The Impact of Dietary Choices on Our Planet
Did you know that the global meat industry is responsible for nearly 15% of all human-induced greenhouse gas emissions? This is more than the emissions from all the cars, planes, and trains in the world combined.
Our dietary choices influence the stability and resilience of the Earth's ecosystem, and consequently, human well-being.
Recognizing this, dietary habits have been included in the Sustainable Development Goals (SDGs) Index as part of the Zero Hunger Goal, which not only measures undernourishment but also addresses obesity and meat consumption, with the Human Trophic Level serving as an innovative metric to assess consumption patterns.
Understanding Trophic Level
The trophic level measures the energy intensity of diet composition, reflecting the relative amount of plants versus animals consumed in each country. A higher trophic level indicates a greater consumption of energy-intensive animals. For instance, herbivores like cows feed on plants (trophic level 1), so their trophic level is 2. Now, imagine splitting your plate equally between veggies and a steak — your trophic level would land at 2.5. Thus, a 0.5 difference in trophic level can signify a completely different diet, ranging from herbivory to omnivory. It’s as if the cow becomes a rather reluctant guest at your vegetarian barbecue.
For carnivorous apex predators on top of the food chain, such as polar bears or killer whales, trophic levels range upto 5.5.
Global Vegetarian Trends
A study from 2010 estimated that there were 1.5 billion vegetarians worldwide (People eating fish were included in this group, which suggests that the authors classified fish as vegetables. As absurd as it sounds it is actually a typical notion in the european restaurants: after introducing myself as vegetarian, I hear quite often the question: "Do you eat fish?".
Trophic Level is immune to this definition challenge, it places a number, which reflects a position in the food chain, does not matter what names we give to different species. And a position in the food chain indicates your environmental footprint, higher the number more energy is required to feed you.
Imagine our dietary choices as investments in the our future on the planet Earth. Opting for a plant-based diet is like putting money in a green energy fund, providing returns in the form of a healthier, more resilient Earth. Conversely, a meat-heavy diet is like investing in coal — profitable in the short term but disastrous for long-term sustainability.
National Dietary Patterns
National Human Trophic Levels ranging between 2.02 and 2.58 reflect a broad diversity of diet. And there is a very clear trend: as soon as people can afford it, they tend to switch to a more meat-based diet. In the 2010 study, only 75 million people were voluntary vegetarians, while 1.45 billion were vegetarians out of necessity and likely to consume more meat as their economic situation improves. This suggests marginal support for plant based diet in the entire world, and a potential decline in the number of vegetarians in the medium term.
Ambitious Targets and Statistical Trends
Can we realistically expect affluent nations to adopt a predominantly plant-based diet?
The target set by the SDG Index team is 2,04, which is around the current level of Burundi and Congo, and it represents almost completely (96.7%) plant based diet.
That sounds very ambitions, and unfortunately completely unrealistic given current trends. Average global Human Trophic Level is 2,2, however it is 2,4 for high income countries, and only 2,1 for low income. Given the convergence of most quality of life indicators towards high income countries, achievement of this goal requires a massive change in the attitudes of individuals towards consumption, particularly in affluent nations with the most significant environmental impact. (For more on the topic of affluent nations, see my previous post ( #13 Population growth or affluence?).
Another Zero Hunger indicator, the prevalence of obesity (BMI ≥ 30% of the adult population), shows that 25% of adults in high-income countries are obese, compared to 7.4% in low-income countries. The target is set as 2.2% (currently the level achieved by just one country in the world - Vietnam) and a trend is again going in the other direction. The gap is closing but upwards.
The Challenge of Sustainability Initiatives
This review of two SDG Index measures highlights a critical challenge for major sustainability initiatives. While they offer high-quality thinking and robust targets, they often misalign with individual expectations of the quality of life, making them difficult to achieve in the long term.
Redefining Lifestyle Choices
Statistically we are going nowhere near achieving those goals unless we redefine and challenge big part of our lifestyle choices. These choices have broad implications beyond convenience and taste, prompting us to ask uncomfortable questions. The Stockholm Resilience Center has proposed adding the concept of interspecies justice to the Planetary Boundaries Framework. Interspecies justice aims to protect humans, other species, and ecosystems, rejecting human exceptionalism. The concept of interspecies justice goes beyond simply reducing meat consumption. It challenges us to rethink our place in the natural world, urging us to see the intrinsic value in all living beings.
That leads to very difficult questions on vegetarianism. if you can survive without taking other species lives, should you continue to take them? is this justice?
Conclusion
As someone who has transitioned to a vegetarian lifestyle, I've encountered resistance to these questions. However, I understand these reactions. Most people have grown up consuming meat and see questioning their dietary choices as an attack on their personal freedom. However, these choices have far-reaching consequences beyond individual preferences, fundamentally impacting our species' resilience. By embracing a plant-based diet, we can contribute to a healthier, more sustainable world.
Follow-up:
Review Take Action Guide from United Nations - Note that eating less meat is one of the measures to become Level 2 - Household Hero.
If you had to make one major change to your diet for sustainability, what would it be?
What are your thoughts on the concept of interspecies justice? Do you believe we have a responsibility to minimize our impact on other species?
Sources:
Gerber, P.J., Steinfeld, H., Henderson, B., Mottet, A., Opio, C., Dijkman, J., Falcucci, A. & Tempio, G. (2013). Tackling climate change through livestock – A global assessment of emissions and mitigation opportunities. Food and Agriculture Organization of the United Nations (FAO), Rome.
Leahy, E., Lyons, S., & Tol, R. S. (2010). An estimate of the number of vegetarians in the world (No. 340). ESRI working paper.
Rockström, J., Gupta, J., Qin, D., Lade, S. J., Abrams, J. F., Andersen, L. S., ... & Zhang, X. (2023). Safe and just Earth system boundaries. Nature, 619(7968), 102-111.
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