AP Environmental Science Topic 5.1, 5.2, 5.10-13.

Goes over Urbanization, Tragedy of the Commons, Clear-Cutting, Reducing Urban Runoff, Ecological Footprint, and Sustainability

Urbanization

Removing vegetation to convert natural landscapes to cities.

CO2 emissions caused by urbanization

• cement production

• construction machinery

• deforestation

• landfills

Why do people move from rural to urban areas?

• jobs

• entertainment

• cultural attractions

Suburbs

Less dense areas surrounding urban areas.

Where is the highest population growth?

Suburban populations

Urban Sprawl

Population movement out of dense, urban areas to less dense, suburban areas surrounding the city.

Causes of urban sprawl

• cheaper property

• cars and expanded highway systems

• domino effect

• declining tax revenue in cities bc of less residents

• businesses leave w/ residents

• abandoned buildings create blight

Solutions for urban sprawl

• urban growth boundaries

• public transport and walkable city designs

• mixed land use

Urban Growth Boundaries

Zoning laws set by cities that prevent development beyond a certain boundary.

Mixed Land Use

Residential, business, and entertainment buildings all located in the same area of a city.

Tragedy of the commons

People will use shared/public resources in their own self interest, degrading them.

Examples of tragedy of the commons

• overgrazing

• overfishing

• water/air pollution

• overusing groundwater

Why does tragedy of the commons happen?

• When no one owns the resource, no one directly suffers the consequences over overusing.

• People assume others will overuse the resources first.

• There’s no penalty for overusing many public resources.

Problems with overfishing

Can lead to fishery collapse, loss of income, and starvation.

Problems with air pollution from coal power plants

can lead to bronchitis, asthma, and increased healthcare costs.

Problems with pesticide runoff from farms

it contaminates drinking water

Externalities

Negative costs associated with human actions that aren’t accounted for in the public.

How to solve tragedy of the commons

• private land ownership

• fees/taxes for use

• taxes, fines, or criminal charges for pollution of shared resources

Examples of taxes, fines, or criminal charges for pollution of shared resources

• clean air act

• clean water act

• safe drinking act

• bureau of land management

Bureau of Land Management

Manages rangelands in western US by collecting grazing fees from ranchers, evaluating land, and repairing effects of overgrazing.

Direct effects of clearcutting

• soil erosion

• increased soil and stream temperature

• flooding and landslides

How is soil erosion a direct effect of clear-cutting?

• it removes soil organic matter and nutrients from forests

• it puts sediment in local streams

How is increased soil/stream temperature a direct effect of clear-cutting?

• tree shade loss increases soil temp.

• soil has lower albedo than tree leaves

• tree shade loss along rivers/streams warms them

• sediment erosion into rivers warms them

How are flooding and landslides a direct effect of clear-cutting?

• logging machinery compacts soil

• increased sunlight dries soil out

• root structure loss = erosion of topsoil and o horizon

• soil’s water holding capacity decreases as a result

Turbidity (water)

Cloudiness of water

Tree Plantations

Areas where the same tree species are repeatedly planted, grown, and harvested.

Tree Plantations are bad bc…

• lower biodiversity

• all trees are the same age (no dead trees for woodpeckers, decomposers, or insects)

Environmental consequences of urban runoff

• decreased infiltration (groundwater recharge)

• rain washes pollutants into storm drains

Urban Runoff pollutants and effects

• salt causes plant/insect death

• sediment causes turbidity

• fertilizer causes eutrophication

• pesticides kill non-target species

• oil/gasoline suffocate fish and kill aquatic insects

solutions to reduce urban runoff

• permeable pavement

• rain gardens

• public transit

• building up, not out

Ecological Footprint

Measure of how much a person/group consumers, expressed in an area of land.

Factors that determine Ecological Footprint

• food production

• raw materials

• housing

• electricity production

• disposing waste produced

Carbon Footprint

All CO2 released from an individual/group’s consumption and activities, measured in tonnes of CO2 produced per year,

Increases Ecological footprint

• affluence

• meat consumption

• fossil fuel usage

Decreases Ecological footprint

• renewable energy use

• public transportation

• plant-based diet

• less consumption/travel/energy use

Sustainability

Consuming a resource/using a space in a way that doesn’t deplete/degrade it for future generations.

maximum sustainable yield

The maximum amount of a renewable resource that can be harvested without reducing/depleting it for future use.