Post on 20-Jan-2018
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Chapter 18 The EnvironmentSection 1 – Global ChangeSection 2 – Effects on EcosystemsSection 3 – Solving Environmental Problems
Acid RainAcidified precipitation caused by nitric
and sulfur-rich air pollutionBurning fossil fuels
Sulfur and nitric acid in atmosphere combined with water vapor falls to Earth and joins the water cycle
How acidic is the precipitation?Drops the pH from 7.0 to 4.0-4.5
What is the impact of acid rain?
Effects of Acid Rain
Largest affect is on aquatic ecosystemsHigh levels of nitric and sulfuric acid are
toxic to organism Toxicity can affect all organisms in a food
chain from producers to large predatorsThe soils of nearby areas can become too
acidic and plants start to become vulnerable to death if they cannot adapt to the new pH
PesticidesChlorinated hydrocarbons broken downThe process is slow and the toxins
accumulate in fatty tissues of animalsBiological Magnification:
Molecules move up the food chain as organisms are consumed
DDTNow banned due its threat to the bird population in 1972
Ozone LayerA protective, upper layer of the
atmosphere that reduces the amount of UV rays that hit the Earth’s surface
Ozone HoleThe concentration of O3 is lower over
AntarcticaExpected to have started becoming less
concentrated from 1978 and onDecrease in concentration has led to
more UV exposure and diseases
Causes of the Ozone HoleMain cause: Chlorofluorocarbons (CFCs)Chlorofluorocarbons (CFCs)
Created in 1920s as stable and harmless coolants
Present in fridges, Styrofoam, air conditioners and aerosol cans Presently banned in the US
Began escaping into the atmosphere breaking down the O3
Cl bonds reacted with oxygen – producing less O3
Global TemperaturesTemperatures have a typical pattern of
increase then decrease for about a centuryEffected by sunspot cycles
Since 1950’s the temperatures have only been increasing
Global WarmingPeriods of steady increase usually followed by
cold periodsHuman activities have contributed to larger
cycles of global warming
The Greenhouse EffectGreenhouse Gases
Water vapor, carbon dioxide, methane and nitrous oxideThese gases insulate the planet
The Greenhouse EffectBonds in carbon dioxide absorb heat radiating off the Earth and this heat is trapped by the atmosphere
As carbon dioxide levels increase, more heat is being absorbed by the atmosphere
Loss of ResourcesNonrenewable resources are being used
at faster rates – leaving a path of destruction in its wake
Effects of Loss of ResourcesExtinction of speciesLoss of TopsoilGround-water Pollution and Depletion
Extinction of SpeciesHuman activities like cutting down parts
of rainforests are leading to the next mass extinction
Approximately 10% of the species are subject to extinction
The worst possible outcome is loss of over 1/5th of the rainforests species
The loss of species can affect not only the ecosystem, but the possible benefit of those species to human kind.
Loss of TopsoilReplacement of topsoil is impossible –
about a centimeter is lost every yearThe causes are from turning the soil to
eliminate weeds, overgrazing and poor agricultural practices
These methods cause water and wind to remove soil from the area
Since 1950 – 1/3rd of the topsoil has been lost
Ground-water Pollution and Depletion
AquifersPorous rock reservoirs that hold ground water
Ground-water is a precious resource that is being used by the buckets at rates that are too large for consumption
Another portion of ground water is being polluted by chemical wastes
Removing of wastes is impossible
Growth of the Human PopulationFundamental causes of destructionAverage Global birth rate = 1,000/yearAverage death = 9 per 1,000/ yearPopulation exceed 6 million in 1999US rate is decliningThird world countries increasingProjected stable 9.7 million by 2050Will our resources support us until then?
Worldwide EffortBegan in 1990s
First Problem: PollutionInternational consensus decided to
reduce or eliminate use of CFCsUS started a ban DDT
Some countries followed suitSewage treatment plantsScrubbers – smoke stacksReduce car use – eco-friendly cars
United States EffortPollution Effective EffortsLaws Forbidding Pollution
Strict standards about what is released into the atmosphere
Clean Air Act of 1990Pollution Tax
To be effective the tax amount must equal the cost of the pollution
Gas tax is most popular
Five Steps to SuccessAssessment
Using data and observations – scientists make ecosystem models
Risk AnalysisModels are used as a trial and error
systemPlug in a disruption and understand the
consequenceFormulate a solution and check possible
progress
Five Steps to SuccessPublic Education
Informing the main cause of the problem of possible alternatives
Also can use the public for ideasPolitical Action
Power of persuasion and a group of followers
Follow-ThroughCollect data over time to evaluate the
progress and report to public
The Nashua River(New England)
Problem:Polluted by mills starting in 1900s
Solution (1966):Marion Stoddart and politicians start a group to finance a water treatment plantIndustrial dumping is now banned
Progress:As of 1990, the river has recovered and abilities to swim are intact
Lake Washington(Seattle)
Problem:Water treatment plan discharge into the lake between 1940 to 1953Blue-green algae started to grow with the new presence of nutrients
Solution:In order to clean-up the lake, taxes financed trunk sewers that divert sewage to Puget Sound
Progress:As 1961, clean bill of health and full of life
Lake Erie Algal blooms
What Can You Do?Conserve energy by walking to
locations, use public transportation or carpool
Energy inventory at home Educate yourself about the environmentRecycle and upcycleCompost