- Accession
- Acid deposition
- Acidification
- Acidity
- Activated carbon
- Adaptation
- Adaptive capacity
- Aerosols
- Afforestation
- Agricultural pollution
- Air pollution
- Airborne particulates
- Algae
- Alien species
- Aquaculture
- Aquatic ecosystem
- Aquifer
- Arable land
- Assimilation
- Bacteria
- Bio-geochemical Cycles
- Biochemical oxygen demand (BOD)
- Biodegradable
- Biodiversity
- Biofuel
- Biogas
- Biogeography
- Biological control
- Biological resources
- Biological treatment
- Biomass
- Biome
- Bioregion
- Biota
- Biotechnology
- Biotic
- Brackish water
- Buffer zone
- Cadmium (Cd)
- Carbon dioxide (CO2)
- Carbon market
- Carbon monoxide (CO)
- Carbon sequestration
- Carcinogen
- Carrying capacity
- Catalytic converter
- Catchment (area)
- Center of diversity
- Characteristic diversity
- Chemical oxygen demand (COD)
- Chemical treatment
- Chlorination
- Chlorofluorocarbons (CFCs)
- Clean technology
- Climate change
- Climate variability
- Co-management
- Combined sewers
- Common property resource management
- Community
- Composting
- Conservation of biodiversity
- Conservation
- Contaminant
- Cooling tower
- Coping capacity
- Corrosion
- Cross-cutting issue
- Cultural diversity
- Dead zone
- Decomposition
- Deforestation
- Degradation
- Demography
- Desertification
- Desulfurization
- Digester
- Disaster risk management
- Disaster risk reduction
- Disinfectant
- Dispersant
- Disposal
- Dissolved oxygen (DO)
- Dissolved solids
- Distillation
- Drainage basin
- Drylands
- Dump
- Early warning
- Eco-labelling
- Ecological footprint
- Ecological security
- Ecology
- Ecosystem approach
- Ecosystem assessment
- Ecosystem management
- Ecosystem
- Ecotourism
- Effluent
- El Niño
- Emission
- Endangered species
- Endemic
- Energy efficiency
- Energy intensity
- Enrichment
- Environmental assessment (EA)
- Environmental audit
- Environmental health
- Environmental impact assessment (EIA)
- Environmental policy
- Environment
- Equity
- Estuary
- Evapotranspiration
- Evolution
- Ex situ conservation
- Exposure
- Extinction
- Fauna
- Filtration
- Flora
- Flue gas
- Fly ash
- Food chain
- Forest degradation
- Forest management
- Forest
- Fossil fuel
- Frugivore
- Fuel cell
- Gene bank
- Gene Flow
- Genetic diversity
- Gene
- Genotype
- Geographic information system (GIS)
- Germplasm
- Global warming
- Globalization
- Green tax
- Greenhouse effect
- Greenhouse gases (GHGs)
- Grey water
- Groundwater
- Guild
- Habitat
- Hazardous waste
- Hazard
- Heavy metals
- Herbicide
- Human health
- Hydrological cycle
- Hydrology
- Incineration
- Incinerator
- Indicator species
- Indigenous peoples
- Indirect discharge
- Infiltration
- Inorganic contaminants
- Insecticide
- Integrated coastal zone management (ICZM)
- Integrated water resources management (IWRM)
- Interlinkages
- Invasive alien species
- Inversion
- Irrigation
- Kuznets curve (environmental)
- Kyoto Protocol
- La Niña
- Lagoon
- Land cover
- Land degradation
- Land use
- Landfills
- Leachate
- Leaching
- Limnology
- Mainstreaming
- Marine protected area (MPA)
- Methane
- Microbes
- Mitigation
- Monitoring
- Multilateral environmental agreements (MEAs)
- Mutualism