Transcript Ch 6 PPT - Blountstown Middle School

Chapter Introduction
Lesson 1
Climates of
Earth
Lesson 2
Climate Cycles
Lesson 3
Recent Climate
Change
Chapter Wrap-Up
What is climate and
how does it impact
life on Earth?
What do you think?
Before you begin, decide if you agree or
disagree with each of these statements.
As you view this presentation, see if you
change your mind about any of the
statements.
Do you agree or disagree?
1. Locations at the center of large
continents usually have the same
climate as locations along the coast.
2. Latitude does not affect climate.
3. Climate on Earth today is the same
as it has been in the past.
Do you agree or disagree?
4. Climate change occurs in short-term
cycles.
5. Human activities can impact climate.
6. You can help reduce the amount of
greenhouse gases released into the
atmosphere.
Climates of Earth
• What is climate?
• Why is one climate different from
another?
• How are climates classified?
Climates of Earth
• climate
• rain shadow
• specific heat
• microclimate
What is climate?
• Climate is the long-term average
weather conditions that occur in a
particular region.
• A region’s climate depends on average
temperature and precipitation, as well as
how these variables change throughout
the year.
What is climate? (cont.)
What is climate?
What affects climate?
The latitude of a location affects climate.
What affects climate? (cont.)
• The amount of solar energy per unit
of Earth’s surface area depends on
latitude.
• Earth’s curved surface causes latitudes
closer to the equator to receive more
direct sunlight than latitudes farther
north or south.
What affects climate? (cont.)
Latitudes near the poles receive less
solar energy and have lower average
temperatures.
What affects climate? (cont.)
Latitudes near the equator tend to have
warmer climates than higher latitudes.
• Climate is influenced by altitude.
• Temperature decreases as altitude
increases in the troposphere.
What affects climate? (cont.)
Mountains influence climate because
they are barriers to prevailing winds.
What affects climate? (cont.)
An area of low rainfall on the downwind
slope of a mountain is called a rain
shadow.
What affects climate? (cont.)
• The high specific heat of water causes
the climates along coastlines to remain
somewhat constant.
• Specific heat is the amount of thermal
energy needed to raise the temperature
of 1 kg of a material by 1°C.
• Prevailing winds extend the moderate
temperatures farther inland.
What affects climate? (cont.)
• Ocean currents modify climate.
• The Gulf Stream is a warm, northward
current along the east coast of North
America.
• The Gulf Stream brings warmer
temperatures to portions of the United
States and Europe.
Classifying Climates
Climates are classified into five types
based on their temperature, precipitation,
and native vegetation.
Classifying Climates (cont.)
How are climates classified?
Classifying Climates (cont.)
• A city’s roads and buildings absorb solar
radiation.
• Cities are often warmer than the
surrounding
area.
• This urban
heat island is
one form of
microclimate.
Classifying Climates (cont.)
A microclimate is a localized climate
that is different from the climate of the
larger area surrounding it.
microclimate
from Greek mikros, means
“small”; and klima, means “region,
zone”
Classifying Climates (cont.)
Why is one climate different
from another?
How Climate Affects Living
Organisms
• Climate influences how humans
determine the crops they grow.
• Climate influences how humans design
buildings.
Animals and plants
have adapted to the
climates in which
they live.
CORBIS
Ingram Publishing/SuperStock
• Climate is influenced by several factors
including latitude, altitude, and an
area’s location relative to a large body
of water or mountains.
• Rain shadows
occur on the
downwind slope
of mountains.
• Microclimates can occur in urban
areas, forests, and hilltops.
Climate is the long-term average
weather conditions that occur
where?
A. around the globe
B. locally
C. in a particular region
D. in the troposphere
An area of low rainfall on the
downwind slope of a mountain is
called what?
A. climate
B. the Gulf Stream
C. a microclimate
D. a rain shadow
Which of these describes a
coastline climate compared
to a continental climate?
A. cooler
B. more constant
C. more erratic
D. warmer
Do you agree or disagree?
1. Locations at the center of large
continents usually have the same
climate as locations along the coast.
2. Latitude does not affect climate.
Climate Cycles
• How has climate varied over time?
• What causes seasons?
• How does the ocean affect climate?
Climate Cycles
• ice age
• interglacial
• El Niño/Southern Oscillation
• monsoon
• drought
Long-Term Cycles
Much of our knowledge about past climates
comes from natural records of climate.
• ice cores from glaciers and ice sheets
• fossilized pollen
• ocean sediments
• growth rings of trees
Long-Term Cycles (cont.)
• Ice ages are cold periods lasting from
hundreds to millions of years when
glaciers cover much of Earth.
• Glaciers and ice sheets advance
during cold periods and retreat during
interglacials—the warm periods that
occur during ice ages.
Long-Term Cycles (cont.)
interglacial
from Latin inter–, means “among,
between”; and glacialis, means
“icy, frozen”
Long-Term Cycles (cont.)
• The most recent ice age began about 2
million years ago.
• At that time, about half the northern
hemisphere was covered by ice.
• About 10,000 years ago, Earth entered
its current interglacial period, called the
Holocene Epoch.
Long-Term Cycles (cont.)
• Earth’s orbit varies between elliptical and
circular about every 100,000 years.
• As Earth’s orbit changes shape, Earth’s
climates change.
Long-Term Cycles (cont.)
When Earth’s orbit is more circular, Earth
averages a greater distance from the Sun,
resulting in below-average temperatures
on Earth.
Long-Term Cycles (cont.)
• Changes in the angle of Earth’s tilt
affect the range of temperatures
throughout the year.
• The tilt of Earth’s axis
changes in
41,000-year cycles.
Long-Term Cycles (cont.)
Movement of Earth’s continents and
changes in ocean circulation influence
long-term climate cycles.
Long-Term Cycles (cont.)
How has climate varied over
time?
Short-Term Cycles
In addition to long-term climate cycles,
climate also changes in short-term cycles.
Short-Term Cycles (cont.)
The changing seasons is an example of
short-term climate change.
Changes in the amount of solar energy
received at different latitudes during
different times of the year give rise the
seasons.
When the northern hemisphere is tilted
toward the Sun, there are more daylight
hours than dark hours, the temperatures
are warmer, and it is summer.
When the northern hemisphere is tilted
away from the Sun, daylight hours are
fewer than nighttime hours, temperatures
are colder, and it is winter.
Short-Term Cycles (cont.)
What causes seasons?
Short-Term Cycles (cont.)
The seasons change as Earth makes a
revolution around the Sun.
revolution
Science Use the action by a
celestial body of going around in
an orbit or an elliptical course
Common Use a sudden, radical,
or complete change
In the northern hemisphere, summer
begins when the northern hemisphere is
tilted toward the Sun.
In the northern hemisphere, fall begins
when the neither hemisphere is tilted
toward the Sun.
In the northern hemisphere, winter
begins when the northern hemisphere
is tilted away from the Sun.
In the northern hemisphere, spring
begins when, once again, neither
hemisphere is tilted toward the Sun.
The El Niño/Southern Oscillation
(ENSO) causes another type of shortterm climate change.
During ENSO, the trade winds weaken
and warm water surges back toward
South America.
Short-Term Cycles (cont.)
A complete ENSO cycle occurs every three
to eight years, with the following effects:
• lots of precipitation along the western
coast of South America
• droughts in normally wet regions
• increased number of violent storms in
California and southern U.S.
Short-Term Cycles (cont.)
• The North Atlantic Oscillation (NAO) is
another cycle that can change the
climate for decades at a time.
• The NAO affects the strengths of
storms throughout North America and
Europe by changing the position of the
jet stream.
Short-Term Cycles (cont.)
• A third short-term climate
change is a monsoon.
• A monsoon is a
seasonal change in wind
direction caused by
changing temperatures
over the ocean and land.
Short-Term Cycles (cont.)
How does the ocean affect
climate?
Other Short-term Climate Changes
• A drought is a period with belowaverage precipitation that can lead to
crop damage and water shortages.
• Droughts are often accompanied by
heat waves—periods of unusually high
temperatures.
Other Short-term Climate Changes
(cont.)
• Droughts and heat waves occur when
large hot-air masses remain in one
place for weeks or months.
• A cold wave occurs when a large polar
air mass stays over a region for days
or weeks.
• Scientists learn about past climates
by studying natural records of
climate, such as ice cores, fossilized
pollen, and growth rings of trees.
• Long-term climate changes, such as
ice ages and interglacials,
can be caused by
changes in the shape
of Earth’s orbit and
the tilt of its axis.
• Short-term climate changes include
seasons, El Niño/Southern
Oscillation, and monsoons.
Glaciers and ice sheets retreat
during which of these?
A. glacial periods
B. ice ages
C. interglacials
D. winter
The tilt of Earth’s axis changes in
cycles that last how long?
A. 10 years
B. 400 years
C. 41,000 years
D. 4,000,000 years
Which marks the beginnings of
winter and summer?
A. solstices
B. seasons
C. equinoxes
D. atmospheric cycles
Do you agree or disagree?
3. Climate on Earth today is the same as
it has been in the past.
4. Climate change occurs in short-term
cycles.
Recent Climate Change
• How can human activities affect
climate?
• How are predictions for future climate
change made?
Recent Climate Change
• global warming
• greenhouse gas
• deforestation
• global climate model
Regional and Global Climate Change
Average temperatures on Earth have
been increasing for the past 100 years.
Regional and Global Climate Change
(cont.)
Temperature change has not been
steady throughout the past 100 years.
Human Impact on Climate Change
• The rise in Earth’s average temperature
during the past 100 years is often referred
to as global warming.
• In 2007, the Intergovernmental Panel on
Climate Change (IPCC) concluded that
most of this temperature increase, or
global warming, is due to human
activities.
Human Impact on Climate Change
(cont.)
• These activities include burning fossil
fuels and the large-scale cutting and
burning of forests, which release
greenhouse gases into the
atmosphere.
• Gases in the atmosphere that absorb
Earth’s outgoing infrared radiation are
greenhouse gases.
Human Impact on Climate Change
(cont.)
Greenhouse gases help keep
temperatures on Earth warm enough for
living things to survive—a phenomenon
called the greenhouse effect.
Human Impact on Climate Change
(cont.)
Recently, global temperatures and
carbon dioxide, CO2, concentration in
the atmosphere have both increased.
Human Impact on Climate Change
(cont.)
• Higher levels of greenhouse gases,
like CO2, create a greater greenhouse
effect.
• Most scientists suggest that global
warming is due to the greater
greenhouse effect.
• Humans use deforestation to obtain
fuel or clear farm land.
Human Impact on Climate Change
(cont.)
Deforestation is the large-scale cutting
and/or burning of forests.
deforestation
from Latin de–, means “down
from, concerning”; and forestum
silvam, means “the outside
woods”
Human Impact on Climate Change
(cont.)
• Deforestation affects global climate
because there are fewer living trees to
help remove CO2 from the air.
• The burning of cut trees also adds more
CO2 to the atmosphere.
• Natural sources of CO2 include volcanic
eruptions and forest fires.
• Cellular respiration in organisms
contributes additional CO2.
Human Impact on Climate Change
(cont.)
• The burning of fossil fuels also
releases tiny liquid or solid particles
into the atmosphere called aerosols.
• Most aerosols reflect sunlight back into
space, preventing some of the Sun’s
energy from reaching Earth and
potentially cooling the climate over
time.
Human Impact on Climate Change
(cont.)
When clouds form in areas with large
amounts of aerosols, the cloud droplets
are smaller and
reflect more
sunlight than clouds
with larger droplets.
Human Impact on Climate Change
(cont.)
How can human activities
affect climate?
Climate and Society
• Increasing temperatures can impact
the environment in many ways.
• Melting glaciers and polar ice sheets
can cause sea levels to rise and
coastal ecosystems to be disrupted.
Climate and Society (cont.)
• Extreme weather events can become
more common.
• Permanently higher temperatures and
other ecosystem changes can affect
migration patterns of insects, birds,
fish, and mammals.
Predicting Climate Change
• Climate forecasts help governments
decide how to respond to future climate
changes.
• A global climate model (GCM) is
a set of complex equations used to
predict future climates.
• GCMs use math and science to predict
future climate changes.
Predicting Climate Change (cont.)
• Summer arctic sea ice is expected to
disappear by the end of this century.
• Sea levels are expected to keep rising
for several centuries.
Predicting Climate Change (cont.)
How are predictions for future
climate change made?
Predicting Climate Change (cont.)
Increasing
populations can
affect climate
change.
Predicting Climate Change (cont.)
• It is predicted that by the year 2030,
two of every three people on Earth will
live in urban areas.
• Large areas of forests are being
cleared for expanding cities.
• Significant amounts of greenhouse
gases and other pollutants will be
added to the atmosphere.
Predicting Climate Change (cont.)
There are ways to reduce pollution and
greenhouse gases.
• developing alternative energy sources,
such as solar and wind energy
• building energy-efficient buildings
• controlling greenhouse gases and
pollution by conserving fuel and
recycling
• Many scientists suggest that global
warming is due to increased levels of
greenhouse gases in the atmosphere.
• Human activities such as deforestation
and burning fossil fuels, can contribute
to global warming.
• Ways to reduce
greenhouse gas
emissions include
using solar and
wind energy and
creating energyefficient buildings.
The burning of fossil fuels releases
tiny liquid or solid particles into the
atmosphere called what?
A. aerosols
B. carbon dioxide
C. greenhouse gases
D. vapor
What term refers to the set of
complex equations used to
predict future climates?
A. global climate model
B. meteorological measurement
C. supercomputer
D. weather report
Deforestation can lead to more of
which of these in the atmosphere?
A. oxygen
B. GCMs
C. fossil fuels
D. carbon dioxide
Do you agree or disagree?
5. Human activities can impact climate.
6. You can help reduce the amount of
greenhouse gases released into the
atmosphere.
Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice
Climate is the longterm average weather
conditions that occur
in an area. It is
influenced by the
interactions between
Earth’s systems.
Living things have
adaptations to the
climate in which they
live.
Lesson 1: Climates of Earth
• Climate is the long-term average weather conditions
that occur in a particular region.
• Climate is affected by factors such as latitude,
altitude, rain shadows on the downwind slope of
mountains, vegetation, and the specific heat of
water.
• Climate is classified based
on precipitation, temperature,
and native vegetation.
Lesson 2: Climate Cycles
• Over the past 4.6 billion years, climate on Earth has
varied between ice ages and warm periods.
Interglacials marked warm periods on Earth during
ice ages.
• Earth’s axis is tilted. This
causes seasons as Earth
revolves around the Sun.
• The El Niño/Southern
Oscillation and monsoons
are two climate patterns
that result from interactions
between oceans and the
atmosphere.
Lesson 3: Recent Climate Change
• Releasing carbon dioxide and aerosols into the
atmosphere through burning fossil fuels and
deforestation are two ways humans can affect
climate change.
• Predictions about future climate change are made
using computers and general circulation models.
What term describes a localized
climate that is different from the
climate of the larger area
surrounding it?
A. weather system
B. rain shadow
C. microclimate
D. Gulf stream
In the troposphere, temperature
decreases as altitude does what?
A. changes
B. decreases
C. increases
D. stabilizes
Which occurs in the northern
hemisphere when it is tilted toward
the Sun?
A. fall equinox
B. spring equinox
C. summer solstice
D. winter solstice
Gases in the atmosphere that
absorb Earth’s outgoing infrared
radiation are called what?
A. aerosols
B. clouds
C. fossil fuels
D. greenhouse gases
Which helps governments decide
how to respond to future climate
changes?
A. weather reports
B. greenhouse effects
C. climate forecasts
D. climate cycles
Which refers to the long-term
average weather conditions that
occur in a particular region?
A. weather
B. specific weather
C. rain shadow
D. climate
Which refers to the amount of
thermal energy needed to raise
the temperature of 1 kg of a
material by 1°C?
A. boiling point
B. climate
C. melting point
D. specific heat
A wind circulation pattern that
changes direction with the
seasons is called what?
A. drought
B. heat wave
C. jet stream
D. monsoon
Which occurs when a large
continental polar air mass stays
over a region for days or weeks?
A. cold waves
B. droughts
C. heat waves
D. monsoons
What refers to the rise in Earth’s
average surface temperature
during the past 100 years?
A. greenhouse effect
B. global warming
C. global cooling
D. deforestation