Transcript ch20 - Napa Valley College

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


Positive Feedback


Change in some condition triggers a response that
intensifies the changed condition
Infrared Radiation


Gas that absorbs 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
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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
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Effects of Global Climate Change

Wildfire in California
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Effects of Global Climate ChangeMelting 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
20.6c
1981
1998
Insert Figure
20.6b
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 ChangeChanging Precipitation Patterns

Some areas will get more water, some areas
will have greater droughts
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Effects of Global Climate ChangeEffects 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
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Effect on Organisms - Vegetation
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Effects on Human Health

Increased number of
heat-related
illnesses and deaths
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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
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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.