A plant-based food system and the Plant-Based Cambridge Campaign

By Tommy Walker Mackay
Posted on 11th May 2023
The Cambridge University Plant-Based Campaign. Image by Rosie Lester.

Of the numerous ways in which human activity impacts the global climate, one that is often overlooked, particularly in discussions relating to how we can reduce our impact on the climate, is the contribution of agriculture and particularly animal agriculture. While it is reasonably well-known that greenhouse gas emissions, particularly methane, from cattle contribute to our impact on the climate, what is less well-known is that this is only one aspect of the impact of agriculture on the climate. Indeed, around 20% of global greenhouse gas emissions originate from agriculture – more than all transport combined (1), before even considering the ecological impacts that are not related to greenhouse gas emissions.

Of course, agriculture is entirely necessary for the functioning of human civilisation. But there is one specific type of agriculture that is almost invariably worse for the climate: animal agriculture. Despite attempts to greenwash certain forms of animal agriculture as “regenerative”, and despite a common misconception that only ruminant meat has an environmental impact significant enough to be taken seriously, one simple fact demonstrates that farming animals will inevitably be inefficient compared to other options. This is the concept of trophic levels, found in ecology, applied to our food system: simply put, every time one organism eats another a certain amount of energy is lost. Thus, for example, if a plant contains 1000 calories and is eaten by a herbivore, then the herbivore may use 900 calories and leave only 100 in its body to be consumed by a carnivore. If the carnivore is then eaten by another carnivore (referred to as a tertiary consumer), the tertiary consumer may only get 10 calories.

Applying this to our food system, in order to consume 100g of protein from chicken meat, it is necessary to feed the chicken food containing around 500g of protein – a 20% efficiency rating (2). Because chickens are genetically altered through selective breeding to maximise this efficiency, a process that primarily consists of making them grow more quickly so that they can be slaughtered at around six weeks of age (3), the efficiency is even worse for other farm animals, and is also worse if measured by calories rather than by protein. Humans are almost invariably responsible for growing the crops fed to the animals we eat, with the only major exception being wild-caught fish. This has its own set of environmental problems – while commonly referred to as “overfishing”, the practice of relying on wild animals for a food source is inherently unsustainable for a human population of its current size and has resulted in recommendations by the fishing industry to move towards aquaculture, in which humans are responsible for the feed of the fish and the same problems with inefficiency arise (4).

Addressing this problem meaningfully would consist of a radical reduction in the percentage of our diets that consist of animal products, and a transition towards a plant-based food system. Unlike many other proposals to reduce greenhouse gas emissions, which often rely on technology that does not yet exist or infrastructure that is not yet in place, the primary barrier to the implementation of this change is cultural. Plant-based food already comprises 82% of calories consumed globally, and 63% of protein (5), and there would be no need for increased crop production because the crops currently grown for animal feed could be repurposed. Indeed, the total area of land used to grow crops would be dramatically reduced, freeing up land for rewilding and eliminating the deforestation problem.

"There would be no need for increased crop production because the crops currently grown for animal feed could be repurposed. Indeed, the total area of land used to grow crops would be dramatically reduced, freeing up land for rewilding and eliminating the deforestation problem."

In February this year, the Cambridge Students’ Union passed a motion to support a transition to 100% plant-based catering by the University Catering Service. The motion was supported by Plant-Based Cambridge, the Cambridge branch of the national campaign Plant-Based Universities. The purpose of this campaign is to get as many universities as possible in the UK to commit to serving 100% plant-based food, in alignment with the goal of transitioning to a plant-based food system. A parallel campaign, Plant-Based Councils, has also seen local councils commit to such a goal.

When I first heard about the campaign, although I have been a strong supporter of it throughout, I assumed that it had no chance of succeeding because it was so far from the way things typically seem to work. In the West, meat and other animal products constitute around 33% of the average diet by calories, which is approximately double the global average (6), and eating meat is just about as much a cultural norm as anything can be. But in the same way that there have been a series of decisions, made by governments and others, to discourage smoking over the last few decades, we can change our attitude to animal products as well.

A question often asked in environmental activism is how radical you should be. But in the context of this campaign, I think a more important question is in what ways we should be radical. I remember a campaign that happened last year in my college to encourage students to choose a vegetarian option in hall on Tuesdays. If we chose to do so, we were supposed to inform catering staff in advance to avoid food wastage, and we were told not to worry if we didn’t manage to do so every Tuesday. This is an example of a campaign that is clearly not radical enough in its aim. The way it was framed was as if a baseline would be to eat meat seven days per week, and that only doing so six days per week would be something for which special accommodation would have to be made.

In this sense the framing of the issue by the Plant-Based Universities campaign is much better: the campaign seeks to normalise plant-based food and make other food the choice for which special arrangements must be made, which makes the environmentally friendly option the easier one. But in another sense, the campaign is not particularly radical because of how it is targeted: it is starting on a small scale with the Catering Services of a small number of universities and seeks to implement a change there before attempting to make a broader change. Engagement with these specific institutions that are likely to be receptive to demands is an important aspect of effective climate activism.

1. Emissions by sector - Our World in Data
2. Feed-to-Meat- Conversion Inefficiency Ratios - A Well-Fed World (awellfedworld.org)
3. What Are Broiler Chickens and How Long Do They Live? (thehumaneleague.org)
4. The State of World Fisheries and Aquaculture 2020 (fao.org)
5. Land Use - Our World in Data
6. Dimensions of need - Staplefoods: What do people eat? (fao.org)