Greenfield, brownfield and urban sprawl
Geography · Key Stage 3 · The School
Two kinds of building site
A GREENFIELD site is undeveloped land, usually farmland, at the edge of a town. It is being built on for the first time. A BROWNFIELD site is land already built on before, inside a city — an old factory, a disused railway yard — being redeveloped instead of built from empty ground. Housing shortages push builders toward whichever site is cheaper and easier. Greenfield land is very often both.
Why urban sprawl happens
URBAN SPRAWL is a city spreading outward onto greenfield land at its edges. It is usually low, spread-out housing rather than tall, space-saving building. It happens for three reasons. Land at the city edge is cheaper than land near the centre. Building on empty fields needs no costly clearing first. And many buyers want a house with a garden, not a flat.
The costs of sprawl
Sprawl uses up farmland and wildlife habitat for good. It raises car dependency, because spread-out edge estates are harder to serve with buses or trains than a compact city centre. It can hollow out a city centre, as shops and people both drift outward. And swapping farmland and grass for roofs and roads raises surface water runoff, which can worsen flooding further down the valley.
A GREEN BELT is a ring of protected land around a city. New building there is tightly limited by law. It is meant to stop sprawl and push new building onto brownfield land instead. It genuinely works in one way: cities with a green belt show far less edge sprawl than cities without one. But it has a real, well-known cost too. Limiting where homes can be built pushes up land prices inside the boundary. That makes housing less affordable for exactly the people who most need cheaper housing. A green belt does not simply solve the sprawl problem. It trades one problem, lost countryside, for another, higher housing costs. A strong answer names both sides, rather than treating the policy as a simple win.