LGCSE Geography key terms

The force of fast-flowing water trapping and compressing air in cracks in a river bed or cliff, weakening the rock until fragments break away. It is a form of erosion requiring no abrasive load.

Erosion caused by rock fragments carried by water, ice or wind scraping and scouring the surface they pass over, smoothing bedrock and undercutting banks or cliffs.

The process by which moving load collides with itself, so particles become smaller and rounder downstream or along a beach. It reduces clast size without necessarily eroding the channel bed.

The zigzag movement of sediment along a coast, where waves approach at an angle and swash carries material up the beach while backwash returns it perpendicular to the shoreline.

A narrow ridge of sand or shingle extending from the land into open water, built where longshore drift continues past a change in coastline direction and deposition outpaces removal.

The laying down of eroded material when a transporting medium loses energy, for example where a river slows on entering a lake or the sea, or where wave swash is stronger than backwash.

Chemical weathering or erosion in which soluble minerals such as limestone and rock salt dissolve in slightly acidic water, carrying ions away in the flow or groundwater.

Chemical weathering in which rainwater containing dissolved carbon dioxide forms weak carbonic acid that reacts with calcium carbonate in limestone and chalk, dissolving it to create caves and pavements.

The downslope transfer of rock, soil and mud under gravity, ranging from slow creep and slumping to rapid landslides and mudflows, often triggered when slopes become saturated.

The in-situ breakdown and decay of rock at or near the surface by physical, chemical or biological processes, producing regolith without transporting the material away.

A high-pressure system with descending air that suppresses cloud formation, giving settled, often clear weather; in winter it can produce frost and fog, and in summer hot, dry spells.

A low-pressure weather system where converging air rises, cools and condenses, producing cloud, rain and often strong winds, typically tracking eastwards across mid-latitude regions.

The boundary between two air masses of different temperature and density. At a warm front, warm air rides over cold air; at a cold front, cold air undercuts and lifts warm air steeply.

The additional warming caused when human emissions of gases such as carbon dioxide, methane and nitrous oxide trap more outgoing long-wave radiation than the natural greenhouse effect would.

Action that reduces the causes or scale of climate change, such as cutting greenhouse-gas emissions, improving energy efficiency, switching to renewables, or sequestering carbon in forests and soils.

Adjustment to actual or expected climate impacts that lowers harm or exploits opportunity, for example flood defences, drought-resistant crops, or changing planting dates and building design.

A community of interacting living organisms together with the non-living parts of their environment, such as soil, water and climate, linked by flows of energy and cycles of nutrients.

A very large global-scale community of plants and animals shaped by climate, such as tropical rainforest, savanna, desert, temperate grassland or tundra, each with characteristic vegetation structure.

The variety of life at genetic, species and ecosystem levels. High biodiversity supports ecosystem resilience, while habitat loss, fragmentation and invasive species are major causes of decline.

The pathway by which elements such as carbon, nitrogen and phosphorus move between living organisms, soil, water and the atmosphere, largely driven by decomposition in humid tropical systems.

The permanent removal of forest cover for timber, agriculture, mining or settlement, which reduces evapotranspiration, raises runoff and soil erosion, and releases stored carbon.

The number of live births per 1,000 people in a population in a given year, influenced by education, contraception, infant mortality, religion and economic conditions.

The number of deaths per 1,000 people in a population in a given year, falling with better healthcare, sanitation, nutrition and control of disease.

Population growth resulting from the excess of births over deaths, usually expressed as a percentage per year and calculated from the gap between crude birth and death rates.

A paired bar graph showing the age and sex structure of a population, whose shape reveals past events, dependency ratios and whether fertility and mortality are high or low.

A negative condition at a place of origin, such as unemployment, conflict, drought or poor services, that encourages people to leave in search of better circumstances.

An attractive condition at a destination, such as jobs, education, healthcare, safety or family links, that draws migrants towards it.

The permanent or semi-permanent movement of people between places, which may be internal or international, voluntary or forced, and which changes both source and receiving areas.

Economic activity that directly extracts or harvests natural resources, including farming, fishing, forestry and mining. Its share of employment usually falls as economies develop.

Economic activity that processes raw materials into manufactured goods, such as food processing, textiles, steel making and vehicle assembly, typically concentrated in industrial regions and zones.

Economic activity providing services rather than goods, including retail, transport, tourism, banking, education and healthcare; it expands as incomes rise and manufacturing declines.

Knowledge-based activity such as research, software development, consultancy, finance and design, which relies on skilled labour and often clusters near universities and major cities.

A company that operates production or service facilities in more than one country, relocating activity to lower costs or larger markets and creating global production chains.

The growing interconnection of economies and societies through trade, investment, migration, information flows and transport, which spreads ideas and goods but can widen inequalities.

The difference in wealth, health and living standards between more and less developed countries or between regions within a country, often measured by GDP per capita or the Human Development Index.

A composite measure of development combining life expectancy, years of schooling and gross national income per person, giving a value between 0 and 1 for comparison between countries.

The rising proportion of a population living in towns and cities, driven by rural-to-urban migration and natural increase, and associated with the growth of informal settlements.

The outward, often low-density expansion of built-up area into surrounding countryside, increasing car dependence, infrastructure costs and loss of farmland or green space.

An area of a town or city dominated by one activity, such as central business district, inner-city industry, residential suburbs or green belt, arranged by land value and access.

A condition where demand for fresh water approaches or exceeds reliable supply, measured by withdrawals as a share of available resources and worsened by pollution and drought.

A shortage of fresh water in a region, either physical where supply is naturally low, or economic where infrastructure and money to abstract and treat water are lacking.

Reliable access to water of acceptable quality and quantity to support health, food production, industry and ecosystems, maintained through storage, treatment and demand management.

A line on a map joining points of equal height above sea level. Closely spaced contours indicate steep slopes, widely spaced ones gentle slopes, and V shapes point upstream in valleys.

The relationship between distance on a map and distance on the ground, shown as a ratio, a statement or a linear bar, and used to convert measured distances accurately.

A geographic information system: software that stores, combines and analyses layers of spatial data so patterns and relationships, such as flood risk against housing, can be mapped.

A map in which areas are shaded in proportion to a value, using graded colours or patterns and a key, to show spatial variation such as population density or rainfall totals.

A profile drawn from a transect of measurements, showing change along a line such as a beach, river channel or slope, used to compare sites and test hypotheses.

Selecting a representative subset of sites or measurements for fieldwork, using random, systematic or stratified methods, so results can be generalised without surveying everything.