IB Geography • Section G4
Sustainable Cities
Future possibilities for the sustainable management of urban systems
Restored from the original AdornGeo Weebly page • syllabus order preserved
Urban Growth Projections for 2050
Urban growth projections for 2050, including regional/continental patterns and trends of rural–urban migration and changing urban population sizes and structures.
The original AdornGeo lesson begins with urban-growth projections rather than with a model city. Projections are possibilities, not certainties: students should read the geography of change, distinguish total urban population from the percentage urban, and ask how migration, natural increase, ageing and changing household structures alter demand for land, housing and infrastructure.
- Most future urban growth is expected in Asia and Africa, but the fastest percentage growth and the largest absolute increase are not necessarily in the same places.
- Rural–urban migration is one part of urban growth; natural increase, reclassification and the outward expansion of built-up areas also matter.
- Growth changes population structure. A city may need to plan simultaneously for a youthful labour force, smaller households, ageing residents and large migrant populations.
- Projections should be evaluated as scenarios shaped by assumptions about fertility, mortality, migration, economics, conflict, climate risk and government policy.
Read the world urban-growth visualisation
- Use the interactive map below to compare the urban share in your birth year, the present and 2050. Capture three contrasting world regions.
- Describe the pattern using place names, direction and data. Separate high current urbanisation from rapid projected change.
- Use the UN report to identify the countries expected to contribute most to absolute urban growth, then explain why this is not the same as the fastest growth rate.
- Create a planning brief for one rapidly growing city: likely changes in size and structure, two infrastructure pressures and one opportunity.
Watch: Sustainable Cities — Crash Course Geography
Resilient City Design
Resilient city design, including strategies to manage escalating climatic and geopolitical risks to urban areas. Two detailed examples to illustrate possible strategies.
A resilient city can absorb a shock, maintain essential functions, adapt and recover without simply transferring risk to a less powerful group or another place. Resilience therefore combines physical protection with robust infrastructure, social capacity, governance, finance and the ability to learn. The same intervention may increase resilience for one stakeholder while increasing cost or displacement for another.
- Climatic risks include heat, drought, wildfire, sea-level rise, river and surface-water flooding and extreme storms.
- Geopolitical risks include conflict, terrorism, cyberattack, energy and food insecurity, migration shocks and disruption to supply networks.
- Redundancy, diversity, modularity, emergency capacity and community networks can make urban systems less brittle.
- Resilience should be judged by who is protected, the return period or scenario used, cost, adaptability and whether risk is displaced elsewhere.
Build and test an urban-resilience strategy
- Choose either Bangkok or Rotterdam. Draw the city as a system of people, water, food, energy, transport, communications and governance.
- Add one acute shock and one chronic stress. Trace first-order and knock-on impacts through the system.
- Classify responses as protect, accommodate, avoid, prepare or recover. Identify the stakeholder responsible for each action.
- Evaluate the strategy against effectiveness, equity, cost, environmental impact, flexibility and long-term uncertainty.
Rotterdam: living with water
Rotterdam combines national-scale flood protection with spatial adaptation inside the city. Barriers and dikes reduce coastal and river risk, while water plazas, green roofs, storage, raised buildings and room for water help manage intense rainfall. The layered strategy illustrates redundancy, but protection can encourage further development in exposed areas and requires sustained public finance.
- Locate the city in the Rhine–Meuse delta and distinguish coastal, river and pluvial flood pathways.
- Compare hard protection with water-sensitive public space and building-scale adaptation.
- Explain how multifunctional design can provide recreation and cooling as well as temporary water storage.
- Evaluate residual risk, unequal protection and the danger of assuming that engineering removes risk completely.
Bangkok: flood resilience in a sinking delta city
Bangkok faces monsoon rainfall, river flooding, coastal influence, land subsidence and rapid development across former flood-storage areas. Pumps, canals, barriers and drainage tunnels are combined with parks, retention space, forecasting and community preparedness. Governance across the metropolitan region is crucial because water and urban growth ignore municipal boundaries.
- Locate the city on the low-lying Chao Phraya delta and map river, canal, coast and subsidence risk.
- Compare grey infrastructure with sponge-city and nature-based approaches such as Chulalongkorn Centenary Park.
- Examine how housing quality, tenure, mobility and income shape the ability to prepare, evacuate and recover.
- Judge whether current strategies address the drivers of risk or mainly manage their consequences.
Eco-City Design
Eco city design, including strategies to manage the urban ecological footprint. Two detailed examples to illustrate possible environmental strategies.
Eco-city design tries to reduce the land, water and productive ecosystems required to supply a city and absorb its waste. The strongest approaches treat the city as a metabolism: reducing inputs, slowing and closing material loops, and cutting harmful outputs while maintaining a good quality of life. A green image is not enough; claims must include construction, imported resources and displaced environmental costs.
- Compact mixed land use can shorten journeys and protect land, but density needs accessible green space, ventilation and affordable housing.
- Circular systems connect energy, water, food and waste—for example, recovering heat, composting organic waste and reusing water.
- Transport, buildings and food systems are major parts of the urban footprint; urban agriculture can reduce some food miles but cannot supply every input.
- Evaluate environmental strategies with life-cycle evidence and social outcomes rather than promotional targets alone.
Eco-city evidence audit
- Use the original Eco & smart city introduction to define a sustainable urban system and draw a linear city metabolism.
- Convert it into a circular system by adding strategies for energy, water, food, mobility, buildings, biodiversity and waste.
- Compare Curitiba and Masdar using the original case-study activity. For every environmental claim, record evidence, scale, beneficiary, limitation and any displaced cost.
- Write a supported judgement: is retrofitting an existing city or constructing a purpose-built eco-city more sustainable?
Curitiba, Brazil
Curitiba is the original AdornGeo page's central eco-city case study. Long-term planning linked high-density development to bus corridors, protected green space, converted flood-prone land into parks and used low-cost recycling schemes. Its strengths lie in integrated and adaptable planning, while congestion, peripheral growth and social inequality complicate the familiar success story.
- Land use and transport: structural corridors align density with bus rapid transit rather than spreading growth evenly.
- Water and biodiversity: parks provide recreation and habitat while storing floodwater more cheaply than extensive concrete channels.
- Waste and inclusion: exchange and recycling schemes connect environmental management with household needs.
- Evaluation: rising car ownership, peripheral settlements and uneven access show the limits of transferring a celebrated model without context.
Watch: Curitiba, Brazil: a sustainable city
Watch: How Curitiba revolutionised urban planning
Watch: A Convenient Truth: urban solutions from Curitiba
Masdar City, United Arab Emirates
Masdar was planned as a compact, low-carbon district using shaded streets, passive design, solar energy, water efficiency and low-emission mobility. It provides a useful contrast with Curitiba because the project began on a new site with large investment and technological ambition, yet its reduced scale, slow build-out, embodied carbon and dependence on the wider fossil-fuel economy demand critical evaluation.
- Design for climate: orientation, narrow shaded streets, a wind tower and efficient buildings reduce cooling demand.
- Energy and water: renewable generation, monitoring and reuse reduce some resource inputs in an arid environment.
- Scale and participation: a planned district can test technology, but it does not reproduce the complexity or democratic negotiation of an existing city.
- Evaluation: compare targets with achieved population, land use, mobility and full life-cycle impacts.
Watch: Masdar City welcome and design overview
Smart City Design
Smart city design and the use of new technology to run city services and systems, including purpose-built settlements and retrofitting technology to older settlements.
A smart city uses connected infrastructure, sensors, spatial data and feedback to operate transport, energy, water, waste, safety and public services. Technology can make flows more visible and responsive, but a city is not automatically sustainable because it is digital. Students should examine ownership, access, surveillance, cybersecurity, bias, maintenance and the material footprint of devices and data centres.
- A smart system links data collection, analysis, decision and response; an isolated app is not a complete urban-management system.
- Purpose-built smart cities can integrate infrastructure from the start, while retrofitting can reach existing residents and institutions but must work around older systems.
- Open data and digital participation may widen access to decision-making, but digital exclusion can reproduce existing inequalities.
- The best evaluation asks whether technology solves a geographical problem more fairly and sustainably than a lower-tech alternative.
Singapore smart-city enquiry
- Use the original Singapore government site and case-study PDF to identify examples in transport, water, housing, energy, health and public services.
- For each system, draw the chain: sensor or data source → analysis → decision → response → intended outcome.
- Classify Singapore's strategies as purpose-built, retrofitted or a combination. Identify who owns the data and who might be excluded.
- Evaluate the statement: ‘A smart city is only sustainable when its technology reduces footprints and expands access.’
IB synthesis: design a future urban district
- Choose a real growth area in Bangkok and locate it on a map. State the 2050 population and risk assumptions behind your plan.
- Combine one resilient, one eco-city and one smart-city strategy; show how the systems interact rather than listing three unrelated ideas.
- Annotate costs, benefits and trade-offs for residents, informal workers, government, developers and the environment.
- Finish with a ten-mark plan: Evaluate one or more sustainable strategies designed to improve life in urban areas.
Watch: City of the Future: Singapore — National Geographic
Watch: The World's Greenest City — lessons from Curitiba
Singapore: retrofitting a smart nation
Singapore was the original page's main smart-city example. A dense city-state can connect transport, housing, utilities and government services at national scale. Electronic road pricing, integrated public transport, water monitoring, smart estates and digital government demonstrate coordinated capacity, while surveillance, unequal digital access, imported resources and the ecological costs displaced beyond the island complicate sustainability claims.
- Transport data can manage road demand and improve network reliability, but pricing affects groups differently.
- Smart water systems matter because Singapore has limited land and freshwater resources and depends on diversified supply.
- Public housing creates an unusual platform for retrofitting energy, mobility, ageing and community technologies at scale.
- Evaluate both operational efficiency inside Singapore and resource extraction, waste and embodied impacts outside its borders.