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Tragedy of the Commons
Indivduals will use shared/public resources in their own self interest, degrading them
examples of tragedy of the commons
overfishing, overgrazing, water and air pollution, overuse of groundwater
Why does the tragedy of the commons occur?
When no one owns the resource, no one suffers the negative consequences of depleting it.
Over fishing can lead to
population crash, loss of income, starvation
air pollution can lead to
bronchitis, asthma, healthcare costs
Externalities
negative costs associated with a human action, that aren't accounted for in the price
Solutions for the Tragedy of the Commons
private land ownership, fees or taxes
Clearcutting
The process of cutting down all the trees in an area at once
Effects of clearcutting
Soil erosion, increased soil and stream temp, flooding and landslides, loss of root structure
Tree plantations
Areas where the same tree species are repeatedly planted, grown, and harvested
Forest benefits
filtering of air pollutants
removal and storage of CO2 from the atmosphere
habitat for organisms
deforestation consequences
-reduces air filtering and carbon storing services
-cutting trees down releases CO2 from decomposition of leftover organic material
slash and burn
Cutting down vegetation and burning it to clear land for agriculture. & return nutrients in plants to soil
Green Revolution
Shift in agriculture away from small, family operated farms to large, industrial scale agribusiness
Mechanization
Increased use of tractors for plowing and tilling fields, and combines for harvesting
High yield variety crops
Hybrid, or genetically modified crops that produce a higher yield
GMO's
Genetically modified crops have genes for drought tolerance, pest resistance, faster growth, and larger fruit/grain
Synthetic fertilizer leads to
excess nitrate, phosphate washed off fields and into nearby waters where they cause eutrophication
irrigation
Drawing water from the ground or nearby surface waters and distributing it on fields to increase plant growth
pesticides can
wash off crops in runoff and kill or harm non-target species in local soil or waters
Monocropping
Growing one single species of crop
monocropping disadvantages
decreases biodiversity, increased soil erosion, decreased habitat diversity
Tilling definition and sideeffects
mixing and breaking up soil to make planting easier, increases erosion, loss of organic matter, increased PM and turbidity
Leaching
water carrie's excess nutrients into groundwater or into surface waters
furrow irrigation
a trench that is flooded with water, easy and inexpensive
flood irrigation
flood entire field, easier but more disruptive to plants
drip irrigation
holes in hose allow water to slowly drip out. most efficient, but most costly
spray irrigation
ground or surface water pumped into spray nozzles. more efficient and more expensive
water logging effects
can saturate soil, filling all soil pore space with water
solution to water logging
drip irrigation or soil aeration
soil salinization
process of salt building up in soil over time
solution to soil salinization
drip irrigation, soil aeration, flushing with fresh water, switch to freshwater source
industrial water use
power plants, metal/plastic manufacturing
muncipial water use
households (toilet, shower, drinking water)
agriculture water use
water for livestock, irrigation water for crops
saltwater intrusion
excessive pumping near coast lowers water table pressure, allowing saltwater to seep into groundwater
cone of depression
forms when water table is lowered by excessive pumpkins, depleting water and drying nearby wells
chemicals toxic to pests
rodenticides, fungicides, insecticides, herbicides
pests can become ___________ to pesticide overuse
resistant
GMO's
gene for pest resistant trait is added to the plant through genetic modification
GM crops are
genetically identical, so they are mor susceptible to disease
CAFOs (concentrated animal feeding operations)
Also called feedlots - densely crowded method where animals are fed grain (corn) to raise them to as quickly as possible
Manure lagoons
Large open storage pits for animal waste
Waste contains
ammonia, hormones, antibiotics, e. coli
Free-range grazing
animals graze on grass and grow at a natural rate without growth hormones
Overgrazing
too many animals in an area of land can remove all vegetation which leads to topsoil erosion
desertification can occur if
plants are killed by overgrazing and soil is compacted so much that it can't hold enough water anymrie
overgrazing can be prevented by
rotational grazing
Producing meat for humans to eat is
far less efficient than producing plants in terms of energy, land, and water use
energy meat inefficiency
all of the energy needed to plant, grow, harvest plants to feed to animals
land meat inefficiency
all of the energy needed to grow plants to feed animals PLUS room the animals take up
water meat inefficiency
all of the water for crops that animals eat PLUS the water the animals drink
Overfishing
overfishing of a species or several species from a body of water at such a rate that they cannot recover
overfishing leads to
collapse in aquatic ecosystems
fisheries
populations of fish used for commercial fishing
fishery collapse
when overfishing causes 90% population decline in a fishery
population may never recover from fishery collapse due to
decreased biodiversity, inability to find mates, inbreeding depression
bottom trawling
Especially harmful fishing method that involves dragging a large net along ocean floor
Bycatch
unintended species being caught
Solutions to overfishing
Turtle exclusion device, licenses, limits on size / number
ore
commercially valuable deposits of concentrated minerals that can be harvested and used as raw materials
metals
elements that conduct electricity, heat, and have structural properties for building (found within ores)
reserve
the known amount of resource left than can be mined
overburden
Soil, vegetation, & rocks that are removed to get to an ore deposit below
tailings and slag
leftover waste material separated from the valuable metal or mineral within ore
surface mining
removal of overburden to access ore near surface
types of surface mining
open pit, strop, mountaintop, removal, placer
subsurface mining is (economically)
More expensive due to higher & health costs for workers
risks to subsurface mining
poor ventilation leading to toxic gas exposure, mine shaft collapse, injury from falling rock, lung cancer, asbestos,fires, explosions
acid mine drainage
rainwater leaks into abandoned mine tunnels & mixes with pyrite, forming sulfuric acid
methane release
Coal mining releases methane gas from rock around coal
PM release
coal mining especially, releases lots of soot and other particulates that can irritate human and animal lungs
mine reclamation
process of restoring land to original state after mining has finished
Urbanization
removing of vegetation to convert natural landscapes to city
impervious surfaces
don't allow water to infiltrate into the ground (concrete, asphalt, cement)
Saltwater intrusion results from
population growth in coastal cities
urban sprawl
Pop. movement out of dense, urban centers to less dense suburban areas surrounding the city
causes of urban sprawl
expanded highway system, cheaper housing, etc
urban growth boundaries
zoning laws set by cities preventing development beyond a certain boundary
mixed land use
Residential, business, and entertainment buildings all located in the same area of a city
ecological footprint
Measure of how much a person / group consumes, expressed in area of land.
carbon footprint
measured in tons of CO2 produced per year
sustainability
consuming a resource or using a space in a way that does not deplete or degrade it for future generations
maximum sustainable yield
The maximum amount of a renewable resource that can be harvested without reducing or depleting the resource for future use
environmental indicators of sustainability
factors that help us determine the health of the environment and guide us towards sustainable use of earth's resources
food production indicated
ability of earth's soil, water, and climate to support agriculture
as human pop grows
resource depletion grows
environmental consequences of urban runoff
decreased infiltration, rain washes pollutants into storm drains and local surface water
permeable pavement
Specially designed to allow stormwater to infiltrate & recharge ground water, decreases runoff
rain garden
gardens planted in urban areas, especially surrounding a storm drain, decreases runoff
public transit
Public transit decreases urban runoff, pollutants on road, CO2 emissions & even traffic
building up, not out
Building vertically decreases impervious surfaces (decreasing urban runoff)
Integrated Pest Management
Using a variety of pest control methods that minimize env. disruption and pesticide use
types of IPM
Biocontrol, crop rotation, intercropping
Biocontrol
introducing a natural predator, parasite, or competitor to control the pest population
crop rotation
rotating crops (planting a different crop each season) can prevent pests from becoming established since it disrupts their preferred food choice
Intercropping
"push" plants emit volatile chemicals that naturally repel pests away from crop while "pull" plants emit chemicals that attract moths to lay eggs in them, instead of crop