IB ESS Exam Guide

ESS Exam Skills & Techniques

Master the IB Environmental Systems & Societies exam. Learn paper structures, command terms, marking criteria, and where to find easy marks.

ESS is available at SL only — no HL option. It counts as both a Group 3 and Group 4 subject.

ESS Assessment at a Glance

25%
Paper 1
Case Study • 1 hour
50%
Paper 2
Short Answer + Essays • 2 hours
25%
Internal Assessment
Individual Investigation • 2,250 words

ESS Paper Structure

Know exactly what to expect in each paper and how to maximize your marks.

Paper 1

Case Study
1 hour35 marks25% of final grade

An unseen case study with data, graphs and images. Questions range from 1-8 marks.

What to expect:

You get a booklet with real-world data about an environmental issue
Questions start easy (define, state) and get harder (explain, evaluate)
You MUST use data from the case study in your answers

Key Tips

  • Skim questions first → then read case study looking for relevant data
  • Underline numbers, dates, and locations as you read
  • Use proper ESS terms (e.g. "biomagnification" not "builds up")

Easy Marks

  • Quote exact data: "CO₂ increased by 23% between 2010-2020"
  • Systems diagrams: inputs → processes → outputs + feedback loops
  • Give the exact number asked: "2 reasons" means write 2, not 1 or 3

Watch Out

  • No case study reference = lost marks
  • Describe = what happens. Explain = why it happens

Paper 2

Short Answer & Essays
2 hours65 marks50% of final grade
Section AShort-answer and data-based questions25 marks
Section BChoose 2 essays from 4 options40 marks

What to expect:

Section A: Quick questions covering all 8 units — no choice
Section B: Pick 2 essays you know best — each worth 20 marks
Essays have parts (a), (b), (c) — marks increase with each part

Key Tips

  • Section A: 2 marks = 2-3 sentences max
  • Section B: 5 min plan + 25 min write per essay
  • Be specific: "Aral Sea, Kazakhstan" not "a lake"

Easy Marks

  • Use real examples: Deepwater Horizon, Aral Sea, Chernobyl
  • Draw labeled diagrams (carbon cycle, Gersmehl)
  • Intro = define terms, Conclusion = answer the question

Watch Out

  • Don't spend too long on Section A — save time for essays
  • For "Evaluate": show BOTH sides or lose half the marks

ESS Command Terms

Command terms tell you exactly what the examiner expects. Grouped by Assessment Objective (AO).

AO1: Knowledge
AO2: Application
AO3: Synthesis & Evaluation
Define1 mark

Give the precise meaning of a word, phrase, or concept.

State1 mark

Give a specific name, value, or brief answer without explanation.

List1 mark

Give a sequence of brief answers with no explanation.

Identify1 mark

Provide an answer from several possibilities.

Label1 mark

Add labels to a diagram.

Outline2-3 marks

Give a brief account or summary of the main points.

Describe2-4 marks

Give a detailed account of characteristics, features, or processes.

Explain3-4 marks

Give detailed reasons or causes. Show connections using "because", "therefore", "this leads to".

Calculate2-3 marks

Obtain a numerical answer showing working and units.

Annotate2-3 marks

Add brief notes to a diagram or graph.

Draw2-3 marks

Represent by means of a labeled, accurate diagram or graph.

Compare4 marks

Give an account of similarities AND differences.

Compare and contrast4-5 marks

Give an account of similarities and differences, with more emphasis on differences.

Analyse4-6 marks

Break down into components; examine relationships and patterns.

Evaluate5-9 marks

Assess strengths and limitations; make a balanced, justified judgment.

Discuss7-9 marks

Present multiple perspectives with evidence. Reach a reasoned conclusion.

To what extent7-9 marks

Consider the evidence on both sides and reach a justified conclusion.

Justify4-6 marks

Give valid reasons or evidence to support an answer or conclusion.

What Examiners Expect

Match your answer depth to the marks available.

1-2 marksBrief, factual answers

Example questions:

  • "Define biodiversity"
  • "State one effect of eutrophication"
  • "List two greenhouse gases"

One clear point per mark. No explanation needed.

3-4 marksExplained answers with reasons/causes

Example questions:

  • "Outline the role of decomposers"
  • "Explain how deforestation affects the carbon cycle"

Use "because", "therefore", "this leads to" to show connections.

5-6 marksDetailed analysis with examples

Example questions:

  • "Analyse the impacts of ocean acidification"
  • "Compare two renewable energy sources"

Include specific examples and consider multiple factors.

7-9 marksBalanced evaluation with judgment

Example questions:

  • "Evaluate strategies for reducing plastic pollution"
  • "Discuss the role of international agreements in addressing climate change"

Show both sides, include EVS perspectives, reach a justified conclusion.

ESS-Specific Skills

These concepts appear throughout ESS exams. Master them to score higher.

Environmental Value Systems

Always consider ecocentric, anthropocentric, and technocentric viewpoints in discussion/evaluate questions.

Systems Thinking

Show understanding of inputs, outputs, storages, flows, feedback loops, and tipping points.

Named Case Studies

Include specific examples with names, locations, dates, and statistics (e.g., Aral Sea, Great Barrier Reef, Deepwater Horizon).

Data Skills

Practice interpreting graphs, calculating ecological footprints, Simpson's index, and percentage changes.

Common ESS Mistakes to Avoid

Learn from others' mistakes. These cost students marks every exam session.

Not using case study data in Paper 1

Reference specific numbers, quotes, or data from the case study

Vague answers without examples

Include named case studies with specific details (location, date, data)

Forgetting Environmental Value Systems

For "discuss/evaluate" questions, include different EVS perspectives

Confusing "describe" and "explain"

Describe = what/how. Explain = why/cause-effect with "because"

Running out of time on essays

Spend 5 mins planning, 25 mins writing per essay. Don't over-write early questions

One-sided arguments in evaluate questions

Always show both strengths AND limitations, then give justified judgment

Internal Assessment (IA)

25% of final grade • 2,250 words maximum

Individual investigation on an ESS research question you design

Marking Criteria

Identifying the context6 marks
Planning6 marks
Results, analysis, conclusion6 marks
Discussion and evaluation6 marks

Tips for Top Marks

  • Choose a local, measurable research question
  • Collect primary data where possible
  • Use statistical tests to analyse your data
  • Link findings to ESS theory and wider implications
  • Discuss limitations and suggest improvements

Ready to Practice?

Apply these exam skills with our ESS practice questions. Get instant AI feedback that shows exactly what scored marks and how to improve.