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IB DP ESS — Topic 5: Land (HL Extension) | HL | Paper 1 & Paper 2
🎯 Learning Intentions By the end of this note, you will be able to:
- Define a sustainable diet and distinguish it from conventional dietary patterns using IB-aligned ESS terminology.
- Explain how food systems function as socio-ecological systems, identifying inputs, outputs, feedback loops, and system boundaries.
- Describe the environmental impacts of different food production methods, including land use, water consumption, greenhouse gas emissions, and biodiversity loss, at local, regional, and global scales.
- Analyse the relationship between dietary choices and planetary boundaries, applying ESS analysis parameters including scale, sustainability, trade-offs, and multiple perspectives.
- Evaluate the effectiveness of strategies — including dietary shifts, food waste reduction, and agroecological approaches — in moving food systems toward sustainability.
- Discuss contrasting worldviews (ecocentric, technocentric, anthropocentric) in relation to food production and consumption, including considerations of food justice and equity between LEDCs and MEDCs.
- Justify the claim that food system transformation is central to achieving multiple Sustainable Development Goals simultaneously.
Real-World Context & Relevance
In 2019, the EAT-Lancet Commission published a landmark report — "Food in the Anthropocene" — that calculated the planetary boundaries of food production for the first time. Their analysis found that feeding a projected 10 billion people by 2050 within safe ecological limits would require a dramatic global dietary shift: roughly a 50% reduction in red meat and sugar consumption, and a doubling of plant-based foods including fruits, vegetables, legumes, and nuts. The report estimated that current food systems are responsible for approximately 26% of global greenhouse gas emissions, 70% of freshwater withdrawals, and 80% of biodiversity loss on land (Willett et al., "Food in the Anthropocene"). These are not marginal pressures — they represent the single largest driver of environmental change on Earth.
The scale of this challenge is made vivid by a single comparison: producing one kilogram of beef requires approximately 15,000 litres of water and generates around 60 kg of CO₂-equivalent greenhouse gases, while producing one kilogram of lentils requires roughly 900 litres of water and generates less than 1 kg of CO₂-equivalent (Poore and Nemecek, "Reducing Food's Environmental Impacts"). Yet globally, meat consumption is rising — particularly in rapidly industrialising nations such as China and Brazil — even as the scientific consensus on its environmental cost has never been clearer. This tension between rising demand and ecological limits sits at the heart of the sustainable diets debate.
🌍 Why This Matters Food systems are simultaneously the world's largest employer, the primary driver of land-use change, a major source of greenhouse gas emissions, and the foundation of human health. Transforming what we eat and how food is produced is therefore not merely an environmental question — it is a question of justice, economics, culture, and survival. For IB ESS students, food systems offer one of the richest case studies of how human societies are embedded within, and are reshaping, Earth's ecological systems.
Core Concepts & Definitions
Before we can evaluate whether a diet is "sustainable," we need to understand what sustainability means in the context of food. A diet does not exist in isolation — it is the end point of an entire system of production, processing, transport, retail, and waste management. Each stage of this system consumes resources, generates emissions, and interacts with ecological systems. To assess sustainability, we must trace these interactions across the full system boundary.
📖 Key Definition — Sustainable Diet A sustainable diet is one that has low environmental impacts, contributes to food and nutrition security, and supports healthy lives for present