5.1 Tragedy of the Commons

• tragedy of the commons - the tendency of a shared, limited resource to become depleted because people act from self-interest for short-term gain

• Reasons for TOTC - Why?

  • when no one owns the resource (land, water, air), no one directly suffers the negative consequences of depleting, degrading, or overusing it

  • people assume others will overuse the resource if they don’t

  • there is no penalty for overusing, degrading, polluting many public resources

• externalities - a cost/benefit of a good or service that is not included in the purchase price of the product of service

  • Positive/Negative Externalities

    • positive - smell of popeye’s when you’re nearby

    • negative - pesticide use on crops leads to negative issues downstream

• Solutions for TOTC

  • privatization

  • fees or taxes (permits, limits, etc…)

  • taxes, fines, criminal charges for pollution or shared air/soil/water resources

    • Clear Air Act (air pollution)

    • Clean Water Act (waste water pollution)

    • Safe Drinking Water Act

5.11 Ecological Footprint

• What are some ways we impact the environment?

• We all have an impact on the environment.

• How is our “ecological footprint” measured?

  • measured by how much an individual or group is consuming - area of land

  • Factors (land required for)

    • food production

    • raw materials (wood, metal, plastic)

    • housing

    • electricity production

    • waste disposal

• Ecological vs Carbon Footprint

  • ecological footprint - measured in land (gha - global hectare), which is a biologically productive hectare (2.57 acres)

  • carbon footprint - measured in tonnes of CO2 produced per year

    • all CO2 released from an individual or groups consumption & activities

      • food production

      • material goods

      • energy use

• Footprint Factors

  • Increase Footprint

    • affluence (wealth) increases carbon and ecological footprint

      • larger houses

      • more travel (gas)

      • more resources needed for material goods

        • ex) cars

    • meat consumption - more land, more water, more energy

    • fossil fuel usage (heating, electricity, travel, plastic)

  • Decrease Footprint

    • renewable energy use (wind, solar, hydroelectric)

    • public transportation (less gas)

    • plant-based diet

    • less consumption, less travel, less energy use

• Footprint Calculations

  • ecological footprint can also be expressed in “number of earths” required if the entire world consumed same level of resources as a given individual or group

5.12 Sustainability

• consuming a resource or using a space in a way that does not deplete or degrade it for future generations

  • ex: using compost (renewable) over synthetic fertilizer (fossil fuel dependent)

• maximum sustainable yield - maximum amount of a renewable resource that can be harvested without reducing or depleting the resource for future generations

  • roughly ½ of the carrying capacity

• Environmental Indicators of Sustainability

  • factors that help us determine the health of the environment and guide us towards sustainable use of earth’s resources

    • biodiversity

    • food production

    • atmospheric temperature & CO₂

    • human population and resource depletion

• Biodiversity

  • genetic, species, and ecosystem

  • higher biodiversity = healthier ecosystems

  • declining biodiversity can indicate pollution, habitat destruction, climate change

  • global extinction decreases species richness of earth

• Food Production

  • indicates ability of earth’s soil, water, and climate to support agriculture

  • major threats to food production = climate change, soil degradation (desertification, topsoil erosion), groundwater depletion

  • increasing meat consumption = further strain on food production (takes away water and land from grain production)

  • global grain production per capita has leveled off and shown signs of decline recently

• Atmospheric Temp & CO₂

  • life on earth depends on very narrow temperature range

  • CO₂ is a GHG (traps infrared radiation and warms earth’s atmosphere)

    • increased CO₂ = increased temp

  • deforestation (loss of CO₂ sequestration) and combustion of FF (emission of CO₂) increase atmosphere CO₂

  • increasing CO₂ = unsustainable (dries our arable farmable ) land, destroys habitats, worsens storm intensity)

• Human Population & Resource Depletion

  • as human population grows, resource depletion grows

  • resources are harvested unsustainably from natural ecosystems & degrade ecosystem health

    • more paper (lumber) = deforestation

    • more food = soil erosion, deforestation, groundwater depletion

    • more travel = FF mining = air, water, soil pollution, habitat destruction

5.9 Impacts of Mining

• Earth’s Composition

  • crust is mostly oxygen (46%)

  • atmosphere is mostly nitrogen (78%)

• ore - concentrated accumulations of minerals from which economically valuable materials can be extracted

• metals - elements with properties that allow them to conduct electricity and heat energy and to perform other important functions

• reserve - the known quantity of the resource that can be economically recovered

• overburden - soil, vegetation, and rocks that are removed to get to an ore deposit below

• tailings and slag - unwanted waste material separated from the valuable metal or mineral within ore (often stored in ponds @ mine site)

• Surface Mining

  • Pros

    • provides low cost energy

    • provides material to make products (plastic)

  • Cons

    • removes large portions of soil, rocks, and vegetation

    • topsoil erosion

    • habitat loss

    • stream turbidity/acidification

    • lowers water pH

    • increased particulate matter/GHG in the air

    • area can be restored but not to its original form

    • strip mining - removal of strips of soil and rock to expose the underlying ore

      • used when ore is relatively close to earth’s surface and runs parallel to it

    • open-pit mining - mining that creates a large visible pit or open hole in the ground

      • used when the resource is close to the surface, but extends beneath the surface both horizontally and vertically

    • mountaintop removal - removal of the entire top of a mountain with explosives

    • placer mining - looking for metals and precious stones in river sediments

    • subsurface mining - digging underground, creating tunnels and rooms underground to obtain materials

      • less direct habitat destruction, but much more dangerous

      • ex) underground coal mining: long walling and room and pillar

      • with fewer reserves available through surface mining, subsurface mining is done more

      • Risks

        • poor vegetation leading to toxic gas exposure

        • mine shaft collapse

        • injury from falling rock

        • lung cancer

        • asbestos

        • fires

        • explosions

    • Effects of Mining

• Mine Reclamation

  • Surface Mining Control and Reclamation Act of 1977 - requires coal mining companies to restore the lands they have ined

  • Process

    • filling of empty mine shafts/hole

    • restoring original contours of land

    • returning topsoil with acids, metals, and tailing removed

    • replanting of native plants to restore community to as close to original state as possible

5.2 Clearcutting

• Commercial Timber Operations

  • 73% privately owned in the US

  • allowed to harvest in exchange for a royalty that is a percentage of revenues

  • government spends more money on management than it receives in royalties (so logging is effectively subsidized)

• Benefits

  • clearcutting - method of harvesting trees that involves removing all or almost all of the trees within an area

  • economics - easiest/most economical way to log timber in large quantities

  • stands are usually replanted

  • benefits are short-term

• Negative Effects

  • reduction in biodiversity

    • fast-growing, direct sunlight species are favored when replanted (tree replantations)

    • less valuable species may have been harvested also (like bycatch)

    • habitat destruction and fragmentation

    • less species diversity = lower resilience

  • increase in soil erosion, loss of soil nutrients

  • stream sedimentation

  • flooding/mudslides

  • increased temperatures

  • loss of carbon sink

5.17 Sustainable Forestry

• Ecologically Sustainable Forestry

  • forestry (using trees for lumber) that minimizes damage to ecosystem (habitat destruction, soil erosion, etc.)

    • selective cutting and strip cutting - only cutting some of the trees in an area biggest and oldest) to preserve habitat (biodiversity) and topsoil

    • creates small openings where trees can reseed

    • regenerated stand has trees of different ages; only works for trees that tolerate shade

• Sustainable Forest Practices

  • reclaimed lumber can reduce the amount of trees being harvested

    • reclaimed wood can come from old houses or furniture, barns, or industrial buildings

  • wood can be chipped and used as mulch for gardens or agricultural fields

  • reforestation - replanting of trees in areas that have been deforested

  • selectively removing diseased trees to prevent spread of infection through entire forest

    • removes host for disease

    • decreases density, making spread less likely

• Fire Management

  • Fire Suppression

    • fire suppression - practice of putting out all natural forest fires as soon as they start

    • leads to more biomass buildup, which makes future fires worse

    • also increases dead biomass - traps nutrients, susceptible to disease and pests

• Prescribed Burns

  • small, controlled fires set deliberately under controlled conditions

    • reduces risk of uncontrolled natural fires by burning up dead biomass

    • promotes nutrient cycling and regeneration

5.10 Urbanization

• urban - population with a relatively high density of people and structures compared to the surrounding area

• rural - an area where population, housing, or territory is in the countryside away from urban areas

• suburban - areas surrounding metropolitan centers with low population densities

• urbanization - the creation and growth of urban areas

• population density: # people / unit area

• Benefits

  • concentration of services

    • business, industry, colleges, commerce, technology, arts, entertainment

  • innovation occurs

  • diverse employment opportunities

  • higher life expectancy

  • higher education rates

  • efficient services

    • health care

    • family planning

    • social services

  • mass transit/recycling

  • preserve surrounding wilderness

• Drawbacks

  • large ecological footprint even though it takes up only 2% of land area

  • urban sprawl

  • urban transportation

  • resource use/depletion

  • pollution and waster

  • poverty

  • high population density

    • inadequate infrastructures

    • lack of affordable housing

    • flooding

    • creation of “slum”

    • crime

    • congestion

• Urban Sprawl

  • urban sprawl - spreading to low-density suburbs and developments around an urban center that spreads into rural areas and removes clear boundaries between the two

  • positive feedback loop! (1/2)

  • Main Causes

    • automobiles and highway construction

    • living costs

    • urban blight

    • government policies

  • urban blight - the degradation of the built and social environments of the city that often accompanies and accelerates migration to the suburbs

• Induced Demand

  • induced demand as a cause of traffic congestion and urban sprawl

    • the use of gasoline tax money to build highways leads to the development of suburbs and traffic congestion, at which point yet more money is spent on highways to alleviate the congestion

    • green arrow indicates the starting point of the cycle

    • positive feedback loop! (2/2)

• Impacts of Urbanization

  • depletion of resources

    • excessive water use (aquifer withdrawal)

    • saltwater intrusion

  • impacts on cycles

    • impermeable surfaces disrupt the water cycle

    • CO2 form fossil fuels alters carbon cycle → climate change

  • air pollution

    • traffic

  • congestion

    • spread of disease

    • buildup of waste - causes need for landfills

    • water pollution

  • noise pollution

  • light pollution

  • not necessarily worse - but is more easily seen in developing countries

• Smart Growth

  • smart growth - makes efficient and effective use of land resources and existing infrastructure

    • mixed land uses

    • create a range of housing opportunities and choices

    • create walkable neighborhoods

    • encourage community and stakeholder collaboration in developer decisions

    • take advantage of compact building design

  • foster distinctive attractive communities with a stronger sense of place

  • preserve open space, farmland, natural beauty and critical environmental areas

  • provided a variety of transportation choices

  • strengthen and direct development toward existing communities

  • make development decisions predictable, fair, and cost-effective

  • Smart Cities of the Future will have Minimal Environmental Impacts

    • rooftop solar panels and wind turbines will generate energy

    • plug-in hybrid cars will serve as a dispersed electrical storage grid

    • food will be grown in rooftop gardens

    • mass transit will move people quickly and inexpensively

    • rainwater will be filtered and reused

    • recycling of metal and glass will be standard

5.13 Reducing Urban Runoff

• Urban Runoff