Urbanisation and Energy Flashcards
Rural to Urban Mirgration
o Rural workers move to cities for better employment or pay
o Rural areas can be left with least educated people – position of even lower social and political power
o Percentage of world’s population living in cities is increasing rapidly
Urban Areas
o Contain settled population not directly involved in primary production of food and other raw materials i.e. non-agricultural
Urban and Rural Populations
o Urbanisation is increasing
o The number of Megacities (very large cities) is increasing
o Poverty in urbanising
o Most rapid urbanisation is occurring in developing countries esp. LCDs, but developed countries currently have greater proportion
o 800 million – 2 billion people live in city slums / shanty towns
Key Trends
o Virtually all population growth will be focussed in urban areas
o In 2007/08, urban dwellers > rural dwellers for first time in history
o In LCDs, ‘rural crisis’ (unemployment of rural workers) forces urbanisation, rather than planned growth
Ecological Footprint
o Compares human demand on nature with biosphere’s ability to regenerate resources and provide services, by assessing biologically productive land & marine area required to produce necessary resources and absorb waste
o In 2003, average was 1.8 global hectares per person (gha/capita)
• U.S. was 9.6 gha/capita, China was 1.6 gha/capita
• Gha = hectare normalised to the average productivity of all bio-productive hectares on earth for a given year
o Carbon footprint, life cycle assessment – similar measures & tools
Resource Supply: Urban Metabolism
o Supply of resources: quantity, quality, efficient use
o Waste outputs: water pollution, air pollution, solid waste
o Extended metabolism: mass & energy balance across urban area, takes into account social aspect (‘liveability’ parameter)
Issues with Rapid Urbanisation
o Supply of resources: quantity, quality, efficient use
o Waste outputs: water pollution, air pollution, solid waste
o Extended metabolism: mass & energy balance across urban area, takes into account social aspect (‘liveability’ parameter)
• Issues with rapid urbanisation
o Resource supply: water, food energy
• Potential long term water deficits
o Waste & pollution: solid waste, sewage, industrial water, air pollution
o Infrastructure: water, waste, transport, electricity
o Public health: disease and natural disaster
• Concentrated populations become increasingly vulnerable to natural disaster
o Social: urbanised poverty = slums
o Urban areas are never self sustaining, cities are points of consumption
o Energy:
• More energy required for population growth and growth in energy use per capita
• Alternative sources due to ‘carbon constraints’
• De-centralisation: neighbourhood level generation – reduced transmission infrastructure and cost
o Air pollution
• City dwellers exposed to much higher pollutant levels
• Vehicles responsible for noise and air pollution
• Microclimate: generated heat, more rain/fog
• Can be trapped by temperature inversions, heat island ‘dust dome’ effects, very small particles of concern
o Water pollution
• Higher pollutant levels & reduced ecosystem health
• Polluted by: direct discharge (sewage, industrial process water), contaminated stormwater runoffs (roads, industry, buildings), polluted groundwater (chemical leaks/spills) discharging into surface water
o Waste
• Australians produce 810 kg of domestic waste per person per year
• Limited space for domestic & industrial waste – export to other locations
o Public health: disease and natural disaster
• Range of challenges: debris limit access
o Infrastructure: transport
• Buses > cars > walking in most large cities
• Switch from putting money & resources into roadways to now putting them into public transport, but this had made little impact on congestion
• Decentralisation of employment & business could reduce pressure on roads in and around CBD
Urban Sprawl
o Expanding cities make big demands on the environment
• Taking over farmland
• Polluting waterways
• Producing large amounts of waste
o Some of the most fertile soil is under suburbs
o Cities’ waste & pollution affects beyond their boundaries – landfills, waterways, coastlines
o Decreases amount of open space, agricultural land, natural habitats
o Spreading highways cut through wildlife corridors – impacts on migration routes and health of population – loss of biodiversity as a result
Urban Heat Island
o Urban landscapes are warmer than landscapes with native vegetation
o Implications for human health & weather patterns
o Issues
• Increases inefficiency
• Encourages use of automobiles: congestion = energy consumption + pollution
• Takes over agricultural land / green reserves
• Reduces bio-capacity – biodiversity ‘disaster zones’
• Infrastructure impacts: transport, water & power supply networks, sewerage, services (waste collection, police, lighting)
Slums
o 1 billion people (1 in 3 urban dwellers) lives in slums
o Definition: live without one or more basic life necessity
• Clean water
• Sanitation
• Sufficient living space
• Durable housing
• Secure land tenure (ownership)
o Insecurity – under constant threat of eviction so the land can be used for more economically productive purposes
o Uncertain water and electricity supplies, limited transport, poor quality food, high pollution and crime rates
o Funding challenges
• Environmental problems in LCD cities due to lack of legislation, poor infrastructure and shortage of funds
o No access to safe drinking water – diarrhoea, typhoid, cholera
o Severe air pollution – unregulated industry and motor vehicles emissions
o Inadequate sewerage systems
o Growing so fast that services and infrastructure cannot keep up
o High unemployment
o Marginalisation and poor governance
Megacities as the ‘green’ future
o Not an option to return the population to rural areas
o Cities could hold the key to sustainable living for the world’s growing population (if built correctly)
o Good economies for: energy generation, recycling, public transport
o Key design principles
• Recycle whatever possible
• Increase public transport use, minimise car use
• Maximise energy-efficient buildings
• Redesign to integrate work & living areas into single neighbourhood
• Separation of residential, commercial & industrial zones no longer optimal
Reducing Environmental Costs in Urban Areas
o Minimise use of imported resources
• Results in less transport impacts
• Introduce efficient industrial process designs
• Local water & energy sources
o Minimise internal transport costs
• Traffic/transport corridors/CBD ring roads
• Restrict heavy traffic flows
o Recover as much energy, water & materials from waste
• Reuse or export (nutrients to farms)
• Helps achieve minimal use of imported resources
• Minimise final disposal requirements
Development Continuum
o Reduce impact of consumption while maintaining lifestyle
o User pays, developer pays, government pays
Energy
o Electric (battery), bio-fuels, shipping, aircraft, hydrogen fuel cell o Global annual energy use:
o Majority of global energy use comes from:
• Oil (36%)
• Coal (23%)
• Gas (21%)
Energy consumption
o ‘Grubb’ curve
o Cost of electricity production from 2015-2030 in Australia
• Levelized COE and CO2 emissions reduced
