Systems and evidence
Trace stores, flows, feedback, resilience, thresholds, and change, then test each explanation against case-study data and the limits of the evidence.
IB Environmental Systems and Societies • HL
IB Environmental Systems and Societies HL
Use this IB Environmental Systems and Societies HL study guide to browse the syllabus topic structure, study materials, and practice resources.
Structured practice
IB Environmental Systems and Societies HL Question Bank
Jump straight into grouped unit practice without losing your place in the syllabus overview.
1 Foundations of ESS
1.1 Environmental Value Systems
1.2 Systems & Models
1.3 Energy & Equilibria
1.4 Sustainability
1.5 Humans & Pollution
2 Ecosystems & Ecology
2.1 Species & Populations
2.2 Communities & Ecosystems
2.3 Flows of Energy & Matter
2.4 Investigating Ecosystems
3 Biodiversity & Conservation
3.1 An Introduction to Biodiversity
3.2 Origins of Biodiversity
3.3 Threats to Biodiversity
4 Water & Aquatic Food Production Systems & Societies
4.1 Introduction to Water Systems
4.2 Access to Fresh Water
4.3 Water Pollution
5 Soil Systems & Terrestrial Food Production Systems & Societies
5.1 Introduction to Soil Systems
5.2 Terrestrial Food Production Systems & Food Choices
5.3 Soil Degradation & Conservation
6 Atmospheric Systems & Societies
6.1 Introduction to the Atmosphere
6.2 Stratospheric Ozone
6.3 Photochemical Smog
7 Climate Change & Energy Production
7.1 Energy Choices & Security
7.2 Climate Change: Causes & Impacts
7.3 Climate Change: Mitigation & Adaptation
8 Human Systems & Resource Use
8.1 Population Dynamics
8.2 Resource Use in Society
8.3 Energy & Equitable Resource Use
Overview
Course overview
How to study IB Environmental Systems and Societies HL
IB Environmental Systems and Societies HL (ESS HL) is an interdisciplinary course first assessed in May 2026. It connects scientific understanding of environmental systems with social, cultural, economic, political, and ethical perspectives. HL students study the shared seven-topic syllabus in greater breadth and depth, additional HL-only content, and three lenses—environmental law, environmental and ecological economics, and environmental ethics. Strong revision therefore connects evidence and systems thinking with the assumptions, trade-offs, and consequences exposed by those lenses.
HL lenses
Use environmental law, environmental and ecological economics, and environmental ethics to reveal different assumptions, incentives, responsibilities, and policy choices.
Connected evaluation
Integrate perspectives, systems, and sustainability across common and HL-only content, using explicit criteria and well-explained examples to support judgements.
Assessment at a glance
For the current ESS HL course with first assessment in May 2026, external assessment accounts for 80% and the individual investigation accounts for 20%. Confirm your examination session and school deadlines with your teacher.
| Component | Format | Weighting |
|---|---|---|
| Paper 1 | 2 hours; unseen case study with data analysis and evaluation | 30% |
| Paper 2 | 2 hours 30 minutes; short-answer and data-based questions plus two structured essays | 50% |
| Internal assessment | 10 hours; individual environmental investigation (maximum 3,000 words) | 20% |
Sources: IB ESS guide (first assessment 2026) and IB Environmental Systems and Societies curriculum update.
Revision plan
- 1.Map every syllabus topic through perspectives, systems, and sustainability, then tag the relevant HL-only content and lens connections.
- 2.Practise interpreting unfamiliar maps, graphs, field data, and legal or economic evidence before introducing memorised examples.
- 3.Build comparison tables that show how environmental law, economics, and ethics can produce different conclusions about the same issue.
- 4.Alternate two-hour Paper 1 case studies with Paper 2 short-answer, data-based, and two-essay practice under the current time limits.
Exam strategy
For Paper 1, make each conclusion traceable to the unseen case study and distinguish what the evidence shows from what you infer. For Paper 2, use precise ESS terminology, connect common and HL-only knowledge to the question, and integrate relevant HL lenses rather than naming them without analysis. In both papers, make evaluative criteria, scale, uncertainty, and competing perspectives explicit.
Practise IB Environmental Systems and Societies HL questionsFrequently asked questions
What is IB Environmental Systems and Societies HL?
IB Environmental Systems and Societies HL is the higher-level version of the interdisciplinary ESS course introduced for first teaching in August 2024 and first assessment in May 2026. It combines environmental science with social, cultural, economic, political, legal, and ethical analysis.
What is the difference between IB ESS HL and ESS SL?
The IB recommends 240 teaching hours for ESS HL and 150 for ESS SL. HL includes additional content, greater breadth and depth, and three lenses—environmental law, environmental and ecological economics, and environmental ethics—which students use to analyse environmental issues and responses.
What are the three concepts that organize the current IB ESS course?
The current IB ESS course is organized around perspectives, systems, and sustainability. HL students apply these concepts across the shared syllabus, HL-only content, and the three HL lenses.
How is IB ESS HL assessed from May 2026?
ESS HL external assessment is worth 80%: Paper 1 lasts two hours and is worth 30%, while Paper 2 lasts two hours 30 minutes and is worth 50%. The individual investigation is worth the remaining 20%.
What is the IB ESS HL internal assessment?
The ESS HL internal assessment is an individual environmental investigation worth 20%. Limited collaboration on methodology is permitted under the guide's conditions, but each student must collect unique data where required and submit an individual report of no more than 3,000 words.