Chapter 21Global 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 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 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

1957

1998

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

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