Key Stage 3 geography · Human and physical interactions

KS3 geography: how people change landscapes and climate

In Key Stage 3, students move beyond describing landscapes to explaining how they change over time through the interaction of human and physical processes. They study how people alter rivers, coasts and forests, how those changes can have unexpected knock-on effects, and how human activity adds to climate change. The skill that matters most is following a chain of cause and effect across a system, rather than learning each fact on its own.

How people change landscapes and climate, explained

A landscape is the product of physical processes, such as erosion, deposition, weathering and the movement of water, and of what people have done to it. A chalk cliff is shaped by waves and weather, but the harbour wall, the sea defences and the houses built on top are human additions that change how those processes work. Students are taught that the two sets of processes are not separate: people respond to physical processes, and their responses then feed back into them.

Coasts are a common example. Waves arriving at an angle move sand and shingle along the beach in a process called longshore drift. Towns that want to keep their beach build wooden or rock barriers called groynes, which trap the moving sediment. The beach grows on one side, but the stretch of coast further along is starved of material, so it erodes faster. A solution in one place becomes a problem in another, and students are asked to describe and explain exactly that kind of knock-on effect.

The same thinking applies inland. Paving over a floodplain means rain cannot soak into the ground, so water reaches the river faster and flood risk rises. Cutting down forests removes the roots that bind soil, so rain washes it away and rivers fill with silt. Farming, mining, building reservoirs and straightening channels all alter the shape and behaviour of the land. Students compare how landscapes look and work in different places, and why a landscape in one area is distinctive compared with another.

Climate is the long-term pattern of weather in a place, usually averaged over about thirty years. Students learn that some greenhouse gases, including carbon dioxide and water vapour, trap heat in the atmosphere and keep the Earth warm enough to live on, which is the natural greenhouse effect. Burning fossil fuels, clearing forests and some kinds of farming add extra gases, so more heat is trapped. That is the enhanced greenhouse effect, and it is the main reason global temperatures are rising. Consequences include rising sea levels, more extreme weather and changes to habitats.

Students are also introduced to ideas of feedback and complexity. For instance, as Arctic ice melts, dark sea water that absorbs more heat replaces bright ice that reflected it, which warms the region further. In the National Curriculum, this is the awareness of increasingly complex geographical systems. Schools pick their own examples, such as a stretch of coastline, a river catchment, a rainforest or a polar region, and your teenager should be able to say which ones they have studied.

Words your child will hear

Interaction: When two things affect each other, such as people changing a coast and the coast then changing in response.
Longshore drift: The movement of sand and shingle along a coast by waves that arrive at an angle.
Groyne: A barrier built out from the shore to trap moving sediment and keep a beach in place.
Deforestation: The clearing of forests, usually for farming, timber or building.
Greenhouse effect: The trapping of heat in the atmosphere by gases such as carbon dioxide, which keeps the Earth warm.
Climate change: A long-term shift in global or regional weather patterns, currently driven mainly by human activity.
Feedback: When a change sets off a process that either strengthens it or weakens it.

What the National Curriculum says

The programme of study for Key Stage 3 says:

Pupils should be taught to understand how human and physical processes interact to influence and change landscapes, environments and the climate; and how human activity relies on the effective functioning of natural systems
Pupils should understand how geographical processes interact to create distinctive human and physical landscapes that change over time.
Pupils should become aware of increasingly complex geographical systems in the world around them.

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

A model answer: explaining a knock-on effect

A seaside town builds groynes to stop its beach disappearing. Explain how this could affect the village further along the coast.

Start with the physical process. Waves approach at an angle, carrying sand and shingle up the beach at the same angle (the swash). The water then runs straight back down the slope of the beach, at right angles to the shoreline (the backwash). Over time, material moves in a zigzag along the coast. This is longshore drift.
Explain what the human action does to it. Groynes are built out from the beach, so they block the sediment that the waves are carrying. Sand piles up against the groynes on the side the material arrives from, and the town’s beach grows.
Follow the chain to the next place. Less sediment now travels past the groynes, so beaches further along the coast receive less. A narrower beach absorbs less wave energy, so waves reach the cliffs or sea wall of the village with more force, and erosion speeds up.
Add a judgement. The town benefits, but the village may lose land or need to pay for its own defences. This is why planners usually consider the whole stretch of coast together rather than each place separately.

By trapping sediment moved by longshore drift, groynes build up the beach in the town but starve the village downdrift. With less sediment, the beach there becomes narrower and offers less protection, so erosion increases. The human response to one physical process has created a new problem in a neighbouring place, which shows how human and physical processes interact in a connected system.

Common mistakes and how to help

Treating weather and climate as the same thing

A cold week or a hot day is easy to point to, so students use it as evidence for or against climate change.

What helps: Weather is what is happening now; climate is the average over many years. It is like the difference between one test score and a whole year’s average.

Thinking the greenhouse effect is entirely harmful

News coverage only mentions the greenhouse effect when it is a problem.

What helps: Without the natural greenhouse effect, the Earth would be too cold for life as we know it. The problem is the extra gases that people add, which trap more heat.

Assuming human intervention always protects a place

Sea walls, dams and flood barriers are built to help, so students expect them to solve problems.

What helps: Ask “who gains and who loses?” every time. Defences move the problem or create new ones, and they cost money to build and maintain.

Mixing up the hole in the ozone layer with climate change

The ozone hole and global warming were in the news together and both involve the atmosphere, so they get merged.

What helps: They are separate issues. The ozone layer shields us from ultraviolet radiation, whereas global warming comes mainly from carbon dioxide, methane and other greenhouse gases.

How to help at home

Spot human changes on a walk. On a walk or a journey, look for places where people have changed a natural process: a culvert under a path, a drained field, a wall holding back a bank, a straightened stream. Ask your teenager what the original landscape might have done differently.
Watch the rain on hard surfaces. After a shower, look at where the water runs and where it soaks away, comparing a lawn, garden or park with a paved area such as a patio or driveway. This shows in miniature why building on land increases the speed and amount of runoff.
Follow a chain of consequences. Pick a news story about flooding, wildfire or a coastal defence and ask your teenager to draw the chain: what happened first, what that caused and who was affected. Practising chains of cause and effect is the main skill the topic builds.
Compare an old and a new map or photograph. If you can find an older picture or map of a nearby place, compare it with now and list the changes caused by people and by nature. Stories of local change make good place-based examples.
Talk about choices with real trade-offs. When a family decision has a climate angle, such as how you travel or heat the home, discuss it as costs and benefits for different people rather than right and wrong. It practises the balanced reasoning that geography teachers look for.

Builds on

Key Stage 2: Climate zones, biomes and vegetation belts
Key Stage 2: Rivers and the water cycle
Key Stage 2: Mountains
Key Stage 2: Volcanoes and earthquakes
Key Stage 2: Settlements and land use
Key Stage 2: Economic activity and trade
Key Stage 2: Natural resources