1. 20
Global Climate Change

2. Overview of Chapter 20 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. Reforestation in Ghana
Question is “how can we mitigate effects of climate change?”
Carbon Mitigation Initiative
Most dangerous consequences at doubling of pre-industrial levels
Certain steps in many areas can reduce effects
Increase fuel economy
Carbon capture and storage
Many more

4. Introduction to Climate Change: Mean Annual Global Temperature 1960–2010
20 warmest years (since ~1880) have occurred since 1990

5. Climate Change Terminology
Greenhouse Gas
Gas that absorbs infrared radiation
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

6. Climate Change Terminology
Greenhouse Effect
Natural trapping of heat in the atmosphere; greenhouse gases absorbs energy and keeps it from leaving
Radiative forcing
Capacity of a gas to affect the balance of energy that enters and leaves Earth’s atmosphere

7. Introduction to Climate Change
Evidence for Climate Change
20 warmest years since mid-1800s have occurred since 1990
Phenological spring in N. hemisphere now begins 6 days earlier (date the buds of specific plants open)
Sea level rise - <2cm/decade for most of 20th century, now ~3cm/decade
Warming is not due to natural causes
Human produced greenhouse gases are most plausible explanation

8. Greenhouse Gases
Greenhouse gas concentrations are increasing

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

10. Greenhouse Effect Enhanced greenhouse effect
Build up of greenhouse gases (CO2 and others) due to human activities

11. Pollutants That Cool the Atmosphere
Atmospheric Aerosols
Both human and natural sources
Tiny particles (or sulfur) that remain in troposphere for weeks or months
Sulfur-laden layer in the atmosphere reduces the amount of sunlight reaching earth
Complicates models of climate change
Aerosol effect
Atmospheric cooling that occurs where and when aerosol pollution is the greatest

12. Climate Models Climate affected by:
winds, clouds, ocean currents, and albedo
Albedo – measure of reflectivity (ice greater albedo than asphalt)
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

13. Climate Models

14. Climate Models Environmental feedbacks are complicated
Positive or negative feedbacks
More cloud production can result in a negative feedback
Most models project climate a few decades or a century from now
Based on different abatement strategies which will affect future CO2 concentration

15. Unpredictable and extreme climate change
We are projecting future climate with incomplete knowledge of environmental feedbacks
Using solid scientific understanding, however environmental complexities abound
Tipping points?
A large rapid change occurs
Examples
Ocean conveyor belt affected by melting of freshwater in Arctic
Polar vortex – cold air from poles move toward equator

16. Effects of Global Climate Change
Wildfire in California

17. Effects of Global Climate Change- Melting Ice and Rising Sea Levels
IPCC projects sea-level rise of18-59cm by 2100
Sea level rise caused in 2 ways
Thermal Expansion
Melting of land ice
Melting has positive feedback
Increased melting decreases ice, which decreases albedo leading to further warming

18. Grinnell Glacier, Glacier National Park
1938
1981
1998
2005

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

20. Effects of Global Climate Change- Changing Precipitation Patterns
Some areas will get more water, some areas will have greater droughts

21. Effects of Global Climate Change- Effects on Organisms
Zooplankton in parts of California Current have decreased by 80% since 1951
Affecting entire food chain
Species have shifted their geographic range
Migrating birds are returning to summer homes earlier
Ecosystems at greatest risk of species loss (short term):
coral reefs, mountain ecosystems, coastal wetlands, tundra, and polar areas

22. Effects on Organisms - Coral Reefs
Coral reefs can be bleached (right) due to increase in water temperature
Affects coral symbiontes and makes them more susceptible to diseases

23. Effect on Organisms - Vegetation

24. Effects on Human Health

25. 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)
Increase in drought frequency
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 will change

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

27. Dealing with Global Climate Change
Two ways to manage climate change
Mitigation: Limiting greenhouse gas emissions to moderate global climate change
Adaptation: Learning to live with environmental changes and societal consequences brought about by global climate change

28. Relationship Between Mitigation and Adaptation

29. Dealing with Global Climate Change - Mitigation
Locate/invent alternative fuels to fossil fuels
Increase efficiency of cars and trucks
Carbon Capture and Storage
Plant and maintain trees to naturally sequester carbon
Geoengineering
Global scale projects to mitigate effects
Example: seeding ocean with iron to stimulate phytoplankton growth and CO2 storage in deep ocean

30. 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
Climate change refugees
People having to leave homes because of climate change effects
Example: rising sea levels, storm surges

31. International Efforts to Reduce Greenhouse Gas Emission
Kyoto Protocol
Legally binding
Provides operational rules on reducing greenhouse gases
By 2014, 192 countries had ratified it
US has not sign it - it will be difficult to implement without US backing
EPA is taking it upon itself to define laws associated with CO2 reduction in U.S.
Obama administration meetings with other nations