Global%20Change%20and%20a%20Sustainable%20Future

1
Global Change and a Sustainable Future

• Chapter 19

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Global Change

• Result of human activities
• a. placed increased demands on natural
  resources
• b. emitted greater amounts of gases (CO2, N,
  and
• S)
• c. agricultural methods
• - fertilizers and pesticides
• d. challenges of waste disposal, sanitation,
  and
• disease

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• Global Change
• a. changes that occur in the chemical,
  biological,
• and physical properties of the planet
• b. natural causes
• ex) Global temperatures
• c. anthropogenic
• ex) emissions from coal-burning power
  plants
• and incinerators (release of mercury)

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• Global Climate Change
• a. changes in global climate
• b. natural causes
• ex) El Nino
• - 3-7 years, alters patterns in
• temperatures and precipitation
• c. anthropogenic
• ex) fossil fuel combustion, deforestation
• ? Global Warming
• warming of the oceans,
  landmasses,
• and atmosphere

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The Sun-Earth Heating System
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Greenhouse Effect

• 2 most common gases in atmosphere
• a. N2 and O2
• b. not greenhouse gases
• Global Temperature
• a. with greenhouse gases (14C)
• b. without greenhouse gases (-18C)

Greenhouse Gas Global Warming Potential Duration in Atmosphere
H2O (water vapor) lt1 9 days
CO2 1 Highly variable
CH4 25 12 years
N2O (nitrous oxide) 300 114 years
CFCs (dont exist naturally) 1,600 to 13,000 55 to gt500 years
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Sources of Greenhouse Gases natural sources
Source Gas
Volcanic eruptions CO2, ash (absorbing sunlight)
Decomposition and digestion CH4 (wetlands, termites)
Denitrification N2O in low oxygen situations
Evaporation H2O (land)
Evapotranspiration H2O (plants)
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• Anthropogenic

Source Gas
Fossil Fuels CO2
Agricultural practices CH4 and N2O
Deforestation CO2
Landfills CH4
Industrial production of chemicals CFCs -phased out by Montreal Protocol - HCFCS introduced but still have high Greenhouse Warming Potential
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• Ranking of Anthropogenic Sources

Gas Top Sources
CH4 Digestive processes of livestock, landfills, production of natural gas and petroleum
N2O Soil receiving synthetic fertilizers, manure, nitrogen-fixing crops (alfalfa)
CO2 Burning of fossil fuels (94)
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Changes in CO2 and Global Temperatures

• Increasing CO2 Concentrations
• a. Charles David Keeling
• 1. Mauna Loa Observatory
• 2. CO2 levels vary seasonally and
  increase
• from year to year
• - seasonal (photosynthesis)
• - annual increase (fossil fuels and
• deforestation)

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• Developed v. Developing
• a. consumption of fossil fuel is greatest in
• developed (leads to greater production of
  CO2)
• b. Emitter of CO2
• 1. China
• 2. U.S.
• c. per capita of CO2
• 1. Australia
• 2. U.S.
• 3. Canada

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• Global Temperatures Since 1880
• a. 1880 2009
• - increase of 0.8C (1.4F)
• Global Temperatures the past 400,000 years
• a. indirect measurements used
• 1. species composition (foraminifera)
• 2. chemical analysis of ice
• b. rapid increase of CO2 in past 50 years
• c. CH4 and N2O in addition to CO2 rose
• dramatically (Industrial Revolution)

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Feedbacks Increasing or Decreasing Impact of
Climate Change

• Positive Feedback Loop
• a. intensifies change
• ex) rise in temperatures
• Negative Feedback Loop
• a. dampens change
• ex) plants response to increases in
• atmospheric carbon

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Consequences due to Global Warming
Impact of Global Warming Effect Global Warming has it
Polar Ice Caps Large openings in the ice Over next 70 years, Arctic warm by (4C-7C)
Glaciers Melting (lack of reliable water supply) Ex) Glacier National Park
Permafrost Melting Tundra and Boreal Forests Shrinks lakes, unstable surface for structures, release of CH4
Sea Levels Increase in total volume due to melting of glaciers and ice sheets, ocean becomes warmer and expands Potential flooding of low-lying land
Heat Waves Increased energy demand for cooling, risk of death, damage to crops, increases use of irrigation
Precipitation Patterns Warmer temperatures drive increased evaporation from Earths surface
Diseases Warmer temperatures allow for easier spread of disease geographically (ex-West Nile)
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Kyoto Protocol

• Control emissions of greenhouse gases
• Countries agreed to different levels of emission
  restrictions
• Grounded on precautionary principle
• - reducing emissions
• - removing CO2 from atmosphere
• carbon sequestration
• U.S. has not yet ratified the agreement