The Geography glossary

A natural resource that comes from non-living parts of the environment, such as minerals, oil, gas, sand or water, rather than from living organisms.

The loss of mass from a glacier by melting, sublimation, evaporation and calving; the zone of ablation is the lower part of a glacier, where annual losses exceed gains.

An erosion process in which material carried by a river, waves, ice or wind is scraped and bounced against a surface, wearing it away; also called corrasion.

A barrier that halts diffusion completely, so that the phenomenon cannot pass beyond it.

The share of a population using facilities that hygienically separate excreta from human contact, measured on the WHO/UNICEF ladder from open defecation to safely managed services.

The process by which a culture changes by adopting features of another, usually more dominant, culture through prolonged contact, for example with visitors or global media.

The addition of mass to a glacier by snowfall, avalanches, wind-blown snow and refreezing meltwater; the zone of accumulation is the upper part of a glacier, where annual gains exceed losses.

Precipitation, fog or dry particles made more acidic than normal by sulphuric and nitric acids formed from sulphur dioxide and nitrogen oxide emissions, which damage lakes, soils, forests and buildings downwind.

The surface layer of soil above permafrost that thaws each summer and refreezes each winter, from a few centimetres to several metres thick.

A sudden, sharp event that threatens a city, such as a flood, earthquake, heatwave, terrorist attack, cyber attack or disease outbreak.

Adjustment in natural or human systems in response to actual or expected climate change and its effects, which reduces harm or makes use of new opportunities.

The ability of a society, organisation or individual to adjust to potential damage from climate change, take advantage of opportunities or respond to its consequences.

An approach in which management decisions are treated as experiments, monitored, and revised as new information about their effects becomes available.

The stage in diffusion at which a person, household or place takes up an innovation or, for a disease, becomes infected (acquisition).

An S-shaped graph of the cumulative percentage of adopters of an innovation over time, rising slowly, then rapidly, then levelling off at saturation.

Tourism that involves physical challenge and a degree of perceived risk, usually in a natural setting, such as trekking, mountaineering, white-water rafting or bungee jumping.

A suspension of tiny solid or liquid particles in the air, such as sulphate droplets, volcanic ash, soot, dust and sea salt, that can reflect or absorb sunlight and affect cloud formation.

Policies that give members of disadvantaged groups preferential access to education, jobs, contracts or political office, such as quotas or reserved seats, to reduce inequality caused by past and present discrimination.

The planting of trees on land that was not recently forested; replanting land that was recently cleared is reforestation.

A period from about 14,500 to about 5,000 years ago, often called the Green Sahara, when stronger monsoon rains turned much of the Sahara into grassland and savanna with lakes and rivers.

A population in which the proportion of people aged 65 and over is increasing and the median age is rising, mainly as a result of low fertility and rising life expectancy.

The clustering of people and economic activity in one place; agglomeration economies are the cost savings and productivity gains firms obtain from locating near each other.

Large-scale commercial farming and the businesses linked to it, including firms that supply seeds, agrochemicals and machinery and those that trade, process, manufacture and sell food.

A shortage of soil moisture during the growing season that reduces crop yields and pasture, caused by low rainfall, high evaporation or poorly timed rain.

An increase in agricultural output per unit of land, achieved by using more labour, capital, technology or inputs such as fertiliser, irrigation and improved seeds on the same area.

A situation in which a country, region or community relies on aid to meet basic needs over a long period, so that its own production, markets and institutions are weakened or fail to develop.

The presence in the atmosphere of gases or particles, from human or natural sources, at concentrations that harm human health, ecosystems or materials.

A scale that converts measured concentrations of several air pollutants into one number and category, used to tell the public how polluted the air is and what precautions to take.

The proportion of incoming solar radiation reflected by a surface, from 0 to 1 or as a percentage; fresh snow reflects about 0.8–0.9 and open ocean about 0.06.

A stage in a scale of warnings, often numbered or coloured, that tells authorities and the public how active a volcano or other hazard is and what actions, such as evacuation, to take.

A rapid increase in algae or cyanobacteria in a body of water, usually caused by excess nutrients, which discolours the water and can release toxins.

A resort where one price, usually paid in advance, covers accommodation, meals, drinks and most activities, so that guests have little need to spend money outside it.

Describes a tourist who seeks new, unfamiliar and adventurous destinations and travels independently, often before a place becomes popular (Plog's 'venturer').

A fan-shaped deposit of sediment formed where a stream or flash flood leaves a narrow valley or mountain front and spreads out onto a plain; merged fans form a bajada.

A movement that supports international co-operation and global links but seeks an alternative form of globalisation based on social justice, workers’ rights and environmental protection rather than free markets alone.

A network of producers, traders and consumers that trades outside or alongside mainstream markets on agreed social and environmental terms, such as Fairtrade, Rainforest Alliance or direct trade.

An illness caused by the low oxygen pressure at high altitude, with headache, nausea, fatigue and breathlessness, usually affecting people who climb quickly above about 2,500 m.

The spread of the culture, products, brands, media and values of the United States to other countries, often seen as a form of cultural imperialism.

A value or place that does not fit the general pattern or trend of a data set, which may be caused by an error in measurement or by a real local factor.

The international agreement, signed in 1959, that reserves Antarctica for peace and science, sets aside territorial claims and, through its 1991 Environmental Protocol, bans mineral extraction.

The amount of water already held in the soil and stores of a drainage basin before a rainfall event, which strongly affects how much of the rain becomes overland flow.

Heat released into the atmosphere by human activities, such as vehicles, heating and air conditioning, industry and people’s own metabolism.

A broad, loosely organised social movement that opposes economic globalisation, especially free trade, the power of transnational corporations and the policies of international economic institutions such as the WTO, IMF and World Bank.

A political or social movement that seeks to reduce or stop immigration, or to restrict the rights of migrants, through campaigning, voting, protest and sometimes violence.

A government policy that aims to reduce the birth rate and family size, for example through family planning services, education, incentives for small families or legal limits on births.

The ability of bacteria, viruses, fungi or parasites to survive drugs that once killed them, so that infections become harder or impossible to treat.

The farming of fish, shellfish, seaweed and other aquatic organisms in ponds, tanks, cages or other enclosures.

A body of permeable rock or sediment that can store water and allow it to move through it; it is unconfined when open to the surface and confined when sealed by impermeable layers.

Land cultivated to grow temporary crops such as cereals, vegetables and fodder, including land left fallow for a short period.

The faster warming of the Arctic than the world as a whole, nearly four times faster since 1979, caused mainly by snow and sea-ice loss (ice–albedo feedback) and the lapse-rate feedback.

The size of the area affected by a hazard event, from a single slope or valley to a whole region or, for ash clouds and tsunamis, an ocean basin.

A narrow, steep-sided rock ridge formed where two cirques or glacial troughs erode back towards each other.

An environment in which potential evaporation greatly exceeds precipitation, giving a water deficit for most or all of the year; its aridity index lies between 0.05 and 0.2.

A soil of arid regions that is dry for most of the year, with little organic matter and often layers of calcium carbonate, gypsum or salts near the surface.

A permanent shortage of moisture in a climate, caused by low precipitation relative to potential evaporation; a long-term characteristic of a place, unlike drought, which is temporary.

A measure of dryness equal to mean annual precipitation divided by mean annual potential evapotranspiration; below 0.05 is hyper-arid, 0.05–0.2 arid, 0.2–0.5 semi-arid and 0.5–0.65 dry sub-humid.

An island created by people by piling sand, rock or other material onto a reef or seabed, or by building a platform; under UNCLOS it generates no territorial sea or EEZ.

A raised embankment of earth, concrete or stone built along a river bank to increase the capacity of the channel and keep floodwater off the land behind it; called a dyke in the Netherlands.

Small-scale mining by individuals, families or small groups using simple tools, often informal or illegal, with little protection for workers or the environment.

The design of buildings and infrastructure so that they bend, absorb or isolate earthquake shaking without collapsing, for example through flexible frames, cross-bracing, shear walls, dampers and base isolation.

A multilateral development bank proposed by China in 2013 and operating since 2015, headquartered in Beijing, which finances infrastructure in Asia and beyond and has over 100 members.

One of the four skill areas against which geography answers are judged: AO1 knowledge and understanding, AO2 application and analysis, AO3 synthesis and evaluation, and AO4 selection and use of skills.

A process in which a minority or migrant group adopts the language, customs and values of the majority society and loses much of its distinct culture.

The weak, partly molten layer of the upper mantle beneath the lithosphere, on which the rigid plates move.

A person who has left their country and applied for international protection as a refugee in another country, and is waiting for a decision on the claim.

The Atlantic part of the global ocean conveyor belt, in which warm surface water flows north, cools and sinks in the North Atlantic, and returns south as cold deep water.

The layer of gases surrounding the Earth, held by gravity, made up mainly of nitrogen and oxygen with small amounts of argon, carbon dioxide, water vapour and other gases.

The study of how far human-caused climate change has altered the likelihood or intensity of a particular extreme weather event, by comparing today’s climate with a modelled climate without human influence.

An erosion process in which particles of load collide with each other and break into smaller, more rounded pieces.

An organised effort using media, social media, events and publicity to inform the public about an issue and change attitudes or behaviour, often the first stage of pressure on decision-makers.

The return flow of water down a beach under gravity after the swash, carrying sediment back towards the sea at right angles to the shoreline.

Water pumped into tanks in a ship’s hull to keep it stable when it carries little cargo, and released in another port, often carrying organisms from a distant ecosystem.

The discharge at which a river fills its channel completely, just before it overflows onto the floodplain.

A ridge of sand or shingle that extends across a bay, joining two headlands and enclosing a lagoon behind it.

A crescent-shaped dune with its horns pointing downwind and its slip face on the concave side, formed where sand is limited and the wind blows from one direction.

Any physical, economic, political, cultural or informational obstacle that slows or prevents the spread of an innovation, idea or disease.

The movement of a glacier over its bed on a film of meltwater, possible only where the base is at the pressure melting point.

The part of a river's discharge supplied by groundwater seeping slowly into the channel, which keeps the river flowing between storms and in dry seasons.

A method of aseismic design in which a building rests on flexible bearings, such as layers of rubber and steel, that absorb ground motion so that less shaking reaches the structure above.

The lowest level to which a river can erode its bed, usually sea level, or the level of a lake for rivers that drain into one.

An international treaty, signed in 1989 and in force since 1992, that controls transboundary movements of hazardous wastes and requires the prior informed consent of importing countries.

The line, normally the low-water line along the coast, from which a state's territorial sea, EEZ and other maritime zones are measured.

The average number of people to whom one infected person passes a disease in a population where nobody is immune and no control measures are taken.

An accumulation of sand or shingle on the shore between the low water mark and the limit of storm waves, shaped by the balance between swash and backwash.

The artificial addition of sand or shingle to a beach, usually dredged from offshore, to make it higher and wider so that it absorbs more wave energy.

A cross-section of a beach from the sea to the back of the beach, measured as a series of slope angles and distances between breaks of slope.

A global infrastructure and investment strategy launched by China in 2013, financing ports, railways, roads, energy and telecommunications through overland corridors and a Maritime Silk Road.

The zone of earthquake foci that dips from the trench into the mantle along a subducting plate, reaching depths of up to about 700 km.

A systematic distortion of results caused by the way sites, people or data are chosen, recorded or interpreted, so that they no longer represent the whole fairly.

A theory (Alonso, 1964) that land users bid for sites according to the value of accessibility to them, so land values and land-use intensity fall with distance from the city centre.

The competitive procedure through which cities or countries apply to host an event, presenting plans, guarantees and campaigns to the owning organisation, which then chooses the host.

Aid given directly from the government of one country to the government of another, often reflecting the donor’s political and commercial links.

The capacity of ecosystems in an area to regenerate the resources people use and absorb their wastes, measured in global hectares, usually per person.

The breeding of food crops, by conventional methods or genetic engineering, so that they contain more vitamins or minerals as they grow.

A fuel made from recently living organic matter, such as ethanol from maize or sugar cane and biodiesel from vegetable oil, used in place of petrol and diesel.

The transfer of carbon from the surface ocean to the deep ocean and sea floor by organisms, as phytoplankton take up CO₂ and dead organisms and faecal pellets sink.

A large-scale ecosystem, such as tundra, boreal forest or tropical rainforest, characterised by its dominant vegetation and closely related to climate.

The measurement of physical or behavioural characteristics, such as the face, fingerprints or iris, to identify individuals automatically, for example at borders or for access to services.

A natural resource obtained from living organisms, such as fish, shellfish, marine mammals or seaweed.

A graph that plots scores on a scale between two opposite descriptions, such as poor and good, usually from −3 to +3, to compare the quality of places.

The number of live births per 1,000 people in a population per year, also called the crude birth rate.

A hollow in a sand dune scooped out by wind erosion where the protective vegetation cover has been broken by trampling, grazing or storms.

Carbon captured and stored by coastal and marine ecosystems, especially mangroves, saltmarshes and seagrass meadows, mostly in their waterlogged soils.

The part of a water footprint made up of surface water or groundwater withdrawn, for example for irrigation, and not returned to the source it came from.

A measure of body weight relative to height, calculated as weight in kilograms divided by the square of height in metres; for adults 25 or more is overweight and 30 or more obese.

A cycle in which a place grows rapidly while a resource is profitable to extract and declines sharply when prices fall or the resource runs out.

The theory, set out by Ester Boserup in 1965, that population growth and pressure on food supplies stimulate agricultural innovation and intensification, so food production rises to meet the needs of more people.

An approach in which local communities identify their own water needs and plan, build and maintain solutions, often small-scale and low-cost, with outside support where needed.

A graph summarising a data set by its minimum, lower quartile, median, upper quartile and maximum, showing its spread and allowing data sets to be compared.

The deliberate refusal to take part in an event, or to buy from or deal with a country or organisation, as a form of protest.

A model that summarises how river channel characteristics change downstream, with discharge, width, depth, velocity and load quantity increasing and particle size, bed roughness and gradient decreasing.

The emigration of highly educated or skilled people, such as doctors, engineers and teachers, from a place, which reduces its human capital and ability to develop.

An intergovernmental group of major emerging economies, founded as BRIC by Brazil, Russia, India and China in 2009, joined by South Africa in 2010 and enlarged from 2024.

Water with a much higher concentration of dissolved salts than seawater, produced as waste by desalination plants or found naturally beneath salt flats.

A method of obtaining lithium and other dissolved salts by pumping mineral-rich groundwater from beneath a salt flat into shallow ponds, where evaporation concentrates it before processing.

A theory, put forward by Wilson and Kelling in 1982, that visible signs of disorder and neglect in an area encourage further antisocial behaviour and more serious crime.

Land that has previously been developed, such as a former factory, dock or railway yard, which may be derelict or contaminated and can be reused.

A genetically modified crop containing a gene from the bacterium Bacillus thuringiensis that makes it produce a protein toxic to certain insect pests, such as bollworms in cotton.

An approach to recovery that uses reconstruction to reduce future disaster risk, for example by rebuilding to stronger codes, moving homes out of hazard zones and improving services.

A set of legal standards that buildings must meet in design and construction, for example to resist earthquake shaking.

The human-made surroundings in which people live and work, including buildings, streets, public spaces and infrastructure.

Heavy fuel oil, a thick residue of crude oil refining, burned in the engines of large ships; it is cheap but high in sulphur, so it pollutes the air along shipping lanes and in ports.

A model (1925, based on Chicago) of a city as five concentric rings around the central business district, in which housing quality and residents' wealth increase with distance from the centre.

A high-capacity bus system with dedicated lanes, stations with fare payment before boarding and frequent services, giving metro-like speed and reliability at lower cost.

A planned area of offices, research and light industrial buildings in a landscaped setting at the edge of a city, with good road or airport access and parking.

An isolated, steep-sided hill with a small flat top, higher than it is wide, formed as a mesa is worn back by weathering and erosion.

Fish and other marine animals, such as dolphins, turtles and seabirds, caught unintentionally while fishing for a target species.

The process by which marine organisms such as corals, molluscs and some plankton build shells and skeletons of calcium carbonate from dissolved calcium and carbonate ions.

A carbon trading system in which a government sets a declining cap on total emissions, issues allowances up to that cap, and lets firms buy and sell them.

A view of development, associated with Amartya Sen, that judges progress by people’s real freedoms to be and do what they value, rather than by income alone.

The total amount of load that a river can carry at a given discharge.

The ability of people, organisations and systems to use their resources and skills to manage a hazard event and its effects.

The upward movement of water through narrow spaces between soil particles, against gravity, which can carry dissolved salts towards the surface.

The harvesting of wild fish and other aquatic animals from the sea, rivers and lakes, as opposed to farming them.

A residential area designed so that most households do not own or need a car, with streets reserved for walking, cycling and access, and any parking placed at the edge.

Technology that captures CO₂ from large sources such as power stations and industrial plants, transports it and stores it permanently in underground rock formations.

The increase in plant growth and water-use efficiency caused by higher carbon dioxide concentrations in the air, strongest in C3 plants such as wheat and rice.

Methods that remove CO₂ from the atmosphere and store it in plants, soils, rocks or the ocean, such as afforestation, direct air capture and enhanced weathering.

The total greenhouse gas emissions, in tonnes of CO₂-equivalent, caused directly and indirectly by a person, organisation, event or product over a period or over its life cycle.

Compensating for greenhouse gas emissions by paying for an equivalent reduction or removal elsewhere, usually by buying carbon credits from projects such as forest protection.

A carbon store that absorbs more carbon from the atmosphere than it releases, reducing the concentration of carbon dioxide in the air; the oceans and growing forests are the main natural sinks.

A reservoir in the Earth system that holds carbon for a period of time, such as the atmosphere, oceans, vegetation, soils, permafrost, fossil fuels and sedimentary rocks.

A tax on the carbon content of fuels or on greenhouse gas emissions, which raises the cost of polluting activities and gives an incentive to cut emissions.

A market-based approach in which permits to emit greenhouse gases are bought and sold, so that emissions are cut where it is cheapest to do so; also called emissions trading.

The maximum population that an area can support indefinitely with its available resources without degrading the environment; for people it depends on technology, trade and levels of consumption.

A chain of hazards in which one event triggers others, such as an earthquake causing landslides, liquefaction and a tsunami, or an eruption followed by lahars.

The proportion of people diagnosed with a disease who die from it, usually expressed as a percentage.

A located, detailed and recent study of one place, event or issue, with data on causes, impacts and responses, used as evidence for discussion in an answer.

A payment of money from a government or aid agency directly to poor or vulnerable households, given either unconditionally or on conditions such as school attendance or clinic visits.

A bond sold to investors that pays a government or insurer a set sum if a defined disaster, such as an earthquake above a given magnitude in a given area, occurs; otherwise investors keep their money and interest.

The suppression or control of speech, writing, media or online content by a government or other authority that considers it harmful, offensive or a threat to security or public order.

The commercial centre of a city, with the highest land values and accessibility, tall buildings, a concentration of offices, shops and services, and few residents.

Christaller's model (1933) of the size, number and spacing of settlements that serve their surrounding areas, in which higher-order centres with larger ranges and thresholds are fewer and further apart.

An irrigation system in which a line of sprinklers mounted on wheeled towers rotates around a central water supply, watering a circular field.

The movement of people or economic activity away from the centre of an urban area, such as suburbanisation and counter-urbanisation.

The movement of people or economic activity towards the centre of an urban area, such as rural–urban migration, gentrification and reurbanisation.

Migration in which people follow relatives, friends or neighbours who have already moved, relying on them for information, housing and work at the destination.

The modification of a river channel by straightening, deepening, widening or lining it, usually to carry floodwater away more quickly; also called channel modification.

The idea, proposed by Jule Charney in 1975, that vegetation loss in drylands raises surface albedo and reduces rainfall, so that less vegetation grows: a positive feedback.

A small, low barrier built across a stream or gully to slow runoff, trap sediment and let water infiltrate and recharge groundwater; the johad of north India is one form.

The decomposition of rock by chemical reactions that change its minerals, such as hydration, oxidation and solution; it needs water and is fastest in warm, wet climates.

A statistical test comparing observed frequencies in categories with the frequencies expected if there were no difference or association, to see whether the gap is significant.

A narrow, strategic passage on a transport route, such as a strait or canal, through which a large share of trade passes and where disruption would block or delay supply.

An acute diarrhoeal disease caused by the bacterium Vibrio cholerae, spread through food or water contaminated with faeces, which can kill through dehydration within hours.

A map that shades areas such as countries or districts in graded tones of one colour according to classes of a value expressed as a rate or ratio, such as density or a percentage.

A slow-moving, long-term pressure that weakens a city over time, such as poverty, inequality, ageing infrastructure, water scarcity or sea-level rise.

A small, steep volcanic cone built from loose fragments of tephra, usually during a single short-lived eruption.

An economic system that designs out waste and pollution, keeps products and materials in use at their highest value through reuse, repair, remanufacture and recycling, and regenerates natural systems.

An urban metabolism in which outputs such as waste, wastewater and heat are reused or recycled as inputs, so the city uses fewer resources and produces less waste.

An armchair-shaped hollow on a mountainside with a steep backwall, an over-deepened rock basin and a lip, eroded by a small glacier; it often holds a tarn after the ice melts.

The reporting of news, images and video by members of the public rather than professional journalists, usually shared through social media.

Scientific research in which members of the public collect, process or analyse data, usually following a standard method designed with professional scientists.

The citizens, groups and organisations that act collectively outside government and business, such as NGOs, community groups, faith groups, trade unions and social movements.

An organisation formed by citizens outside government and business to pursue shared interests or values, such as a charity, campaign group or trade union; an international one works across several countries.

A model of sector shift in which, as an economy develops, employment moves from the primary sector to the secondary sector and then to the tertiary and quaternary sectors.

The use of measures such as regrading, drainage, toe protection, rock bolts and vegetation to reduce erosion and mass movement on a cliff.

The view that climate change is an ethical and political issue because those least responsible for emissions are often most vulnerable to its effects, so the costs of responding should be shared fairly.

A computer simulation of the climate system, based on the physics of the atmosphere, oceans, land and ice, used to project future climate under different scenarios of greenhouse gas emissions.

The planned, permanent movement of a community away from a place made unsafe or uninhabitable by the effects of climate change, such as erosion or permafrost thaw.

A plausible, internally consistent description of how the climate might develop under particular assumptions about emissions and socio-economic change, such as the IPCC’s Shared Socioeconomic Pathways; not a prediction.

A theory that live, round-the-clock television and online news coverage of a crisis influences governments’ decisions, for example by creating public pressure to send aid.

The planning and use of strategies to reduce coastal erosion and flood risk and to balance the competing human and environmental uses of a coastline.

The division of a coastline and its waters into zones in which particular uses, such as ports, tourism or conservation, are permitted or banned.

A measure of relative variability equal to the standard deviation of a set of values divided by their mean, multiplied by 100; for annual rainfall, a higher percentage means less reliable rain.

An ocean current colder than the surrounding water and air, usually flowing from high latitudes towards the Equator on the eastern side of an ocean basin.

A glacier whose base is below the pressure melting point and frozen to the bedrock, so it moves only slowly by internal deformation and does little erosion.

A word or phrase at the start of an examination question, such as describe, explain or evaluate, that states what kind of answer is wanted and how much depth it needs.

Farming in which crops or livestock are produced mainly for sale, with the aim of making a profit.

The process by which cultural traditions, objects, places or experiences are turned into products to be bought and sold, often for visitors.

The principle that certain areas and their resources, such as the deep seabed beyond national jurisdiction, belong to all humanity and must be managed for the benefit of all.

A customs union in which goods, services, capital and people can also move freely between member states.

A resource, such as an aquifer or fishery, from which it is difficult to exclude users and where each user's consumption reduces what is left for others.

An illness caused by a pathogen such as a bacterium, virus or parasite that can pass between people or animals, directly or through water, food, air or a vector.

A member of a community, given basic training, who provides health education, preventive care, simple treatment and referrals in that community, often where doctors are scarce.

The involvement of local water users in decisions about the planning, construction, operation, maintenance and financing of water services and resources.

An approach in which local people identify the hazards they face and plan, carry out and monitor their own risk reduction actions, often with support from governments and NGOs.

Tourism that is owned and managed by a local community, which decides how visitors are received and keeps most of the income.

A system in which consumers pay a farm in advance for a share of its produce for the season, so that consumers and the farmer share the risks and rewards of production.

A town or village, usually beyond the edge of a city, whose residents mostly travel to work in the city each day.

An urban form with relatively high residential density and mixed land uses, which reduces travel distances and the amount of land built on.

The size of the largest particle that a river can transport at a given velocity.

A steep-sided cone built from alternating layers of ash and lava erupted from viscous magma, often explosively, such as Mount Fuji.

A bar graph in which each bar is divided into parts showing the components of a total, either as values or as percentages of 100.

A technology in which mirrors focus sunlight onto a receiver to heat a fluid that drives a turbine; the heat can be stored, for example in molten salt, to generate power after dark.

A coastline where bands of rock of different resistance run parallel to the shore, so that a resistant outer band protects weaker rock behind it.

The policy conditions, such as spending cuts, tax rises or privatisation, that a borrowing country must accept in order to receive a loan from the IMF or another lender.

The funnel-shaped lowering of the water table around a well that pumps groundwater faster than it can flow in from the surrounding aquifer.

A grid that compares each pair of land uses or activities in an area and shows whether they are compatible, in conflict, or compatible only under certain conditions.

A low, long and gentle wave, breaking about 6–8 times a minute, whose strong swash and weak backwash move sediment up the beach and build it up.

The use of a place's scenery, heritage or atmosphere as a product that visitors experience and pay for, which can change or degrade the landscape being consumed.

The emissions caused by the goods and services consumed in a country, wherever they were produced: territorial (production-based) emissions minus emissions in exports plus emissions in imports.

Expansion diffusion through direct contact between people or neighbouring places, so that spread is strongly affected by distance from the hearth.

The transport of goods in standard-sized steel containers that can be moved between ships, trains and lorries without unpacking, which cut shipping costs and required large new port terminals.

A situation in which different stakeholders compete for the same urban land or disagree over how it should be used or changed, usually because they gain or lose differently from the change.

The belt of sea from 12 to 24 nautical miles from a state's baseline, in which the state may enforce its customs, tax, immigration and health laws.

The thick, less dense layer of mainly granitic rock, about 25–70 km thick, that forms the continents; it is too buoyant to subduct and parts are about 4 billion years old.

In law, the seabed and subsoil beyond a state's territorial sea to 200 nautical miles, or to the edge of the continental margin up to 350 nautical miles, over whose resources the state has rights.

The effect of distance from the sea on climate: places deep inside a large continent have a larger annual temperature range and usually less precipitation than coastal places at the same latitude.

Permafrost that underlies 90–100% of the ground surface, found where mean annual temperatures are well below freezing; it is often hundreds of metres thick.

A line on a map joining points of equal height above sea level; the vertical distance between adjacent contours is the contour interval.

An arrangement in which a buyer, usually a company, agrees in advance to purchase a farmer’s produce at an agreed price, quantity and quality, often supplying inputs and advice in return.

A circulation in which hot, less dense material rises, spreads and cools, then sinks again; in the mantle it transfers heat outward over millions of years.

A plate boundary where two plates move towards each other, so that one plate subducts or the crust is crumpled in a collision.

A roof with a light-coloured or reflective surface of high albedo, so that it absorbs less solar radiation and stays cooler than a conventional dark roof.

The whitening of corals when unusually warm water makes them expel the algae living in their tissues that supply most of their food; if the heat lasts, the corals die.

A structure built over thousands of years from the calcium carbonate skeletons of reef-building corals, in warm, shallow, clear tropical seas, supporting very high biodiversity.

A region with a concentration of people, economic activity, investment and political power, usually centred on a capital city, port or industrial area.

A spatial pattern in which a dominant core region, holding most of a country’s wealth, investment and power, is surrounded by less developed peripheral regions that depend on it.

The apparent deflection of moving air and water caused by the Earth’s rotation, to the right in the northern hemisphere and to the left in the southern hemisphere; zero at the Equator.

Describing the optimistic view that human ingenuity, technology and markets will always find ways to overcome resource shortages, so population and economic growth can continue.

The idea and practice that businesses should take responsibility for their effects on society and the environment, going beyond legal requirements and profit.

A relationship between two variables in which one changes as the other changes: positive when both rise together, negative when one rises as the other falls.

A method of appraising a project by comparing its expected costs and benefits, usually in monetary terms over its lifetime, to judge whether it is worthwhile.

The net movement of people from large urban areas to smaller towns, villages and rural areas beyond the edge of the city.

Products made and sold with a copied trademark or design so that they appear to be genuine branded goods, in breach of intellectual property law.

An international initiative led by Gavi, CEPI and the WHO, with UNICEF, to buy and distribute COVID-19 vaccines fairly to all countries, especially low- and middle-income countries.

A small area in which crime occurs much more frequently than in the surrounding area, identified by mapping recorded crimes.

An approach that reduces opportunities for crime by designing buildings and public spaces with natural surveillance, clear boundaries, good lighting and maintenance.

The lowest mean velocity at which a particle of a given size is picked up and set in motion by flowing water; also called the entrainment velocity.

The systems and assets, such as energy, water, transport, telecommunications and health services, that are essential to a city’s functioning and whose loss would cause severe disruption.

The value from a statistical table that a calculated test statistic must reach for the result to be significant at a chosen level, for a given sample size or degrees of freedom.

A side view of the shape of the land surface along a straight line between two points, drawn from contour heights on a map or from field measurements.

Obtaining information, ideas, services or funds from a large number of people, usually through the internet or mobile phones, rather than from employees or official sources.

Raising money for a project, cause or person by collecting small contributions from a large number of people, usually through an online platform.

Mapping in which many volunteers add data, such as roads, buildings or damage seen on satellite images or reported by phone, to a shared online map used by responders.

The parts of the Earth’s surface where water is frozen, including ice sheets, glaciers, sea ice, lake and river ice, snow cover and permafrost.

The spread of cultural traits, ideas and products from their place of origin to other places and peoples, through migration, trade, media, tourism and the internet.

The variety of cultures, languages, ethnicities and identities found in a place, from the local to the global scale.

The creation of new cultural forms, such as foods, music, languages or festivals, by mixing traits from two or more cultures.

The spread and dominance of one society’s culture, products and values over others, through economic and political power, so that local cultures are weakened or replaced.

A landscape shaped by the people who live in it, whose buildings, land uses, signs and sacred sites show their culture and how it changes.

A single element of a culture, such as a language, a religious practice, a food, a style of dress, a type of music or a custom.

The shared beliefs, values, customs, practices, language and material goods of a group of people, learned and passed on from one generation to the next.

A process in which an initial advantage attracts investment and growth, which create further advantages and growth, so success builds on itself in an upward spiral.

Rights to own or use land that come from the traditions of a community, such as a village, clan or herding group, rather than from a title registered by the state.

A free trade area whose members also set a common external tariff on imports from non-member countries.

Crime carried out using computers and the internet, either by attacking computer systems and data or by using digital networks to commit offences such as fraud, theft and extortion.

The protection of computer networks, devices, programs and data from attack, damage or unauthorised access, through technology, procedures, training and cooperation between organisations and states.

A self-reinforcing sequence in which low income leads to poor housing, diet, health and education, which lead to low-paid work or unemployment, keeping income low and passing disadvantage to the next generation.

A barrier built across a river or stream to hold back water, raise its level or control its flow.

Travel to places associated with death, suffering, atrocity or disaster, such as battlefields, genocide memorials, former prisons and disaster zones.

An incident in which personal or confidential data held by an organisation are accessed, copied, stolen or published by someone who is not authorised to do so.

The transfer of digital information, such as communications, financial transactions, media and business data, between places across networks, especially across international borders.

An area of a lake or sea where oxygen levels are so low, usually because of eutrophication, that most aquatic life cannot survive.

The number of deaths per 1,000 people in a population per year, also called the crude death rate.

A fast-moving, water-saturated mixture of mud, rock and vegetation that flows downslope, often along a channel.

Money that a government, firm or household owes to lenders and must repay, usually with interest; a country’s external debt is the part owed to foreign lenders.

The partial or total cancellation of a country’s debt, or the rescheduling of its repayments on easier terms, by its creditors.

The breaking of the link between economic growth and environmental pressure, so that GDP rises while emissions grow more slowly (relative decoupling) or fall (absolute decoupling).

The extraction of mineral deposits such as polymetallic nodules, seafloor massive sulphides and cobalt-rich crusts from the deep-ocean floor.

A theory of residential design, put forward by Oscar Newman in 1972, that crime falls where the layout of buildings and spaces gives residents a sense of ownership and the ability to watch over them.

The removal of loose, fine particles from the ground surface by wind, which lowers the land and can form deflation hollows.

The permanent clearance of forest and its replacement by another land use, such as farming, grazing, mining or settlement.

How cut off a place is from transport routes, communications and outside help, which affects how quickly rescue and relief arrive after a hazard event.

The long-term decline of manufacturing industry, measured by its share of employment or output, in a city, region or country.

A landform of sediment deposited where a river enters a sea or lake faster than waves and currents can remove it, often divided by distributaries; arcuate, bird's-foot and cuspate are its main shapes.

An approach to water scarcity that reduces or reshapes demand, through pricing, metering, restrictions, efficient technology and education, rather than increasing supply.

The boost to economic growth that can result when falling fertility makes the working-age population (15–64) larger relative to the dependent population of children and older people.

A model showing how a population moves from high to low birth and death rates as a country develops, in five stages, with the resulting changes in natural increase and total population.

The process by which residents, especially young people, copy the behaviour, dress and consumption patterns of visitors, which can change local values and aspirations.

The number of people aged 0–14 and 65 and over for every 100 people aged 15–64, split into youth and old-age dependency ratios.

The loss of parks, gardens, wetlands, farmland and other vegetated areas within a city to building and paving.

The laying down of sediment by a river, waves, ice or wind when its velocity, and so its energy, falls too low to carry the load.

A lack of access to the goods, services, resources and opportunities considered normal in a society, such as adequate housing, education, health care, work and a safe environment.

The distance from the Earth's surface down to the focus of an earthquake, classed as shallow (0–70 km), intermediate (70–300 km) or deep (300–700 km).

The removal of dissolved salts from seawater or brackish groundwater to produce fresh water, usually by reverse osmosis or distillation, which requires large amounts of energy.

A surface layer of closely packed pebbles and stones left when deflation removes the finer particles, which then protects the ground from further wind erosion.

Land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities (UNCCD definition).

A map that shows straight lines from each user's place of origin to a facility or destination, used to show its sphere of influence.

A high, steep and frequent wave, breaking about 10–14 times a minute, whose strong backwash removes sediment from the beach and carries it offshore.

A sentence or two of specific evidence that supports a point in an answer, giving a named location and usually a date, an amount or another precise fact.

A point in an answer that is extended beyond a bare statement by an explanation of how or why it works, a consequence, or a located example, so it can earn more than one mark.

A multidimensional process of positive change in the economic, social, political, environmental and cultural conditions of people’s lives, improving their wellbeing and choices.

A graph that plots four development indicators on four axes from a common centre, so that the shapes of the diamonds drawn for two or more places can be compared.

The difference in wealth, wellbeing and opportunity between the most and least developed places or groups, between countries or within one country.

A measurable statistic, such as life expectancy, school enrolment or GNI per capita, used to describe and compare one aspect of the level of development of a place.

A population that has spread from its original homeland to other countries while keeping cultural, emotional or family links with it.

The average amount of food energy available for human consumption in a country, in kilocalories per person per day, calculated from national food balance sheets.

The unequal susceptibility to harm of different groups within the same place exposed to the same hazard, because of differences in income, gender, age, disability, ethnicity, legal status or housing.

Pollution that enters water from many dispersed sources across a wide area, such as fertiliser runoff from fields, so that no single source can be identified.

The spread of a phenomenon, such as an innovation, an idea or a disease, from its place of origin across space and over time.

The gap between people, places or countries that have access to modern digital technology and the internet and those that have limited or no access.

An electronic record and means of proving a person’s identity, such as a chip-based identity card, online account or biometric number, used to access services, make transactions or cross borders.

An effect caused immediately and physically by a hazard event, such as deaths, injuries, collapsed buildings and destroyed roads or crops.

A measure of the burden of disease in which one unit is one year of healthy life lost, through premature death or through years lived with illness or disability.

A serious disruption of a community caused by a hazard event, involving loss of life, property or livelihoods beyond the community's ability to cope with its own resources.

A model, devised by Park in 1991, that shows how quality of life falls during a hazard event and recovers through the phases of relief, rehabilitation and reconstruction.

The policies and actions that aim to prevent new disaster risk, reduce existing risk and manage what remains, so that losses of life, livelihoods and assets are reduced.

The change over time in the number of recorded disasters, the deaths they cause, the people affected or their economic losses, usually shown by year or by decade.

The volume of water passing a point in a river per unit of time, found by multiplying the cross-sectional area of the channel by the mean velocity, and measured in m³ s⁻¹ (cumecs).

Permafrost that underlies 50–90% of the ground, broken by unfrozen areas beneath lakes, rivers and warmer slopes.

A coastline where bands of rock of different resistance run at right angles to the shore, so that weak rock is eroded into bays and resistant rock forms headlands.

Time free from paid work, study, sleep, personal care and household or caring obligations, which a person can choose how to spend.

The total impact of disease and injury on a population, measured by deaths and, more fully, by disability-adjusted life years (DALYs) lost.

The range of diseases arranged from diseases of poverty, which dominate where living conditions are poor, to diseases of affluence, which grow as incomes and lifespans rise.

Measures that stop a disease from occurring or spreading, such as vaccination, clean water and sanitation, bednets, health education, screening and the regulation of tobacco and food.

Medical care that cures or controls a disease after a person has become ill, such as drugs, oral rehydration, surgery and hospital care.

Non-communicable diseases such as heart disease, type 2 diabetes and many cancers, which become more common as incomes rise, diets change, activity falls and people live longer.

Diseases most common among people in low-income conditions, mainly communicable diseases such as diarrhoea, TB, malaria and HIV, plus undernutrition and maternal conditions.

The involuntary movement of residents or businesses out of an area because of rising rents and prices, redevelopment or eviction.

The income a household has available to spend or save after paying income taxes and social security contributions.

A new technology that significantly changes the way goods are produced, services are delivered or power is exercised, displacing established products, methods or institutions.

The decline in an interaction, such as the number of visitors to a facility, as distance from it increases.

A channel that branches off from the main river and flows away from it, usually across a delta, to reach the sea separately.

A system that supplies heat to many buildings from a central source, such as waste heat, biomass or a heat pump, through a network of insulated pipes.

The difference between the highest and lowest temperatures at a place within 24 hours, or between the mean daily maximum and mean daily minimum for a month.

A plate boundary where two plates move apart and new crust forms from rising magma, as at mid-ocean ridges and continental rifts.

The selling of shares, bonds or other investments in companies or industries, such as fossil-fuel producers, for ethical, environmental or financial reasons.

Tourism by residents of a country to places within the same country but outside their usual environment.

A decline in the willingness of governments and the public to give aid, usually during a long or repeated crisis, which leads to falling funds even when needs remain high.

A map showing the distribution of a phenomenon with dots, each representing one feature or a fixed number of them, placed where they occur.

A situation in which a population has high levels of communicable disease at the same time as rising levels of non-communicable disease.

The coexistence of undernutrition, including micronutrient deficiency, with overweight, obesity or diet-related diseases in the same population, household or individual.

The number of years a population would take to double at its current growth rate, estimated as 70 divided by the growth rate in % per year.

A model (1975) suggesting that residents' attitudes to tourists pass through four stages, euphoria, apathy, annoyance and antagonism, as visitor numbers grow.

An area of land drained by a river and its tributaries, from which all precipitation that is not lost to the atmosphere flows to the same outlet; also called a catchment.

The total length of all streams in a drainage basin divided by the area of the basin, measured in km per km².

The removal of sediment from the bed of a river, harbour or channel to make it deeper, increasing its capacity or allowing ships to pass.

A method of irrigation that delivers water slowly through pipes and emitters directly to the roots of each plant, reducing losses to evaporation and seepage.

An aircraft without a human pilot on board, controlled remotely or flying autonomously, used for military, commercial, scientific and private purposes.

An extended period, usually a season or more, in which water availability is well below normal: meteorological (low rainfall), agricultural (low soil moisture) or hydrological (low river flow and groundwater).

Growing crops without irrigation in areas of low rainfall by conserving soil moisture, for example through fallowing, mulching and drought-tolerant crop varieties.

Areas with an aridity index below 0.65, made up of hyper-arid, arid, semi-arid and dry sub-humid lands, in which water is the main limit on plant growth and human activity.

The legal status of a person who is a citizen of two countries at the same time, with the rights and duties of both.

A process in which a company identifies, prevents, reduces and accounts for the harm its own operations and its supply chain cause to people and the environment.

The rebuilding or stabilising of sand dunes by planting marram grass, fencing, thatching and controlling access, so that they store sand and protect the land behind.

A damp hollow between dune ridges where the surface lies close to the water table, supporting moisture-loving plants such as reeds, rushes and willows.

The length of time for which a hazard event lasts, from seconds for an earthquake's main shaking to months or years for an eruption or a slow landslide.

In the PAR model, the processes such as rapid urbanisation, population growth or a lack of training that turn root causes into unsafe conditions.

The delivery of public services and information through digital channels, such as online applications, digital identity and electronic voting.

A passport with an embedded chip that stores the holder’s details and biometric data, digitally signed by the issuing state so that border systems can verify it.

Discarded electrical and electronic equipment and its parts, which contain valuable materials such as copper and gold and hazardous substances such as lead and mercury.

A system that detects or forecasts a hazard and sends timely, understandable warnings to people at risk so that they can act to protect themselves and their property.

The calculated date each year on which humanity’s demand on nature exceeds what the Earth can regenerate that year: world biocapacity divided by world footprint, multiplied by 365.

A system that detects the first, faster seismic waves of an earthquake and sends automatic alerts that arrive seconds to tens of seconds before the strongest shaking reaches more distant places.

An environment, especially online, in which people mainly encounter opinions that match their own, so that their views are reinforced rather than challenged.

A city or urban district planned or redeveloped to minimise its ecological footprint, through renewable energy, efficient buildings, low-car transport, recycling, green space and compact, mixed-use development.

The level of visitor use a site can sustain before damage to its ecosystems, such as erosion, coral loss or wildlife disturbance, becomes unacceptable or irreversible.

The amount by which a population’s ecological footprint exceeds the biocapacity available to it; when biocapacity is larger, the difference is an ecological reserve.

The area of biologically productive land and sea needed to produce the resources a person or population consumes and absorb its wastes, especially CO₂, measured in global hectares.

The level of tourism beyond which it displaces other economic activities or raises costs for residents, such as housing, to the point that the local economy is harmed.

The monetary value of the damage and disruption caused by a hazard event, including destroyed property and infrastructure and lost production, whether or not it is insured.

A person who moves voluntarily, within a country or between countries, mainly to find work or earn higher wages.

A common market whose members also co-ordinate or share economic policies, often including a single currency and a central bank, as in the euro area.

A shortage caused by a lack of investment, infrastructure or institutional capacity rather than of water, so that people cannot access water that is physically available.

The benefits people obtain from ecosystems, grouped as provisioning (food, water), regulating (flood control, purification), supporting (habitat, nutrient cycling) and cultural (recreation, heritage) services.

Responsible travel to natural areas that conserves the environment, sustains the well-being of local people and involves education about the environment; one form of sustainable tourism.

A concentration of offices, shops and entertainment that grows at the edge of a metropolitan area, usually around a motorway junction, far from the traditional city centre.

A volcanic eruption in which low-viscosity magma flows out gently as lava because gases escape easily.

The warm phase of ENSO, in which the trade winds weaken, warm water spreads east across the equatorial Pacific, upwelling off South America weakens and rainfall shifts east.

The irregular cycle of coupled changes in sea surface temperature and air pressure across the tropical Pacific, with a warm phase (El Niño), a cold phase (La Niña) and a neutral state.

An explanation of earthquakes in which rocks on either side of a locked fault bend as stress builds, then break and spring back, releasing energy as seismic waves.

The Emergency Events Database, a global record of disasters since 1900 kept by the Centre for Research on the Epidemiology of Disasters in Belgium, which lists events that meet set thresholds for deaths, people affected or calls for help.

The greenhouse gases released in producing and transporting a good or service, carried in effect from the producing country to the consuming country when the good is traded.

The volume of fresh water used to produce a good or service, such as a kilogram of beef, which is traded invisibly when the product is exported; also called virtual water.

A small, young and unstable sand dune at the top of a beach, formed where sand collects around obstacles and is colonised by salt-tolerant pioneer plants such as sea couch grass.

A coastline where the land has risen relative to the sea, leaving former shoreline landforms such as raised beaches and relict cliffs above the reach of waves.

A middle-income country with rapid economic growth, industrialisation and a growing role in world trade and investment, such as China, India, Brazil, Indonesia or Mexico.

A state or union of states whose rapidly growing economic, military, political and cultural influence may allow it to become a superpower, such as China or India.

A process in which people, especially groups who have been excluded, gain the power, resources, rights and confidence to make choices and influence decisions that affect their lives.

A language at risk of falling out of use, usually because children no longer learn it from their parents as their first language.

Describing a disease that is constantly present in a particular population or region at a fairly stable, expected level.

The balance between the incoming shortwave radiation the Earth absorbs from the Sun and the outgoing longwave radiation it emits to space; when the two are equal, global mean temperature is stable.

The food energy produced by a farming system divided by the energy put into it from labour, animals and fossil fuels; a value above 1 means more energy is produced than used.

The share of a country’s energy use met by net imports, calculated as energy imports minus exports divided by energy use, times 100; negative values indicate a net exporter.

The combination of primary energy sources, such as oil, coal, gas, nuclear power and renewables, used to meet the energy needs of a country, region or the world.

The route by which energy resources travel from source to consumer, such as an oil or gas pipeline, a tanker shipping lane or an electricity transmission line.

A lack of access to modern energy services, especially electricity and clean cooking fuels, or the inability to afford enough energy for basic needs.

The uninterrupted availability of energy sources at an affordable price, including the ability to cope with sudden supply disruptions and to meet future demand.

The strengthening of the natural greenhouse effect by human emissions of greenhouse gases, which raise their concentrations, trap more longwave radiation and warm the Earth’s surface.

A set of forecasts made by running a weather or flood model many times with slightly different starting conditions, so that the spread of results shows the probability of each outcome.

A theory, set out by Amartya Sen in 1981, that famines happen when groups of people lose their ability to obtain food through production, wages, trade or transfers, not only when total food supply falls.

The quantity, timing and quality of water released or left in a river to sustain its ecosystems and the people who depend on them.

A person who moves within or across borders mainly because sudden or gradual environmental change has damaged their life or living conditions; “climate refugee” has no legal status.

A fieldwork method that scores the quality of a place on several criteria, such as litter, noise and building condition, on a set scale to allow comparison.

The level of use or stress beyond which an environment's condition changes sharply, so that damage accelerates or can no longer be reversed naturally.

A river that flows only for short periods after rainfall and is dry for most of the year, common in arid regions; an intermittent river flows seasonally.

The point on the Earth's surface directly above the focus of an earthquake, usually close to where the shaking is strongest.

A sudden increase in the number of cases of a disease well above the level normally expected in a population or area.

A model (Omran, 1971) of the long-term shift in a population’s main causes of death from communicable diseases, famine and malnutrition to non-communicable diseases as development proceeds.

The line on a glacier, often given as an altitude, at which annual accumulation equals annual ablation, separating the zone of accumulation from the zone of ablation.

The wearing away and removal of rock and sediment by a moving agent such as a river, waves, ice or wind.

A rock fragment, often a large boulder, transported by ice and deposited far from its source on bedrock of a different type, showing the direction and extent of former ice.

The tidal mouth of a river where fresh water mixes with sea water, and where tides and waves remove sediment rather than letting it build a delta.

A residential area in which one ethnic or cultural group is concentrated and has its own businesses, places of worship and community institutions.

Membership of a group of people who share, or believe they share, a common ancestry, history, culture and often language or religion.

A worldwide change in sea level caused by a change in the volume of ocean water, such as water stored in ice sheets during glacial periods or melting and thermal expansion today.

The enrichment of a body of water with nutrients, especially nitrates and phosphates, causing excessive growth of algae and plants and leading to oxygen depletion.

The skill of weighing strengths and limitations, costs and benefits, or competing arguments and evidence, and reaching a reasoned judgment about their value or importance.

The process by which liquid water is changed into water vapour and returned to the atmosphere from surfaces such as oceans, lakes, soil and wet vegetation.

The combined loss of water to the atmosphere by evaporation and transpiration; potential evapotranspiration (PET) is the amount that would be lost if water were always available.

The number of deaths from all causes in a period above the number expected from previous years, used to estimate the full death toll of a crisis.

The area of sea up to 200 nautical miles from a state's baseline in which that state has sole rights to the natural resources of the water and seabed, while other states keep freedom of navigation.

Diffusion in which a phenomenon spreads to new areas while remaining present in its place of origin, so that the total area or number affected grows.

The first stage of Butler's model, when small numbers of independent, adventurous visitors arrive and there are almost no facilities built for tourists.

A volcanic eruption in which gas trapped in viscous magma expands violently, shattering the magma into ash and tephra.

The presence of people, livelihoods, infrastructure, ecosystems or economic assets in places that could be adversely affected by a hazard, such as a low-lying coast or a drought-prone region.

A longer written answer of 10 marks or more, such as an essay, marked holistically with a markband for knowledge, analysis, evaluation and structure.

Farming that uses low inputs of labour and capital per unit of land over large areas, producing low yields per hectare.

An environment in which climate and relief set severe limits on plant growth, human comfort and economic activity, so that it supports few people without special adaptation; cold, high-altitude and hot arid environments are the main types.

Living on less than the World Bank’s international poverty line, US$3.00 a day per person at 2021 purchasing power parity, a level at which basic needs can barely be met.

A weather event that is rare at a particular place and time of year, such as a heatwave, extreme rainfall, drought or intense storm.

The calm, often cloud-free centre of a tropical cyclone, typically 20–50 km across, where air sinks and surface pressure is lowest.

The ring of towering thunderclouds around the eye of a tropical cyclone, where air rises fastest and the strongest winds and heaviest rain occur.

The general idea of trading partnerships that pay producers in poorer countries a fair price and offer fair working conditions, of which certified Fairtrade is one system.

The certified trading system run by Fairtrade International, which guarantees certified producers a minimum price and an extra Fairtrade Premium, and labels their products with the Fairtrade Mark.

A measure of water availability as renewable freshwater per person per year, with thresholds of 1,700 m³ for water stress, 1,000 m³ for scarcity and 500 m³ for absolute scarcity.

The part of a storm hydrograph after the peak that shows discharge decreasing as the basin drains; also called the recession limb.

A model of the stages a person passes through, from young single adult through partnership and parenthood to the empty nest and retirement, each with typical patterns of income, time and leisure.

The number of children born to a couple or a woman; at national scale it is measured by the total fertility rate, the average number of births per woman over her reproductive life.

An extreme food crisis in an area where at least 20% of households face an extreme lack of food, over 30% of children are acutely malnourished and over two people per 10,000 die each day (IPC Phase 5).

The supporters of a sports team, from local season-ticket holders to national and global followers who watch through broadcasting and social media.

A low-cost method of restoring degraded farmland in which farmers protect and prune shoots growing from the living stumps and roots of trees and shrubs so they grow into trees.

A type of agriculture defined by its combination of inputs, processes and outputs, such as subsistence or commercial, intensive or extensive, and arable, pastoral or mixed farming.

An attitude to hazards in which people accept losses as inevitable or as the will of a higher power and believe that little can be done to prevent them.

A fracture in the Earth's crust along which rocks on either side have moved relative to each other.

A chain of processes in a system in which a change produces effects that act back on the original change, either amplifying it or reducing it.

The application of dissolved fertiliser through an irrigation system, usually drip irrigation, so that nutrients reach plant roots in the amounts and at the times the crop needs them.

An organised event, held regularly or once, that celebrates music, culture, religion, sport or arts and attracts large numbers of people to a place for a short time.

The distance of open water over which the wind blows to generate waves; the longer the fetch, the larger and more powerful the waves can become.

A simple labelled drawing of a landscape or feature made in the field, showing only the features relevant to the investigation, with annotations.

A focused, geographical question about a precise local place that can be answered by collecting and analysing primary data in the field.

Granular, compacted snow that has survived at least one summer melt season and is turning into glacier ice as burial squeezes out its air.

A population of one fish species in a particular area that is managed as a single unit.

A limit on the amount of fish that a country, fleet, vessel or business may catch, usually a share of a total allowable catch.

A long, narrow, deep and steep-sided coastal inlet formed when a glacial trough was flooded by the sea, often with a shallow rock threshold at its mouth.

The sudden collapse of a large part of a volcano's side, producing a fast debris avalanche and sometimes a tsunami.

A flood that rises within minutes or a few hours of intense rainfall, usually in a small, steep or urban drainage basin, giving very little warning.

A storm hydrograph with a short lag time, steep rising and falling limbs and a high peak discharge; a subdued hydrograph has a long lag time and a low, broad peak.

An event in which water covers land that is normally dry, for example when a river's discharge exceeds the capacity of its channel and water spills onto the floodplain.

The prediction of when and where a flood will happen and how large it will be, by combining weather forecasts and river measurements with hydrological models.

A graph of annual peak discharge plotted against recurrence interval, usually on a logarithmic axis, used to estimate the size of a flood expected once in a given number of years.

Any action taken to reduce the likelihood of flooding or the harm that floods cause to people, property and the economy.

Actions taken before a flood to reduce its impact, such as flood plans, sandbags, flood boards, raised homes, emergency kits, shelters and evacuation routes.

An artificial channel that takes part of a river's flow around a settlement during high discharge and returns it downstream, reducing the flood level in the main channel.

The likelihood that a flood of a given size will occur in a place combined with the harm it would cause to people, property and activities there.

The wide, flat area of a valley floor on either side of a river that is covered by water during floods and built of layers of alluvium.

A map showing movements between places with lines or arrows whose direction shows the route and whose width is proportional to the volume of the flow.

A way of employing workers at remote mines in which they are flown to the site for a shift of one to several weeks, living in camps, then flown home for a rest period.

The point inside the Earth where a fault first ruptures and an earthquake begins, and from which seismic waves spread out.

Collecting water from fog by placing large vertical mesh nets in its path, so that droplets gather on the mesh and drip into a trough below.

Food provided free or at reduced cost to people or countries that cannot produce or buy enough, given either in kind as food or as cash or vouchers to buy it.

The United Nations agency, founded in 1945 and based in Rome, that leads international efforts against hunger by collecting food data, giving early warning and technical advice, and setting food standards.

The supply of food physically present in a country or area, from domestic production, imports, stocks and food aid, less exports and losses; one of the four pillars of food security.

An FAO survey-based measure of the severity of food insecurity, built from eight questions to individuals about their experiences of limited access to food over the previous 12 months.

The decrease in the quantity or quality of food between harvest and the retail stage, for example through pests, spoilage in storage or damage in transport.

Any activity that promotes a food or drink product to consumers, including advertising, sponsorship, packaging, price promotions, social-media content and product placement.

The distance food travels from where it is produced to where it is consumed, used as a rough indicator of the environmental impact of transporting food.

A situation in which all people, at all times, have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.

The ability of a country to meet its food needs from its own production rather than imports, often measured as domestic production as a percentage of consumption.

Food that is discarded or left uneaten at the retail, food service or household stage, even though it was fit to eat.

The removal of people from their homes or land against their will, without appropriate legal protection, consultation or compensation.

The movement of people compelled to leave their homes, within or across borders, by threats such as conflict, persecution, natural disasters or development projects.

A young, mobile sand dune behind the embryo dunes, dominated by marram grass, with bare sand between the plants giving it a yellow colour; also called a yellow dune.

Investment by a company in productive assets in another country, such as building or buying factories, hotels or resorts, in which it keeps a lasting ownership interest and control.

The addition of vitamins or minerals, such as iodine, iron, folic acid or vitamin A, to food during processing to prevent micronutrient deficiencies.

A non-renewable energy source such as coal, oil or natural gas, formed over millions of years from buried organic remains, which releases CO₂ when burned.

Groundwater that accumulated long ago, often in a wetter past climate, and receives little or no recharge today, so it is effectively non-renewable.

A method of extracting oil and gas by injecting water, sand and chemicals at high pressure into shale or other dense rock to fracture it and release the hydrocarbons.

A closed league in which membership is fixed by the league, with no promotion or relegation, and teams (franchises) may relocate to other cities.

The right of citizens of the member states of a bloc, such as the EU, to travel, live and work in any other member state without a visa or work permit.

A group of countries that remove tariffs and quotas on trade in goods between themselves, while each keeps its own trade policy towards non-members.

A designated area within a country, often at a port or airport, where imported goods can be stored, processed and re-exported free of customs duties and with simplified regulations.

The principle that Indigenous peoples may give or withhold consent to a project affecting their lands or resources, freely, before it begins and with full information about its impacts.

The right of ships of all states to sail through international waters, and through EEZs, without interference, as set out in UNCLOS.

The breakdown of rock by repeated freezing and thawing of water in cracks and pores, which expands by about 9% when it freezes and pries the rock apart.

The relocation of supply chains to countries that are political allies, to reduce the risk that geopolitical tension, sanctions or conflict will disrupt production.

Simple nutrition information, such as warning symbols or traffic-light colours, printed on the front of food packaging to show consumers which products are high in sugar, salt, fat or calories.

The upward swelling of the ground during freezing, caused by ice lenses growing in fine soil as water is drawn to the freezing front; it lifts stones towards the surface.

An informal forum of seven major high-income democracies (USA, Japan, Germany, UK, France, Italy, Canada, with the EU) whose leaders co-ordinate economic and political policy; the G8 while Russia was a member (1998–2014).

A forum of 19 countries, the European Union and the African Union, including the major high-income and emerging economies, which produces about 85% of world GDP and co-ordinates global economic policy.

A wire-mesh cage filled with stones, stacked to form a wall or slope that absorbs wave energy; a cheap but short-lived coastal defence.

An area of an ocean gyre where floating plastic and other debris carried by surface currents accumulates in high concentrations.

A residential area enclosed by walls or fences, with controlled entrances, private security and often its own services, that restricts access to residents and their guests.

A situation in which women and men have equal rights, opportunities, resources and power in all areas of life, including education, work, health, politics and the family.

The difference between women and men farmers in access to land, credit, inputs, technology, advice and markets, and the resulting difference in their yields and incomes.

A composite index published by the UNDP that measures inequality between women and men in reproductive health, empowerment and labour market participation, from 0 (equality) to 1 (extreme inequality).

A technique, such as CRISPR, that changes an organism’s DNA at a precise location, usually by altering or switching off existing genes rather than adding genes from another species.

A plant, animal or micro-organism whose genetic material has been altered by genetic engineering, for example by inserting a gene from another species, to give it a new trait.

The movement of higher-income households into a low-income, often inner-city area, renovating housing and changing its social character, which usually raises property values and displaces existing residents.

Deliberate large-scale intervention in the Earth’s climate system to reduce global warming, either by removing CO₂ from the atmosphere or by reflecting more sunlight back to space.

The separation of a place from other places by distance or physical barriers such as oceans, mountains, deserts or ice, which increases the cost and difficulty of interaction.

A hazard caused by processes in the solid Earth: earthquakes, volcanic activity and mass movements.

Strained relations between states or other political actors over territory, resources, security, trade routes or influence, which can escalate into conflict.

The study of how geographical factors such as location, territory, borders and natural resources shape political power and relations between states.

A measure of inequality from 0 (perfect equality) to 1 (maximum inequality): the area between the line of equality and the Lorenz curve divided by the total area under the line.

A sudden release of water from a lake dammed by a glacier or moraine when the dam is overtopped or breached, often after an ice or rock avalanche falls into the lake.

A long cold phase within an ice age, lasting tens of thousands of years, during which global temperatures fall, ice sheets and glaciers advance over large areas and sea level falls.

A glacier viewed as an open system, with inputs of snowfall, avalanches and wind-blown snow, stores of snow, firn and ice, transfers by ice flow, and outputs by melting, sublimation and calving.

A deep, straight valley with steep sides and a wide, flat floor, formed when a glacier deepens, widens and straightens a former river valley.

A large mass of ice, formed on land from compacted and recrystallised snow, that moves slowly downslope or outwards under its own weight.

The difference between a glacier's accumulation and ablation over a year, usually in metres of water equivalent; a positive balance leads to advance, a negative balance to thinning and retreat.

The shrinking of a glacier, with its front moving back up its valley, when melting and calving exceed the accumulation of new snow over a period of years.

The slow rise of the Earth’s crust after the melting of an ice sheet that had pressed it down, continuing for thousands of years.

An agreement by Commonwealth heads of government in 1977 to discourage sporting contact and competition with South Africa, as part of the campaign against apartheid.

A city that is a major node of the global economy, concentrating the headquarters of transnational corporations, financial markets and advanced business services, with strong international connections.

A long-term change in the Earth’s climate, including temperature, precipitation, ice cover and extreme events, now driven mainly by human greenhouse gas emissions; global warming is the rise in global mean surface temperature within it.

An area or resource outside the jurisdiction of any single state, such as the high seas, the atmosphere or Antarctica, that is shared by all.

A reduction in the solar radiation reaching the Earth’s surface, caused by aerosols from volcanic eruptions and air pollution that reflect sunlight and make clouds brighter.

The movement of goods, services, capital, people, information or ideas across international borders, between places that are linked by networks.

A composite index by Economist Impact scoring the food security of 113 countries from 0 to 100 (higher is better) on affordability, availability, quality and safety, and sustainability and adaptation.

A unit of area representing one hectare of land or sea with world-average biological productivity, used to express ecological footprints and biocapacity.

A composite index measuring hunger in a country on a 0–100 scale, where lower is better, by combining undernourishment, child stunting, child wasting and under-five mortality.

The exchanges and connections between places and peoples worldwide, including flows of goods, services, capital, people, information and ideas, and political and cultural links.

An internationally agreed minimum rate of tax, set at 15% under the OECD/G20 Pillar Two rules, on the profits of large multinational companies in every country where they operate.

A broad term for the wealthier, mainly high-income countries of North America, Europe, East Asia and Australasia, describing their shared economic and political position rather than their location.

The global pattern of the thermohaline circulation, in which dense water sinks in the North Atlantic and around Antarctica, flows through the deep ocean and returns as surface currents in about 1,000 years.

The relocation of manufacturing, and later some services, from high-income countries in Europe and North America to lower-cost countries, especially in East and South-East Asia, since the 1970s.

A broad term for the lower-income countries of Africa, Latin America, Asia and Oceania, many of them former colonies, describing their shared economic and political position in the world.

A measure of how much heat a mass of a greenhouse gas traps over a set period, usually 100 years, compared with the same mass of carbon dioxide, which has a value of 1.

The growing interconnection and interdependence of places, economies and societies around the world through flows of goods, services, capital, people, information and ideas.

A composite measure that combines several indicators of international flows and connections into a single score, used to compare how far countries participate in global interactions.

The adaptation of a global product, service or brand to local cultures, tastes, religions and regulations so that it sells in many different places.

A variety of rice genetically modified to produce beta-carotene, a source of vitamin A, intended to reduce vitamin A deficiency where rice is the staple food.

The ways in which a society is managed and decisions are made and enforced, by governments and other institutions, including how laws are applied and how accountable those in power are.

The use of fixed satellite navigation (GNSS) receivers on a volcano or fault to measure ground movement of a few millimetres, such as the uplift caused by magma collecting below.

An African Union initiative adopted in 2007 to restore degraded land across the Sahel from Senegal to Djibouti, aiming to restore 100 million hectares by 2030.

A ring of protected open land around a city in which new building is strictly limited, to prevent urban sprawl and protect the countryside.

A planned network of natural and semi-natural features in a city, such as parks, street trees, green roofs, wetlands and rivers, managed to provide cooling, flood control, cleaner air and habitats.

The spread, from the 1960s, of high-yielding varieties of cereals together with irrigation, chemical fertilisers and pesticides, which greatly increased crop yields in many parts of Asia and Latin America.

A roof partly or wholly covered with vegetation and a growing medium, which insulates the building, absorbs rainfall and cools the surface through evapotranspiration.

The part of a water footprint made up of rainwater stored in the soil and used by plants, then lost through evapotranspiration.

A form of foreign direct investment in which a firm builds a new facility, such as a factory, office or mine, in another country rather than buying an existing one.

Land that has not previously been built on, such as farmland or open countryside, often at the edge of an urban area.

The natural process by which gases in the atmosphere absorb longwave radiation from the Earth’s surface and re-emit part of it downwards, keeping the surface about 33 °C warmer than it would otherwise be.

A gas in the atmosphere that absorbs and emits longwave (infrared) radiation, such as water vapour, carbon dioxide, methane, nitrous oxide, ozone and CFCs.

Misleading claims or marketing that make a company, product or activity appear more environmentally friendly than it really is.

A more stable sand dune further inland, darkened by humus and colonised by mosses, lichens and other plants, with more acidic soil than younger dunes.

The part of a water footprint equal to the volume of freshwater needed to dilute the pollutants released in making a product to an agreed water quality standard.

Lightly used household wastewater from sinks, baths, showers and washing machines, but not toilets, which can be reused for purposes such as flushing or irrigation.

A set of numbers locating a square or point on a map grid, easting before northing: four figures identify a 1 km square, six figures a point to the nearest 100 m.

A model (1980) of the Latin American city with a central business district and commercial spine lined by an elite sector, surrounded by zones of maturity, in situ accretion and peripheral squatter settlements.

The total value of all goods and services produced within a country’s borders in one year, regardless of who owns the businesses producing them.

The total income earned by a country’s residents and businesses in a year, including income from abroad and excluding income paid to non-residents; GNI per capita divides it by the population.

The increase in the strength of earthquake shaking where seismic waves pass from hard rock into soft sediments.

Water stored in the pore spaces and cracks of rocks and sediments below the water table; its slow movement through rock towards rivers is groundwater flow.

A long-term fall in the volume of groundwater stored in an aquifer, caused when abstraction exceeds recharge.

A barrier built at right angles to the shoreline to trap sediment carried by longshore drift and so build up a wider beach.

A warm, fast ocean current flowing from the Gulf of Mexico along North America and across the Atlantic as the North Atlantic Drift, carrying heat towards north-west Europe.

The rule that, in a region, the number of earthquakes falls by about ten times for each one-unit rise in magnitude.

A large, roughly circular system of surface ocean currents in an ocean basin, driven by prevailing winds and the Coriolis effect; clockwise in the northern hemisphere, anticlockwise in the southern.

Gaining unauthorised access to a computer, network, account or data, for example by exploiting a weakness in software or by stealing passwords.

A large atmospheric circulation in which air rises near the Equator, flows poleward at 12–15 km, sinks near 30° latitude, creating subtropical high pressure, and returns towards the Equator as the trade winds.

A model (1953) in which an innovation spreads outward from an innovation centre through primary, diffusion, condensing and saturation stages, mainly by personal contact, declining with distance.

The worldwide spread of South Korean popular culture, including K-pop, television dramas, films, food and beauty products, since the late 1990s.

A tributary valley whose floor lies high above the floor of a main glacial trough, because its smaller glacier eroded less deeply; its stream enters the trough by a waterfall.

The use of artificial structures such as sea walls, groynes and rock armour to control natural coastal processes and protect the land behind them.

The use of coercion or payment, such as military force, economic sanctions, aid or trade deals, to make other states act in a particular way.

A potential threat to people, property or the environment from a natural or human process.

Adjusting land use, buildings, behaviour and institutions so that people can live with a hazard and suffer less harm from it, without trying to stop the hazard itself.

A diagram or table that compares the physical characteristics of a hazard event, such as magnitude, frequency, duration, areal extent, speed of onset and spatial predictability, on a scale from low to high.

Estimating the probability of a hazard event of a given size occurring in an area over a period of time.

How often a hazard event of a given magnitude occurs in a place, often expressed as a recurrence interval or an annual probability.

The size or energy of a hazard event, measured on a scale such as moment magnitude, the VEI or the volume of a landslide.

The way in which individuals or groups understand and judge the threat posed by a hazard, shaped by experience, knowledge, culture, religion, wealth and trust in authorities.

Stating precisely when and where a hazard event will occur and how large it will be.

The probability of harm or loss from a hazard event, which depends on the hazard, the exposure and vulnerability of people and assets, and their capacity to cope.

A widespread layer of air pollution, made mainly of fine smoke particles and gases from fires and industry, that reduces visibility and harms health, and can be carried across borders.

A measurable characteristic of a population, such as life expectancy, infant mortality or doctors per person, used to describe its health or the factors that influence it.

The average number of years a person can expect to live in full health, after allowing for years lived in less than full health because of disease or injury; the WHO’s measure.

The place where a phenomenon, such as an innovation or a disease, originates and from which it diffuses; the source of diffusion.

A city or regional plan to reduce deaths and illness in heatwaves, combining early warnings, public information, cooling centres, protection of vulnerable groups and long-term cooling measures.

A cross-section of air temperature across an urban area, showing a steep rise (cliff) at the urban edge, a suburban plateau, a peak over the CBD and cooler sinks over parks and water.

The strain on the body when it cannot lose enough heat to keep its core temperature stable, caused by high temperature, humidity, sunshine and exertion; it ranges from heat exhaustion to heat stroke.

A period of several consecutive days with temperatures unusually high for a particular place and season, defined by each national weather service.

A programme of the IMF and the World Bank, launched in 1996, that cancels much of the external debt of the poorest, most indebted countries once they meet conditions on reform and poverty reduction.

The dominance of one state over others, exercised through military and economic strength and through leadership of the rules, institutions and ideas that other states accept.

A corkscrew-like flow of water through a meander bend, in which surface water moves towards the outer bank and returns along the bed towards the inner bank.