Human Impacts, Biodiversity, and Environmental Issues Flashcards

Pollutants Impair Air Quality

• Major concerns regarding air pollution:
  • Global warming
  • Destruction of the ozone layer
  • Acid precipitation
  • Smog production

Air Pollutants and Their Sources

• Nitrogen oxides (NOx): Vehicle exhaust, fossil fuel burning; contribute to global warming, ozone layer destruction, acid precipitation, and smog.
• Hydrocarbons (HC): Vehicle exhaust, fossil fuel burning, paints; contribute to global warming and smog.
• Carbon monoxide (CO): Vehicle exhaust, fossil fuel burning; contributes to global warming and smog.
• Sulfur dioxide (SO2): Fossil fuel burning; contributes to acid precipitation and smog.
• Halons (contain bromine, Br): Fire extinguishers; contribute to ozone layer destruction.
• Methane (CH4): Deforestation, farms; contributes to global warming.
• Chlorofluorocarbons (CFCs): Refrigerants, aerosol sprays, plastic foam; contribute to global warming and ozone layer destruction.
• Carbon dioxide (CO2): Deforestation, fossil fuel burning; contributes to global warming.

Excessive Greenhouse Gases Lead to Global Warming

• Greenhouse gases trap heat and prevent it from escaping the atmosphere, causing the atmosphere to heat up.
• Examples:
  • Water vapor
  • Carbon dioxide (CO2)
  • Methane (CH4)
  • Nitrous oxide (N2O)
  • Chlorofluorocarbons (CFCs)
  • Halons

Greenhouse Effect

• Gases let sunlight through but trap heat from radiating back outward into space.
• Responsible for global warming.
• Human activities have increased levels of CO2, a major greenhouse gas, through deforestation and the burning of fossil fuels.

CFCs Deplete the Ozone Layer

• Ozone exists in two different atmospheric locations:
  • Pollutant in the troposphere (near Earth’s surface): Toxic, causes respiratory difficulties.
  • Protective shield in the stratosphere: Shields Earth’s surface from UV light.
• Stratospheric ozone layer is depleted by reaction with chlorofluorocarbons (CFCs).
• Concern about excess UV radiation exposure.
• CFCs come from refrigerants and aerosol sprays.
• CFC use has decreased due to international agreement.

Pollutants Produce Acid Precipitation

• Sulfur dioxide from high-sulfur coal and oil.
• Nitrogen oxides from car exhaust.
• Sulfur\ dioxide + nitrogen\ oxide + water\ vapor = sulfuric\ acid + nitric\ acid
• Acid precipitation damage includes:
  • Corrosion of metal and stone.
  • Disruption of forest and aquatic ecosystems.
• In North America, the northeastern United States and parts of Canada have been the most affected.
• Acid precipitation is decreasing due to pollution abatement measures.

Smog Blankets Industrial Areas

• Smoke + fog = smog.
• Components of smog include:
  • Nitrogen oxides
  • Hydrocarbons
  • Eye and respiratory irritants
  • Small oil droplets, wood particles, coal ash, asbestos, lead, animal waste, dust
• Major source: burning of fossil fuels.
• Thermal inversion: atmospheric conditions that trap smog and prevent its dispersal.
• Control: air pollution abatement measures.

Pollution Jeopardizes Scarce Water Supplies

• Human activities have three major detrimental effects on water quality and availability:
  • Humans use excessive water, depleting freshwater supplies.
  • Building roads/parking lots prevents rainwater from soaking in, causing runoff.
  • Human activities pollute water sources.

Water Is Scarce and Unequally Distributed

• Distribution of Earth’s water:
  • Freshwater: <1%
  • Saltwater: 97%
  • Glaciers/polar ice caps: 2%
• Industrialized countries use 10 to 100 times more water than less industrialized countries.
• Some desert and semiarid countries have reached carrying capacity with regard to water supplies.
• Diversion of water impacts other human populations and other species.

Urbanization Increases Storm Water Runoff

• Combined sewage overflow (CSO) created:
  • Stormwater combined with sewage.
• CSO overwhelms receiving streams and oceans.
• Human disease spread by CSO-carried pathogens:
  • Gastroenteritis
  • Ear and eye infections
  • Skin infections
  • Respiratory infections
• Leads to stream erosion.

Human Activities Pollute Freshwater

• Organic pollutants:
  • From sewage and industry.
• Inorganic pollutants:
  • Nitrates
  • Phosphate fertilizers
  • Sulfates from detergents
• May result in eutrophication: In a shallow body of water, rapid growth of plant life leads to the death of animal life, resulting from excessive organic or inorganic nutrients.

Human Activities Pollute Freshwater Further

• Toxic pollutants:
  • Polychlorinated biphenyls (PCBs)
  • Oil and gasoline
  • Pesticides
  • Herbicides
  • Heavy metals
• Biological magnification: the concentration of toxic pollutants is higher in the tissues of organisms higher on the food chain.
  • Example: accumulation of mercury in fish.

Groundwater Pollution May Impair Human Health

• Contaminates drinking water supplies.
• Very slow exchange of the groundwater pool: “cleans” slowly.
• Common contaminants:
  • Organics (e.g., carbon tetrachloride, pesticides, fertilizers [nitrates], radioactive waste)
• Suspected effects:
  • Miscarriages, skin rashes, nervous disorders, birth defects.

Oil Pollution and Garbage Are Damaging Oceans and Shorelines

• Oil pollution sources:
  • 50% natural seepage
  • 30% runoff from land
  • 20% accidents at sea
• 2010: This fraction will likely be larger due to the Deepwater Horizon explosion and "spill."
• Ultimate fate of oil released at sea:
  • 25% evaporates
  • 50% degraded by bacteria
  • 25% sediments
• Near shore: significant damage to shoreline ecosystems.

Garbage in Oceans

• Garbage, primarily plastics, degrades very slowly.
• Floating garbage ends up on shorelines or in big floating “rafts” in the open ocean.
• Example: Pacific Trash Vortex.

Pollution and Overuse Damage the Land

• One-third of Earth’s landmass has been altered by human activity.
• Fifty percent of forests have been removed.
• Migration to cities: footprint of cities expands, consuming productive land and increasing water runoff issues.
• Desertification: transformation of marginal land into near-desert conditions, unsuitable for future agriculture.
• Wars.
• Garbage disposal.

Energy: Many Options, Many Choices

• Nonrenewable resources: fossil fuels (coal, oil, gas)
• Renewable energy sources:
  • Nuclear energy: safety, disposal issues
  • Biomass fuels (biofuels): Use of plant materials for fuels; land use issues (food or fuel?)
  • Hydroelectric power
  • Wind farms
  • Geothermal energy
  • Solar power

Environmental Change and Loss of Biodiversity

• Biodiversity: species richness, the assortment of living organisms on Earth.
• Currently, scientists have identified 1.75 million different species.
• Estimates of 10–30 million or more different species.
• Biodiversity represents the variety of all forms of life.
• Human activities have reduced biodiversity worldwide.

Humans Alter and Destroy Habitats

• Pollution
• Overexploitation of natural resources
• Farming
• Overfishing
• Exploitation of scarce forest resources
• Logging
• Deforestation

Urbanization Is a Major Force for Environmental Change

• Worldwide shift to cities.
• Less plant and animal diversity.
• Worldwide, cities cause:
  • 78% of carbon emission
  • 60% of residential water usage
  • 76% of wood use for industry
• Ecological footprint much larger than city size.

Biodiversity Is Healthy for Humans, Too

• Plants (through photosynthesis) recycle carbon dioxide for oxygen.
• Plants: source of medicines.
• Food sources.
• Stability of ecosystems.

Toward Sustainable Development

• Sustainable development: development that meets the needs of the present without compromising the ability of future generations to meet their economic needs.

Measuring Sustainability and Quality of Life

• GDP (Gross Domestic Product):
  • Total market value of all goods and services produced within a country per year.
  • Standard indicator of economic progress.
• GPI (Genuine Progress Indicator):
  • Market value of goods and services PLUS
  • Environmental costs of the production of goods and services
  • Social costs
  • Quality of life

Strategies to Support Sustainable Development

• Consume less
• Recycle more
• Support sustainable agriculture
• Support green roofs
• Lower worldwide fertility rate
• Reduce rural world poverty
• Conserve energy at home
• Use environmentally preferable products
• Protect ecosystems that provide ecoservices