38 of the ESS glossary’s terms, each with the part of the syllabus where you first meet it.
The cool phase of ENSO, in which the Walker circulation and the trade winds strengthen, cold upwelling off western South America increases and the western Pacific becomes wetter.
The first phase of an S-shaped growth curve, in which a population grows slowly because there are few individuals to reproduce.
The seasonal mixing of a whole lake from top to bottom when surface and deep water reach the same temperature and density, usually in spring and autumn.
Aldo Leopold's ecocentric principle that an action is right when it tends to preserve the integrity, stability and beauty of the biotic community, and wrong when it tends otherwise.
The legal or customary rights of individuals or communities to own, use, control and pass on land and its resources.
Planning rules that control what land may be used for in each area, for example banning new homes on floodplains or in zones at risk of storm surges.
A planetary boundary process covering the conversion of forests, grasslands and wetlands to farmland, settlements and other uses, measured by remaining forest cover.
A site where waste is buried in the ground; a sanitary landfill is engineered with a liner, daily cover and systems to collect leachate and landfill gas.
The rate at which air temperature falls with increasing altitude in the troposphere: about 1 °C per 100 m for rising dry air and on average about 0.65 °C per 100 m in the real atmosphere.
Energy absorbed or released when a substance changes state without a change in temperature, such as the heat taken in by evaporation and given out by condensation.
The angular distance of a place north or south of the equator, measured in degrees from the centre of the Earth, from 0° at the equator to 90° at the poles.
A rule that governs human behaviour, made and enforced by a social or governmental authority, so that breaking it can bring a penalty such as a fine, an order to repair damage or prison.
The liquid formed when water percolates through waste, carrying dissolved substances such as organic compounds, ammonia and heavy metals that can pollute soil, groundwater and rivers.
The removal of dissolved minerals and nutrients from soil as water percolates downwards through it, carrying them to lower horizons or groundwater.
The layer of fallen leaves, twigs, bark and other dead plant parts lying on the soil surface, the main input of dead organic matter to most soils.
The IUCN Red List category for species that have been assessed and do not qualify for a higher-risk category, usually because they are widespread and abundant.
The status of being recognised by law as able to hold rights and duties and to sue or be sued, given to companies and increasingly to natural entities such as rivers and forests.
A plant of the pea and bean family, such as clover, beans, peas, lentils and soya, whose root nodules hold nitrogen-fixing bacteria.
Land sown with grass, often mixed with clover and herbs, for a few years as part of a rotation, grazed or cut, then ploughed for arable crops.
The sequence of stages an organism passes through from the start of its life to reproduction and death, including its timing and lifespan.
The average number of years a person can expect to live, usually measured from birth, if the death rates at each age at the time stay the same throughout their life.
A method for measuring aquatic primary productivity by comparing the change in dissolved oxygen in clear and darkened bottles of water incubated together for a set time.
A rating scale on which respondents show how strongly they agree or disagree with a statement, usually with five or seven points from strongly disagree to strongly agree.
A sedimentary rock made mostly of calcium carbonate, often from the shells and skeletons of marine organisms; the largest carbon store on Earth, holding carbon for hundreds of millions of years.
The addition of crushed limestone or other calcium compounds to acidic soil to raise its pH and make nutrients more available to plants.
The environmental factor, abiotic or biotic, that is in shortest supply relative to need and therefore restricts the growth, abundance or distribution of a population.
A method of estimating the size of a population of mobile animals from capture-mark-release-recapture data, calculated as (M × N) ÷ R.
A graph that plots values of a dependent variable against a continuous independent variable, usually time, and joins the points with lines to show change and trends.
A straight line or smooth curve drawn through a set of plotted points so that it represents the general trend, with the points spread roughly evenly on either side of it.
A transect along which every organism touching the line is recorded at set intervals.
An economic model in which raw materials are extracted, made into products, used and then discarded as waste; often summarised as take, make, waste.
Natural gas, mainly methane, cooled to a liquid at about −162 °C so that it can be shipped in tankers and turned back into gas at an import terminal.
The rigid outer layer of the solid Earth, made of the crust and the uppermost mantle, which forms the base of soils and landforms.
The attempt by individuals, companies or interest groups to influence the decisions of lawmakers and governments in favour of their own interests, through meetings, donations, campaigns or funded research.
A deposit of wind-blown silt, often many metres thick, that forms fertile but easily eroded soils, as on the Loess Plateau of China.
Harm from climate change that cannot be avoided by mitigation or adaptation, such as destroyed homes or land lost to the sea, and the finance provided to help vulnerable countries recover.
A method of estimating the organic matter content of a dry soil sample by burning off the organic matter at high temperature and measuring the loss in mass.
An area of a city where the most polluting vehicles are banned or must pay a charge to enter, in order to improve air quality.