Key Idea: Topic 13.4 is about how cities can be made fit for the future — low-impact, liveable and able to cope with shocks. It pulls together two micros: 13.4.1 — sustainable & smart urban design: sustainable design shrinks a city's ecological footprint (compact form, renewables, green space, recycling), while a smart city uses data and sensors to run services efficiently. Key models are the 15-minute city, superblocks and eco-cities (Barcelona, Curitiba, Singapore — and the built-from-scratch Masdar and Songdo). 13.4.2 — resilience, infrastructure & governance: urban resilience is a city's ability to absorb shocks; infrastructure is its transport, water, energy and waste backbone; governance is who plans, funds and runs it. Upgrading infrastructure is hard (land in use, ageing systems, cost, opposition); growth and infrastructure shape each other (Lagos strained, Curitiba steered, Detroit shrinking); and resilient design protects cities but is costly and uneven. This is Option G content, examined on Paper 1: a short structured question plus a [10] Examine or Evaluate extended answer (SL answers 2 options, HL answers 3 — same questions at both levels).
🏙️ 13.4.1 — Sustainable & smart urban design
Sustainable urban design plans a city to meet today's needs without using up resources or harming the environment for the future — it aims to shrink the ecological footprint (the land and water needed to supply resources and absorb waste). A smart city goes further, using sensors, data and digital networks to run traffic, energy and waste more efficiently. The data-response often shows an urban-sustainability figure — a 15-minute-city travel-time chart or a footprint-vs-population data set. Estimate or State a value, Determine a mean or total, or Identify the highest/lowest — always quoting the units (minutes, people, Mt CO2).
Read the key first: which destinations sit inside the 15-minute walking target, and which fall outside it?
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Sustainable vs smart — and how each design choice cuts the footprint
| Strategy | How it lowers the ecological footprint |
|---|---|
| Compact, mixed-use form (15-minute city) | Homes near jobs and shops → people walk or cycle → fewer car trips → lower transport emissions |
| Superblocks / car-free zones | Through-traffic removed → less driving and pollution → road space reused for green areas and people |
| Renewable energy + green buildings | Solar, wind and efficient buildings replace fossil-fuel power → far less CO2 per unit of energy |
| Recycling + circular economy | Reusing materials and recycling waste → less landfill and fewer raw resources extracted |
| Green space + urban trees | Parks and street trees absorb CO2, cool the city and manage storm water |
| Smart technology (sensors + data) | Real-time data optimises traffic, energy and waste collection → less congestion, fuel and waste |
Key terms — sustainable & smart design
- Ecological footprint — the land + water area a city needs to supply its resources and absorb its waste.
- Eco-city — a city designed to be environmentally low-impact (renewables, green space, recycling, compact form).
- Smart city — a city that uses sensors, data and digital networks to run services more efficiently.
- 15-minute city — a layout where residents reach work, shops, schools and health care within a 15-minute walk or cycle.
- Superblock — grouping several street blocks and removing through-traffic to reclaim space for people.
Example: Barcelona groups nine blocks into a superblock and removes through-traffic, reclaiming road space for plazas, trees and cycling. Curitiba built its city around fast Bus Rapid Transit decades ago, so a high share of residents use public transport — a low-cost, low-footprint model. Singapore uses sensors and data for traffic (electronic road pricing), water recycling and energy, with strict green-building rules. Songdo was built as a smart city with pneumatic waste collection and city-wide sensors — though critics note the high cost and under-occupancy (as at Masdar).
🏗️ 13.4.2 — Resilience, infrastructure & governance
Urban resilience is a city's ability to absorb shocks and stresses (floods, heat, decline, rapid growth) and keep recovering. Infrastructure is the transport, water, sanitation, energy, waste and housing backbone, and governance is who plans, funds and runs it. Growth and infrastructure are two-way: growth drives demand for infrastructure, and existing infrastructure shapes where a city can grow. The stimulus is often a bar chart of infrastructure provision: Estimate a value and Describe how far services lag behind growth, before being asked to Explain the challenges of upgrading.
Why upgrading is hard, and how growth & infrastructure shape each other
| Theme | Recap |
|---|---|
| Land already in use | New roads or pipes need built-on land → resettlement, compensation cost and sprawl |
| Ageing systems & cost | Old pipes and roads are costly to replace under a working city; fast-growing cities lack capital |
| Opposition & planning | Residents and pressure groups object to disruption; permits and rules cause delay |
| Growth strains infrastructure | Lagos — rapid growth outpaces roads, drainage and waste, so services break down |
| Infrastructure shapes growth | Curitiba — built BRT corridors first, steering dense, compact growth along them |
| Governance is the deciding factor | Detroit — managing decline; strong governance decides if infrastructure leads or chases growth |
Key terms — resilience & governance
- Urban resilience — the capacity to cope with and bounce back from shocks (climatic, economic, social).
- Infrastructure — transport, water, sanitation, energy, waste, housing and digital networks.
- Urban governance — how a city is run and decisions are made across government, business, NGOs and citizens.
- Future-proofing — designing today's infrastructure to cope with future climate and population pressures.
- Resilient-city design — flood defences, drainage, zoning off flood plains, green space and future-proofing.
Example: Singapore uses the Marina Barrage and ABC (Active, Beautiful, Clean) Waters programme to manage floods and store fresh water, plus green roofs to cool the city. Barcelona's superblocks reclaim road space for pedestrians and greenery, cutting pollution and adding shade and rain-absorbing surfaces. Both work — but both are wealthy, well-governed cities, so resilient design's cost and unevenness is the key limit in fast-growing, low-income cities.
✍️ IB-style questions
Explain two ways planners can use technology to run a smart city more sustainably.
🔒 Model answer plan
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Evaluate how effective sustainable and smart urban design is for building cities that are both low-impact and resilient for the future.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
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What is a city's ecological footprint? The area of land and water a city needs to supply its resources and absorb its waste — sustainable design aims to shrink it.
Sustainable vs smart design — what's the difference? Sustainable = the low-footprint outcome (compact form, renewables, green space); smart = the data/technology tool (sensors, road pricing, smart meters) used to get there.
Why is upgrading urban infrastructure so difficult? Land is already built on (forcing resettlement and sprawl), systems are ageing and costly to replace, funding is short, and residents or planners often oppose disruptive projects.
How do urban growth and infrastructure shape each other? Growth drives and strains infrastructure (Lagos), while existing infrastructure shapes where a city grows (Curitiba's BRT corridors). Governance decides whether infrastructure leads or chases growth.
What does a top [10] Examine/Evaluate answer need? Both sides (gains AND limits), named cities/schemes (Barcelona, Curitiba, Singapore, Masdar, Songdo), accurate terms, and a justified judgement that answers 'how effective'.
🎯 Highest-yield exam reminders
Exam Tips
- Option G is examined on Paper 1: a short structured question + a [10] Examine/Evaluate essay per chosen option (SL does 2, HL does 3 — same questions).
- Sustainable = low-footprint OUTCOME; smart = the DATA/SENSOR tool. A good city is usually both.
- Always give the mechanism: design → how → smaller footprint (15-minute city → homes near services → less driving → lower emissions).
- Data-response: read each bar with its UNITS (minutes, % access, Mt CO2); the 15-minute target line is 15 minutes.
- Upgrading infrastructure is hard — name the challenge (land in use, ageing systems, cost, opposition) + DEVELOP the mechanism; growth strains it (Lagos), infrastructure shapes it (Curitiba).
- On the [10] essay, weigh both sides with a NAMED city (Barcelona, Curitiba, Singapore, Masdar, Songdo, Lagos) and finish on a justified judgement — one-sided or no example caps mid-band.