Notes · GeographyUK · A-Levels

Contemporary Urban Environments

An optional human topic on urbanisation and the challenges of managing cities sustainably. It covers global urbanisation and urban change processes, urban forms and land-use models, the urban climate and drainage, waste and other environmental issues, and the pursuit of sustainable, liveable cities, illustrated by contrasting urban case studies.

5 sections~17 min reading time3 competenciesLevel Standard 2 · Advanced 3

T·0999 / 12

Exam profile

AO1 · Understand urbanisation processes, urban forms and models, urban climate and drainage, and sustainabilityAO2 · Apply understanding to contrasting cities and evaluate management and sustainability strategiesAO3 · Interpret land-use models, heat-island profiles, urbanisation curves and pollution data

Operators:explainanalyseassessevaluateto what extentexaminedescribe the distributioninterpret

basic level

At AS-Level the focus is on describing urbanisation, urban forms and the main urban environmental issues.

higher level

The full A-Level requires the analysis of urban processes and climate and evaluation of sustainable urban development.

Depth

Text

Contents · 5 sections

Contemporary Urban Environments

Urbanisation and urban change processes#

StandardAQA 7037 3.2.3DfE GCE Geography - urbanisation

The rise of the urban population

Fig. 1Illustrative global urbanisation: the urban share of the population rises past half and is projected to keep growing.

Urbanisation is the increase in the proportion of a population living in urban areas. It is driven by rural-to-urban migration (people moving to cities, pulled by jobs, services and opportunity and pushed by rural poverty) and by natural increase within cities. Globally the majority of people now live in urban areas, and urbanisation is proceeding fastest in the lower-income and emerging economies, producing megacities (over ten million people) and a network of world cities that exert global economic and cultural influence far beyond their national borders.

As cities and economies mature, a sequence of urban change processes reshapes them, often summarised as the urban cycle. Suburbanisation is the outward spread of the city as people and activities move from the centre to the edge, aided by transport; counter-urbanisation is the movement of people out of cities altogether to rural and smaller settlements, seeking a better quality of life; and re-urbanisation is the movement of people and investment back into the inner city, often through regeneration. A given city may show different processes in different areas at the same time.

These processes are linked to economic change. Deindustrialisation - the decline of manufacturing in older industrial cities - caused inner-city decline, unemployment and dereliction in the later twentieth century; the growth of the service and knowledge economy has since driven the revival of some city centres. Urban policy and regeneration schemes have sought to reverse decline and manage growth, so the fabric and fortunes of a city reflect the interaction of these economic shifts with deliberate intervention.

The pace and form of urbanisation create both opportunities and severe challenges. Rapid urbanisation in lower-income countries can outstrip the provision of housing, jobs, services and infrastructure, producing informal settlements, congestion, pollution and inequality; the reshaping of wealthier cities produces its own issues of segregation, gentrification and environmental pressure. Understanding these processes is the foundation for the topic's central concern - how cities can be made more sustainable and liveable.

Urban change processes

Fig. 2The urban cycle: growth of the city, outward spread, movement beyond it, and revival of the centre.

Worked example

Sequencing the urban cycle

A city grows rapidly, then its wealthier residents move to the edge, then some move out to villages, and finally its centre is regenerated and repopulated. Name and explain each stage.

Growth and spread
Rapid growth is urbanisation; as transport improves and the centre becomes crowded, people and businesses move to the edge - suburbanisation.
Moving beyond
Seeking a rural quality of life while keeping urban links, some move out of the city to villages and small towns - counter-urbanisation.
Return to the centre
Regeneration and the revival of the service economy draw people and investment back into the inner city - re-urbanisation, completing the cycle.

Result: The stages are urbanisation, suburbanisation, counter-urbanisation and re-urbanisation - the urban cycle, driven by transport, quality-of-life and economic change.

Typical mistakes

Confusing suburbanisation (spread to the edge of the city) with counter-urbanisation (movement out to rural areas beyond it).
Assuming urbanisation is fastest in wealthy countries - it is now fastest in lower-income and emerging economies.

Active revision

Explain the processes of suburbanisation and re-urbanisation and how they are linked to economic change in cities.

Active recall

Recall the key points — then reveal.

Sources: GCE AS and A level subject content for geography (Department for Education) · AQA A-level Geography 7037 specification (AQA)

Urban forms and land-use models#

StandardAQA 7037 3.2.3DfE GCE Geography - urban form

The Burgess concentric model

Fig. 3The Burgess model: land-use zones form rings around the CBD, with newer, more spacious housing towards the edge.

The internal structure of a city - where different land uses and social groups are located - is not random, and geographers have long used models to generalise the patterns. The Burgess concentric model represents the classic industrial city as a series of rings around the central business district (CBD): a transition zone of older housing and light industry, then successive rings of workers' housing, better residential areas and, at the edge, the commuter zone. It reflects the idea that the city grew outward from the centre, with newer, more spacious housing further out.

The Hoyt sector model modifies this by adding the influence of transport routes and topography: instead of neat rings, land uses form wedges or sectors radiating out from the CBD along routeways. Industry follows transport lines (rivers, railways, roads), lower-cost housing clusters near the industry (and its pollution), and higher-cost housing occupies the more pleasant sectors away from it. Both models are simplifications, useful for describing the broad pattern and as a starting point for comparison, but no real city fits them exactly.

Contemporary cities have developed new urban landscapes that the old models do not capture. Town-centre mixed developments combine retail, leisure and housing; cultural and heritage quarters regenerate old districts around the arts and history; gentrified areas see run-down inner districts renewed by wealthier incomers; edge cities grow up at the periphery around motorway junctions; and fortress developments (gated communities, secured retail) reflect concerns about security and exclusivity. The postmodern western city is fragmented and diverse, without the clear order of the classic models.

Urban form also differs greatly between the cities of the wealthy world and those of lower-income and emerging economies. Many rapidly urbanising cities have a very different structure - for example a wealthy core and formal districts alongside extensive informal settlements on the periphery or on marginal land - reflecting rapid, often unplanned growth. Applying and critically evaluating the models, and comparing the form of contrasting cities, is the analytical skill the specification develops: the models are tools for thinking, not descriptions to be learned uncritically.

The Hoyt sector model

Fig. 4The Hoyt model: land uses form wedges radiating from the CBD, guided by transport routes.

Worked example

Evaluating a land-use model

Explain how the Hoyt model differs from the Burgess model, and evaluate how well either describes a real city.

Burgess
Burgess sees the city as concentric rings around the CBD, with land value and housing quality changing with distance from the centre.
Hoyt
Hoyt adds transport and topography: land uses form sectors radiating along routeways, so industry and the housing beside it form wedges rather than rings.
Evaluate
Both capture broad tendencies (a central CBD, poorer housing near industry), but neither fits a real city exactly - modern cities have edge cities, gentrified quarters and, in lower-income countries, informal settlements the models ignore - so they are useful starting frameworks, not descriptions.

Result: Hoyt replaces Burgess's rings with transport-guided sectors; both usefully generalise land-use patterns but oversimplify the fragmented form of real modern cities.

Typical mistakes

Treating the models as accurate descriptions - they are simplifications, and no real city fits them exactly.
Assuming all cities share the Western model - rapidly urbanising cities often have very different forms, including large informal settlements.

Active revision

Compare the Burgess and Hoyt models and assess how useful they are for understanding the structure of a modern city.

Active recall

Recall the key points — then reveal.

Sources: GCE AS and A level subject content for geography (Department for Education) · AQA A-level Geography 7037 specification (AQA)

The urban climate: heat island and air quality#

AdvancedAQA 7037 3.2.3DfE GCE Geography - urban climate

The urban heat island transect

Fig. 5Illustrative heat-island profile: temperature rises across the built-up area and peaks over the dense city centre.

Cities create their own climate, distinct from the surrounding countryside, and the most important feature is the urban heat island - the tendency for a city to be warmer than its rural surroundings, especially at night. The temperature difference can be several degrees and is greatest under calm, clear conditions. It arises because urban surfaces (concrete, brick, tarmac) absorb and store more heat during the day and release it slowly at night; because tall buildings trap heat and reduce cooling by wind; because there is little vegetation and water to cool the air by evapotranspiration; and because human activity - heating, industry, traffic - releases waste heat directly.

Plotting temperature along a transect from the countryside across the city and out again produces the characteristic profile: temperatures rise sharply at the rural-urban fringe (a 'cliff'), stay high across the built-up area with a peak over the dense city centre, and fall again at the far edge. Parks and rivers show as cooler dips within the city. Understanding this profile, and being able to interpret it, is a core skill, and it links directly to the design of cooler, greener cities.

Air quality is a second major feature of the urban climate. Cities concentrate pollution from traffic, industry and heating: particulates and gases such as nitrogen oxides and sulphur dioxide, and, under sunlight, photochemical smog. The urban form can trap pollutants, and temperature inversions can hold them near the ground. Poor air quality damages health - respiratory and cardiovascular disease - and disproportionately affects poorer communities near busy roads and industry, making it an issue of environmental justice as well as health.

Cities also modify precipitation and winds. The heat island and the particulates that act as condensation nuclei can increase cloud and rainfall over and downwind of cities; and the arrangement of tall buildings channels and accelerates winds along some streets (the canyon effect) while sheltering others. Managing the urban climate - through cleaner transport, low-emission zones, green roofs and urban greening, and better building and street design - is central to making cities healthier and more liveable, and evaluating such measures is a key assessment task.

Worked example

Explaining the night-time heat island

Explain why the urban heat island is usually strongest on a calm, clear night.

Daytime storage
During the day, urban surfaces such as concrete and tarmac absorb and store large amounts of heat, more than vegetated rural surfaces.
Slow night-time release
At night the city releases this stored heat slowly, and tall buildings trap it and reduce cooling; waste heat from heating and traffic adds more.
Why calm and clear
Calm air means little mixing to carry the heat away, and clear skies let the countryside cool rapidly by radiation while the city stays warm - so the urban-rural difference is greatest.

Result: Stored daytime heat released slowly, trapped by buildings and supplemented by waste heat, keeps the city warm while calm, clear conditions let the countryside cool - maximising the heat island.

Typical mistakes

Saying the heat island is simply because cities are crowded - the key causes are the thermal properties of surfaces, waste heat, and the lack of vegetation and wind.
Confusing the heat island (a temperature effect) with air pollution (a chemical effect), though the two are linked.

Active revision

Explain why a city is warmer than its rural surroundings, especially at night.

Active recall

Recall the key points — then reveal.

Sources: GCE AS and A level subject content for geography (Department for Education) · AQA A-level Geography 7037 specification (AQA)

Urban drainage, waste and environmental issues#

AdvancedAQA 7037 3.2.3DfE GCE Geography - urban environmental issues

How urbanisation increases flood risk

Fig. 6Impermeable surfaces speed runoff and flashen the hydrograph, raising flood risk; SUDS restore storage and infiltration.

Urbanisation transforms the local water cycle. Replacing permeable soil and vegetation with impermeable concrete, tarmac and roofs greatly reduces infiltration and interception, so far more rainfall becomes rapid surface runoff. Drains and sewers deliver this water to rivers quickly, so the urban storm hydrograph is flashy - a short lag time and a high peak discharge - which raises the risk of flash flooding. This links directly to the water-cycle topic, and it is why urban flood risk is a growing concern, especially with more intense rainfall under climate change.

The response is to manage urban drainage more sustainably. Sustainable urban drainage systems (SUDS) aim to restore natural processes: permeable paving, green roofs, soakaways, retention ponds and constructed wetlands slow the flow, increase infiltration and storage, and reduce the peak discharge, while also improving water quality and amenity. River restoration - re-naturalising channels that were straightened or culverted - reduces flood risk and improves habitats. These are practical applications of the systems thinking developed in the physical topics.

Cities also generate vast quantities of waste, and its disposal is a major environmental issue. Options include landfill (which consumes land and can pollute), incineration (which reduces volume and can generate energy but raises air-quality concerns), recycling and composting, and reducing waste at source. The management of waste raises questions of cost, environmental impact and equity - waste and its facilities are often located near poorer communities - and moving towards a more circular use of materials is part of making cities sustainable.

These issues sit within a wider set of urban environmental pressures - air and water pollution, the loss of green space, high resource and energy consumption, and a large ecological footprint (the area of land and sea needed to supply a city and absorb its waste, typically far larger than the city itself). Recognising that cities concentrate both people and environmental impact frames the topic's central question: how can cities be managed to reduce these impacts while remaining liveable, which is the concern of sustainable urban development.

Worked example

Explaining SUDS

A city suffers flash flooding after heavy rain. Explain how installing permeable paving, green roofs and retention ponds would reduce the risk.

The problem
Impermeable surfaces and drains send rainfall rapidly to the river, giving a short lag time and a high peak discharge - a flashy hydrograph that causes flooding.
How SUDS help
Permeable paving and green roofs let water infiltrate and be stored rather than running straight off; retention ponds hold water and release it slowly.
The effect
These restore storage and infiltration, so less water reaches the river quickly - the lag time lengthens and the peak discharge falls, reducing flood risk.

Result: SUDS restore infiltration and storage, lengthening the lag time and lowering the peak discharge, so the flashy urban hydrograph and its flood risk are reduced.

Typical mistakes

Saying urbanisation increases rainfall as the cause of flooding - the main effect is faster runoff from impermeable surfaces, not more rain.
Treating SUDS as merely drains - they work by restoring infiltration and storage to slow the flow and lower the peak.

Active revision

Explain how sustainable urban drainage systems reduce the flood risk created by urbanisation.

Active recall

Recall the key points — then reveal.

Sources: GCE AS and A level subject content for geography (Department for Education) · AQA A-level Geography 7037 specification (AQA)

Sustainable urban development and case studies#

AdvancedAQA 7037 3.2.3DfE GCE Geography - sustainable cities

Dimensions of a sustainable city

Fig. 7A sustainable city balances the environmental, economic and social dimensions - transport, resources, green space and equity.

Sustainable urban development means meeting the needs of a city's present residents without compromising the ability of future generations and other places to meet theirs. Because cities concentrate people, consumption and environmental impact, making them sustainable is essential, and it has social, economic and environmental dimensions that must be balanced - a genuinely sustainable city is also a liveable and equitable one, not merely a low-carbon one.

A range of strategies pursues this goal. Sustainable transport - public transport, cycling and walking networks, low-emission and congestion-charging zones - reduces pollution, congestion and emissions. Sustainable resource use - energy efficiency, renewable energy, water conservation and recycling, and moving towards a circular economy that reuses materials - cuts the ecological footprint. Green infrastructure - parks, street trees, green roofs and SUDS - improves the climate, drainage, air quality and wellbeing. Compact, mixed-use design reduces the need to travel.

Sustainability also has a strong social dimension. A liveable city provides affordable housing, access to services, green space and employment for all its residents, and tackles the segregation and inequality that urbanisation can produce. Community involvement in planning, and attention to who benefits from and who bears the costs of urban change, are part of sustainability - a city that regenerates by displacing its poorer residents is not sustainable in the fullest sense.

The specification requires case studies of two contrasting urban areas to illustrate these issues and their management, and the evaluative task is to judge how far a city's strategies genuinely deliver sustainability. Real cities face trade-offs - between growth and emissions, between regeneration and displacement, between the interests of different groups - and progress is usually partial and contested. The strongest answers use the case studies as evidence, weigh the social, economic and environmental dimensions together, and reach a supported judgement rather than presenting any city as a finished sustainable model.

Worked example

Evaluating a sustainability strategy

A city introduces a low-emission zone, extends its cycle network and regenerates a riverside district with green space. Evaluate how far these measures make it sustainable.

Environmental gains
The low-emission zone and cycle network cut pollution and emissions; the green space improves the urban climate, drainage and wellbeing - real environmental progress.
Social questions
The riverside regeneration may raise prices and displace poorer residents, and low-emission charges can burden those who cannot afford cleaner vehicles - so the benefits and costs are unevenly shared.
Reach a judgement
A balanced conclusion is that the measures make the city more environmentally sustainable but only partly socially sustainable; genuine sustainability requires that the gains are shared and existing residents are not displaced.

Result: The measures deliver real environmental gains but risk social inequity, so the city becomes more sustainable environmentally while its social sustainability depends on who benefits.

Typical mistakes

Treating sustainability as only environmental - it must also be social (equity, liveability) and economic.
Presenting a city as fully sustainable - real progress is partial and involves trade-offs between competing interests.

Active revision

'A truly sustainable city must be socially equitable as well as environmentally friendly.' To what extent do you agree?

Active recall

Recall the key points — then reveal.

Sources: GCE AS and A level subject content for geography (Department for Education) · AQA A-level Geography 7037 specification (AQA)

References & sources

Sources

Department for Education

GCE AS and A level subject content for geography

AQA

AQA A-level Geography 7037 specification

Contemporary Urban Environments

5 sections~17 min reading time3 competenciesLevel Standard 2 · Advanced 3

Contemporary Urban Environments

Key points

Sequencing the urban cycle

Key points

Evaluating a land-use model

Key points

Explaining the night-time heat island

Key points

Explaining SUDS

Key points

Evaluating a sustainability strategy

Sources

Contemporary Urban Environments

Key points

Sequencing the urban cycle

Key points

Evaluating a land-use model

Key points

Explaining the night-time heat island

Key points

Explaining SUDS

Key points

Evaluating a sustainability strategy

Sources