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.

Indirect protection from an infectious disease that occurs when a large enough share of a population is immune, through vaccination or previous infection, that the disease cannot spread easily.

Travel to experience places, buildings, artefacts and traditions that represent the history and culture of a people, such as ancient monuments, historic cities and religious sites.

Expansion diffusion through an ordered sequence of places or people, typically from large, well-connected cities or influential groups down to smaller places.

The ranking of clubs in a sports league system into levels or divisions, from a top tier with a few wealthy clubs down to many smaller ones.

The parts of the ocean beyond any state's exclusive economic zone, open to all states and governed by international law.

A mountain or plateau environment outside the polar regions where low temperature, low air pressure, intense solar radiation and steep relief make conditions extreme because of height above sea level.

A country whose GNI per capita (World Bank Atlas method) is above the high-income threshold, US$14,375 in the classification published in July 2026.

A specialised facility that is used infrequently, has a large range and threshold population, and draws users from a large sphere of influence, such as a national park or national stadium.

A crop variety bred to give much larger yields per hectare than traditional varieties, usually when supplied with enough water, fertiliser and pesticide.

A graph that shows the mean velocity at which particles of different sizes are eroded, transported or deposited by a river, plotted on logarithmic axes from laboratory measurements.

A coastal management policy of keeping the shoreline in its present position by maintaining existing defences or building new ones.

A process in which places and cultures become more alike, as global products, brands, media and building styles replace local differences.

A place that attracts large numbers of visitors because of its attractions and facilities; managers may develop honeypots deliberately to concentrate visitors where damage can be controlled.

The merger or takeover of companies at the same stage of a supply chain, such as two hotel groups combining, to gain market share and economies of scale.

Physical measures such as bollards, barriers, planters and street furniture placed to stop vehicles being driven into crowds or buildings.

An arid environment with very low annual precipitation, usually under 250 mm, high daytime temperatures for most of the year and sparse vegetation, such as the Sahara or the Kalahari.

An area of volcanic activity fed by a mantle plume, often far from a plate boundary, such as Hawaii or Yellowstone.

A model (1939) of a city in which land uses form wedge-shaped sectors growing outwards along transport routes from the centre, with high-class housing in sectors away from industry.

A transport network in which routes from many smaller places (spokes) connect to a central node (the hub), where passengers or goods change routes, rather than travelling directly between every pair of places.

The knowledge, skills, health and experience of a population, which determine how productive its people can be; it is increased by investment in education, training and healthcare.

A process of enlarging people’s freedoms and capabilities, so that they can live long, healthy, educated and secure lives of their own choosing; wider than economic growth.

A composite index published by the UNDP that combines life expectancy, education (mean and expected years of schooling) and GNI per capita (PPP) into a value between 0 and 1.

The right of every person to sufficient, safe, acceptable, physically accessible and affordable water for personal and domestic use, recognised by the UN General Assembly in 2010.

The recruitment, transport, transfer or holding of people by force, coercion, fraud or abuse of vulnerability, for the purpose of exploitation such as forced labour, sexual exploitation or slavery.

The quality of people's lives in all its dimensions, including health, safety, housing, income and livelihoods, education, social relationships, culture and the ability to make choices.

Short-term assistance given in an emergency such as a war, disaster or famine to save lives and relieve suffering, including food, water, shelter, medical care and protection.

A tropical cyclone that forms in the North Atlantic, Caribbean Sea, Gulf of Mexico or north-east Pacific, with sustained winds of at least 119 km/h.

An erosion process in which the force of moving water, and air compressed into cracks by it, loosens and removes material from the bed and banks of a channel or from a cliff.

A measure of channel efficiency found by dividing the cross-sectional area of a channel by its wetted perimeter; a larger value means less water in contact with the bed and banks and less friction.

A chemical compound of hydrogen and carbon; in energy geography, the collective term for crude oil and natural gas.

Electricity generated by the flow of water through turbines, usually water released from a reservoir behind a dam.

The continuous circulation of water between the oceans, atmosphere, land and living things, driven by solar energy and gravity; at the global scale it is a closed system.

A period in which river flows, lake and reservoir levels and water tables fall well below normal, usually lagging months behind a meteorological drought.

A method of growing plants without soil, with their roots in water containing dissolved mineral nutrients.

An opening in the seabed, usually on a mid-ocean ridge, from which water heated by magma flows out, depositing metal-rich sulphide minerals and supporting unique ecosystems.

A dangerous fall in the body's core temperature below 35 °C, caused by losing heat faster than it is produced, especially in cold, wet or windy conditions.

A testable statement predicting a relationship or difference between variables, based on geographical theory, which fieldwork data can support or reject.

A condition of very low dissolved oxygen in water, usually below about 2 mg per litre, that most aquatic animals cannot survive; anoxia is the complete absence of oxygen.

A dome-shaped mass of glacier ice covering less than 50,000 km², usually over an upland or plateau, from which ice flows outwards in all directions.

A seasonal road built across frozen lakes, rivers, sea ice or tundra in winter, usable only while the ice is thick enough to carry vehicles.

A mass of glacier ice covering more than 50,000 km² of land, burying almost the whole land surface; the two present-day ice sheets cover Antarctica and Greenland.

An artificial glacier made in winter by piping and spraying stream water into cold air so that it freezes into a tall cone of ice, which melts slowly to supply water in spring.

The way a person or group understands who they are and how they belong, built from characteristics such as ethnicity, nationality, religion, language, gender and place; often multiple and changing.

The use of another person’s personal information without permission, usually to commit fraud such as opening accounts, borrowing money or making purchases in their name.

A cross-border movement of people, goods, services or money that is prohibited by law, such as human trafficking, the smuggling of narcotics or counterfeit goods, and illicit financial transfers.

Fishing that breaks national or international rules, is not reported to the authorities, or takes place where no rules apply, for example by stateless vessels.

A measure of a hazard's impact divided by the population of the area affected, such as deaths per 100,000 people, so that impacts on places of different size can be compared fairly.

A contract between a resource company and an Indigenous community setting out the jobs, training, payments and monitoring the community receives in return for supporting a project.

A surface such as tarmac, concrete or roofing that does not allow water to soak through it, so rainfall becomes overland flow.

A government limit on the quantity or value of a particular good that may be imported over a given period.

A development strategy in which a country protects and builds up domestic industries to replace imported goods, usually behind high tariffs and quotas.

Improving an informal settlement where it stands by providing infrastructure, services and secure tenure, instead of demolishing it and moving its residents elsewhere.

Meat produced by growing animal cells in a nutrient medium in bioreactors instead of raising and slaughtering animals; also called cultivated or cultured meat.

The physical difficulty of reaching a place because of barriers such as mountains, ice, sea ice, sand seas or a lack of roads, ports and airstrips, which may vary with the season.

The number of new cases of a disease in a population during a given period, often expressed per 1,000 or per 100,000 people per year.

The time between a person being infected with a pathogen and the appearance of the first symptoms of the disease.

A measure from 0 to 100 of how unevenly two groups are spread across the districts of a city, equal to the percentage of either group that would have to move for both to be evenly distributed.

A composite measure that combines weighted indicators of several domains of deprivation, such as income, employment, health, education, crime and housing, to rank small areas from most to least deprived.

The understanding, skills and practices developed by a local or indigenous community over many generations through close interaction with its environment, and passed on through culture and practice.

The descendants of the people who lived in a region before later settlers or states arrived, who keep distinct languages, cultures and ties to their land, such as the Inuit, Sámi or Tuareg.

An effect that follows from the direct damage of a hazard event, often later or further away, such as lost income, disease, interrupted schooling or disrupted supply chains.

A share of a total allowable catch held by an individual or company, which can be bought, sold or leased.

The increase in traffic that follows an increase in road capacity, because faster journeys encourage more and longer trips, so that congestion often returns.

A planned area of factories, warehouses and workshops, usually at the edge of a city near major roads, where firms share access roads and services.

A collaboration in which separate firms, usually located close together, exchange materials, energy, water and by-products, so that the waste or surplus of one becomes a resource for another.

The uneven distribution of income, wealth, resources or opportunities between people, groups or places, measured for example by the Gini coefficient.

A version of the HDI, published by the UNDP since 2010, that discounts each dimension for inequality between people, so that it falls further below the HDI the more unequal a country is.

The number of deaths of infants under one year old per 1,000 live births in a year.

The inability of a soil to support healthy plant growth because it lacks nutrients, organic matter or a suitable structure, or contains harmful levels of salt or other toxins.

The downward movement of water from the ground surface into the soil.

The maximum rate at which water can soak into a soil under given conditions, measured in mm per hour; it falls as the soil becomes wetter or more compacted.

An overabundance of information, both accurate and false, that spreads rapidly during an epidemic or other crisis and makes it difficult for people to find trustworthy guidance.

A visual summary of information that combines headline figures, charts, maps, icons and short text to communicate a message about an issue quickly.

Economic activity that is not registered, taxed or regulated by government, such as street trading or casual labour, with low, irregular pay and no legal protection.

An area of housing built without legal title to the land or planning permission, usually lacking secure tenure, safe water, sanitation and drainage; often called a slum.

The infrastructure and devices, such as cables, satellites, mobile networks, computers and smartphones, and the software and services used to store, process and transmit information.

The agreement of a person to take part in a survey or interview after being told its purpose, how the answers will be used and that they may decline.

The basic physical structures and networks a settlement needs to function, such as transport routes, water and sewerage pipes, power supply, waste facilities and telecommunications.

The right of foreign ships to sail through a state's territorial sea without stopping, provided they do not threaten its peace, order or security.

Interferometric synthetic aperture radar: a satellite technique that compares radar images taken at different times to map ground uplift or subsidence of a few millimetres over large areas.

A financial arrangement in which people or businesses pay regular premiums to an insurer, which pays for repairs and losses after an event such as a flood.

The part of the economic loss from a hazard event that insurance companies pay out to policyholders; it is usually a large share of losses in high-income countries and a small share in low-income countries.

An approach that plans and manages all the uses of a coastal area together, across land and sea and across sectors and levels of government, with the participation of all its stakeholders.

The coordinated planning of land and water across a whole drainage basin, regardless of administrative or national borders, involving all stakeholders and balancing economic, social and environmental goals.

A standardised five-phase scale, from Minimal (Phase 1) to Catastrophe or Famine (Phase 5), used by governments and agencies to classify the severity of food insecurity and malnutrition.

A process that coordinates the development and management of water, land and related resources to maximise economic and social welfare equitably without harming the sustainability of ecosystems.

The use of sensors, communications and data to manage traffic and public transport in real time, for example through adaptive signals, live passenger information and road pricing.

Farming that uses high inputs of labour, capital, fertiliser or technology per unit of land to obtain high yields from a relatively small area.

The capture and temporary storage of precipitation by vegetation before it reaches the ground; some intercepted water later evaporates and the rest drips or runs to the ground.

A relationship in which countries or places rely on each other, for example for trade, investment, energy or security, so that a change in one affects the others.

A warmer phase between glacial periods, lasting thousands to tens of thousands of years, when ice sheets retreat to roughly their present extent; the present interglacial is the Holocene.

A medium-sized city, usually of about 50,000 to 1 million people, that links rural regions with larger cities and holds a large and growing share of the world’s urban population.

The slow flow of glacier ice as individual ice crystals deform and slide past one another under the pressure of the ice above.

The heat generated inside the Earth by the radioactive decay of uranium, thorium and potassium isotopes, together with heat left over from the planet's formation.

Migration within the borders of one country, such as from a rural area to a city or from one region to another.

A person forced to leave their home by conflict, violence, human rights violations or disaster who has not crossed an internationally recognised border.

An organisation of tour companies, founded in 1991, that sets and enforces rules for safe and environmentally responsible private travel to Antarctica among its members.

A legally binding agreement, revised in 2005, under which states must detect, assess and report to the WHO any public health event that could spread across borders, and respond to it proportionately.

Migration across an international border, from one country to another, to live there for at least a year.

An international financial institution of 191 member countries, founded in 1944, that promotes monetary co-operation and financial stability and lends to countries facing balance-of-payments crises, with conditions.

A non-profit organisation, independent of governments, that operates in several countries to pursue humanitarian, environmental, development or human rights goals, such as Oxfam or Greenpeace.

The global governing body of the Paralympic movement, founded in 1989 and based in Bonn, which organises the Paralympic Games and sets classification rules.

The income threshold the World Bank uses to measure extreme poverty worldwide, set at US$3.00 a day per person in 2021 PPP dollars from June 2025.

The organisation set up under UNCLOS that regulates mineral exploration and mining on the seabed beyond national jurisdiction, based in Kingston, Jamaica.

Tourism that involves crossing an international border, either by residents travelling abroad (outbound tourism) or by non-residents visiting a country (inbound tourism).

The arrival of an overnight visitor in a country other than their country of residence; arrivals count trips rather than individual people.

An attitude of openness to and curiosity about other cultures, perspectives and global issues, combined with respect for others and a sense of responsibility for the wider world.

The ability of people to access, use and publish on the internet without censorship, shutdowns, unlawful surveillance or punishment for lawful online expression.

A network of physical objects, such as sensors, meters, vehicles and appliances, connected to the internet so that they can collect and exchange data without human input.

An intentional disruption of internet or mobile data access, or of particular online services, by a government or other authority, making them unavailable or unusable for a population or area.

A measure of spread equal to the difference between the upper and lower quartiles, covering the middle 50% of an ordered data set and unaffected by extreme values.

A barrier between a place of origin and a destination, such as distance, travel cost, a border, immigration laws or language, that makes migration more difficult.

The way food is shared among members of the same household, which can be unequal by gender, age or status, so that some members are undernourished even when the household has enough food.

An earthquake that occurs within a tectonic plate, far from a plate boundary, on an older zone of weakness.

A species introduced by human activity to an area outside its natural range, which spreads and harms native ecosystems, the economy or human health.

The artificial application of water to land to help crops grow, using canals, flooding, sprinklers, drip systems or pumped groundwater.

A map with lines (isolines) joining places of equal value of a continuously varying quantity, such as temperature (isotherms), rainfall (isohyets) or pressure (isobars).

A map showing lines that join places that experienced the same intensity of earthquake shaking.

A change in the level of the land relative to the sea, caused by the crust rising or sinking, for example under the weight of an ice sheet or after it melts.

A system of manufacturing in which materials and components are delivered just as they are needed, so that little stock is held, reducing costs but increasing vulnerability to disruption.

A final judgment that answers the question at the extent asked and gives the reasons for that judgment, drawn from the evidence and arguments already presented.

A sponsorship system, used mainly in Gulf states, Jordan and Lebanon, that ties a migrant worker’s visa and legal residence to one employer, who controls the worker’s ability to change job or leave.

A wind of cold, dense air that flows downslope under gravity from an ice sheet, plateau or mountain, often reaching very high speeds where it is channelled into coastal valleys.

The graph of atmospheric carbon dioxide concentration measured at Mauna Loa, Hawaiʻi, since 1958, showing a steady, accelerating long-term rise with a regular seasonal cycle.

A graph showing how the abundance of several species changes along a transect, each species drawn as a band whose width is proportional to its abundance at each point.

A sudden break of slope in the long profile of a river, often marked by a waterfall or rapids, where resistant rock or a fall in base level interrupts the smooth curve.

An annual index by the KOF Swiss Economic Institute that scores countries from 0 to 100 on economic, social and political globalisation, combining actual flows (de facto) and enabling policies (de jure).

The 1997 agreement under the UNFCCC, in force from 2005, that set legally binding emissions targets for industrialised (Annex I) countries for 2008–2012 and later to 2020.

The cold phase of ENSO, an intensified form of normal conditions, in which stronger trade winds increase upwelling off South America and rainfall over the western Pacific.

The time between the peak of rainfall and the peak of discharge in a river, usually measured in hours.

A volcanic mudflow of ash, rock and water, formed by heavy rain or melting ice, that follows river valleys far from the volcano.

A long-term decline in the biological or economic productivity of land, caused by processes such as soil erosion, nutrient loss, salinisation and loss of vegetation.

The creation of new land from the sea, a lake or a wetland by draining it or filling it with sand, rock or other material.

The gradual sinking of the ground surface, often caused by the compaction of clay and silt layers when groundwater is pumped out.

The system of rules, set in law or by custom, that decides how land is owned, used, inherited and transferred, and by whom.

The purpose for which an area of land is used, classified in towns and cities as residential, commercial, industrial, transport, open space, institutional or vacant land.

The planning control of what can be built or done on different areas of land, used on floodplains to keep housing and vital services away from the highest-risk zones; also called floodplain zoning.

A site where waste is disposed of by burying it in the ground; a sanitary landfill uses liners, leachate drainage and daily cover to limit pollution.

A low- or middle-income country with no direct access to the sea, which depends on transit through neighbouring countries for its seaborne trade.

The everyday term for the rapid downslope movement of rock, soil or debris, used for most falls, slides and flows.

Deliberate efforts to halt the decline of an endangered language and increase its number of speakers, for example through schools, broadcasting and official status.

The rate at which air temperature falls with increasing height in the lower atmosphere; the environmental lapse rate averages about 6.5 °C per 1,000 m but varies with time and place.

The purchase or long-term lease of large areas of land, typically thousands of hectares, by companies, investment funds or foreign governments, often for export farming; called a land grab by critics.

The time, between about 26,000 and 20,000 years ago, when the ice sheets of the most recent glacial period reached their greatest extent and sea level was about 125 m lower than today.

Travel to see places, landscapes or species that are disappearing or changing, such as glaciers, coral reefs or polar wildlife, before they are lost.

The energy absorbed when water evaporates and released when water vapour condenses, without a change in temperature; the main energy source of tropical cyclones.

A ridge of till along the side of a glacier or glacial valley, formed mainly from rock that fell from the valley sides.

Changing the path of a lava flow away from settlements and infrastructure by building earth barriers or channels, or by cooling the flow front with water.

The downward removal of soluble substances, such as nitrates or salts, from the soil by water percolating through it.

The proportion of tourist spending that leaves the host country's economy, through imports, profits repatriated by foreign owners, wages of foreign workers and commissions paid abroad.

The long-term effects of hosting an event that remain after it ends, such as new infrastructure, urban regeneration, sports participation, debt or a changed international image.

The discretionary time left after work, study, sleep, personal care and obligations such as housework and caring, and the activities people freely choose to do in that time.

A raised bank along the edge of a river channel; natural levees are built of coarse sediment deposited when floodwater spills out of the channel and loses velocity.

The tendency for flood defences such as artificial levees to encourage more building on the land they protect, so that losses are larger when an extreme flood overtops or breaches them.

The average number of years a newborn baby would live if current age-specific death rates stayed the same throughout its life.

A method that measures the environmental impacts of a product, such as its greenhouse gas emissions, across every stage of its life from raw materials and production to transport, use and disposal.

A management approach that defines how much change in a site's environmental and social conditions is acceptable, monitors indicators of those conditions and acts when a limit is approached.

The boundaries, set mainly by temperature, rainfall and growing-season length, beyond which a particular crop cannot be grown successfully or profitably.

An economic system based on “take, make, dispose”, in which raw materials are extracted, made into products, used and then discarded as waste.

An urban metabolism in which resources flow into the city, are used once and leave as waste and pollution, with little reuse or recycling.

A process in which shaking raises the pore-water pressure in saturated sand or silt so much that it loses strength and behaves like a liquid.

The water content of the material in a mass movement, from dry falls and slides to wet flows; one of the criteria used to classify mass movements.

The physical and chemical characteristics of a rock, such as mineral composition, hardness, grain size and permeability, which affect its resistance to erosion and weathering.

The rigid outer shell of the Earth, made of the crust and the uppermost mantle, about 100 km thick on average and broken into tectonic plates.

A cool period from about 1300 (or the 16th century) to about 1850, during which glaciers in the Alps and elsewhere advanced to their largest extent of recent millennia.

The attempt to influence the decisions of legislators, officials or international negotiators through direct contact, evidence and argument, by companies, industry groups or civil society organisations.

A currency, usually backed by the national currency, that can be spent only with participating businesses in a particular town or region, intended to keep spending within the local economy.

The practice of buying food, goods and services from producers in the same locality or region rather than from distant suppliers, to support the local economy and reduce dependence on global supply chains.

A ratio comparing an activity's share of the total in an area with its share in a larger reference area: above 1 means the activity is more concentrated locally.

A fine, yellowish, unstratified silt deposited by wind, often far from the desert or glacial outwash from which it was blown; it forms fertile but easily eroded soils.

A graph scale on which each equal distance represents a tenfold increase, used for data spanning a wide range; a constant rate of growth plots as a straight line.

The international treaty of 1972 controlling the deliberate dumping of wastes at sea from ships, aircraft and platforms; since 1993 it has banned dumping radioactive waste.

A graph or section showing how the height of a river bed changes with distance from its source to its mouth, typically a concave curve that flattens towards base level.

A tourist destination far from the visitor's home, usually reached by a flight of more than about six hours, often in another continent.

The movement of sediment along a coast by waves approaching at an angle, as swash carries material diagonally up the beach and backwash returns it straight down; also called littoral drift.

Infrared energy emitted by the Earth’s surface and atmosphere, at longer wavelengths than solar radiation because the Earth is much cooler than the Sun; also called terrestrial radiation.

A graph plotting the cumulative percentage of income or wealth against the cumulative percentage of the population, ranked from poorest to richest, to show inequality.

Harm from climate change that cannot be avoided by mitigation or adaptation, such as land lost to the sea or livelihoods destroyed, and the finance to address it, including the fund agreed at COP27.

A defined urban area in which the most polluting vehicles are banned or must pay a daily charge, to reduce traffic emissions; London’s Ultra Low Emission Zone is an example.

An airline that offers low fares by cutting costs, for example through one aircraft type, secondary airports, quick turnarounds, online booking and charges for extras.

A country whose GNI per capita (World Bank Atlas method) is at or below the low-income threshold, US$1,175 in the classification published in July 2026.

A common facility that is used frequently, has a small range and threshold population, and serves a small local area, such as a neighbourhood park or gym.

The inverse relationship between the size of hazard events and how often they occur: small events are frequent and large events are rare.

A vector-borne disease caused by Plasmodium parasites and spread to humans by the bites of infected female Anopheles mosquitoes, causing fever, anaemia and, if untreated, death.

Deficiencies, excesses or imbalances in a person’s intake of energy or nutrients, covering undernutrition, micronutrient deficiency and overnutrition (overweight and obesity).

The theory, set out by Thomas Malthus in 1798, that population grows geometrically while food supply grows only arithmetically, so population will outstrip food and be held back by famine, disease and war.

The planned movement of people, buildings and infrastructure away from places at high risk from hazards such as sea-level rise, coastal erosion or flooding.

A salt-tolerant tree or shrub that grows in the intertidal zone of sheltered tropical and subtropical coasts; mangrove swamps are forests of these trees.

A narrow column of unusually hot rock rising from deep in the mantle that melts as it nears the surface and produces a hotspot.

The ratio between a distance on a map and the same distance on the ground, shown as a representative fraction such as 1:25,000, a scale bar or a statement.

A period of days to months in which ocean temperatures in a region are unusually high for the time of year, commonly above the 90th percentile for at least five days.

Plastic waste in the sea, from large items such as bottles, bags and fishing nets to tiny fragments known as microplastics.

An area of sea or coast in which human activities such as fishing, mining or development are restricted by law to protect its ecosystems and resources.

A disagreement between states over sovereignty of islands or other features, the boundaries of maritime zones, or rights to use the sea and its resources.

A range of marks, such as 7–8 out of 10, with a description of the typical qualities of an answer in that range, used to mark extended answers as a whole rather than point by point.

The guidance examiners use for one examination paper, listing creditable points for structured questions and question-specific notes for applying the markbands to extended answers.

The International Convention for the Prevention of Pollution from Ships (1973, modified 1978), which regulates discharges of oil, chemicals, sewage, garbage and air pollutants from ships.

A coarse grass adapted to coastal dunes, with rolled leaves that reduce water loss, deep roots and rapid growth when buried by sand, which binds and builds foredunes.

The downslope movement of rock, soil or debris under the influence of gravity, from very slow creep to sudden falls and flows.

Tourism in which large numbers of people visit the same destinations, usually on standardised and relatively cheap products such as package holidays, often at the same times of year.

Public transport that carries large numbers of passengers along fixed routes, such as metros, commuter railways, trams and bus rapid transit.

The number of women who die from causes related to pregnancy or childbirth, during pregnancy or within 42 days of its end, per 100,000 live births in a year.

The largest catch that can be taken from a fish stock year after year without reducing its size, reached when the stock is kept at a medium level.

A term coined by George Ritzer in 1993 for the spread of the fast-food restaurant’s principles of efficiency, calculability, predictability and control to more and more of society and the world.

A model (1967) of the South-east Asian port city, centred on the port, with western and alien commercial zones, mixed land use, squatter areas, and industrial estates and market gardening at the edge.

An average found by adding all the values in a data set and dividing the total by the number of values.

A sinuous bend in a river channel, with erosion on the outer bank and deposition on the inner bank, that migrates across the floodplain over time.

A band of debris running along the middle of a glacier, formed where the lateral moraines of two joining glaciers merge.

An average equal to the middle value of a data set arranged in order, or the mean of the two middle values when the number of values is even.

The age that divides a population into two equal halves, so that half the people are younger and half are older.

A large, short-lived event of international significance, such as the Olympic Games or the FIFA World Cup, that attracts many visitors and global media coverage and requires major investment by the host.

An urban area (urban agglomeration) with a population of 10 million or more.

A very large dam, usually more than about 150 m high, with a reservoir of several cubic kilometres or a capacity above 1,000 MW, whose impacts extend across a whole basin.

A very large earthquake on the gently dipping fault between a subducting plate and the overriding plate, which can exceed magnitude 9.

A form of foreign direct investment in which a firm buys (acquisition) or combines with (merger) an existing firm in another country, rather than building a new facility.

An isolated, flat-topped hill with steep sides, wider than it is high, left where a resistant caprock protects weaker horizontal rocks as the surrounding plateau is eroded.

An urban area with more than 20 million people, a term used by UN-Habitat for the very largest urban agglomerations.

A period in which precipitation is well below the long-term average for a place, usually over several months; the first stage of a drought.

An ice-like solid in which methane is trapped within a lattice of frozen water molecules, found in ocean-floor sediments and beneath permafrost where temperatures are low and pressures high.

Business tourism for meetings, incentives (reward trips for employees), conferences and exhibitions or events.

Very small loans, usually without collateral, made to people on low incomes to start or expand a small enterprise; the lending part of microfinance.

The provision of small-scale financial services, including loans, savings, insurance and money transfers, to people on low incomes who are excluded from conventional banks.

A lack of one or more vitamins or minerals, such as iron, vitamin A, iodine or zinc, that the body needs in small amounts; it can occur in people who eat enough calories.

A piece of plastic smaller than 5 mm, either manufactured at that size, such as microbeads, or formed when larger plastic breaks down.

A country whose GNI per capita (Atlas method) lies between the low- and high-income thresholds (US$1,176–14,375 in July 2026), split into lower-middle and upper-middle income at US$4,635.

The movement of people from one place to another with the intention of settling, temporarily or permanently, usually for at least a year.

Regular long-term changes in the Earth’s orbit (eccentricity), axial tilt (obliquity) and axis direction (precession) that alter the distribution of solar radiation and pace the ice ages.

An armed group that is not part of a state’s regular armed forces, such as a rebel or paramilitary force, which may control territory and resources by force.

Eight international development goals adopted by the United Nations for 2000–2015, focused mainly on reducing poverty, hunger, disease and illiteracy in low- and middle-income countries.

An urban area with a population of one million people or more.

The removal of valuable solid minerals such as metal ores and diamonds, or of oil and natural gas, from the ground or the seabed by mining or drilling.

The food energy, in kilocalories per day, a person needs for light physical activity and a minimum acceptable body weight for their height; typically about 1,800 kcal averaged over a population.

A group of people who differ from the majority of a population in ethnicity, religion, language or another identity and who usually hold less power, whatever their numbers.

The shortfall in the number of women and girls in a population compared with the number expected if they had received the same nutrition, health care and survival chances as men and boys.

In climate change, action to reduce the causes of warming by cutting greenhouse gas emissions or enlarging carbon sinks; in hazard management, action to reduce a hazard’s impact.

Development that combines housing, shops, offices, services and leisure in the same area or building, so that people can meet daily needs within a short distance.

An average equal to the value or class that occurs most frequently in a data set, often used for categories such as shop types or modes of transport.

A scale from I to XII that measures the intensity of earthquake shaking at a place from what people feel and the damage it causes.

A logarithmic scale that measures the energy released by an earthquake from the fault area, the slip and the rock strength; each whole number is about 32 times more energy.

The cultivation of a single crop species over a large area, often for years in succession, which simplifies large-scale farming but reduces biodiversity and increases dependence on agrochemicals.

A ridge or mound of till carried and deposited by a glacier, named by its position as lateral, medial, terminal or recessional.

The risk that people take fewer precautions, or choose riskier places to live, because insurance or a government will pay for their losses.

Travel to places that have appeared in films or television series, or where they were made, such as film sets and filming locations; also called film-induced tourism.

A fast flow of fine-grained, water-saturated material such as clay and silt down a slope or channel.

An organisation whose members are the governments of several countries, which co-operate under shared rules on issues such as trade, security or the environment; trade blocs are one type.

A society, or a policy, in which several cultural or ethnic groups live together and keep their distinct identities, with equal rights and mutual respect.

An index developed by OPHI and the UNDP in 2010 that counts people deprived in at least a third of ten weighted indicators of health, education and living standards.

Aid that donor governments give to international organisations, such as the World Bank, UN agencies or regional development banks, which then allocate it to recipient countries.

The presence of two or more long-term health conditions in the same person at the same time, such as diabetes, heart disease and arthritis; it becomes more common with age.

A model (Harris and Ullman, 1945) of a city that grows around several separate centres, such as the central business district, industrial districts and outlying business districts.

The process by which spending in an economy is re-spent locally, creating further rounds of income and employment, so that the total effect is larger than the initial spending.

A distribution of global power in which three or more states or groups of states have significant influence, so that no single superpower dominates.

A dam and reservoir project designed to serve several purposes at once, such as hydroelectric power, irrigation, flood control, water supply and navigation.

The solid waste collected by or for local authorities from households, businesses and public spaces, such as food waste, packaging, paper, plastics, glass, metals and textiles.

The illegal cultivation, manufacture, transport and sale of controlled drugs such as cocaine, heroin, cannabis and synthetic drugs across international borders.

An organised competition in which clubs from one country play each other over a season, often arranged in a hierarchy of divisions.

The transfer of a privately owned company or industry into ownership by the state, with or without compensation to its previous owners.

A political ideology and sense of identity that places the interests, culture and independence of a nation above those of other nations or international bodies.

A country’s own pledge under the Paris Agreement setting out how it will reduce emissions and adapt to climate change, renewed with greater ambition every five years.

An approach to flood mitigation that slows and stores water in a drainage basin using natural processes, for example by planting trees, building leaky dams and restoring wetlands and floodplains.

A hazard caused by a natural process in the Earth's surface, atmosphere or interior, such as an earthquake, eruption, landslide or tropical cyclone.

The growth of a population caused by births exceeding deaths, ignoring migration; the natural increase rate is (birth rate − death rate) ÷ 10, in % per year. Deaths exceeding births is natural decrease.

The presence, quantity and accessibility of natural resources, such as fuels, minerals, fertile land, water and forests, in a place, which influences the investment and trade it attracts.

A unit of distance used at sea and in maritime law, equal to 1.852 km and based on one minute of latitude.

A tide with the smallest tidal range, occurring twice a month when the Sun and Moon are at right angles to each other relative to the Earth.

The relocation of production by a TNC to a country close to its main market, such as Mexico for the USA, to shorten supply chains while keeping some cost advantage.

A measure of the pattern of points on a map from the mean distance between each point and its nearest neighbour: 0 clustered, about 1 random, 2.15 perfectly regular.

A feedback loop in which the response to a change reduces or reverses it, helping the system return towards its starting state, as when a warmer Earth radiates more longwave energy to space.

The tendency for people to adopt an innovation, or acquire a disease, after contact with nearby people who already have it, so that diffusion reaches nearby places first.

Describing the modern view, developed from Malthus’s ideas, that continued growth in population and consumption will exceed the Earth’s resources and environmental limits unless growth is controlled.

The number of people moving into an area minus the number moving out, when arrivals exceed departures.

The difference between the number of people moving into an area and the number moving out over a period, usually a year; positive when more arrive than leave.

A state in which the greenhouse gases emitted by a country, company or person are balanced by an equal amount removed from the atmosphere, so their net contribution to warming is zero.

A set of interconnected places (nodes) joined by links, such as transport routes, communication cables or business relationships, along which flows move.

A multilateral development bank founded by the BRICS countries in 2014, headquartered in Shanghai, which lends for infrastructure and sustainable development and gives its five founders equal shares.

People, mostly in emerging economies, whose household spending of about US$11–110 a day per person (2011 PPP) allows them to buy goods and services beyond basic needs.

Tourism that offers a specialised product, built around a particular interest or activity, to a small and clearly defined market segment, in contrast to mass tourism.

The economic activity of a city in the evening and at night, such as bars, clubs, restaurants, theatres and late transport, often associated with concentrations of crime and disorder.

A coastal management policy under which no investment is made in building or maintaining defences, so that natural processes are allowed to shape the coast.

An area of sea, usually within a marine protected area, in which all fishing and collecting of marine life is banned.

A way of life in which herders move their livestock between seasonal pastures and water sources instead of farming fixed fields, using mobility to cope with variable rainfall.

A disease that is not passed from person to person, usually chronic and slow to develop, such as cardiovascular disease, cancer, chronic respiratory disease or type 2 diabetes.

A not-for-profit organisation independent of government that pursues social, environmental or humanitarian aims through campaigning, research, legal action or projects.

Water that is produced and put into a supply network but not billed to customers, because of leaks, theft through illegal connections or metering errors.

Any restriction on imports other than a tariff, such as a quota, licence, product standard, customs procedure or preference for domestic suppliers.

A satellite-derived measure of the greenness and density of vegetation, calculated from reflected red and near-infrared light, ranging from −1 to +1, with higher values meaning more vegetation.

The shipping route along Russia’s Arctic coast between the Kara Strait and the Bering Strait, part of the Northeast Passage between Europe and East Asia, made more usable as Arctic sea ice declines.

Electricity generated from the heat released by nuclear fission of uranium in a reactor; a low-carbon but non-renewable source that produces radioactive waste.

A statement that there is no relationship or difference between the variables being tested, which a statistical test accepts or rejects at a chosen significance level.

The forecasting of weather by solving equations of atmospheric physics on supercomputers, starting from observations of the present state of the atmosphere.

A small plastic pellet, usually under 5 mm across, made as the raw material for plastic products; nurdles spilled in production and shipping are a major source of microplastic pollution.

A measure of the quantity or quality of food available to or eaten by a population, or of its nutritional status, such as calories per person, undernourishment or child stunting.

The shift in diets that accompanies rising incomes and urbanisation, from mainly cereals, roots and pulses towards more meat, dairy, vegetable oils, sugar and processed food.

A fertile area in a desert where groundwater reaches or comes close to the surface, through springs, wells or channels, allowing permanent settlement and irrigated farming.

Excessive accumulation of body fat that harms health, defined for adults as a body mass index of 30 or more.

The decrease in seawater pH caused by absorbing carbon dioxide, which forms carbonic acid and reduces the carbonate ions that corals, shellfish and plankton use to build shells.

A continuous, directed movement of seawater, driven at the surface mainly by prevailing winds and at depth by differences in water density.

The introduction by people of substances, objects or energy into the sea that harm living resources, human health or legitimate uses of the sea.

The thin, dense layer of basaltic rock, about 5–10 km thick, that forms the floor of the ocean basins; it is younger than about 200 million years because it is recycled at subduction zones.

NOAA’s index of ENSO: the three-month running mean of sea surface temperature anomalies in the Niño 3.4 region; +0.5 °C or more indicates El Niño and −0.5 °C or less La Niña.

Government aid, as grants or concessional loans, given to lower-income countries with the main aim of promoting their economic development and welfare, as defined by the OECD Development Assistance Committee.

A barrier of rock or concrete built in the sea parallel to the coast, so that waves break and lose energy before they reach the shore.

Petroleum and natural gas extracted from rocks beneath the seabed using fixed platforms, floating production units or drill ships.

The relocation of some of a company’s production or services to another country, either to its own facilities or to foreign contractors, usually where costs are lower.

The release of liquid petroleum into the environment, especially the sea, from tankers, pipelines, offshore platforms or wells.

China’s anti-natalist policy from 1980 to 2015, which limited most urban couples to one child using fines, workplace sanctions, contraception and sterilisation, with exemptions for many rural families and minorities.

A website or app that sells travel products such as accommodation, flights and car hire from many suppliers, earning a commission on each booking.

A wider alliance, formed in 2016, in which OPEC members co-ordinate oil production with other major exporters, most importantly Russia, to influence world oil prices.

The disposal of human faeces in fields, bushes, open water, beaches or other open spaces, or with solid waste; the lowest rung of the sanitation ladder.

A method of surface mining in which ore is removed from a large, stepped excavation open to the sky after the overlying rock and soil have been stripped away.

The theoretical population size at which, with the available resources and technology, the standard of living or output per person is at its highest.

An intergovernmental organisation of 38 mainly high-income member countries, founded in 1961, that collects economic data, compares policies and sets standards on aid, tax and investment.

An intergovernmental organisation of oil-exporting countries, founded in 1960, that co-ordinates its members’ oil production in order to influence world oil prices.

A large shopping centre or group of stores at the edge of an urban area, usually near a motorway or ring road, with extensive free parking.

The contracting of a task or process, such as manufacturing, customer service or IT, to another firm instead of carrying it out within the firm itself, in the same country or abroad.

Sorted, rounded and often layered sand and gravel deposited by meltwater streams beyond or beneath a glacier.

Farming land so intensively, for example by shortening or abandoning fallow periods, that the soil loses nutrients, organic matter and structure faster than they are replaced.

Catching fish from a stock faster than it can replace itself through reproduction and growth, so that the stock declines.

Keeping more livestock on an area of pasture than its vegetation can support, so plants are eaten faster than they regrow and the soil is left bare and compacted.

The movement of water over the ground surface towards a channel, when rainfall exceeds the infiltration capacity of the soil or falls on soil that is already saturated; also called surface runoff.

A visitor who stays at least one night in collective or private accommodation in the place visited; UN Tourism calls overnight visitors tourists.

A form of malnutrition in which energy intake exceeds energy use over a long period, leading to overweight and obesity and a higher risk of non-communicable diseases.

A situation in which the population of an area is too large for its resources and technology to support at an adequate standard of living, shown by poverty, unemployment, food shortages or environmental degradation.

A situation in which the number of visitors to a destination is so high that it damages the quality of life of residents, the experience of visitors or the environment.

A crescent-shaped lake on a floodplain formed when a river cuts through the narrow neck of a meander and deposition seals off the abandoned loop.

A compressional seismic wave that pushes and pulls rock in its direction of travel; it is the fastest wave and passes through solids and liquids.

The belt of subduction zones, volcanoes and earthquakes that surrounds the Pacific Ocean, where about two-thirds of the world's volcanoes and most large earthquakes occur.

A holiday sold at a single price that combines at least transport and accommodation, often with transfers, meals and excursions, usually organised by a tour operator.

An epidemic of an infectious disease that has spread across a large region, such as several countries or continents, and affects a large number of people.

The main international multi-sport event for athletes with physical, visual or intellectual impairments, held after the Olympic Games in the same host city.

The 2015 treaty under the UNFCCC in which almost every country agreed to limit warming to well below 2 °C, pursue 1.5 °C, and set and regularly strengthen national emissions pledges.

A scheme in which drivers leave their cars at car parks on the edge of a city and complete their journey to the centre by public transport.

The percentage of a population, or of a group within it, that takes part in a particular activity over a stated period.

Solid or liquid particles suspended in the air, classed by diameter as PM10 (up to 10 micrometres) and PM2.5 (up to 2.5 micrometres), which penetrate deep into the lungs and bloodstream.

A microorganism, such as a virus, bacterium, protozoan or fungus, that causes disease in the organism it infects.

A regular pattern of stone circles, polygons, nets or stripes on the ground in periglacial areas, produced mainly by frost heave, sorting of stones and, on slopes, solifluction.

An arrangement in which those who benefit from an ecosystem pay the people who manage it to keep it intact, for example through blue carbon credits.

The highest discharge reached by a river during a storm or flood event, read from the top of the storm hydrograph.

The point within a central business district with the highest land values, usually the junction of the busiest shopping streets.

A wetland in which waterlogged conditions slow decomposition, so partly decayed plant matter accumulates as peat and stores large amounts of carbon.

A fieldwork method that records the number of people passing a fixed point in a set time, used to measure how busy different parts of a settlement are.

The facilitation, for financial gain, of a person’s irregular entry into a country of which they are not a citizen or resident; the person usually consents and the relationship ends on arrival.

A country’s total greenhouse gas or carbon dioxide emissions divided by its population, usually given in tonnes per person per year.

The change in a value expressed as a percentage of its original value: the difference between the new and original values, divided by the original value, multiplied by 100.

The level of crowding that visitors will tolerate before their experience of a site is spoiled; also called psychological carrying capacity.

The slow downward movement of water from the soil into the underlying rock, where it may reach the groundwater store.

The growth of urban populations, housing and economic activities in the zone just beyond a city's formal boundary, often unplanned and mixing urban and rural characteristics.

A cold, non-glacial environment near ice sheets or glaciers or at high altitude, in which the ground is frozen for much or all of the year and repeated freezing and thawing shapes the land.

A region with lower levels of economic development, investment and services than the core, which often loses young people and resources to the core.

Ground (soil, sediment or rock) that remains at or below 0 °C for at least two consecutive years, storing large amounts of frozen organic carbon in the Arctic and on high plateaus.

The warming and melting of ground ice in permafrost, which deepens the active layer, causes subsidence and releases stored carbon as carbon dioxide and methane.

A barrier that slows or weakens diffusion but allows part of the phenomenon to pass through.

A toxic carbon-based chemical that resists breakdown, accumulates in the fatty tissue of organisms and is carried long distances by air and water, such as DDT or PCBs.

The ability of individuals to think, speak, communicate, travel and associate with others as they choose, without unjustified interference by the state or other powerful actors.

The capacity of individuals and households to prepare for, cope with and recover from a hazard event, for example through emergency plans, savings, insurance and knowledge of what to do.

The different viewpoints from which an issue can be seen, such as those of stakeholders, places, scales or time periods, which shape how costs, benefits and priorities are judged.

An attempt to trick people into revealing passwords, bank details or other personal information through messages or websites that appear to come from a trusted organisation.

A brownish haze formed when nitrogen oxides and volatile organic compounds, mainly from vehicle exhausts, react in strong sunlight to produce ground-level ozone and other secondary pollutants.

A technology that converts sunlight directly into electricity in semiconductor cells, usually made of silicon, mounted in panels.

The maximum number of visitors a site can physically hold at one time, limited by its space and facilities, such as seats, beds or beach area.

A shortage in which natural water supplies cannot meet all demands, including environmental flows; usually defined as more than about 75% of river flows being withdrawn.

The breakdown of rock into smaller fragments without any change in its chemical composition, by processes such as thermal fracture, salt crystallisation and freeze-thaw.

An input indicator of health care: the number of medical doctors, generalist and specialist, per 1,000 people in a country (published by the WHO per 10,000 people).

Microscopic plant-like organisms, mainly algae and cyanobacteria, that drift in the sunlit surface ocean and photosynthesise, forming the base of most marine food webs.

A small trial of the fieldwork methods carried out before the main data collection, to test equipment, timing, safety and questionnaire wording.

A dome-shaped hill with a core of ice, up to about 70 m high, formed in permafrost areas when water under pressure freezes near the surface, in drained lake beds (closed system) or from rising groundwater (open system).

The emotional bond between people and a place, built through family history, community, identity and livelihoods, which can lead people to stay in or return to hazardous places.

A framework that sets limits for nine Earth-system processes, such as climate change, biosphere integrity and freshwater change, within which humanity can operate without risking abrupt or irreversible environmental change.

A settlement designed as a whole before it is built, with its street layout, land-use zones and services decided in advance by a government or developer.

The deliberate design of a product so that it becomes unusable, unrepairable or out of date after a limited period, encouraging consumers to replace it.

Flood mitigation that changes how people use, prepare for and respond to flood-prone land, such as zoning, insurance, warnings and preparation, rather than changing the river itself.

The zone where two tectonic plates meet and move relative to each other, where most earthquakes and volcanoes occur.

A model (1974) that classifies tourists by personality on a scale from psychocentric (familiar, safe, organised travel) to allocentric (new, unfamiliar, independent travel), with most people mid-centric.

Glacial erosion in which meltwater freezes onto jointed bedrock, so that moving ice pulls away blocks of rock.

A gently sloping deposit of sand and gravel on the inside of a meander bend, where water is shallow and flow is slow.

Pollution that enters water from a single identifiable place, such as a sewage outfall, factory pipe or slurry tank, so it can be measured and regulated.

A system of migration control in which applicants gain points for characteristics such as a job offer, skills, qualifications, language ability and salary, and may apply for a visa if they reach a set threshold.

An environment in the high latitudes, mostly within the Arctic and Antarctic Circles, where the warmest month averages below about 10 °C, winters are long and dark, and precipitation is usually low.

The idea that, as trade and investment become freer, polluting industries relocate to places with weaker or less enforced environmental rules, shifting pollution towards lower-income countries.

A lump of minerals a few centimetres across, rich in manganese, nickel, cobalt and copper, that forms very slowly on the deep-ocean floor.

The number of people living in a unit of area, calculated as total population divided by land area and usually given in people per km².

The way in which people are spread across an area, describing where they are concentrated and where they are sparse or absent.

An estimate of the future size and structure of a population calculated from assumptions about fertility, mortality and migration, usually given in several variants to show uncertainty.

A pair of back-to-back horizontal bar charts showing the percentage or number of males and females in each five-year age group of a population.

The composition of a population by age and sex, usually shown as a population pyramid.

A political approach that claims to represent “the people” against an elite seen as corrupt or self-serving, often promising simple solutions to complex problems; it can be combined with left-wing or right-wing ideas.

The pressure of water held in the spaces between particles of soil or rock; when it rises it pushes the grains apart and reduces friction.

A feedback loop in which the response to a change amplifies the original change, pushing the system further from its starting state, as when melting ice exposes darker surfaces that absorb more heat.

The actions taken after a hazard event to save lives, meet urgent needs and restore and improve communities, usually divided into rescue, rehabilitation and reconstruction.

A mental health condition that can follow a frightening or distressing event such as a disaster, with symptoms including flashbacks, anxiety, sleep problems and avoidance that can last for months or years.

A condition in which a person or household lacks the income or resources to meet basic needs such as food, clean water, shelter, health care and education; also called absolute poverty.

A sampling method that chooses sites or people that are safe, accessible and available, used where random or systematic sites cannot be reached.

The measures taken before a hazard event to reduce its impact, including monitoring, warnings, land-use planning, building design, defences, education and evacuation plans.

The knowledge, plans, resources and practised actions that individuals, households and communities have in place to respond effectively before and during a hazard event.

A model of disaster risk in which root causes, dynamic pressures and unsafe conditions build vulnerability, and a disaster happens when this vulnerability meets a hazard.

The total number or proportion of people in a population who have a disease at a particular time, including both new and existing cases.

Information collected first-hand by the investigator in the field, for example by measurement, counting, observation, questionnaires or interviews.

A hazard caused directly by an eruption or earthquake, such as lava flows, ash fall or ground shaking.

Economic activities that extract raw materials directly from the natural environment, such as farming, fishing, forestry, mining and quarrying.

Features that exist independently of tourism and attract visitors, such as climate, landscape, coasts, wildlife, historic buildings, culture and religious sites.

A city that is much larger than any other in its country, usually more than twice the size of the second city, and dominates its economic, political and cultural life.

A government policy that aims to increase the birth rate and family size, for example through child benefits, tax relief, paid parental leave, subsidised childcare and housing support.

A map showing the level of a hazard, such as ground shaking, that has a stated chance of being exceeded in a given period, used for building codes and insurance.

Ethiopia’s social protection programme, begun in 2005, that gives cash or food to chronically food-insecure households in return for work on public projects, with unconditional support for those unable to work.

The transfer of profits earned by a TNC’s foreign subsidiaries back to the parent company in its home country or headquarters, rather than reinvesting them in the host country.

A system in which the most successful teams in a division move up to a higher division and the least successful move down at the end of each season.

A map with symbols, usually circles, placed at locations and drawn with their area proportional to an absolute value there, such as population or visitor numbers.

A government policy of restricting imports, through tariffs, quotas, subsidies or other barriers, to protect domestic producers and jobs from foreign competition.

A plant succession that develops on bare sand, as on coastal dunes, from salt-tolerant pioneer plants near the beach to heath or woodland inland.

Describes a tourist who prefers familiar, safe and well-developed destinations, organised travel and familiar food and surroundings (Plog's 'dependable').

A formal declaration by the WHO, under the International Health Regulations, that an extraordinary disease event is a risk to other states through international spread and may need a coordinated response.

A positive feature of a destination, such as jobs, higher wages, services or safety, that attracts migrants to it.

An adjustment that converts incomes into a common currency according to what they can buy locally, so that differences in the cost of living between countries are taken into account.

A tourist resort planned and constructed specifically for tourism, often on a largely undeveloped site, rather than growing gradually from an existing settlement.

A town or city planned and built from the beginning on an undeveloped site, with its layout, infrastructure and technology designed in advance.

A negative feature of a place of origin, such as unemployment, poverty, conflict or environmental hazard, that encourages people to leave it.

A steep, pointed mountain summit with three or more faces, formed where three or more cirques have eroded back into the same peak, leaving arêtes between them.

A fast, ground-hugging current of hot gas, ash and rock that flows down a volcano at hundreds of degrees Celsius and often over 100 km per hour.

A gently sloping underground tunnel that carries groundwater by gravity from an aquifer in higher ground to the surface at a lower point, with vertical shafts for construction and maintenance.

A square frame of known size, often 0.5 m by 0.5 m, placed on the ground to measure the percentage cover or number of plants or particles inside it.

Information recorded as words, images or opinions, such as interview answers, photographs or field sketches, which can be coded or described.

Information recorded as numbers, such as measurements and counts, which can be processed with calculations, graphs and statistical tests.

The most recent geological period, from about 2.58 million years ago to the present, characterised by repeated cycles of glacial and interglacial periods.

Knowledge-based economic activities, such as research and development, information technology, consultancy and financial services.

A set of written questions asked in the same order to a sample of people to collect facts, behaviour or opinions that can be compared.

The part of a river's discharge during a storm that arrives rapidly by overland flow and fast throughflow, shown as the area above the base flow line on a storm hydrograph; also called stormflow.

Material that emits ionising radiation, produced by nuclear power, fuel reprocessing, weapons and medicine, which must be isolated from people and the environment.

The reduction of precipitation on the leeward side of a mountain range, because moist air loses its water as it rises over the windward side and then descends, warms and dries.

The degree to which annual rainfall at a place differs from its long-term average from year to year; high variability means low reliability and is usually greatest where rainfall is lowest.

The collection and storage of rainwater, from roofs or the land surface, for later use or to recharge groundwater.

A former beach, now above present high tide level, left behind when the land rose relative to the sea; usually a flat terrace backed by a relict cliff.

An international treaty signed at Ramsar, Iran, in 1971, under which countries commit to the conservation and wise use of wetlands and designate Wetlands of International Importance.

A wetland designated as being of international importance under the Ramsar Convention, which its country commits to conserve.

A sampling method in which every member of a population or every point in an area has an equal chance of being chosen, usually using random numbers.

The maximum distance people are prepared to travel to use a particular service or facility.

A measure of spread equal to the difference between the largest and smallest values in a data set.

A change in the geographical area where a species lives, usually towards the poles or to higher altitudes as the climate warms.

A rule stating that in a country's urban system the population of the city ranked n is one nth of the population of the largest city.

Malicious software that encrypts or locks a victim’s files or systems and demands a payment, usually in cryptocurrency, to restore access.

An increase in the maximum sustained wind speed of a tropical cyclone of at least 55 km/h (30 knots) within 24 hours.

The return of production or services by a TNC from an overseas location to its home country, usually to reduce supply-chain risk, gain government incentives or use automation.

The downward movement of water from the surface into an aquifer, replenishing groundwater; it may come from rainfall, rivers or irrigation.

The long-term phase of post-event management, lasting months to years, in which buildings, infrastructure and the economy are rebuilt, ideally to a safer standard than before.

An activity undertaken voluntarily in leisure time for enjoyment, relaxation or refreshment, usually at or near home or in the local area.

The average time between floods of at least a given size, calculated from a long record of annual peak discharges; a 1-in-100-year flood has a 1% chance of happening in any year.

The reprocessing of waste materials such as paper, glass, metals and plastics into new products or raw materials, reducing the need to extract new resources.

The inclusion of spare or duplicate capacity in a system, such as back-up power or alternative routes, so that it keeps functioning if one part fails.

Active intervention to help a damaged coral reef recover, for example by growing coral fragments in nurseries and transplanting them or stabilising rubble so corals can settle.

A person who has crossed an international border because of a well-founded fear of persecution, as defined by the 1951 Refugee Convention, or, under wider regional and UNHCR definitions, to escape armed conflict.

The long-term improvement of a declining urban area through investment in its economy, buildings, infrastructure, environment and community.

The phase of post-event management, lasting weeks to months, in which temporary housing is provided and basic services, infrastructure and livelihoods are restored.

In Butler's model, a renewed growth in visitor numbers after stagnation, brought about by new attractions, investment, re-branding or new markets.

A condition in which a person’s income or resources are well below the average of the society they live in, usually below 50% or 60% of median household income.

The change in the level of the sea compared with the land at a particular place, the combined result of eustatic and isostatic change.

The degree to which a method gives consistent results when repeated in the same conditions, by the same or a different investigator.

A former sea cliff no longer reached by the waves, because the land has risen or the coast has advanced, and now shaped by subaerial processes.

The emergency provision of food, water, shelter, medical care and other essentials to people affected by a disaster, mainly during the rescue phase.

Diffusion in which a phenomenon is carried to a new area by people who migrate or travel, so that it may leave or weaken in its place of origin.

Money or goods sent by a migrant to family or friends in their home country, usually as small, regular transfers.

The distance, in space, time or cost, between a place and the main centres of population, markets, services and political power, which raises transport and labour costs and isolates residents.

Energy from sources naturally replenished on a human timescale, such as sunlight, wind, flowing water, geothermal heat and biomass.

The difference between the rent a property earns in its current, run-down state and the much higher rent it could earn if renovated, which makes gentrification profitable.

The total fertility rate at which a population exactly replaces itself from one generation to the next without migration, about 2.1 children per woman where child mortality is low.

The first phase of post-event management, lasting hours to days, in which survivors are found and freed, the injured are treated and urgent needs for shelter, water and food are met.

An artificial lake formed behind a dam, in which water is stored for later use.

The settling of sediment in the still water of a reservoir, which reduces its storage capacity and starves the river downstream of sediment.

Earthquakes triggered by the filling of a large reservoir, where the water's weight and raised pore pressure along faults allow them to slip.

The spatial separation of different social groups, such as ethnic, religious or income groups, into different residential areas of a city.

The capacity of people, places or systems to absorb a hazardous event, recover from it, and adapt so that they are better able to cope in future.

A global network of cities, successor to the Rockefeller Foundation’s 100 Resilient Cities programme (2013–2019), that shares methods for planning urban resilience to shocks and stresses.

A separate booklet issued with an examination paper that contains the maps, graphs, photographs and other stimulus material the questions refer to.

The use of natural resources such as water, land, food, energy and materials by individuals, countries or the world, including use of the environment’s capacity to absorb waste.

The tendency of some countries with abundant natural resources, especially oil and minerals, to experience slower economic growth, weaker institutions or more conflict than countries with fewer resources.

The assertion by a state of greater control over the natural resources in its territory, through state companies, ownership limits, taxes, royalties or bans, so that more of the benefit stays in the country.

The careful and responsible management of resources by individuals, businesses, communities and governments so that they are used efficiently, conserved and passed on in good condition to future generations.

A wall built at the foot of or across a slope to hold back soil or rock and prevent it from sliding, often with drains to let water out from behind it.

Adding new technology, materials or design features to existing buildings, infrastructure or urban areas to improve their performance, such as smart sensors, insulation or flood protection.

The movement of migrants back to their country or place of origin, temporarily or permanently, after living elsewhere.

The growth of population and investment in the central and inner areas of a city after a period of decline, often through redevelopment, conversion of older buildings and gentrification.

A desalination method in which seawater or brackish water is pumped at high pressure through a semi-permeable membrane that lets water pass but holds back dissolved salts.

A sloping structure of concrete, stone, timber or rock placed at the foot of a cliff or back of a beach, on which waves run up and lose energy.

A drowned river valley formed when a rise in sea level flooded an unglaciated valley, becoming wider and deeper towards the sea.