20 Global Climate Change

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

Introduction to Climate Change Evidence for Climate Change 16 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) Warming is not due to natural causes Human produced greenhouse gases are most plausible explanation © 2012 John Wiley & Sons, Inc. All rights reserved.

Introduction to Climate Change: Mean Annual Global Temperature 1960–2010 © 2012 John Wiley & Sons, Inc. All rights reserved.

Greenhouse Gases Greenhouse gas concentrations are increasing © 2012 John Wiley & Sons, Inc. All rights reserved.

Causes of Climate Change Increased concentration of CO2 (right) Burning fossil fuels in cars, industry and homes Deforestation Burning of forests © 2012 John Wiley & Sons, Inc. All rights reserved.

Greenhouse Effect © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

Climate Models © 2012 John Wiley & Sons, Inc. All rights reserved.

Effects of Global Climate Change Wildfire in California © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

Melting Ice and Rising Sea Levels 1938 Insert Figure 20.6a Insert Figure 20.6b 1981 1998 Insert Figure 20.6c Insert Figure 20.6d 2005 Grinnell Glacier, Glacier National Park © 2012 John Wiley & Sons, Inc. All rights reserved.

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) © 2012 John Wiley & Sons, Inc. All rights reserved.

Effects of Global Climate Change- Changing Precipitation Patterns Some areas will get more water, some areas will have greater droughts © 2012 John Wiley & Sons, Inc. All rights reserved.

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 spas © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

Effect on Organisms - Vegetation © 2012 John Wiley & Sons, Inc. All rights reserved.

Effect on Organisms - Vegetation © 2012 John Wiley & Sons, Inc. All rights reserved.

Effects on Human Health Increased number of heat-related illnesses and deaths © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

International Implications of Climate Change Developed vs. Developing countries Differing self- interests Differing ability to meet the challenges of climate change © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

Relationship Between Mitigation and Adaptation © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

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 © 2012 John Wiley & Sons, Inc. All rights reserved.

International Efforts to Reduce Greenhouse Gas Emission Kyoto Protocol Legally binding Provides operational rules on reducing greenhouse gases By 2010, 183 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 US © 2012 John Wiley & Sons, Inc. All rights reserved.