Human Impacts, Biodiversity, and Environmental Issues

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• Human Impacts, Biodiversity, and Environmental
  Issues

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Pollutants Impair Air Quality

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

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Figure 24.1
Halons (contain bromine, Br)
Chlorofluorocarbons (CFCs)
Ozone layer destruction
Nitrogen oxides (NxOx)
Carbon monoxide (CO)
Carbon dioxide (CO2 )
Sulfur dioxide (SO2 )
Hydrocarbons (HC)
Acid precipitation
Contributes to
Global warming
Methane (CH4 )
Air pollutant
Smog
Source
Vehicle exhaust
Fossil fuel burning
Paints
Deforestation
Farms
Refrigerants
Fire extinguishers
Plastic foam
Pesticides
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Excessive Greenhouse Gases Lead to Global Warming

• Greenhouse gases
• Trap heat from escaping the atmosphere
• Cause atmosphere to heat up
• Examples
• Water vapor
• Carbon dioxide (CO2)
• Methane (CH4)
• Nitrous oxide (N2O)
• Chlorofluorocarbons (CFCs)
• Halons

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Excessive Greenhouse Gases Lead to Global Warming

• Greenhouse effect
• Gases let sunlight through, but trap heat from
  radiating back outward into space
• Greenhouse effect responsible for
• Global warming
• Human activities have increased levels of CO2, a
  major greenhouse gas
• Deforestation
• Burning of fossil fuels

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Figure 24.2
Solarradiation
Radiated heat(reflected radiation)
Stratosphere
Clouds
Earth
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The Effects of Global Warming
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CFCs Deplete the Ozone Layer

• Ozone two different atmospheric locations
• Pollutant in troposphere (near Earths surface)
• Toxic, causes respiratory difficulties
• Protective shield in the stratosphere
• Shields the Earths surface from UV light
• Statospheric ozone layer
• Depleted by reaction with chlorofluorocarbons
  (CFCs)
• Concern about excess UV radiation exposure
• CFCs come from refrigerants, aerosol sprays
• CFC use has decreased due to international
  agreement

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Figure 24.3
Cl ? (2)O3
O3
O3
(3)O2
O3
O3
O3
Cl
O2
O2
Cl (chlorine)
Earth
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Figure 24.4
1979
1996
2011
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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 decreasing due to pollution
  abatement measures

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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 fossil fuels
• Thermal inversion atmospheric conditions that
  trap smog and prevent its dispersal
• Control air pollution abatement measures

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Figure 24.5
Pittsburgh at the height ofthe steelmaking era,
beforesmog cleanup efforts began.
Pittsburgh after programswere instituted to
reducesmog.
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Water Is Scarce and Unequally Distributed

• Distribution of Earths water
• Fresh water ?1
• Salt water 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

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Urbanization Increases Storm Water Runoff

• Combined sewage overflow (CSO) created
• Storm water 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

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Figure 24.6
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Human Activities Pollute Freshwater

• Organic pollutants
• From sewage and industry
• Inorganic pollutants
• Nitrates
• Phosphate fertilizers
• Sulfates from detergents
• May result in eutrophication
• Rapid growth of plant life leading to death of
  animal life in a shallow body of water resulting
  from excessive organic or inorganic nutrients

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Figure 24.7
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Human Activities Pollute Freshwater

• 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

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Figure 24.8
Shark ?1 ppm
Herring 0.05 ppm
Zooplankton 0.005 ppm
Bacteria 0.0005 ppm
Ocean 0.00003 ppm
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Groundwater Pollution May Impair Human Health

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

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Oil Pollution Damages Oceans and Shorelines

• Oil pollution sources
• 50 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

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Figure 24.9
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Pollution and Overuse Damage the Land

• 1/3 of Earths landmass has been altered by human
  activity
• 50 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

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Figure 24.10
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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

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Figure 24.11
A wind farm. Wind farms are increasingly being
used togenerate power in areas that have
sustained winds.
Photovoltaic solar panels. Photovoltaic panels
canprovide enough electricity to power a home.
A solar power plant. This power plant is in
Australia.
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Humans Are Creating a Biodiversity Crisis

• Biodiversity species richness, the assortment of
  living organisms on Earth
• Currently, scientists have identified 1.75
  million different species
• Estimates of 1030 million or more different
  species
• Biodiversity represents the variety of all forms
  of life

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Humans Alter and Destroy Habitats

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

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Figure 24.12
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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

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Biodiversity Is Healthy for Humans

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

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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 production of goods and
  services
• Social costs
• Quality of life

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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