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
Melting Ice and Rising Sea Levels 1957 1998 Glacier National Park
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
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 moisturerequiring 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 selfinterests 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