GGRA03H3 – Week 8 – Urban Political Ecology
Urban Ecology Basics
- Ecology OF cities, not IN cities
- A new way of understanding and seeing cities and urban processes
- Ecology is the study of the relations of living organisms to each other and to their
- Ecology studies flows within particular ecosystems, of nutrients, energy, waste, and the
subsystems that structure those flaws
- Cities are a special kind of ecosystem
- Lots of research still to do on what kinds of ecosystem cities are
Cities as Biotic Systems
- Some urban ecologists study cities as biotic systems.
- Examine the ways in which cities create new ecological niches for certain species
(plants and animals)
- City ecosystems selectively breed animals like raccoons, squirrels, pigeons, etc. by
eliminating predators, and providing sources of food
o Very few predators for those animals, thus higher population
o Large amount of food
- Urban monocultures represent a radical simplification of ecological systems, through
design, chemical warfare, impermeable surfaces, and flamethrowers.
- Cities are not an ecological void, but a setting rich in certain species of plants, animals,
birds, insects, diseases
- What kinds of long-term impacts of cities on ecosystems might be of concern?
- Cities provide breeding grounds for invasive species and diseases such as dengue
fever, West Nile fever.
- Invasive species are in part a product of urban monocultures, globalization, materials
and product flows.
Key Concept 1
- The idea of studying cities as ecosystems gave rise to Urban Ecology
o Cities are a special kind of ecosystem, created by people
o Cities are not an empty space, but provide distinctive ecological niches and
habitats o Those ecological niches support complex and city-specific plan and animal
o Urban monoculture ecosystems can be ideal breeding grounds for disease
- Urban ecology is the study of the relation of living organisms with each other and their
surroundings in the context of an urban environment
Closed and Open loops
- Natural ecosystems contain multiple relatively stable nutrient loops
- There is no waste in natural ecosystems
o All wastes end up being recycled and reused.
- Seeing cities as ecosystems makes clear that cities are not closed loops
- Cities import water, energy, food on a vast scale, from very long distances
o And export their wastes into global waste sinks
- Most waste disposal solutions so far have involved finding better waste sinks, not
reducing or re-using.
- Industrial ecology seeks to close loops
- At a global scale, all loops are closed.
Key Concept 2
- A major contribution of urban ecology is to see cities as flows, inputs & outputs
o In nature there are no ‘waste products’ or garbage, as all outputs are inputs to
o But cities are not closed loops, but open loops, in which large volumes of inputs
are converted into wastes, which are not re-used within the system.
o A major focus of urban engineering is the find ways to close these loops
Cities as Flows
- Some key work on urban ecology studies cities as flows (of people, energy, goods,
water, nutrients, etc.)
- A fundamental characteristic of contemporary cities is that they depend on huge flows of
- Electricity, gasoline, natural gas, food
o Coal is cheap, but very dirty. - Over the last 200 years, a transformation of cities has been permitted by the change
from human and animal power to hydro-electric, fossil fuels, nuclear power, and recently
solar and wind.
- For most of that period, energy prices have been declining relative to income.
Flows of Energy
- Huge inputs of fossil fuels make contemporary cities possible
- Energy use per capita accelerated dramatically in 20 century
- We all know that this creates problems of pollution, global warming, etc.
- But it also means that cities represent important sites of potential efficiencies in energy
- Public transit, co-generation and district heating can save huge amounts of energy.
o Public transit is fast, and much more cost efficient than driving in a place like
Flows of Food
- Picture the food inputs to Toronto
- Sourced from around the world
- Enormous diversity, 1000s of different products
- Processing industries
- Distribution, retailing
- Need to keep fresh, wastage
- Huge amounts of energy at each stage
- LOCAL food? Why is this a recent public issue?
Reasons for local food
- A significant debate has emerged during the last 10 years about the potential benefit of
local food sourcing
- In favour:
o Reduced energy inputs
o Promoting local suppliers
o Greater freshness & quality control
o More variety
o Promoting sustainable agriculture - But many of these advantages are disputed by those who argue that markets are likely
to promote production in the most efficient location and climate.
Key Concept 3
- Energy is one of the primary flows into cities, and producer of wastes
o A key way to study ecological systems is to examine nutrient (energy) flows.
o Contemporary cities depend on huge flows of energy in part because energy has
been so cheap for 100 years
o Dependence on cheap energy is a major risk factor
o Food is still a major input to cities with complex logistics systems moving food
o Local food sourcing is often proposed as an alternative but the benefits are
Ecological Footprint Analysis
- Asks what is the total area o