1.1A Perspective, values, and worldview

1.1B Environmental value system

1.1C Environmental movements

1.2A Systems

1.2B Negative feedback loops

1.2C Positive feedback loops

1.2D Models

1.2E Emergent properties

1.2F Resilience of a system

1.3A Sustainability and its pillars

1.3B Sustainable development

1.3C Unsustainable use of natural resources

1.3D Common indicators of economic development

1.3E Environmental justice and inequality

1.3F Sustainability indicators

1.3G Biocapacity

1.3H Citizen science

1.3I Frameworks and models for sustainability

2.1A Organisms

2.1B Population

2.1C Ecological Niche and Population Interactions

2.1D Carrying capacity

2.1E Population size and growth

2.1F Population abundance estimation

2.1G Community

2.1H Habitat

2.1I Ecosystems

2.1J Keystone species

2.1K Planetary boundaries model and biosphere integrity

2.1L Classification methods (HL)

2.1M Niche (HL)

2.1N r- and K strategists (HL)

2.1O Knowledge of species' classification (HL)

2.2A First law of thermodynamics

2.2B Photosynthesis and cellular respiration

2.2C Second law of thermodynamics

2.2D Food Chain and Energy Loss

2.2E Gross productivity and Net productivity

2.2F Food Web and Biomass

2.2G Ecological Pyramids

2.2H Pollutants and human activities

2.2I Productivity and Ecological efficiency (HL)

2.2J Modes of nutrition (HL)

2.3A Biogeochemical cycles

2.3B Carbon cycle

2.3C Carbon in lithosphere (HL)

2.3D Methane (HL)

2.3E Nitrogen cycle (HL)

2.4A Climate

2.4B Biomes

2.4C The tricellular mode of atmospheric circulation

2.4D Climate in biomes (HL)

2.4E El Nino (HL)

2.4F Tropical cyclones (HL)

2.5A Zonation

2.5B Succession

2.5C Ecosystem resilience

2.5D Community and productivity in succession (HL)

2.5E Climax communities and plagioclimax (HL)

3.1A Biodiversity

3.1B Natural selection and speciation

3.1C Species diversity

3.1D Genetic Diversity and Reproductive Isolation (HL)

3.1E Biodiversity hotspots (HL)

3.1F Human activities and selective forces (HL)

3.1G Earth history and the Anthropocene (HL)

3.2B Invasive species

3.2C IUCN

3.2D Tragedy of the commons

3.2E Key biodiversity hotspots and areas (HL)

3.2F Traditional indigenous approaches to land management (HL)

3.2G Environmental justice and conservation efforts (HL)

3.2H Loss of biosphere integrity (HL)

3.3A Arguments for conservation and strategies

3.3B Regeneration and rewilding

3.3C Choice of conservation

3.3D Success in conservation and eco-tourism (HL)

3.3E Rewilding projects (HL)

4.1A Hydrological cycle

4.1B Characteristics of water (HL)

4.1C Oceans as a carbon sink (HL)

4.1D Stratification (HL)

4.1E Thermohaline circulation (HL)

4.2A Water security

4.2B Water supply

4.2C Water scarcity

4.2D Water conservation

4.2E Freshwater resources and use (HL)

4.2F Water footprints and Citizen Science (HL)

4.2G Water stress (HL)

4.3A Phytoplankton and macrophhytes

4.3B Consumption of organisms from freshwater and marine environments

4.3C Maximum sustainable yield

4.3D Impact on freshwater and marine ecosystems

4.3E Productivity, thermal stratification, nutrient mixing, and loading (HL)

4.3F Conservation and Management of Global Fisheries (HL)

4.3G Ethical Issues in Harvesting Seals, Whales, and Dolphins (HL)

4.4A Water pollution

4.4B Water quality

4.4C Eutrophication

4.4D Pollutants in water (HL)

4.4E Algal blooms and anoxic/hypoxic waters (HL)

4.4F Sewage treatment (HL)

4.4G Water quality management (HL)

5.1A Soil system

5.1B Contribution of soil

5.1C Soil texture

5.1D Soil as a carbon sink

5.1E Soil horizons (HL)

5.1F Soil formation (HL)

5.1G Soil properties (HL)

5.2A Land and land use

5.2B Agriculture systems

5.2C Synthetic fertilizers

5.2D Soil conservation

5.2E Diet and food security

5.2F Agricultural choices and farming approaches (HL)

5.2G Sustainability of different diets (HL)

5.2H Traditional or indigenous methods (HL)

5.2I Uneven distribution of food (HL)

6.1A Atmosphere

6.1B Tricellular model of atmospheric circulation

6.1C Greenhouse effect

6.1D Atmosphere system (HL)

6.1E Milankovitch cycles (HL)

6.1F Quaternary period (HL)

6.2A Climate and anthropogenic GHG emissions

6.2B Climate change

6.2C Climate models (HL)

6.2D Tipping cascades (HL)

6.2E Varying responsibility for climate change (HL)

6.3A Mitigation and adaptation strategies

6.3B Stakeholder responses (HL)

6.3C Technology to aid mitigation of climate change (HL)

6.3D Challenges to overcome (HL)

6.3E Geoengineering (HL)

6.3F Climate change perspectives (HL)

6.3G Tragedy of the commons in action (HL)

6.4A UV radiation

6.4B Ozone depletion

6.4C The Montreal protocol

6.4D Stratospheric ozone depletion and ODSs (HL)

7.1A Natural resources

7.1B Ecosystem services

7.1C Natural capital

7.1D Resource scarcity and use of natural resource

7.1E Management and intervention of strategies to influence use of natural resources (HL)

7.1F Environmental impact assessment (HL)

7.1G Unsustainable extracting, harvesting, transporting, and processes

7.1H Economic interests (HL)

7.1I Natural resource insecurity and security (HL)

7.2A Energy sources, global energy consumption and energy choices

7.2B Energy storage systems

7.2C Energy conservation and energy efficiency

7.2D Energy security (HL)

7.2E Global economy and fossil fuels (HL)

7.2F Nuclear power and battery storage (HL)

7.3A Solid domestic waste

7.3B Waste disposal and management

8.1A Birth and Immigration as Inputs to Population Growth

8.1B Human population management

8.1C Age-sex pyramids and demographic transition model

8.1D Rapid population growth (HL)

8.1E Dependency ratio and population momentum (HL)

8.1F Environmental migration (HL)

8.2A Urban systems

8.2B Urbanization and suburbanization

8.2C Urban planning

8.2D Principles of ecological urban planning (HL)

8.2E Sustainable urban systems (HL)

8.3A Urban air pollution

8.3B Acid rain

8.3C Photochemical smog (HL)

8.3D Tropospheric ozone (HL)