IB Environmental Systems & Societies · 2025 Syllabus

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IB ESS

Spaced repetition flashcards and daily games — covering all 8 IB ESS units with 255+ key definitions and case study terms. Free, forever.

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255+
IB ESS key terms
8
Units covered
Defs + Cases
Both card types
100%
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All 8 IB ESS Units

Cramly covers every unit of the IB ESS syllabus with both definition cards and real case study examples — the two question types you'll face in Papers 1 and 2.

Tip: IB ESS combines science and social science. Paper 2 often asks you to evaluate issues from different environmental value systems (EVS) — ecocentric, anthropocentric, and technocentric. Cramly includes EVS vocabulary in Unit 1 cards.
Unit 1

Foundations of ESS

Environmental value systems (EVS), systems thinking, positive and negative feedback, inputs and outputs, sustainability, and the nature of environmental science.

Unit 2

Ecology and Ecosystems

Ecosystems, trophic levels, food webs, energy flow, nutrient cycling (carbon, nitrogen, phosphorus), biomes, and ecological productivity.

Unit 3

Biodiversity, Conservation and Change

Species diversity, genetic diversity, ecosystem diversity, IUCN Red List, in situ and ex situ conservation, extinction threats, and invasive species.

Unit 4

Water and Aquatic Food Production

Freshwater and marine systems, the hydrological cycle, eutrophication, overfishing, aquaculture, water scarcity, and water security.

Unit 5

Soil Systems and Terrestrial Food Production

Soil formation and horizons, soil degradation, salinisation, desertification, agriculture (industrial and sustainable), food security, and land use.

Unit 6

Atmospheric Systems and Societies

The structure of the atmosphere, the carbon and oxygen cycles, air pollution, acid deposition, ozone depletion, photochemical smog, and indoor air quality.

Unit 7

Climate Change and Energy Production

The greenhouse effect, global warming, the IPCC, climate tipping points, renewable and non-renewable energy sources, nuclear power, and carbon capture.

Unit 8

Human Systems and Resource Use

Human population dynamics, ecological footprint, resource depletion, solid domestic waste, urbanisation, the circular economy, and sustainable development goals (SDGs).

Key vocabulary

Essential IB ESS Definitions

IB ESS mark schemes reward precise definitions. Here's a sample of the terms covered in Cramly — all with spaced repetition flashcards.

Abiotic Factor
Acid Deposition
Anthropocentric EVS
Aquaculture
Biodiversity
Bioaccumulation
Biomagnification
Biome
Carbon Cycle
Carbon Sink
Carrying Capacity
Circular Economy
Climate Feedback
Community
Decomposer
Deforestation
Desertification
Ecocentric EVS
Ecological Footprint
Ecological Niche
Ecological Succession
Ecosystem
Ecosystem Services
El Niño
Endemic Species
Eutrophication
Extinction
Food Security
Food Web
Fossil Fuel
Greenhouse Effect
Greenhouse Gas
Gross Primary Productivity
Habitat Fragmentation
Hydrological Cycle
IPCC
IUCN Red List
Keystone Species
Leaching
Net Primary Productivity
Nitrogen Cycle
Ozone Layer
Photochemical Smog
Pollution
Population
Positive Feedback
Negative Feedback
Resilience
Salinisation
Saprotrophic Nutrition
SDGs
Simpson's Diversity Index
Soil Horizon
Species Diversity
Stability
Sustainability
Systems Thinking
Technocentric EVS
Tipping Point
Trophic Level
Urban Heat Island
Water Table
Wetland

Practice all 255+ terms in the app with spaced repetition flashcards.

IB ESS Revision FAQ

What is IB ESS?

IB Environmental Systems and Societies (ESS) is a transdisciplinary IB subject that bridges Group 3 (Individuals and Societies) and Group 4 (Experimental Sciences). It can count as either a Group 3 or Group 4 subject, making it a popular choice for students who want to cover both requirements with one subject.

ESS explores how environmental systems work and how human societies interact with them, using both scientific analysis and social/ethical evaluation.

What topics are covered in IB ESS?

IB ESS has 8 units: 1 Foundations of ESS (environmental value systems, systems thinking), 2 Ecology and Ecosystems, 3 Biodiversity, Conservation and Change, 4 Water and Aquatic Food Production, 5 Soil Systems and Terrestrial Food Production, 6 Atmospheric Systems and Societies, 7 Climate Change and Energy Production, and 8 Human Systems and Resource Use.

What are environmental value systems (EVS) in ESS?

Environmental value systems (EVS) are a core part of IB ESS Paper 2 essays. There are three main perspectives:

Ecocentric — places nature's intrinsic value at the centre; humans are just one part of a wider ecosystem and must live within ecological limits.

Anthropocentric — humans are the most important species; nature has value primarily for human use, but we should manage it wisely for future generations.

Technocentric — technology can solve environmental problems; economic growth and human ingenuity can overcome resource limits.

Essay questions often ask you to evaluate an environmental issue from different EVS perspectives.

Is IB ESS only available at SL?

Yes — IB ESS is only offered at Standard Level (SL). It cannot be taken at Higher Level. This is one reason it's a popular choice for students who find the full HL science load challenging, as it still counts as a Group 4 subject.

What is the best way to revise for IB ESS?

Definitions and terminology — ESS Paper 2 mark schemes reward precise definitions. Use Cramly's spaced repetition flashcards to lock in key terms from all 8 units.

Case studies — The IB ESS syllabus requires you to know real-world case studies. Cramly includes case study cards alongside definitions for every unit.

EVS perspectives — Practice structuring arguments from ecocentric, anthropocentric, and technocentric viewpoints for Paper 2 essay questions.

Past papers — The style of Paper 1 (based on a pre-seen case study) is unique to ESS. Practice with released past papers to get familiar with the format.

Is Cramly free for IB ESS?

Yes — completely free. All IB ESS flashcards, daily games, and progress tracking are available at no cost. No account is needed to start.

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