IB Diploma · session May 2027

Environmental Systems and Societies

Guide launched February 2024 and first assessed May 2026.

Mocks: in the future, hold tight!

Topic 1

The theory The syllabus content of this unit, explained in order. Read → Worked examples Answers written the way a scheme rewards, with the commentary that explains the marks. Read → Practice test A timed test on this unit, with the marks shown against each part. Read → Mark scheme What earns each mark, point by point, and what is accepted instead. Read →

The course in one page

The course in one page. Standard and higher level, for the guide launched February 2024 and first assessed May 2026 — the guide May 2027 candidates sit.

What is distinctive about this subject

ESS counts for either Group 3 or Group 4. It is the only DP subject that does, and taking it as your Group 4 science frees a slot elsewhere. It is genuinely interdisciplinary: half environmental science, half the study of how societies value and argue about the environment.

Two consequences for how it is examined. First, there is no single right answer to most of the big questions — you are assessed on how well you argue, and on whether you recognise that people holding different values reach different conclusions from the same data. Second, case studies are not decoration. Named, specific, factual examples are the difference between a 4 and a 7, and generic answers ("in some countries, pollution is a problem") score close to nothing.

HL is newly a full course. Previously ESS was SL-only; it now runs at both levels, with higher level adding three lenses through which every topic can be re-examined.

The topics

	Topic
1	Foundation — systems, models, value systems, sustainability
2	Ecology
3	Biodiversity and conservation
4	Water
5	Land
6	Atmosphere and climate change
7	Natural resources
8	Human populations and urban systems

Higher level lenses: HL.a Environmental law · HL.b Environmental and ecological economics · HL.c Environmental ethics.

Topic 1 is not an introduction to be got through. Systems thinking, feedback and environmental value systems are the framework the other seven topics are examined in, and they reappear in almost every extended-response question.

The papers

	Standard level	Higher level
Paper 1: case study	60 min, 35 marks	120 min, 70 marks
Paper 2	120 min, 60 marks	150 min, 80 marks

Paper 1 is a resource booklet. You are given data — graphs, maps, tables, extracts — about a real situation you have not studied, and asked to interpret it, apply course concepts to it, and evaluate what it does and does not show. It is the most AO3-heavy paper in the subject and cannot be revised for by memorisation. It is revised for by practising data questions.

Paper 2 is short answer plus extended response drawn from the whole course.

How it is marked

Short answers use point-based schemes. Extended responses use mark bands, and the bands reward specific things:

a balanced answer that considers more than one perspective
named, specific case studies with real detail
explicit use of course terminology — feedback loop, carrying capacity, ecological footprint
a conclusion that actually concludes, rather than restating the question

The most common way to lose marks on a 9-mark question is to write a well-informed one-sided answer. A perspective you disagree with still has to appear.

Assessment objectives

		Roughly
AO1	Knowledge	define, state, outline
AO2	Application	apply concepts to a specific situation or dataset
AO3	Analysis, evaluation and synthesis	interpret data, weigh perspectives, judge a solution

Command terms, and what each one obliges you to write

Term	What must appear on the page
State / Identify	The answer alone.
Define	A precise meaning.
Outline	A brief account, main points only.
Describe	What happens, or what the data shows. No why.
Explain	The reason or mechanism.
Compare and contrast	Similarities and differences.
Distinguish	Differences set against each other.
Suggest	A plausible answer for an unfamiliar situation.
Justify	Reasons supporting a choice, ideally against the alternative.
Evaluate	Strengths and limitations, then a judgement.
Discuss	A balanced review of more than one perspective.
To what extent	A judgement with a degree attached — not simply yes or no.

Evaluate and discuss carry the highest marks and are where the bands bite. Both require more than one side on the page before any conclusion.

Educerie · written from the published IB Diploma Programme structure for Environmental Systems and Societies, first assessment 2026. Original text. Paper durations and mark totals checked against the May 2027 examination schedule. Last reviewed 5 September 2026.