- K - Environment/Nature
- K.01 - Natural resources/Raw materials top
- K.01.01 - Natural resources/Raw materials, general
- Asbestos
- Bauxite
- Diamonds
- Drinking water
- Iron ore
- Light metals
- Lime
- Marine resources
- Metal crude ores
- Metals
- Mineral crude ores
- Mineral resources
- Natural resources
- Nitrates
- Non-renewable resources
- Nonferrous metals
- Nonmetallic minerals
- Ores
- Phosphates
- Precious metals
- Precious stones
- Raw materials
- Raw materials deposits
- Raw materials reserves
- Renewable resources
- Salt (mineral)
- Uranium
- Water
- K.01.02 - Chemical elements and compounds
- Antimony
- Cadmium
- Calcium
- Carbon (chemical element)
- Carbon dioxide
- Chemical compounds
- Chemical elements
- Chlorinated hydrocarbons
- Chromium
- Cobalt
- Copper
- Dioxin
- Fluorochlorohydrocarbons
- Gold
- Hydrogen
- Iron (chemical element)
- Lead
- Lithium
- Magnesium
- Manganese
- Mercury (metal)
- Nickel
- Nitrates
- Nitric oxides
- Nitrogen
- Oxygen
- Ozone
- Phosphorus
- Platinum
- Plutonium
- Silicon
- Silver
- Sulphur
- Sulphur dioxide
- Tin
- Titanium
- Tungsten
- Uranium
- Vanadium
- Zinc
- K.01.03 - Energy
- Bioenergy
- Electric power
- Energy
- Energy resources
- Geothermal energy
- Nuclear energy
- Renewable energy sources
- Solar energy
- Water power
- Wind power
- K.01.04 - Fuel types
- Biological fuels
- Charcoal
- Coal
- Fossil fuels
- Fuel types
- Gas fuels
- Lignite
- Natural gas
- Petroleum
- K.02 - Fauna/Animals top
- Animals
- Birds
- Domestic animals
- Evolutionary species
- Fauna
- Fish
- Game (animals)
- Insects
- Mammals
- Marine animals
- Pests/vermin
- Predatory animals
- Reptiles
- K.03 - Flora/Plants top
- Algae
- Evolutionary species
- Flora
- Flowers
- Forests
- Grass
- Medicinal plants
- Plants
- Sea vegetation
- Tree population
- Trees
- Useful plants
- Vegetation
- Vegetation zones
- K.04 - Climate top
- K.04.01 - Climate, general
- Climate
- Climate change
- Climate policy
- Climate protection
- Greenhouse effect
- Greenhouse gases
- Meteorology
- Temperature
- Weather
- Weather satellites
- K.04.02 - Climatic zones/Climatic periods
- Arid zones
- Climatic zones
- Dry season
- Frigid zones
- Humid zones
- Polar regions
- Rainy season
- Seasons/climatic periods
- Semiarid zones
- Subtropical zones
- Temperate season
- Tropics
- K.04.03 - Air, Wind, Precipitation
- Air
- Air temperature
- Clouds
- Cyclones
- Humidity
- Monsoons
- Precipitation
- Storms
- Wind
- K.05 - Earth/Physical geography top
- K.05.01 - Earth, general
- Airspace
- Continents
- Earth
- Earth surface
- Geographical data
- Geographical space
- Geological formations
- Geological/geographical factors
- Interior of the earth
- Temperature of the earth
- World
- K.05.02 - Surface formations of the earth
- Archipelagoes
- Coastal mountains
- Coasts/coastal areas
- Earth surface
- Geographical reliefs
- Glaciers
- Gulfs/bays
- High mountain range
- Inland seas
- Inland waters
- Islands
- Lakes
- Mountains
- Plains
- Plateaus
- River beds
- River courses
- Rivers
- Straits
- Uplands
- Valleys
- Volcanoes
- K.05.03 - Forms of landscape
- Arable land
- Arid areas
- Cultivated landscapes
- Deserts
- Forest areas
- Forests
- Forms of landscape
- Inland waters
- National parks
- Natural landscapes
- Oases
- Pastures
- Savannah
- Steppes
- Tropical rain forests
- Wetlands
- K.05.04 - Inland waters/Seas
- Coastal waters
- Continental shelf (geographic)
- Deep sea
- Deep seabed
- Estuaries
- Flooding
- Fresh water
- Groundwater
- Gulfs/bays
- Inland seas
- Inland waters
- Lakes
- Oceans
- River beds
- River courses
- Rivers
- Salt lakes
- Sea water/salt water
- Seabed
- Seabed subsoil
- Seas
- Straits
- Tidal waves
- Tides
- Transnational waters
- Transport of water
- Water
- Water consumption
- Water demand
- Water resources
- Water storage
- Water supply
- Water temperature
- K.05.05 - Topography, regions, cardinal points
- East
- Equator/equatorial zones
- Geographical distribution
- Geographical position/location
- North
- North pole
- Northeast
- Northern hemisphere
- Northwest
- Parts of a country
- South
- South pole
- Southeast
- Southern hemisphere
- Southwest
- Topographic data
- West
- K.06 - Outer space top
- K.06.01 - Outer space, general
- Astronomical units
- Atmosphere
- Lower atmosphere
- Outer space
- Ozone layer
- Terrestrial space
- Upper atmosphere
- K.06.02 - Planets/Celestial bodies
- Planets/celestial bodies
- K.07 - Environment/Ecology top
- K.07.01 - Environment/Ecology, general
- Air quality
- Balance of ecological impacts
- Biodiversity
- Catastrophes
- Ecological balance
- Ecological catastrophes
- Ecological security
- Ecological systems
- Environment/ecology
- Environmental assets
- Environmental damage
- Environmental factors
- Environmental hazards
- Environmental impact
- Environmental sciences
- Environmental technology
- Environmental tolerance
- Global challenges
- Nature
- Nature reserves
- Physical living conditions
- Quality of the environment
- Regeneration (environment)
- Toxicity
- Utilization of the environment
- Water quality
- K.07.02 - Natural occurences
- Cyclones
- Drought
- Earthquakes
- Fire
- Flooding
- Natural catastrophes
- Natural occurrences
- Storms
- Tidal waves
- Volcanic eruptions
- K.07.03 - Environmental damage, general
- Behaviour causing environmental damage
- Causes of environmental damage
- Changes in the ecological balance
- Climate change
- Consequences of environmental damage
- Damage to human health
- Dangerous products
- Decrease/change in vegetation
- Decrease/illness in animal population
- Endangered species
- Environmental damage
- Environmental damage perpetrators
- Environmental impact
- Environmental warfare
- Global warming
- Industrial pollution
- Long-term damage
- Noise pollution
- Nuclear winter
- Pesticides
- Radiation damage
- Radioactive contamination
- Radioactive fallout
- Reduction of emissions
- Toxins/pollutants
- Wildlife exploitation
- K.07.04 - Environmental damage to the soil
- Artificial landscape changes
- Chemical waste
- Damage to food/feedstuff
- Deforestation
- Desertification
- Destruction of forests
- Dumping (waste disposal)
- Forest damage
- Heavy metal pollution
- Oil pollution
- Overexploitation
- Overfertilization
- Radioactive waste
- Silting
- Soil destruction or contamination
- Soil erosion
- Toxic waste
- Waste
- K.07.05 - Environmental damage to the air
- Acid rain
- Air pollution
- Drought
- Pollutant emission
- Pollution of higher atmosphere
- Smog
- Waste gases
- K.07.06 - Environmental damage to the water
- Changes in water supply/water level
- Heavy metal pollution
- Increase in water temperature
- Marine pollution
- Oil pollution
- Overfishing
- Pesticides
- Pollutant emission
- Waste water
- Water pollution
- K.08 - Environmental protection top
- K.08.01 - Environmental protection, general
- Animal protection
- Climate protection
- Coast protection/river regulation
- Ecological farming
- Environmental controls
- Environmental management
- Environmental protection
- Forest conservation and afforestation
- Game management
- Global commons
- International environmental protection
- Landscape protection/conservation
- National environmental protection
- Natural preserves
- Natural resources management
- Nature reserves
- Nature/wildlife conservation
- Plant protection
- Protection of species
- Regional environmental protection
- Resource protection
- Water protection
- K.08.02 - Environmental policy
- Ecological movements
- Environmental consciousness
- Environmental debates
- Environmental education
- Environmental ethics
- Environmental planning
- Environmental policy
- Environmental standards
- International environment policy cooperation
- International environmental policy
- Ministries of environmental affairs
- Polluter pays principle (environmental policy)
- Prevention principle (environmental policy)
- Public burden principle (environmental policy)
- K.08.03 - Legal, financial and economic aspects of environmental protection
- Cross-border environmental damage
- Economic problems of environmental protection
- Emission rights (environmental assets)
- Emissions trading
- Environmental damage
- Environmental law
- Environmental protection charges
- Environmental protection taxes
- International environmental agreements
- International environmental law
- Legal problems of environmental protection
- Measurement/assessment of environmental damage
- Right to environmental assets
- Right to natural resources control
- Utilization of the environment
- K.08.04 - Environmental protection technology/protection measures
- CBRN protection
- Decontamination
- Desalination
- Disposal
- Ecological production processes
- Ecological products
- Environmental industry
- Environmental protection measures
- Environmental restoration
- Environmental technology
- Final storage of radioactive waste
- Interim storage of radioactive waste
- Noise protection
- Radiation protection
- Recycling (raw materials)
- Sewage systems
- Sewage/purification plants
- Waste disposal
- Waste gas cleaning
- Waste water sewage