Environment in the News
nayo0f033
chapter_9.pptGlobal Atmospheric Changes
Chapter 9
Case Study
Melting Ice and Rising Sea Levels
- Antarctic Ice pack has lost 40% of volume since 1980
- Muir Glacier, Alaska
- Compare photographs from 1903 to 2004
- Human-caused: increase in atmospheric CO2
from fossil fuel burning
- Challenges of global atmospheric changes:
- Climate change
- Ozone depletion
- Acid deposition
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The Atmosphere and Climate
- Learning Objectives:
Distinguish between Weather and Climate
Summarize the effects of solar energy on Earth’s temperature
Explain several reasons for regional precipitation differences
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The Atmosphere and Climate
- Weather
- Conditions in the atmosphere at a given place and time. Varies hour to hour, day to day.
- Temperature, atmospheric pressure, precipitation, cloudiness, humidity, wind.
- Climate
- Typical weather patterns that occur in a place over a period of years. Determined by:
- Temperature (average and seasonal variability)
- Precipitation (average and seasonal variability)
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The Atmosphere and Climate
- The Earth has many different climates
- Organisms adapted to specific climates
- Rapid changes to climates may lead to extinction and ecosystem degradation
The Atmosphere and Climate
- Solar Radiation and Climate
- Insolation = sunshine
- Major determinant of climate
- Makes life on Earth possible
- Liquid water
- Warm planet
- Photosynthesis
- Powers Earth’s biogeochemical cycles
- Drives winds and ocean currents
The Atmosphere and Climate
- Solar Radiation and Climate
- Temperature changes with Latitude and Season
- Based on the amount of sunlight received
The Atmosphere and Climate
- Precipitation: any form of water that falls from the atmosphere
- 3 factors determine precipitation:
- Amount of water in atmosphere
- Geographic location
- Topographic features
The Atmosphere and Climate
- What a Scientist Sees: Rain Shadow
How do you distinguish between weather and climate?
What are the two most important climate factors?
What are some of the environmental factors that produce areas of precipitation extremes, such as rain forests and deserts?
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Global Climate Change
- Learning Objectives:
List the five main greenhouse gasses and describe the enhanced greenhouse effect
Discuss some of the potential effects of global climate change
Give examples of strategies to mitigate or adapt to global climate change
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Global Climate Change
- Earth’s average temperature is increasing
- Based on daily measurements taken by:
- Meteorological stations, weather balloons, sea-surface buoys
- NOAA: global temperatures in1995 and 2001–2009 may have been highest in the last 1000 yrs
- Spring in Northern Hemisphere comes 6 days earlier than in 1959, Autumn comes 5 days later
- Increase in heat waves, heat-related deaths
- Sea levels rising, glaciers retreating, more severe hurricanes
Global Climate Change
- Scientific Consensus:
- Human activities are largely responsible for current climate change
- IPCC: United Nations Intergovernmental Panel on Climate Change Predicts
- 1.8 to 4.0 °C (3.2-7.2 °F) increase in global temperature by 2100
- Higher maximum temperatures
- More hot days, fewer cold days
- Increase in heat index
- Changes in precipitation patterns
Global Climate Change
- Causes:
- Increase of atmospheric gases due to human activities:
- Greenhouse gases:
- Carbon Dioxide (CO2)
- Nitrous Oxide (N20)
- Methane (CH4)
- Chlorofluorocarbons (CFCs)
- Ozone (O3)
- Water (H2O) - steady amount-does not increase due to human activity
Global Climate Change
- Aerosols tend to cool the atmosphere
- Reflect sunlight into space
- Cooling effect much weaker than enhanced greenhouse effect
- Human and natural causes of aerosols
- Sulfur emissions from fossil fuels
- Volcanic eruptions
Global Climate Change
- Effects:
- Sea-level rise
- Polar ice caps and continental glacier melts
- Warm water expands in volume
- Changes in precipitation patterns
- More droughts in some areas
- More flooding in some areas
- Fresh water availability
Global Climate Change
- Effects:
Impacts on agriculture
- Rising sea levels will flood deltas
- Pests will become more prevalent
- No irrigation water
- Productivity may increase in some areas
Global Climate Change
- Effects:
Impacts on human health
- Heat-related illnesses
- Disease-carrying mosquitoes will expand their range and transmit more malaria, Dengue fever, yellow fever
Global Climate Change
- Effects:
Impact on biodiversity and ecosystems
- Warmer oceans lead to decline in populations of krillsilverfishAdelie penguins
- Warmer temperatures makes frogs more susceptible to fungal diseases
- Polar seas, coral reefs, coastal wetlands, tundra
- Ocean acidification
- Coral bleaching
Environmental InSight
Environmental InSight
Global Climate Change
- Dealing with global climate change:
- Mitigation
- Moderation or postponement of effects by reducing greenhouse emissions
- Adaptation
- Response to changes caused by climate change
- Will require a combination of both
- Focus on CO2 reduction
Global Climate Change
- Mitigation
- Develop alternatives to fossil fuels
- Reduce energy use
- Increase energy efficiency
- Plant and maintain forests
- Carbon Management
- Trap CO2 from smokestacks
- Sequester CO2 into geological formations or depleted oil/gas wells
Global Climate Change
- Adaptation
- Move coastal settlements inland
- Construct sea walls on coastal areas
- Prevent saltwater intrusion
- Find substitute crops to grow on warming land
- Develop heat and drought resistant crops/trees
- City planning
- Sewer systems
- Storm runoff
Global Climate Change
What are greenhouse gasses?
What is the enhanced greenhouse effect? How does it affect global climate?
What are two examples of each of the approaches to global climate change:
mitigation and adaptation?
Ozone Depletion in the Stratosphere
- Learning Objectives:
Describe the importance of the stratospheric ozone layer
Explain how ozone thinning takes place and relate some of its harmful effects
Relate how the international community is working to protect the ozone layer
Ozone Depletion in the Stratosphere
- Ozone - O3
- Human-made pollutant in troposphere
- Natural component of stratosphere
- Ozone layer shields Earth’s surface from UV radiation
Ozone Depletion in the Stratosphere
- Ozone thinning
- Occurs naturally over Antarctica
- Has become worse due to human activity
- Ozone ‘hole’
- 70% reduction in O3 over Antarctica
- 10% reduction over Europe and N. America
- Noticeable reduction over Arctic
Ozone Depletion in the Stratosphere
Ozone Depletion in the Stratosphere
- Causes
- CFCs: Freon
- Coolants, aerosol propellants, Styrofoam
- Halons: fire retardant
- Methyl Bromide: pesticide
- Methyl Chloroform: industrial solvent
- Carbon Tetrachloride: industrial solvent
- Nitrous Oxides: coal burning waste and fertilizer breakdown
Ozone Depletion in the Stratosphere
Ozone Depletion in the Stratosphere
- Effects
- More UV reaches Earth’s surface
- Ecosystem disruption, e.g., Antarctic phytoplankton
- Damage to wildlife, e.g., Antarctic fish, amphibians
- Human health problems: cataracts, skin cancer, lowered immunity
- Mitigation and Recovery
- Worldwide bans and reductions in use
- 1978: US banned CFC use as propellants
- 1987: Montreal Protocol - 50% reduction by 1998
- CFCs phased out by 1996 in developed countries
- CFCs phased out by 2005 in developing countries
- CFCs are extremely stable and continue to deplete stratospheric ozone decades after decades
- Full recovery is expected sometime after 2050
Ozone Depletion in the Stratosphere
What is the stratospheric ozone layer?
How does the ozone layer protect life on Earth?
What is stratospheric ozone thinning?
What role do CFCs play in ozone thinning?
What are two harmful effects of ozone depletion?
EnviroDiscovery
- Attach link to video/animation if this becomes available
Acid Deposition
- Learning Objectives:
Define acid deposition and explain how acid deposition develops
Relate examples of the effects of acid deposition
Acid Deposition
- A type of air pollution
- Sulfuric and nitric acids in precipitation
- Dry acid particles that settle out of the air
- Observed since the Industrial Revolution
- Serious threat to the environment:
- In US alone, annual damage of $10 billion
- In China, acid deposition affects 40% of country
Acid Deposition
- How Acid Deposition Develops:
- Sulfur and Nitrogen oxides released by fossil fuel use
- Wind carries pollutants
- Pollutants react with water in atmosphere
- Forms acids (nitric and sulfuric)
- Acids are precipitated as rain, sleet, fog, snow or as dry particles
Acid Deposition
- Effects of Acid Deposition
- Decline in fish and bird populations
- Decline in forest ecosystems
- Damage to agriculture
- Damage to metals, building materials, statues
- Changes in soil chemistry
- Acidity
- Nutrient leaching
Acid Deposition
- Politics
- Sulfur and Nitrous oxides produced in one place are transported and deposited hundreds of km away.
- Midwestern states produce 50-75% of acid
deposition that pollutes New England and Canada
- Coal burning pollution from England is blown away to Sweden and Norway
- Who pays?
Acid Deposition
- Facilitating Recovery
- Reducing emissions of Sulfur and Nitrous Oxides reduces acid deposition
- Install scrubbers in smokestacks of coal-fired plants
- Use clean-coal technologies when burning coal
- Switch from high-sulfur to low-sulfur coal
- Reduce use of gasoline and diesel engines
What is acid deposition?
What are the main sources of atmospheric acid?
What are the harmful effects of acid deposition on materials, aquatic organisms, and soils?
Why does managing acid deposition often require international cooperation?
Case Study
- International Implications of Global Climate Change
- Social, economic, political factors
- Per capita emissions much higher in developed than developing countries,
- Population sizes tend to be larger in developing countries
- Emissions must be reduced, but vast disagreement because fossil fuels are seen as route to industrial development.
