Chapter 21 Global Climate Change

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

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  Greenhouse Effect  Increase of heat in a system where energy enters (often as light), is absorbed as heat, and released sometime later

Introduction to Climate Change  Evidence for Climate Change  14 warmest years since mid-1800s have occurred since 1990  Phenological spring in N. hemisphere now begins 6 days earlier  Warming is not due to natural causes  Human produced greenhouse gases are most plausible explanation

Introduction to Climate Change: Mean Annual Global Temperature 1960–2007

Causes of Climate Change  Greenhouse gas concentrations increasing

Causes of Climate Change  Increased concentration of CO 2 (right)  Burning fossil fuels in cars, industry and homes  Deforestation  Burning of forests

Greenhouse Effect

Pollutants That Cool the Atmosphere  Atmospheric Aerosols  Both human and natural sources  Tiny particles that remain in troposphere for weeks or months  Often contain sulfur  Complicates models of climate change

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

Climate Models

Effects of Global Climate Change  Wildfire in California

Effects of Global Climate Change: Melting Ice and Rising Sea Levels  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

Glacier National Park Melting Ice and Rising Sea Levels

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)

Effects of Global Climate Change: Changing Precipitation Patterns  Some areas will get more water, some areas will have greater droughts

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  Species have shifted their geographic range  Migrating birds are returning to summer homes earlier

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

Effect on Organisms: Vegetation

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

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

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

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

Relationship Between Mitigation and Adaptation

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

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

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