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IB DP ESS — Topic 1: Foundations | SL & HL | Paper 1 & Paper 2
🎯 Learning Intentions By the end of this note, you will be able to:
- Define sustainability and sustainable development using IB-aligned ESS terminology, distinguishing between weak and strong sustainability.
- Explain the three-pillar model of sustainability (environmental, economic, social) and how interactions between pillars create trade-offs in real-world contexts.
- Describe the Brundtland definition of sustainable development and its significance as a foundational international framework.
- Outline the Planetary Boundaries framework and identify which boundaries have already been transgressed at the global scale.
- Analyse the Doughnut Economics model as an integrated sustainability framework using the ESS analysis parameters of scale, perspectives, sustainability, and trade-offs.
- Evaluate the strengths and limitations of different sustainability models in guiding environmental policy and decision-making.
- Discuss contrasting worldviews — ecocentric, technocentric, and anthropocentric — in relation to how sustainability is defined and prioritised.
- Compare and contrast the UN Sustainable Development Goals (SDGs) with earlier sustainability frameworks, identifying areas of progress and ongoing tension.
Real-World Context & Relevance
In September 2023, the Stockholm Resilience Centre published updated data confirming that six of the nine Planetary Boundaries — the safe operating limits for Earth's systems — had been transgressed. Climate change, biosphere integrity, land-system change, freshwater change, biogeochemical flows, and novel entities (including synthetic chemicals and plastics) had all exceeded their thresholds. This was not a prediction about the future; it was a measurement of where humanity already stood. The question this raised was not whether environmental limits existed, but whether the frameworks guiding human development were adequate to keep societies within them.
At the same time, approximately 700 million people still lived in extreme poverty in 2023, according to World Bank data, and over 2 billion lacked access to safe drinking water (WHO/UNICEF Joint Monitoring Programme). These two realities — ecological overshoot and persistent human deprivation — sit at the heart of the sustainability challenge. Any framework that addresses only one side of this tension is incomplete. The models explored in this topic — from the Brundtland definition to Planetary Boundaries to Doughnut Economics — represent successive attempts to hold both sides of this tension in view simultaneously.
🌍 Why This Matters Sustainability frameworks are not abstract academic constructs — they directly shape international agreements, national policies, corporate strategies, and local planning decisions. Understanding how these models are built, what they assume, and where they fail is essential for evaluating any environmental policy claim. ESS students who can critically apply these frameworks are equipped to engage with the most pressing governance challenges of the 21st century.
Core Concepts & Definitions
Before any formal definition can be useful, it is worth asking: what problem is the concept of sustainability trying to solve? The industrial era produced extraordinary gains in human welfare — longer lives, reduced poverty, expanded literacy — but it did so by drawing down natural capital at rates that exceeded the Earth's capacity to regenerate it. Fisheries collapsed, soils degraded, aquifers were depleted, and the atmosphere accumulated greenhouse gases. The concept of sustainability emerged as a response to this pattern: a recognition that development pathways which undermine their own ecological foundations are, by definition, self-defeating.
📖 Key Definition — Sustainability Sustainability is the capacity of a system — ecological, economic, or social — to maintain its essential functions, structures, and processes over time without depleting