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IB ESS - Environmental Systems and Societies
Your complete study hub for IB ESS. Free notes, flashcards, mock exams, and AI-powered practice for every topic.
Subject Group
Group 3 + 4
Available Levels
SL and HL
Teaching Hours
150 (SL) / 240 (HL)
Exam Papers
Paper 1 · Paper 2 · IA
01—The course
What is IB ESS?
IB Environmental Systems and Societies (ESS) is an interdisciplinary subject that explores how human societies interact with the natural environment. It combines environmental science with an understanding of the political, economic, and social frameworks that shape environmental decisions.
ESS is unique in the IB Diploma because it can fulfil either a Group 3 or Group 4 requirement. From May 2026, ESS is available at both Standard Level and Higher Level, with HL students studying the same 8 topics in greater breadth and depth plus additional HL lenses.
02—Assessment
IB ESS Assessment
Paper 1 - Case Study
Students analyse a previously unseen case study using provided data. All questions are compulsory.
Paper 2 - Short Answer and Essay
Section A contains short-answer and data-based questions. Section B contains structured essay questions with limited choice.
Internal Assessment
An individual scientific investigation in which students gather and analyse data to answer their own research question.
03—Syllabus
IB ESS Syllabus - All Units and Topics
Unit 1Foundations of ESS
- 1.1Perspectives10 sub-topics
- 1.2Systems18 sub-topics1.2.1 Systems1.2.2 Storages and flows1.2.3 System diagrams1.2.4 Transfers and transformations1.2.5 Open and Closed Systems1.2.6 The Earth as a system1.2.7 Systems at different scales1.2.8 Negative feedback1.2.9 Stable equilibrium1.2.10 Positive feedback1.2.11 Tipping points1.2.12 Regime shifts1.2.13 Models1.2.14 Limits of models1.2.15 Emergent properties1.2.16 Resilience1.2.17 What makes a system resilient1.2.18 Humans and resilience
- 1.3Sustainability21 sub-topics1.3.1 Sustainability1.3.2 Pillars of sustainability1.3.3 Environmental sustainability1.3.4 Social sustainability1.3.5 Economic sustainability1.3.6 Sustainable development1.3.7 Ecosystem collapse1.3.8 GDP and Green GDP1.3.9 Environmental justice1.3.10 Inequality and access to water, food and energy1.3.11 Operating scales1.3.12 Sustainability indicators1.3.13 Ecological footprints1.3.14 Carbon and water footprints1.3.15 Biocapacity1.3.16 Citizen science1.3.17 Sustainability frameworks and models1.3.18 UN Sustainable Development Goals1.3.19 Planetary boundaries1.3.20 Doughnut economics1.3.21 Circular economy
Unit 2Ecology
- 2.1Individuals, populations, communities and ecosystems25 sub-topics2.1.1 The biosphere2.1.2 Organisms and species2.1.3 Classification2.1.4 Identification of organisms2.1.5 Populations2.1.6 Distribution: abiotic and biotic factors2.1.7 Abiotic factors2.1.8 Niches2.1.9 Population interactions2.1.10 Carrying capacity2.1.11 Density-dependent factors2.1.12 Population growth curves2.1.13 Limits on human population growth2.1.14 Human carrying capacity2.1.15 Sampling methods2.1.16 Random quadrat sampling2.1.17 Capture-mark-release-recapture2.1.18 Community2.1.19 Habitat2.1.20 Ecosystems as open systems2.1.21 Sustainability as a natural property of ecosystems2.1.22 Human activity and tipping points2.1.23 Keystone species2.1.24 Biosphere integrity2.1.25 Reversing biodiversity loss
- 2.2Energy and biomass in ecosystems21 sub-topics2.2.1 Energy and matter in ecosystems2.2.2 The first law of thermodynamics2.2.3 Photosynthesis and respiration transform energy and matter2.2.4 Photosynthesis: from light to biomass2.2.5 Producers: the first trophic level2.2.6 Cellular respiration: releasing energy2.2.7 Respiration and heat2.2.8 The second law of thermodynamics2.2.9 Consumers and their feeding strategies2.2.10 Producers and consumers in food chains2.2.11 Food chains and trophic levels2.2.12 Losses of energy and organic matter along food chains2.2.13 Gross and net productivity2.2.14 Why food chains are short2.2.15 Food webs2.2.16 Measuring biomass2.2.17 Ecological pyramids2.2.18 Bioaccumulation and biomagnification2.2.19 Microplastics and pollutants2.2.20 Human impacts on energy and matter2.2.21 Autotrophs and heterotrophs
- 2.3Biogeochemical cycles11 sub-topics2.3.1 Biogeochemical cycles2.3.2 Stores, sinks and sources2.3.3 Organic and inorganic carbon stores2.3.4 Carbon flows between stores2.3.5 Carbon sequestration2.3.6 Ecosystems as stores, sinks or sources2.3.7 Fossil fuels2.3.8 Agriculture and the carbon cycle2.3.9 Oceans and carbon dioxide2.3.10 Ocean acidification2.3.11 Reducing human impacts on the carbon cycle
- 2.4Climate and biomes7 sub-topics
- 2.5Zonation, succession and change in ecosystems8 sub-topics
- 2.6Human impact on ecosystems (to redistribute to Topics 3 & 6)0 sub-topics
Unit 3Biodiversity and Conservation
- 3.1Biodiversity and evolution9 sub-topics
- 3.2Human impact on biodiversity7 sub-topics
- 3.3Conservation and regeneration9 sub-topics3.3.1 Why preserve species and habitats3.3.2 Species-based and habitat-based conservation3.3.3 A mixed conservation approach3.3.4 The Convention on Biological Diversity3.3.5 Habitat conservation strategies3.3.6 Designing effective reserves3.3.7 Rewilding3.3.8 Measures that reverse biodiversity decline3.3.9 Values and conservation choices
Unit 4Water
- 4.1Water systems6 sub-topics
- 4.2Water access, use and security8 sub-topics
- 4.3Aquatic food production systems10 sub-topics4.3.1 Phytoplankton and macrophytes4.3.2 Food from fresh water and the sea4.3.3 Rising demand for aquatic food4.3.4 Unsustainable fishing methods4.3.5 Fishery collapse4.3.6 Maximum sustainable yield4.3.7 Climate change, acidification and aquatic life4.3.8 Managing fisheries4.3.9 Marine protected areas4.3.10 Aquaculture
- 4.4Water pollution8 sub-topics
Unit 5Land
- 5.1Soil systems14 sub-topics5.1.1 Soil as a system5.1.2 What soil is made of5.1.3 Soil profiles and horizons5.1.4 Inputs to soil5.1.5 Outputs from soil5.1.6 Transfers in soil5.1.7 Transformations in soil5.1.8 Systems diagrams of soil5.1.9 Soil and plant growth5.1.10 Soil biodiversity5.1.11 Soil and nutrient recycling5.1.12 Soil texture5.1.13 Soil texture and productivity5.1.14 Soil as a carbon sink, store or source
- 5.2Agriculture and food12 sub-topics5.2.1 Land as a finite resource5.2.2 Land use and marginalized groups5.2.3 Enough food, unevenly shared5.2.4 How farming varies around the world5.2.5 What shapes farmers' choices5.2.6 Nomadic pastoralism and slash-and-burn5.2.7 The Green Revolution5.2.8 Synthetic fertilizers and natural productivity5.2.9 Soil conservation5.2.10 Diets and trophic levels5.2.11 Strategies for a sustainable food supply5.2.12 Food security
Unit 6Atmosphere and Climate Change
Unit 7Natural Resources
- 7.1Natural resources—uses and management11 sub-topics7.1.1 Natural resources7.1.2 Natural capital7.1.3 Natural income7.1.4 Natural capital as a perspective7.1.5 Ecosystem services7.1.6 Renewable and non-renewable resources7.1.7 The values of natural capital7.1.8 How the value of resources changes7.1.9 Managing natural capital sustainably7.1.10 Resource security7.1.11 What shapes resource choices
- 7.2Energy sources—uses and management6 sub-topics
- 7.3Solid waste9 sub-topics
Unit 8Human Population and Urban Systems
04—Resources
Free IB ESS Study Resources
05—FAQ
Frequently Asked Questions about IB ESS
What is the difference between ESS SL and HL?
SL and HL share the same core topics and both sit Paper 1 and Paper 2. HL covers the same syllabus in greater depth with additional HL lenses, longer papers, and deeper analytical expectations.
Is IB ESS hard?
IB ESS is often considered one of the more accessible IB sciences. The main challenge is breadth across the syllabus, while HL adds more depth and evaluation.
How do I get a 7 in IB ESS?
Master all 8 units, practise past papers regularly, learn IB command terms, connect theory to real-world case studies, and aim for full marks on your IA through careful planning and analysis.
Can IB ESS count as a Group 3 subject?
Yes. ESS is the only transdisciplinary IB subject and can fulfil either a Group 3 or Group 4 requirement.
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