IB Environmental Systems & Societies Topics: Full List

Feeling uncertain about what IB Environmental Systems & Societies (ESS) actually covers? You’re not alone. With the newly updated Standard Level (SL) course and the introduction of a brand-new Higher Level (HL) course, students have more choices than ever—but that can also make things confusing.

That’s where this guide comes in.

Here, I’ll cut through the complexity and give you a clear breakdown of exactly what ESS includes at both SL and HL. You’ll leave with:

• A full understanding of the topics

• The key differences between levels

• What to expect from the exam papers

I know how important this is because I’ve guided countless students through ESS during my previous roles as a teacher and Head of Department of ESS. I’ve seen the questions students ask, the challenges they face, and the clarity they need. Let’s make sure you walk away with all the answers.

What exactly is ESS?

The IB Environmental Systems & Societies (ESS) course explores environmental issues through both scientific and societal perspectives.

If you need a reminder, we’ve written a helpful article on everything you need to know about Environmental Systems & Societies.

We’ve also asked author and educational consultant Dr. Andrew Davis, who was involved with the recent ESS curriculum review for the IB and coauthored the Pearson ESS textbook, for his thoughts on the IB ESS courses available to students:

“The ESS course has always sought to explain Earth systems, examine how humanity has affected them, and then explore the options available to navigate a more sustainable future.

This has always been a lot to unpack within a SL course!

The new SL program of study covers all essential aspects of the subject, with the HL course adding additional content to each topic, expanding and further explaining the components and functioning of Earth and human systems.

Three ‘HL lenses’ delve deeper into the legal, economic and ethical aspects important to the understanding and management of the planet on which we live.

Skills, essential to the study of ESS, are covered in context within each subtopic, many of which will help you with your IA (Internal Assessment). Throughout the course, you are encouraged to explore the course content through real-life examples, which give you authentic illustrations of environmental issues.”

-Dr. Andrew Davis 06/02/2025

There are several different options for IB ESS textbooks with the updated SL and HL courses that are now available for students to purchase

IB Environmental Systems & Societies Topics

Full List of IB ESS Topics

1. Foundation (SL & HL)

2. Ecology (SL & HL)

3. Biodiversity and Conservation (SL & HL)

4. Water (SL & HL)

5. Land (SL & HL)

6. Atmosphere and Climate Change (SL & HL)

7. Natural Resources (SL & HL)

8. Human Populations and Urban Systems (SL & HL)

Higher Level Lenses (HL Only)

• HL.a Environmental Law

• HL.b Environmental Economics

• HL.c Environmental Ethics

A visual breakdown the content covered in the ESS SL and HL courses

IB Environmental Systems & Societies Topic Breakdown

Topic 1: Foundation

You will explore three core concepts that underpin the IB ESS course.

Subtopics include:

• Perspectives—Understanding different worldviews on environmental issues.

• Systems—Using models to analyse environmental interactions.

• Sustainability—Examining strategies for long-term environmental management.

Topic 2: Ecology

You will learn about the interactions between organisms and their environment.

Subtopics include:

• Ecosystem interactions—Understanding relationships between organisms and their habitats.

• Energy flows—Examining how energy moves through ecosystems.

• Population dynamics—Exploring factors that influence population sizes and changes.

• Biogeochemical cycles—Investigating nutrient cycles such as the carbon and nitrogen cycles.

• Climate and biomes—Understanding how climate affects global biome distribution.

• Zonation and succession—Exploring ecological succession and spatial changes in ecosystems.

Topic 3: Biodiversity and Conservation

You will examine the importance of biodiversity and the need for conservation efforts.

Subtopics include:

• Species diversity—Understanding different levels of biodiversity.

• Conservation strategies—Exploring methods to protect and restore ecosystems.

• Threats to biodiversity—Analysing factors leading to species extinction.

• Habitat fragmentation—Investigating how human activity disrupts ecosystems.

• Endangered species and keystone species—Understanding their role in ecosystem stability.

• Protected areas and ecological restoration—Exploring conservation planning.

Topic 4: Water

You will study the importance of water resources and their sustainable management.

Subtopics include:

• Hydrological cycle—Understanding the movement of water through Earth's systems.

• Water pollution—Examining human impacts on water quality.

• Water management—Exploring sustainable use and conservation strategies.

• Aquifers and groundwater storage—Investigating water availability.

• Marine ecosystems and fisheries—Understanding the role of oceans in global water dynamics.

• Desalination and water scarcity solutions—Exploring technological advancements.

Topic 5: Land

You will analyse land use, soil systems, and sustainable management practices.

Subtopics include:

• Soil properties—Investigating soil composition and formation.

• Agricultural practices—Evaluating sustainable and unsustainable farming methods.

• Land degradation—Examining causes and solutions for soil erosion and desertification.

• Deforestation and afforestation—Understanding human impacts on land cover.

• Urban expansion and land use planning—Examining sustainable urban growth.

• Waste management and landfill impacts—Exploring solutions to reduce environmental damage.

Topic 6: Atmosphere and Climate Change

You will explore atmospheric processes and the impacts of climate change.

Subtopics include:

• Atmospheric structure—Understanding layers and their functions.

• Climate change causes—Investigating natural and human-induced climate influences.

• Mitigation and adaptation—Exploring strategies to reduce climate change impacts.

• Greenhouse gases and global warming—Analysing their role in climate regulation.

• Extreme weather events—Understanding their frequency and intensity due to climate change.

• Carbon footprints and emissions reduction—Exploring strategies to decrease global impact.

Topic 7: Natural Resources

You will study resource use, sustainability, and depletion.

Subtopics include:

• Types of resources—Differentiating between renewable and non-renewable resources.

• Resource consumption—Analysing patterns and impacts of human resource use.

• Sustainability strategies—Exploring ways to manage resources for future generations.

• Mining and extraction industries—Understanding their environmental consequences.

• Forestry and sustainable logging—Investigating sustainable resource use.

• Circular economy and waste reduction—Exploring innovative sustainability models.

Topic 8: Human Populations and Urban Systems

You will investigate human population growth and the environmental challenges of urbanisation.

Subtopics include:

• Population growth—Understanding demographic changes and their impacts.

• Urbanisation—Examining city expansion and its environmental effects.

• Sustainable cities—Exploring planning strategies for reducing urban environmental impact.

• Carrying capacity and ecological footprints—Measuring human impact on ecosystems.

• Smart cities and green infrastructure—Investigating future urban solutions.

• Megacities and urban sprawl—Examining environmental consequences of rapid urbanisation.

Higher Level Lenses (HL Only)

Environmental Law

• International agreements and policies on environmental protection

• Legal frameworks for managing pollution and conservation

Environmental and Ecological Economics

• The economic value of ecosystems

• Market-based approaches to sustainability

Environmental Ethics

• Ethical considerations in resource management

• Different philosophical perspectives on environmental responsibility

IB Environmental Systems & Societies Exam Overview

What is Covered in IB ESS Paper 1

• Format: Data-based questions on an unseen case study

• Skills Assessed:

  • Data interpretation and analysis

  • Application of concepts to real-world scenarios

  • Critical thinking and evaluation

• Topics Covered:

  • Any syllabus topic could appear, but questions will be based on the provided case study.

What is Covered in IB ESS Paper 2

• Format:

  • Section A: Short-answer and data-based questions

  • Section B: Structured essay questions

    • Each question is split into three parts (there is always a 4 mark question, 7 mark question and 9 mark question)

• Skills Assessed:

  • Knowledge recall and understanding

  • Application and analysis of environmental issues

  • Evaluation and synthesis of arguments

• Topics Covered:

  • All syllabus topics are examinable.

  • HL students explore additional depth and complexity, making more connections between diverse areas of the syllabus.

  • HL students must also apply the three HL lenses when analysing environmental issues.

Revision Resources for IB Environmental Systems & Societies

If you're sitting your ESS exams this May, check out our revision notes and exam questions to help you prepare.

If you’ll be sitting your exams from 2026 onwards, check our syllabus-aligned revision notes for the new ESS course, including updated SL revision notes, brand new HL revision notes, and notes on the three HL lenses.

Improve Your Grades with Save My Exams

Save My Exams helps students to study effectively and get higher grades than they ever thought possible. Our revision resources are written by teachers and examiners. That means notes, questions by topic and worked solutions that show exactly what the examiners for each specific exam are looking for. 

IB Environmental Systems and Societies Revision Resources

References

IB Environmental Systems & Societies Updates

IB Environmental Systems & Societies Subject Brief

More about IB ESS expert Dr. Andrew Davis

Dr. Andrew Davis has been an ESS teacher for over 15 years and was Head of Department for Environmental Science at St Edward's School, Oxford (2010-2018). He has been an IB Curriculum Developer for ESS (2017-2022) and an IB examiner for ESS (2014-present).