 2 — Healthy + Vegan: All meat-eaters adopt healthy eating guidelines, and all vegetarians adopt vegan diets.

Scenario 3 — Flexitarian + Vegan: All meat-eaters adopt flexitarian diets, and all vegetarians adopt vegan diets. 

The researchers acknowledge that there is limited research relating to vegetarian diet-related behavior. As a result, it is difficult to predict exact future outcomes. To account for some of this uncertainty, researchers ran a total 10,000 simulations, each using a different set of values relating to human behavior. The result was a range of possible outcomes for each of the four scenarios. 

Looking at all scenarios, the estimated number of vegetarians by 2100 ranged from less than 5% to over 60% of the total population. Most often, the number of vegetarians hovered near 20%. By this estimate, it is unlikely that there will be a large shift towards vegetarianism by the end of the century. For comparison, this paper estimates that 21.5% of the population was vegetarian in 2010. 

Interestingly, the largest increase in vegetarianism by 2100 occurred in the reference (no change) scenario. This is because of a negative feedback loop of environmental and health risks. If societies continue to eat meat at current rates until 2050, health and environmental threats will become more visible. In theory, this will motivate consumers to actively avoid risks by reducing meat consumption.   

At the same time, the reference and healthy + reference scenarios resulted in comparatively higher agricultural emissions. The largest decrease in emissions came from the low meat scenario. This model suggests that positive environmental changes can only occur when meat-eaters reduce their consumption, even in cases when 40% of the population is vegetarian  Encouragingly, the model also shows that farm emissions can return to 2020 levels in any scenario, despite an increasing population. 

Researchers also looked at which psychological and social factors had the most impact on rates of vegetarianism. Three factors stood out as especially important:

1. The young (aged 15-44) population’s reaction to early shifts towards vegetarianism. Researchers found that after a certain portion of the population went vegetarian, the diet became normalized. Then, future shifts towards vegetarianism occurred even faster. Whether that turning point occurs sooner or later is important to driving sustained change. The younger population is a key demographic because they are more sensitive to social norms. 
2. Self-efficacy (an individual’s belief that they can carry out a behavior) in the young population. Young female self-efficacy was especially important. This study assumed that women had higher self-efficacy in relation to meat consumption. Females see environmentalism as a more defining part of their identity and are more egalitarian than men. High school graduates are another important group, because they make up the largest percentage of the young population by education level. This being said, the authors point to recent studies suggesting that self-identity is not always linked to expected behaviors. Animal advocates should be cautious about focusing on self-efficacy as an intervention strategy. It is also possible that collective efficiency (the belief that one’s group is able to carry out change)  is even more important than self-efficacy. 
3. The base percentage of meat-eaters who intend to switch to a vegetarian diet. 

The study provides two major takeaways that may be helpful for animal advocates. First, it is important to advocate with an awareness of group dynamics and psychology — not just the hard facts of health and climate risk. Second, it is vital to include meat-eaters in efforts to help the environment through diet change. As this study shows, we can change the crash course that animal agriculture has set us on, but the scenarios outlined above all require us to continue to work to make that happen.