37 of the ESS glossary’s terms, each with the part of the syllabus where you first meet it.
A process in succession in which one species changes the conditions, for example by adding nitrogen or organic matter to the soil, in a way that helps other species to establish.
A measure of water availability based on renewable freshwater per person per year: below 1,700 m³ indicates water stress, below 1,000 m³ scarcity and below 500 m³ absolute scarcity.
The practice of leaving farmland uncropped for one or more seasons so that soil nutrients, organic matter and structure can recover.
The services, information and means, such as contraception, that allow people to decide whether, when and how many children to have.
An extreme and widespread lack of food in a region, causing large numbers of deaths from starvation and disease, resulting from failures of food availability and access.
The return of part of the output of a process to affect the same process, so that a change in a system either reduces itself (negative) or increases itself (positive).
A field method of estimating soil texture by moistening and rubbing a small sample between the fingers to judge grittiness, smoothness and stickiness.
The cell of atmospheric circulation between about 30° and 60° latitude, in which air sinks in the subtropics, moves poleward at the surface and rises near 60°.
A substance added to soil or plants to supply nutrients, especially nitrogen, phosphorus and potassium, and so increase growth and yield.
Money, credit and other financial assets that can be used to buy or invest in other forms of capital.
The physical law that energy can be transformed from one form to another but cannot be created or destroyed, so the total energy entering a system equals the total leaving or stored.
A population of one fish species in a defined area that breeds largely within itself and is assessed and managed as a single unit.
An activity or industry that catches or farms a particular aquatic species in a particular area, together with the people, vessels and methods involved.
A dramatic and lasting decrease in a fish stock to a level at which it can no longer support a commercial fishery and cannot recover quickly, even when fishing stops.
The amount of fishing carried out over a period, measured for example as the number of vessels, days at sea, hours of trawling or hooks set.
A legal limit on the amount of a species, usually in tonnes, that a country, fleet or vessel may catch in a period, often set from a total allowable catch.
A charismatic species, such as the giant panda or the tiger, used to raise public awareness and funding for conservation of its habitat and of the many less-known species that share it.
A sudden flood that rises within minutes to a few hours of intense rainfall, usually because surface run-off reaches rivers or drains faster than they can carry it.
A structure such as a levee, embankment, sea wall or storm surge barrier built to stop river or sea water from flooding land.
The movement of energy or matter between storages, or into or out of a system, measured as a rate and drawn as an arrow in systems diagrams.
A sequence of organisms in which each feeds on the one before, showing the path of energy and biomass from a producer to higher consumers.
The distance food travels from where it is produced to where it is eaten, used as a rough indicator of the environmental impact of food transport.
A situation in which all people at all times have physical and economic access to enough safe and nutritious food to meet their dietary needs for an active, healthy life.
Food fit to eat that is discarded at the retail, food-service or household stage; food lost earlier, during harvest, storage, processing and transport, is called food loss.
A network of interconnected food chains in an ecosystem, showing all the feeding relationships, including species that feed at more than one trophic level.
The large-scale death of trees across a forest, often from drought, heat, fire or pests, which can turn the forest from a carbon store into a carbon source and shift it towards savanna.
An approach to conservation that creates protected areas by excluding local and Indigenous people, removing settlements and banning their use of land and resources.
A carbon-rich fuel such as coal, oil or natural gas, formed over millions of years from the partly decomposed remains of ancient organisms buried in sediments.
The total collection of preserved remains and traces of past organisms found in rocks, in the order in which they were laid down, used to reconstruct the history of life.
A forest restoration method that plants a mix of fast-growing native trees chosen to close the canopy quickly and attract seed-dispersing animals, which then bring in other species.
A market in which prices and quantities are set by the voluntary exchange between buyers and sellers, with little or no government control.
An atom or molecule with an unpaired electron, such as a chlorine atom released from a CFC, which makes it highly reactive.
A person or country that enjoys the benefits of a shared resource or collective action without paying its share of the cost, such as a country that lets others cut emissions.
Water with a low concentration of dissolved salts, usually below about 1 g per litre, found in rivers, lakes, groundwater, ice and the atmosphere, and usable for drinking and irrigation.
A planetary boundary process covering human disturbance of the water cycle, measured by changes in river flows (blue water) and in soil moisture (green water).
A device that converts the chemical energy of a fuel, usually hydrogen, directly into electricity by combining it with oxygen, producing water and heat as by-products.
The full range of conditions and resources in which a species could survive and reproduce if there were no limiting biotic factors such as competition or predation.