1. Chapter 21 Global Climate Change

2. Overview of Chapter 21 Introduction to Climate Change
Causes of Global Climate Change
Effects of Climate Change
Melting Ice and Rising Sea Level
Changes in Precipitation Patterns
Effects on Organisms
Effects on Human Health
Effects on Agriculture
Dealing with Global Climate Change

3. Introduction to Climate Change- Mean Annual Global Temperature 1960-2005

4. Climate Change Terminology
Greenhouse Gas
Gas that absorbs infrared radiation
Ex: Carbon dioxide, methane, nitrous oxide, chlorofluorocarbons and tropospheric ozone
Positive Feedback
Change in some condition triggers a response that intensifies the changed condition
Infrared Radiation
Radiation that has a wavelength that is longer than that of visible light, but shorter than that of radio waves
Greenhouse Effect
Increase of heat in a system where energy enters (often as light), is absorbed as heat, and released sometime later

5. Introduction to Climate Change
Evidence for Climate Change
11 of the 12 years between 1995 and 2006 were among the twelve warmest years since the mid-1800s
Phenological spring in N. hemisphere now comes 6 days earlier
Warming is not due to natural causes (are we sure?)
Human produced greenhouse gases are most plausible explanation

6. Causes of Climate Change
Greenhouse gas concentrations increasing

7. Causes of Climate Change
Increased concentration of CO2 (right)
Burning fossil fuels in cars, industry and homes
Deforestation
Burning of forests

8. Greenhouse Effect

9. Other Pollutants Cool the Atmosphere
Atmospheric Aerosols tend to cool the atmosphere
Both human and natural sources
Tiny particles that remain in troposphere for weeks or months
Contain many chemicals, but often contain sulfur
Complicates models of climate change

10. Climate Models Climate affected by:
winds, clouds, ocean currents, and albedo
Used to explore past climate events
Advanced models can project future warming events
Models are only as good as the data and law used to program them
They have limitations

11. Climate Models

12. Effects of Global Climate Change
Ocean as CO2 sink - excess CO2 is starting to harm ocean life

13. Effects of Global Climate Change- Melting Ice and Rising Sea Levels
Sea level rise caused in 2 ways
Thermal Expansion
Water expands as it warms
Melting of land ice
Retreat of glacier and thinning of ice at the poles
Melting has positive feedback
Increased melting decreases ice, which decreases albedo leading to further warming

14. Melting Ice and Rising Sea Levels
1957
1998

15. Case-In-Point Impacts in Fragile Areas
Eskimo Inuit live traditional life dictated by freezing climate
Climate change is altering their existence
Wildlife are smaller or displaced
Reduced snow cover and shorter river ice seasons
Thawing of permafrost (right)

16. Effects of Global Climate Change- Changing Precipitation Patterns
Some areas will get more water, some areas will have greater droughts
Ex: Hurricanes will likely get stronger

17. Effects of Global Climate Change- Effects on Organisms
Zooplankton in parts of California Current have decreased by 80% since 1951
Effecting entire food chain
Decline in krill around Antarctica
Caused decrease in penguin populations
Species have shifted their geographic range
Migrating birds are returning to summer homes earlier
Food is not available at this time

18. Effects on Organisms - Coral Reefs
Coral reefs can be bleached (right) due to increase in water temperature
Affects coral symbiotes and makes them more susceptible to diseases to which they would otherwise be immune

19. Effect on Organisms - Vegetation Beech Tree Range

20. Effects on Human Health
Increased number of heat-related illnesses and deaths

21. Effects on Agriculture
Difficult to anticipate
Productivity will increase in some areas and decrease in others
Rise in sea level will inundate flood plains and river valleys (lush farmland)
Effect on pests is unknown
Warmer temperatures will decrease soil moisture- requiring more irrigation
Location (i.e. elevation and altitude) where certain crops can be grown may have to change

22. International Implications of Climate Change
Developed vs. Developing countries
Differing self-interests
Differing ability to meet the challenges of climate change

23. Dealing with Global Climate Change
To avoid the worst of climate change, CO2 levels must be stabilized at 550ppm
50% higher than current levels
Two ways to attempt to manage climate change
Mitigation
Focuses on limiting greenhouse gas emissions to moderate global climate change
Adaptation
Focuses on learning to live with to the environmental changes and societal consequences brought about by global climate change

24. Dealing with Global Climate Change- Relationship Between Mitigation and Adaptation

25. Dealing with Global Climate Change- Mitigation
Locate/invent alternative fuels to fossil fuels
Increase efficiency of cars and trucks
Sequestering carbon before it is emitted
Plant and maintain trees to naturally sequester carbon

26. Dealing with Global Climate Change- Adaptation
Rising sea levels and coastal populations
Move inland
Construct dikes and levees
Adapt to shifting agricultural zones
NYC sewer line

27. International Efforts to Reduce Greenhouse Gas Emission
Kyoto Protocol
Legally binding
Provides operational rules on reducing greenhouse gases
US and Australia have not signed it- it will be difficult to implement without US backing