Global Environmental Concerns

Chapter 3 (3.3 & 3.4); Chapter 5 (5.1 & 5.3); Chapter 6 (all)

Environmental Science Textbook

World PopulationCalculate the rate of world population growth

World Pop Clock WebsiteAnalyze the graph of world population growthWhat are some of the problems?Any solutions?

Technology

GRAPH

BIODIVERSITYBIODIVERSITY – the number of different species in an area

Bio – life; diversity – differencesThe more biodiversity, the healthier, more stable the ecosystem is

• High biodiversity – rainforests, coral reefs• Low biodiversity – deserts, tundra, arctic, open/deep ocean

FACTORS AFFECTING BIODIVERSITY:Area – how much space there isClimate – rainfall and temperature are most important

• Rainforests vs desert climatesNiche Diversity – does the habitat allow for species to use it in a variety of ways

• Coral reefs vs deep ocean

BIODIVERSITYVALUE OF BIODIVERSITY

Economic – making money from living resources• Medicines – taxol, foxglove• Foods• Building materials

Environmental – each species in an ecosystem is interconnected

• Keystone species – a single species that is extremely important to the survival of many other species

– Sea starsGene pool diversity – the different genes and traits in an ecosystem

• More genetic differences, better able for species to adapt and resist diseases, parasites, and drought

BIODIVERSITYTHREATS OF BIODIVERSITY:

Levels:• Threatened – first warning level; population numbers

are declining, need to watch• Endangered – second warning level; population

numbers are really low; could become extinct if nothing is done to help

• Extinct – no living members of a population; once extinct, can not recover

– Dodo bird, carrier pigeon– Extirpated – no longer found in an area; can be

reintroduced because found in different areas– Mountain lions, buffalo – currently extirpated– Otters, fishers, elk – have been reintroduced

BIODIVERSITYTHREATS OF BIODIVERSITY

Causes of extinction:• #1 – habitat loss

– Habitat destruction and habitat fragmentation• Poaching

– Dian Fossey – Gorillas• Pollution• Introduction of exotic species

– Indigenous species (native) – naturally found in an area– Exotic – species brought from one ecosystem to another

either by accident or on purpose– Invasive species– Gypsy moth, virginia creeper– Nene Goose example (Hawaii)– Austalia and Rodents

BIODIVERSITYPROTECTING BIODIVERSITY

Captive BreedingReintroductionLaws and Treaties• Endangered Species Act of 1973

Habitat Preservation• National parks, forests

Getting involved• Personal decision making• Lots of environmental organizations

AIR POLLUTIONComposition of Air:

Mixture composed of 78% Nitrogen (N2), 21% Oxygen (O2), 0.06% Carbon Dioxide (CO2)Also contains water vapor, gaseous pollutants, and solid particles (particulates)

Air Pollution – a change to the atmosphere that has harmful effects

Types of Air Pollution• Smog• Acid Rain• Global Warming• Destruction of the Ozone Layer• Indoor Air Pollution

AIR POLLUTIONSmog – combination of smoke and fog

Photochemical Smog – thick, brownish haze when certain gases in the air react with sunlight

• Gases mainly come from cars and trucks • Gases form ozone – a toxic gas

Temperature Inversion – a layer of warm air prevents the pollution (smog) from rising above the cityProblems include:

• Itchy, watery eyes• Scratchy throat• Lung problems• Harms the body’s defense against illness

AIR POLLUTIONAcid Rain - a condition that arises when certain gases in the atmosphere react with rain water, turning it acidic

Nitrous and Sulfer Oxides + water nitric acid and sulfuric acid

• Gas pollutants come from car engines (nitrous oxide) and coal burning plants (sulfer oxides)

Lowers pH of rain water below its normal value• pH – a scale that measures the acidity of solutions• Acid – below 7; Neutral – 7; Base – above 7 (14 is

highest)• Unpolluted rain water is 5.2 (slightly acidic) acid rain is

when the pH falls well below that levelDamages environment

• Can kill large areas of forests• Releases heavy metals out of the soil• Makes waterways unsuitable for aquatic life• Can destroy certain materials in buildings and statues

AIR POLLUTIONOzone Depletion

Ozone Layer – a layer of the atmosphere that contains a small amount of ozone (O3) gas

• About 30 km above surface• Absorbs ultraviolet (UV) radiation from sun

– Protect against sunburn and skin cancer– Sunblock – SPF #

Ozone is recycled (see Figure 6, P. 145)Chlorofluorocarbons (CFC’s) – molecules that react with ozone, stopping it from being recycled

• Come from air conditioners, refrigerators, fire extinguishers, aerosol cans

• Now CFC’s are banned in most countriesLarge hole over Antarctica and Australia

AIR POLLUTIONGlobal Warming – the idea that certain pollutants in the atmosphere are causing the temperature of the Earth to rise too quickly

Greenhouse effect – certain compounds trap the heat entering the Earth’s atmosphere

• Greenhouse gases– Carbon dioxide– Methane, water vapor, nitrous oxide, ozone

• Main Causes:– Burning of Fossil Fuels– Deforestation

Potential Consequences• Dramatic changes in climate • Coastal flooding – melting of polar ice caps• Mass extinction – weather changing faster than organisms can

adaptNOT ALL SCIENTISTS AGREE THAT GLOBAL WARMING IS HAPPENING!

• Natural and needed• Geologic history of changes in temperature

AIR POLLUTIONIndoor Air Pollution

Allergens such as pollen, dander, dustCigarette smokeAsbestos – used to be used as an insulator

• Associated with lung disease• Carcinogenic – linked to causing cancer• Has to be removed now in public buildings

Carbon Monoxide – CO• Description: Colorless odorless gas• Problem: Binds with blood cells that carry oxygen – keeps

oxygen from getting to body cells• Source: when wood, coal, oil or gas are not burned completely• Can by detectors to warn if levels get too high

Radon• Description: colorless, odorless gas that is radioactive• Problem: can cause lung problems and cancers• Source: formed naturally by rocks underground; leaks in

through cracks in basements• Can install ventilation units to keep Radon from building up

AIR POLLUTIONSolutions:

Emissions control• Emissions – solid particles and gas that are released into the

air• Laws set up to limit what factories can put into the air• Scrubber – using water to clean emissions before releasing

into atmosphere• Catalytic converter – a device in cars and trucks that reduces

emissions of carbon monoxide, hydrocarbons, nitrogen oxides

– Forms less harmful carbon dioxide and waterCFC substitutesGeneral Conservation Practices

• “Carbon Footprint• Reduse, reuse, recycle• Carpool, find alternative ways for transportation• Use less energy• Support agencies and organizations that are for protecting

the environment

Energy ResourcesEnergy – the ability to do work

Fuel – a substance that can provide a form of energy from a chemical reaction (usually burning)

Fossil Fuels – energy rich substances formed from the remains of once living organisms

Nonrenewable resource takes millions of years to formCondensed hydrocarbons – contain stored energyCoal, Oil and Natural Gas

• Coal found in Reserves; mainly used to produce electricity• Oil is a thick, black, liquid fossil fuel; Also called petroleum

– Refinery – a plant that changes crude oil into useful products– Petrochemicals – compounds made from oil; plastics, paints,

medicines, cosmetics• Natural Gas – a mixture of methane and other gases trapped

underground– Large amount of energy, lower amount of air pollution– Highly flammable, dangerous if there is a leak; naturally odorles

but gas companies put in a “gas smell” for safety

Energy ResourcesSolar Energy – capturing and using energy from sunlight

Advantages: abundant supply that will not run out for billions of years; does not cause pollution; each day, enough energy reaches the Earth to supply the demands for 40 yearsDisadvantages: not a constant supply (varies at night and cloudy days); requires huge areas; expensive technologyUses:

• Uses solar energy to heat water produce electricity• Soar cells – solar energy converted directly to an electric current• Passive (no fans) and active (fans needed) heating systems

Wind EnergyAdvantages: no pollution; relatively cheapDisadvantages: need a steady supply of wind; lots of treadmills needed

Hydroelectric Power – using flowing water to turn turbinesAdvantage: no pollution; relatively cheap; steady supplyDisadvantage: Dams need to be created, damages existing ecosystems

Energy ResourcesTidal energy – energy from the rise and fall of ocean tides

Advantages – no pollution; steady supplyDisadvantage – not many places suitable for this type of energy

Biomass fuels – burning once living materials or products from living materials

Advantages: renewable resourceDisadvantage: expensive; still causes some air pollutionGasohol – gasoline + alcohol (ethanol)

Geothermal energy – getting energy from heated magma below the Earth’s suface

Advantages: constant supplyDisadvantage: need magma close to Earth’s surface to use it

Hydrogen Power – forming hydrogen gas and burning it for energy

Advantage: found in water; burns cleanlyDisadvantage: hard to form and collect

Energy ResourcesNuclear Energy – releasing the energy stored in the nuclei of atoms

Einstein theory of relativity – E = mc2• Matter can be changed into energy (very large amounts

of energy)• Nuclear fission – splitting an atom to release the energy

– Nuclear power and nuclear weapons– Chain reactions split uranium-235 which cause other U-235

atoms to split– Energy released is used to heat water produce electricity

Advantages: clean form of energy (no air pollution); cheaper than coal energyDisadvantages: produces radioactive wastes need a place to safely store these waste products for long periods of time (Yucca Mountains); public opinion threat of meltdowns

• Three Mile Island and Chernobyl

Energy ResourcesNuclear Power Plants

Reactor vessel – special chamber where fission reactions are performedFuel rods – rods of U-235Contol rods – metal (cadmium) rods used to slow reaction down to control how fast the energy is released

Nuclear Fusion – the next stepCombining two atoms to form one bigger atom

• 2 hydrogen atoms come together to form 1 helium atom

The sun uses this type of energyVery hard to perform on Earth

Energy ResourcesEnergy Conservation

Changing what individuals and companies do to help lower the amount of energy neededUse good conservation practices at home

• Turn out lights• Use more efficient light bulbs – use fluorescent bulbs

instead of incandescent lights• Car pool, public transportation, drive less, use cars with

higher gas mileage• Make sure your home is well insulated and use heat

and air conditioning units less• Recycle and used recycled goods

Although the actions of a single individual do not amount to much, if millions of people practice this the effects can be HUGE!