IB Environmental Systems and Societies (ESS) is an interdisciplinary science course in the International Baccalaureate Diploma Programme that examines environmental processes, sustainability, and the interactions between human societies and natural environmental systems.

This page provides a complete overview of the new IB ESS syllabus (first examinations 2026). You will find:

• ESS course structure (SL and HL)
• Syllabus topics and concepts
• Assessment overview
• Internal Assessment (IA) guidance
• Video lessons and learning resources

These resources are designed to help IB students understand environmental systems clearly and support teachers delivering the new ESS course.

What Is IB Environmental Systems and Societies (ESS)?

IB Environmental Systems and Societies is a transdisciplinary course combining elements of:

• environmental science
• ecology
• geography
• economics
• social sciences

Students explore how natural systems function, how human societies interact with the environment, and how sustainable solutions can be developed to address global environmental challenges.

The course emphasizes:

• systems thinking
• sustainability
• environmental case studies
• scientific investigation

ESS can be taken at Standard Level (SL) or Higher Level (HL).

Who This IB ESS Website Is For

This website is designed for:

IB ESS Students

• clear explanations of every topic
• flashcards of essential vocabulary
• guided notes
• visual diagrams and videos
• exam preparation support

IB ESS Teachers

• topic summaries
• lesson resources
• syllabus guidance
• student workbooks

Anyone interested in environmental science

• sustainability concepts
• ecosystems
• climate change
• biodiversity

IB ESS Course Structure (SL vs HL)

The new IB ESS course includes both Standard Level (SL) and Higher Level (HL) options.

Standard Level (SL) ESS

Students study the core environmental systems topics, complete practical investigations, and conduct an Internal Assessment (the ESS IA).

Higher Level (HL) ESS

Higher Level students study the same core topics but also explore environmental issues in greater depth through additional lenses (themes) such as

• environmental law
• environmental economics
• environmental ethics

HL students develop a deeper understanding of how societies manage environmental challenges while also completing practical investigations and the ESS IA.

IB ESS Assessment Overview

Students are assessed through a combination of external exams and internal investigation.

External Assessments (ESS Exams)

The final exams evaluate

• systems thinking
• data interpretation
• environmental case studies
• problem solving

Standard Level (SL) ESS Exams

• 75% of the final ESS grade
• Paper 1: 25%
  • 1 hour, 35 marks
  • Case study with data analysis and evaluation
• Paper 2: 50%
  • 2 hours, 60 marks
  • Section A: short-answer and data-based questions (40 marks)
  • Section B: one structured essay from a choice of two (20 marks)

Higher Level (HL) ESS Exams

• 80% of the final ESS grade
• Paper 1: 30%
  • 2 hours, 70 marks
  • Case study with data analysis and evaluation
• Paper 2: 50%
  • 2.5 hours, 80 marks
  • Section A: short-answer and data-based questions (40 marks)
  • Section B: two structured essays from a choice of three (40 marks)

IB ESS Internal Assessment (IA)

All students complete an individual environmental investigation. This investigation involves:

• establishing a research question within an environmental context
• collecting environmental data
• analyzing results
• evaluating environmental impacts
• communicating scientific findings

The ESS IA contributes either 25% of the final grade at Standard Level (SL) or 20% of the final grade at Higher Level (HL).

IB ESS Syllabus Topics (2026)

Explore each topic in detail at the links below.

Topic 1 Foundations – Perspectives, Systems, and Sustainability. Students learn how environmental systems function and how systems thinking can be used to analyze sustainability.

Topic 2 Ecology. This topic explores ecosystem structure, energy flows, food webs, and ecological interactions.

Topic 3 Biodiversity and Conservation. Students investigate the value of biodiversity, threats to ecosystems, and conservation strategies.

Topic 4 Water Systems and Water Security: This topic examines freshwater systems, water resources, and global water challenges.

Topic 5 Land and Soil Systems: Students study soil formation, agriculture, land use, and sustainable land management.

Topic 6 Atmosphere and Climate Change: This topic examines atmospheric systems, greenhouse gases, and global climate change.

Topic 7 Natural Resources and Waste: Students analyze resource use, waste generation, and strategies for sustainable resource management.

Topic 8 Human Populations and Urban Systems: In this topic, students learn about population dynamics, urbanization, and environmental impacts of human development.

Higher Level ESS:

HL.a Environmental law: rules for resource use, sustainability and justice

HL.b Environmental economics: ecological economics, perspectives and sustainability

HL.c Environmental ethics: moral responsibility toward the environment

Each topic is explored through environmental case studies and system analysis.

Practical Work in IB ESS

Practical investigations are an important part of the ESS course. Students develop scientific skills by:

• collecting environmental data
• conducting fieldwork
• analyzing ecological systems
• evaluating environmental impacts

Practical work supports the ESS Internal Assessment investigation and helps students develop strong scientific reasoning skills.

Learn IB ESS With Video Lessons

This website also includes video explanations for ESS topics to help students visualize environmental systems and complex concepts. Video lessons include:

• ecosystem processes
• energy flow and food webs
• biodiversity conservation
• climate change
• sustainability models

These videos complement my student workbooks for every topic in the IB ESS syllabus to support classroom learning and exam revision. The workbooks are aligned with the official IB ESS syllabus as well as the Pearson ESS textbook (which my current classes use) as well as the Oxford ESS textbook.

All content aligns with the IB Environmental Systems and Societies syllabus for first examinations in 2026.

About the Author

Mr Kremer is an international science teacher with experience teaching IB Environmental Systems and Societies, IB Biology, AP Physics, MYP Integrated Sciences, and general secondary sciences. The resources on this site are designed to help students apply systems thinking to understand complex environmental issues using clear explanations and visual models.

Frequently Asked Questions About IB ESS

Is IB ESS a science subject?

Yes. IB Environmental Systems and Societies is an interdisciplinary course combining environmental science and social science perspectives.

What is the difference between SL and HL ESS?

Both levels study the eight core environmental systems topics, but Higher Level students explore environmental issues and the science behind them in greater depth.

When do the new ESS exams start?

The new IB ESS syllabus was published in 2024, and the first examinations take place in 2026.

Does IB ESS include fieldwork?

Yes. Students complete practical investigations in natural environments as well as laboratory settings. They also plan, conduct, and evaluate an individual investigation in the ESS Internal Assessment (IA).

Let’s get started!

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