Global Climate Change

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