20 global climate change. overview of chapter 20 introduction to climate change causes of global...

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


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


Introduction to Climate Change: Mean Annual Global Temperature 1960–2010


Greenhouse Gases

Greenhouse gas concentrations are increasing


Causes of Climate Change

Increased concentration of CO2 (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 (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


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

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


Melting Ice and Rising Sea Levels


1938

1998

Grinnell Glacier, Glacier National Park

1981

2005

Insert Figure 20.6a

Insert Figure 20.6b

Insert Figure 20.6c

Insert Figure 20.6d

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 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


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 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


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