IB ESS SL Topic 8.2: Urban Systems and Planning - Comprehensive Notes

Urban Systems and Planning

  • Guiding Question

    • To what extent are urban systems similar to natural ecosystems? How can reimagining urban systems create a more sustainable future?
    • This prompts comparison between urban and natural system dynamics, and exploration of design approaches for sustainability.

  • Urban Ecosystems

    • Urban areas contain urban ecosystems composed of both biotic and abiotic components:
    • Biotic: plants, animals, and other living organisms.
    • Abiotic: soil, water, air, climate, and topography.
    • There are at least 10 types of urban ecosystems, including:
    • Residential Gardens
    • Industrial Sites
    • Inner City Derelict Land
    • Green Areas and Open Spaces
    • Cemeteries
    • Traffic Corridors
    • Waste Disposal Areas
    • Forests
    • Fields
    • Waterbodies (lakes and rivers)
    • Urban habitats are highly unstable due to severe human impact and disturbance.
    • Most species are introduced; few native species remain.
    • A large proportion of urban species are scavengers or opportunists (e.g., raccoons, foxes).
    • Species that are omnivorous, nocturnal, or twilight feeders have an advantage in urban environments.

  • Urban Areas vs Rural Areas

    • Urban Area: a built-up area with high population density, buildings, and infrastructure used for residential, cultural, productive, trade, and social purposes.
    • Rural Area: relatively low population density with dispersed settlements.
    • Classifications include cities, towns, and suburbs.

  • Task Context (Class Activities)

    • Task – Urban Areas vs Rural Areas: Collect a document from the teacher and complete a task following website instructions to compare urban and rural characteristics.
    • Task – Urban Systems Diagram: In groups, create a systems diagram for a typical city (e.g., Jakarta, Beijing, Vancouver) showing inputs and outputs, integrating the Circular Economy model.

  • Urban Areas as Systems (Core Concept)

    • An urban area works as a system: an interconnected network of
    • Buildings and Infrastructure
    • Microclimate
    • Transport
    • Goods and Services
    • Power/Energy
    • Water and Sewage Supply
    • Humans, Plants, and Animals
    • Buildings and Infrastructure
    • Form the physical framework for housing, business, and public services.
    • Require energy, maintenance, and resources; impact sustainability.
    • Microclimate
    • Influenced by urban heat islands, vegetation, and water bodies.
    • Affects air quality, temperature, and human comfort; influences energy use (e.g., heating/cooling).
    • Transportation
    • Facilitates movement of people and goods.
    • Relies on infrastructure (roads, railways, public transit).
    • Generates emissions and affects urban air quality.
    • Goods and Services
    • Essential for economic activity and quality of life.
    • Depend on supply chains and distribution networks.
    • Efficiency and equity in access are critical for urban function.
    • Power/Energy Systems
    • Supply energy for buildings, transport, and industries.
    • Transition to renewable energy is key for sustainability.
    • Vulnerable to disruptions; resilience is required.
    • Water and Sewage Systems
    • Provide clean water and manage wastewater.
    • Depend on efficient distribution and treatment infrastructure.
    • Susceptible to pollution and resource depletion.
    • Humans, Plants, and Animals
    • Humans drive urban development and shape the system.
    • Urban green spaces support biodiversity and enhance well-being.
    • Wildlife adapts to urban conditions but faces habitat loss and other challenges.

  • Sustainability and Resilience (Urban Systems)

    • Key challenge: balance human population growth with environmental sustainability.
    • Dense urban populations generate significant waste and pollution, impacting air, water, and soil quality.
    • Long-term sustainability requires resource efficiency and minimising consumption and waste generation.
    • Strategies include:
    • Closed-loop systems for material reuse and recycling.
    • Transition to clean energy sources.
    • Compact, walkable urban development patterns.
    • Building resilience: the ability to withstand and adapt to environmental shocks.
    • Green infrastructure and robust waste management enhance a city’s ability to adapt to climate change and other pressures.

  • Urbanisation and Rural-Urban Migration

    • Urbanisation is the population shift from rural to urban areas; land use becomes more built-up and densely settled.
    • Rural-Urban Migration: an increasing proportion of the population lives in urban systems; often internal within countries.
    • Example: Shenzhen, China — from a small fishing village in 1979 to a city with over 16{,}000{,}000 people by 2022.
    • Reasons for migration include access to markets, labor, and opportunities in urban areas; industries often relocate to urban centers.

  • Push-Pull Factors (Rural-Urban Migration)

    • Push factors: negative aspects of the place people leave (e.g., lack of opportunities).
    • Pull factors: perceived benefits of the destination (e.g., jobs, services).

  • Push-Pull Factors Game (Educational Activity)

    • Students participate in a game to understand push and pull dynamics driving migration.

  • Rural-Urban Migration Variants

    • Migration is generally voluntary but can be forced by natural disasters (e.g., drought, desertification).
    • Example: Drought-driven expansion of the Gobi Desert in China pushing farmers toward crowded urban areas.

  • Deurbanisation in High-Income Countries (HICs)

    • Some people move from cities to rural areas seeking higher quality of life.
    • Post-COVID-19 pandemic trends include increased rural property prices and relocations (e.g., London residents buying houses in Scotland).

  • Suburbanisation (Urban Sprawl)

    • Movement from dense central urban areas to lower-density peripheral areas.
    • Suburbanisation is often referred to as urban sprawl due to larger land areas required by lower-density settlements.
    • Post-World War II trend driven by economic prosperity, desire for space, and cultural factors (e.g., the American Dream).
    • Benefits vs Drawbacks:
    • Benefits: more space, potentially better schools, community opportunities.
    • Drawbacks: increased traffic, car-dependency, air pollution, social exclusion historically (minority access limitations).

  • Environmental Impact of Urban Expansion

    • Expansion changes the environment:
    • Loss of agricultural land, forests, and ecosystems; habitat fragmentation; reduced carbon sequestration due to deforestation.
    • Changes to water quality: increased runoff and pollution, groundwater contamination, sedimentation and nutrient loading from construction.
    • Changes to river flows: altered flow regimes due to impervious surfaces; higher flood risk; reduced base flows in dry periods.
    • Air pollution: higher greenhouse gas and particulates emissions; poorer local air quality; urban heat islands exacerbate ozone and smog.

  • Urban Planning (Key Concepts)

    • Urban planning decides how to use land and buildings to meet physical, environmental, social, economic, and health needs.
    • Many stakeholders are involved, including public sector, governments, professional planners, residents, community groups, environmentalists, developers, and investors.
    • Planning decisions require debate, trade-offs, and compromises.

  • The Three Magnets (Planning Tensions)

    • A visual representation of competing forces in planning, illustrating tensions among economic development, social opportunity, and the quality of natural spaces.
    • (Note: content displayed as a stylised schematic with competing priorities and constraints.)

  • Modern Urban Planning – Sustainability (Core Indicators)

    • Sustainable urban planning considerations include:
    • Quality and affordable housing
    • Integrated public transport systems
    • Green spaces
    • Security, education, and employment
    • Use of renewable resources
    • Reuse and recycling of waste
    • Energy efficiency
    • Community involvement
    • Green buildings

  • Copenhagen: A Case Study in Sustainable Urban Planning

    • Copenhagen is regarded as one of the world's most sustainable cities.
    • Air quality initiatives: Project Air View uses Google Street View cars with air-quality sensors to identify pollution sources and develop solutions.
    • Transportation model: cycling is the primary mode; extensive bike lanes, bike-sharing, and a Green Wave system that coordinates traffic lights for cyclists.
    • Energy and buildings: aims to be carbon neutral by 2025; centralized biomass heating, solar and wind power; smart street lights to reduce energy use; over 0.98 of households are connected to centralized heating (i.e., ~98%).
    • Urban planning initiatives: recognized for air-quality monitoring, smart street lights, cycling promotion; strong university partnerships for innovation.

  • Ecological Urban Planning (Holistic Approach)

    • Treats the urban system as an ecosystem, focusing on biotic-abiotic relationships and sustainability.
    • Core components include:
    • Urban Ecology: green spaces, habitats for wildlife, allotments, parks, canals, ponds.
    • Urban Farming: beekeeping, horticulture, aquaculture, and city farms.
    • Biophilic Design: living green walls and roofs, water features, natural light.
    • Resilience Planning: vertical farming, flood-prone area design (building on stilts), fail-safe grids.
    • Regenerative Architecture: building skins that scrub air, rainwater harvesting that replenishes aquifers, and integration of solar/wind/biodigesters for energy export.

  • Ecological Urban Planning: Key Components

    • Urban Ecology
    • Scientific study of relationships among living organisms and their surroundings in urban environments.
    • Integration of green spaces (parks, canals, ponds) to support biodiversity.
    • Creation of habitats for urban wildlife (pollinators and birds).
    • Promotion of allotments for community gardening and local food production.
    • Urban Farming
    • Cultivating crops, livestock, or foods in urban settings to increase food security and reduce food miles.
    • Common elements: beekeeping, horticulture, aquaculture, and city farms.
    • Urban Farming: Advantages and Disadvantages
    • Advantages: production of foods, income, employment, urban greening, reduced food miles, improved wellbeing, utilization of unused land.
    • Disadvantages: potential soil contamination, poorer air quality, higher costs of energy for indoor farming, potential for pest/disease issues.
    • Beekeeping
    • Increasing practice in urban areas (e.g., gardens, rooftops, abandoned land).
    • Example: Birmingham, UK – 50,000 bees on the rooftop of the Custard Factory.
    • Early flora success: willowherb, brambles, buddleia; area not treated with pesticides supports thriving bee populations.
    • Horticulture (Urban Farming)
    • Growth of crops in urban areas; scales range from pots to urban rooftop farms.
    • Example: Nature Urbaine in Paris – covers 14{,}000 ext{ m}^2.
    • FAO note: market gardening is a major source of locally grown fresh food in over one-third of Africa.
    • Aquaculture (Urban Farming)
    • Involves aquatic organisms in rivers, ponds, lakes, and canals.
    • Advantages: increased food supply, food security for lower-income residents, job creation, reduced food miles.
    • Disadvantages: theft, water pollution, disease, and high costs for fish feed.
    • Aquaculture (South Africa Example)
    • Annual aquaculture increased from about 3{,}000 tonnes in 2000 to 100{,}000 tonnes in 2020.
    • The Fish Farm in Philippi, Cape Town, is a shipping-container aquaculture project in an underserved community, producing 4 tonnes per container annually (tilapia in summer, trout in winter).
    • The container farming system is designed to be profitable, affordable, repeatable, transportable, lockable, and stackable.
    • Water from tanks and fish waste (decomposed by nitrogen-fixing bacteria) provides nitrates that aid crop growth (e.g., cucumbers, lettuce, onions, spinach).
    • City Farms (Global Examples)
    • New York: Square Roots transforms shipping containers into farm spaces growing herbs, leafy greens, eggplants, turnips, strawberries, and tomatoes.
    • Retail radius: produce delivered to outlets within 8 ext{ km} of the site using battery-powered tricycles.
    • Note: indoor farms rely heavily on LED lighting and are major energy consumers.

  • Task Notes and Applications

    • Several tasks involve applying these concepts to real-world cities (e.g., Cairo development maps, urban systems diagrams, ecological urban planning case studies).
    • The overarching goal is to understand how urban planning, sustainability, and ecological design intersect to create resilient, equitable, and efficient urban systems.

  • Summary for Examination Focus

    • Key concepts: urban ecosystems, urban areas as systems, sustainability and resilience, urbanisation and migration patterns, environmental impacts of expansion, urban planning ethics and stakeholders, and ecological urban planning practices.
    • Important case studies: Copenhagen’s sustainable mobility and energy system; ecological urban planning practices (urban farming, beekeeping, horticulture, aquaculture); Shenzhen growth as an example of rapid urbanisation; Cairo urban development mapping as a planning exercise.
    • Quantitative references to remember (selected):
    • Shenzhen population growth: from a small fishing village in 1979 to over 16{,}000{,}000 by 2022.
    • Copenhagen: aim for carbon neutrality by 2025; >0.98 of households connected to centralized heating.
    • Urban farming scale examples: Nature Urbaine in Paris = 14{,}000 ext{ m}^2; aquaculture container projects producing 4 tonnes per container annually.
    • Beekeeping in urban contexts (example: 50{,}000 bees on a rooftop in Birmingham).
    • Energy examples: centralized biomass, solar and wind power, smart street lighting; indoor farms as energy-intensive components.

  • Key Definitions (Glossary in Brief)

    • Urban ecosystem: An ecosystem contained within an urban area, including biotic and abiotic components.
    • Circular Economy: An economic model aimed at eliminating waste and the continual use of resources through reuse, repair, refurbishment, and recycling.
    • Green infrastructure: Networks of natural and semi-natural areas designed to deliver ecosystem services (e.g., flood mitigation, carbon sequestration, heat mitigation).
    • Biophilic design: Design approach that connects people with nature through living walls/roofs, water features, and natural light.
    • Regenerative architecture: Building designs that not only minimize harm but actively improve environmental health (e.g., air purification, rainwater harvesting).

  • Important Equations and Figures (Illustrative Examples)

    • Urban population growth scenarios (illustrative): population(p) over time t can be studied via demographic projections; e.g., population in Shenzhen grew to over 16{,}000{,}000 by 2022.
    • Energy and emissions relations (conceptual): as energy demand in buildings and transport increases, emissions may rise; transition to renewables and efficiency reduces net emissions. The exact functional form depends on city specifics but follows the general principle of energy balance: total energy input = usable energy output + losses, with renewables reducing the carbon intensity of the input.

  • Practical Implications for Exam Review

    • Be able to describe how urban systems mimic ecological systems and where they diverge (e.g., stability, species composition, energy flows).
    • Explain how urban planning can incorporate circular economy principles to reduce waste and improve resilience.
    • Discuss the role of green infrastructure and urban farming in enhancing biodiversity, food security, and human well-being.
    • Compare different city models (e.g., Copenhagen’s cycling-first design vs. car-dependent sprawls) and evaluate sustainability outcomes.
    • Understand the drivers of urbanisation and migration, including push/pull factors and the social/economic consequences for both urban and rural areas.