Educerie · IB Diploma · Environmental Systems and Societies
Topic 1 — Foundation
Topic 1 gives you the vocabulary the whole course is examined in. Learn it properly now and the other seven topics become applications of it.
Environmental value systems
An environmental value system (EVS) is the worldview that shapes how a person or group perceives and evaluates environmental issues. It is itself a system: inputs are education, media, culture, religion and personal experience; outputs are decisions, behaviour and policy.
Three positions sit on a spectrum:
- Ecocentric — nature has intrinsic value, independent of use to humans. Prefers minimal intervention, self-restraint, and solutions that reduce consumption rather than technologies that enable it. Deep ecologists and self-reliance soft ecologists sit here.
- Anthropocentric — humans must manage the environment for sustainable use. Trusts regulation, taxation, population policy and debate to produce good outcomes. The centre ground of most governments.
- Technocentric — technology and human ingenuity will solve environmental problems. Prefers innovation, market mechanisms and growth. Environmental managers sit toward the centre; cornucopians at the far end believe resources are effectively unlimited given technology.
These are positions on a continuum, not boxes. The examinable skill is not labelling people but explaining why two people looking at the same evidence reach opposite conclusions — because their EVS assigns different value to the same facts. A question asking why there is disagreement about, say, nuclear power is asking exactly this.
Systems and models
A system is a set of interrelated parts working together, defined by storages (where matter or energy accumulates) and flows (transfers and transformations between them).
Three types, distinguished by what crosses the boundary:
| System | Matter | Energy |
|---|---|---|
| Open | crosses | crosses |
| Closed | does not cross | crosses |
| Isolated | does not cross | does not cross |
Almost all natural systems are open. The Earth as a whole is effectively closed — energy enters as sunlight and leaves as heat, but matter essentially does not. Isolated systems do not exist in nature; they are a theoretical construct. Stating that confidently is often a mark.
A model is a simplified representation of reality. Its strengths and weaknesses are examinable almost every session:
Strengths — allows prediction, makes complex systems comprehensible, permits testing scenarios that would be impossible or unethical in reality, and can be adjusted as data improves.
Weaknesses — simplification means detail is lost; accuracy depends entirely on the quality of the input data and assumptions; different assumptions produce different outputs, which is why credible climate models disagree; and a model's apparent precision can create false confidence.
Energy and equilibria
The first law of thermodynamics: energy is neither created nor destroyed, only transformed. The second law: energy transformations increase the entropy (disorder) of a system, because some energy is always dispersed as heat and becomes unavailable to do work.
This is why energy transfer between trophic levels is only about 10 % efficient, and therefore why food chains are short and why a given area of land feeds more people growing crops than raising cattle. Ecosystems maintain their order only because sunlight continuously supplies energy — they are open systems.
Equilibrium is a state of balance. Distinguish:
- Steady-state equilibrium — continuous inputs and outputs, but the system's overall state remains stable over time. A mature forest: individual trees die and are replaced, while the forest persists.
- Static equilibrium — no inputs or outputs, no change. Rare in nature; a pile of rocks.
Feedback loops are the mechanism behind stability and collapse alike:
- Negative feedback counteracts change and returns a system toward its equilibrium. It is stabilising. Predator numbers rise, prey numbers fall, predators then starve and decline, prey recover.
- Positive feedback amplifies change and drives the system further from equilibrium. It is destabilising. Ice melts, exposing darker ocean, which absorbs more heat, which melts more ice.
"Negative" does not mean bad and "positive" does not mean good. Negative feedback is usually the desirable one. Getting this backwards is the single most common error in the whole subject.
A tipping point is the threshold beyond which positive feedback takes over and the change becomes self-sustaining and effectively irreversible.
Resilience is a system's ability to absorb disturbance and still function. Greater diversity, larger storages and faster reproduction rates all increase it.
Sustainability
Sustainability is the use of resources at a rate that allows natural regeneration and does not degrade the environment for future generations. In systems terms: living on the income, not the capital.
- Natural capital — natural resources that produce a yield, such as a forest or a fish stock.
- Natural income — the sustainable yield that capital produces, such as the annual growth of timber. Harvesting only the income leaves the capital intact.
Ecological footprint is the area of land and water required to supply a population's resources and absorb its waste. Where the footprint exceeds the area actually available, the population is in ecological deficit and is drawing down capital. It is a useful comparative indicator, but it is a model — it aggregates very different impacts into a single number and is sensitive to the assumptions used.
Planetary boundaries define a safe operating space for humanity across nine processes, including climate change, biosphere integrity and biogeochemical flows. Several have already been crossed. The framework's value is that it treats environmental limits as interconnected rather than as separate problems.
The UN Sustainable Development Goals attempt to reconcile environmental limits with development, which is where the tension in this subject lives: the countries with the smallest footprints are generally those with the greatest need to grow.
What actually loses marks in this topic
- Swapping positive and negative feedback. Negative is stabilising.
- Treating ecocentric, anthropocentric and technocentric as boxes rather than a spectrum.
- Confusing steady-state with static equilibrium.
- Saying the Earth is an open system. For matter it is effectively closed.
- Claiming isolated systems exist in nature.
- Confusing natural capital with natural income.
- Evaluating a model with only weaknesses, or only strengths. Evaluate requires both.
- Writing generic examples. Name the place, the species, the year.
- Answering discuss or to what extent with one perspective.
Educerie · written from the published IB syllabus structure for Environmental Systems and Societies Topic 1, first assessment 2026. Original text. Last reviewed 5 September 2026.