File envsci11_c16_pr1

Global Climate Change
Rising Seas May Flood the
Maldive Islands
• Sea levels are rising worldwide.
• Scientists link this to global climate change.
• Global climate change threatens the Maldives, a group of
islands in the Indian Ocean, with flooding, severe storms,
erosion, and saltwater contamination.
Talk About It Why are rising sea levels a concern for all
people, not just those who live on the Maldives Islands?
Lesson 16.1 Our Dynamic Climate
Without greenhouse gases, Earth
would be too cold to support life.
Lesson 16.1 Our Dynamic Climate
The Greenhouse Effect
• A natural process in
which greenhouse
gases absorb heat and
release it slowly back
into the atmosphere
• Greenhouse gases do
not trap energy that has
been converted to heat
at Earth’s surface.
Did You Know? Greenhouse gases
absorb heat and release it slowly,
while an actual greenhouse traps
warm air inside a structure.
Lesson 16.1 Our Dynamic Climate
The Effect of Latitude
• Latitude is a measure of
a place’s distance from
the equator.
• In general, the greater
the latitude, the cooler a
location’s overall climate
will be.
• The seasons are also
caused by the changing
angles at which sunlight
strikes Earth.
Lesson 16.1 Our Dynamic Climate
• Caused by convection currents
resulting from rising warm
air and falling cool air
• Transports moisture
and heat
• Global wind patterns
move warm air away
from equator, toward
• Cold air moves from
poles toward equator.
• Winds pick up moisture and
can carry it for long distances
until it falls as precipitation.
Lesson 16.1 Our Dynamic Climate
The Oceans and Climate
• Ocean currents, which are
caused by a combination of
unequal heating of water and
unequal salinity, affect climate
by transporting heat.
• El Niño and La Niña are
disruptions to normal climate
patterns caused by variations
in the typical interactions
between the ocean and the
Did You Know? The ocean absorbs a lot of
carbon dioxide, causing a global cooling effect.
The ocean can hold 50 times more CO2 than is
found in the atmosphere.
Lesson 16.1 Our Dynamic Climate
Other Factors That Affect Climate
• Topography: Higher altitudes have
cooler temperatures; mountain ranges
affect rainfall patterns.
• Volcanoes: Gases and particles can
temporarily block sunlight, causing air
to cool.
• Vegetation: Plant life promotes cloud
formation and absorbs carbon dioxide.
• Earth’s orbit: Changes in Earth’s
orbit and the tilt of Earth’s axis affect
the distribution of solar radiation.
Did You Know? Ice ages are at least partially
caused by changes in Earth’s orbit and axis.
Mount St. Helens
Lesson 16.2 Climate Change
According to NASA’s Goddard Institute
for Space Studies, 2009 tied for second
warmest year on record, just behind
2005. The decade spanning 2000–2009
was the warmest on record.
Lesson 16.2 Climate Change
Evidence of a Warming Earth
• Rising global surface temperatures
• Changes in precipitation patterns
• Melting ice (glaciers, polar ice)
• Rising sea level
Both photos show
Sperry Glacier in
Montana’s Glacier
National Park.
Top: 1913:
Bottom: 2008
Did You Know? Since 1986, the
Larsen Ice Shelf near Antarctica
has lost an area more than
3 times the size of Rhode Island.
Lesson 16.2 Climate Change
Studying Climate Change
• Direct measurement is used to
study today’s climate.
• Proxy indicators, such as
patterns in tree rings, give clues
about past climates.
• Models are used to make
predictions about future
Cross-section of a tree trunk
Lesson 16.2 Climate Change
Finding the Cause of
Climate Change
• According to studies, increases in greenhouse gases are the
primary cause of climate change.
• The increase in greenhouse
gases is mainly due to
burning of fossil fuels and
changes in land use.
Lesson 16.3 Effects of Climate Change
In 2003, a severe
heat wave in
Europe killed
35,000 people.
Lesson 16.3 Effects of Climate Change
Effects on Organisms
• Habitats shift, usually toward
the poles or to higher
• Migrations start earlier in
the spring.
• Loss of ice makes hunting
seals difficult for polar bears.
Migrating sandhill cranes
Did You Know? Robins arrive on a
Colorado mountaintop about 2 weeks
earlier than they did in 1970.
Lesson 16.3 Effects of Climate Change
Effects of a Changing Ocean
• An increase in ocean
temperature is associated
with a process called coral
bleaching, in which algae
living within corals die.
Without the algae, coral
cannot survive.
• Changes in ocean acidity,
resulting from an increase
in dissolved carbon dioxide,
can harm organisms.
The color of healthy brain coral comes from algae.
When the algae die, coral bleaching occurs.
Lesson 16.3 Effects of Climate Change
Current Effects of Global
Climate Change
• Agriculture and forestry: Effects are complex.
• Can be positive: Lengthened growing season for some crops
• Can be negative: Droughts and forest fires
• Economy: Decreased yields;
increased property damage
due to severe storms and
climate conditions
• Human health: Extreme
heat waves increasingly
common, can cause
heat stroke and death
Damage caused by Hurricane Katrina, in 2005
Lesson 16.3 Effects of Climate Change
Future Effects of Climate Change
• Diseases: Warmer temperatures can
promote spread of diseases transmitted
from animals to people.
• Sea level: Low-lying populated coastal
areas may flood as sea levels rise.
• Water supply: Saltwater contamination
of aquifers resulting from rising sea levels
and a decrease in glacial ice may
threaten freshwater supplies.
Did You Know? In the United
States, 53% of the population
lives in coastal areas.
Black-legged ticks, known
to spread Lyme disease
Lesson 16.4 Responding to Climate Change
Fossil fuel combustion generates
70% of the electricity used in the
United States.
Energy conserving light bulbs
Lesson 16.4 Responding to Climate Change
Use and Production of Electricity
• Carbon footprint: The amount of
carbon dioxide for which an individual
or group is responsible
• Most electricity is generated by
burning fossil fuels.
• Reducing electricity use reduces
carbon footprints.
• Ways to reduce electricity use:
• Use energy-efficient technologies,
which lessen the electricity needed to
do a job.
• Reduce the use of electrical devices
and appliances.
Lesson 16.4 Responding to Climate Change
Alternate Sources of Electricity
• Alternative Sources of Electricity
• Nuclear power
• Solar power
• Wind power
• Hydroelectric power
• Geothermal power
Wind turbines
Lesson 16.4 Responding to Climate Change
Advances in Vehicle Technology
• Transportation is the second largest source of greenhouse
gas emissions in the United States, second only to electricity.
• Alternatives to fuel-only
cars include:
• Gasoline-electric
hybrid vehicles
• Vehicles that use
alternative fuels such as
compressed natural gas
• Vehicles that use
hydrogen fuel cells.
Energy Loss in a Car
Lesson 16.4 Responding to Climate Change
Reducing Dependence on Cars
• Biking, walking, and using public transportation are all
ways to reduce fossil fuel use.
• Many communities lack good
public transportation.
Did You Know? The average
American family makes 10 trips by car
each day.
Lesson 16.4 Responding to Climate Change
Strategies for Reducing
Greenhouse Gases
• Agriculture / forestry: Reduce soil erosion
and replace cut trees, to curb CO2 emissions
• Cap-and-Trade: System of emission
allowances that can be sold or traded, gives
companies incentive to reduce emissions
• Carbon tax: A tax per unit on emissions
• Carbon offsets: Instead of directly reducing
emissions, companies can make a voluntary
payment to a group that reduces or curbs
greenhouse gases.
• Carbon sequestration: Technology is used to
trap and store carbon dioxide emissions.
Lesson 16.4 Responding to Climate Change
Cooperation Among Nations
• The Kyoto Protocol is a binding
international effort to reduce
greenhouse gases to below
1990 levels.
• The United States did not
sign the Kyoto Protocol.
• Many nations are planning to
develop a new binding
agreement to address global
climate change some time in
the future.

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