Download climate change?

WHAT CAUSES
CLIMATE CHANGE?
Earth’s climate is a balance between how
much energy is received from the Sun and
how much energy leaves Earth. Climate
change happens any time the balance is
altered.
NATURAL CAUSES OF
CLIMATE CHANGE
Sometimes Earth receives more energy
from the Sun than usual. The Sun has
active periods during which it gives off
more energy than at other times. There is
evidence that these periods, which occur
in cycles of about 11 years, correspond to
warming trends on Earth.
The tilt of Earth’s axis also changes the
amount of energy received from the Sun.
The tilt of Earth’s axis ranges from 22° to 25°
in a 41 000-year cycle. The differences in tilt
could change climate conditions. Locations
tilted closer to the Sun will warm. Locations
tilted farther from the Sun will cool.
Volcanic eruptions can throw huge
amounts of dust and ash high into the
atmosphere (Figure 2.22). This dust and ash
can remain there for months or even years.
This material reflects solar energy back into
space, reducing the amount of heat entering
Earth’s climate system.
FIGURE 2.22 Mount Pinatubo
in the Philippines erupted in
1991. The ash cloud was so
large that it lowered the global
average temperature for a
period of one to three years.
I wonder what other effects
this volcanic eruption caused?
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UNIT 1: Physical Patterns in a Changing World
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THE GREENHOUSE EFFECT
Natural events such as volcanic eruptions release huge amounts of
greenhouse gases into the atmosphere. Greenhouse gases are gases that
absorb energy from the Sun. Greenhouse gases include CO2, methane,
and ozone. These gases have the same effect on Earth as glass does in a
greenhouse. The Sun’s energy passes through the glass of the greenhouse
and some of it becomes trapped inside to warm the plants. In the same way,
the Sun’s energy passes through Earth’s atmosphere. The greenhouse gases
prevent some of the energy from going back into space, and the trapped
heat warms Earth (Figure 2.23). The greenhouse effect is an important
natural process. It helps keep Earth warm enough to support life. However,
if the amount of greenhouse gases increases, more of the Sun’s energy gets
trapped in Earth’s system. It changes the balance between incoming and
outgoing energy, and can cause climate change.
The average temperatures on Earth’s surface increased by 0.8 degrees
Celsius in the past 100 years. But in the past 66 years, between 1948 and
2013, the average temperature in Canada warmed by 1.6 degrees Celsius.
More greenhouse gases in the atmosphere have caused the average
temperature to rise.
greenhouse gases gases
in the atmosphere that
contribute to the greenhouse
effect by absorbing energy
from the Sun; they include
CO2, methane, and ozone
Some sunlight passes through the
atmosphere to warm Earth’s surface.
Greenhouse gases in the atmosphere trap some of
the radiated thermal energy, keeping Earth warm.
Some sunlight is
reflected back to space
by the atmosphere.
atmosphere
FIGURE 2.23 The greenhouse effect traps warmer air close to Earth. Without the greenhouse
effect, the average temperature on Earth would be about 33 °C colder than it is now.
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CHAPTER 2: Changing Patterns of Climate
67
HUMAN ACTIONS
CAUSING CLIMATE
CHANGE
350
CO2 (parts per million)
Scientists agree that global warming is
related to the rising amounts of greenhouse
gases in the atmosphere (Figure 2.24).
Where are these extra greenhouse gases
coming from? Scientists have considered
both natural and human-made sources of
greenhouse gases. The increase in CO2, the
most common greenhouse gas, began with
the widespread use of fossil fuels in the
1800s. Fossil fuels are fuels obtained from
beneath Earth’s surface. Examples of fossil
fuels include oil, natural gas, and coal. You
will learn more about these in Chapter 8.
CO2 Levels in the Atmosphere
400
300
250
200
150
100
50
0
1010 1110 1210 1310 1410 1510 1610 1710 1810 1910 2010
Years
FIGURE 2.24 This line graph shows CO2 levels in the atmosphere from
1010 to 2010.
HUMAN-MADE SOURCES OF GREENHOUSE GASES
fossil fuels fuels, such as
oil, natural gas, and coal,
formed millions of years ago
from the remains of plants
and animals
What human activities produce greenhouse gases? Most people would say
energy production and transportation. But many other human activities
also produce greenhouse gases (Figure 2.25). The major human activities
that produce greenhouse gases include the following:
What might be
• Electricity production: We burn fossil fuels, such as natural gas, oil,
some ways of reducing
and coal, to produce electricity.
our use of fossil fuels
• Transportation: Most cars, trains, ships, and planes are powered by fossil
for transportation?
fuels, such as gasolineGeography
and diesel.7 SB
• Industry: Many industries,
such as the steel industry, use fossil fuels to
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produce heat for making
products.
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• Homes and businesses:
burned
for heat. Some
Crowle
Art Group
CO Fossil fuels are
of the chemicals we use in our homes or businesses, such as the
Passalso give off 3rd pass
coolants in refrigerators,
greenhouse gases. Approved
Canada’s Greenhouse Gas Emissions, 2011
Not Approved
• Agriculture: Greenhouse
gases are
waste
produced in animals’ digestive tracts
7%
and emitted into the air. They are also
agriculture
given off when animal waste decays. The
10%
decaying of unused plant materials, such
energy
production
as waste from food crops, also produces
industry
36%
greenhouse gases.
11%
• Waste: Household wastes and industrial
wastes release greenhouse gases as
homes and
they decompose.
businesses
12%
transportation
24%
FIGURE 2.25 Energy production and transportation are major sources of
greenhouse gases. However, other human activities are also a significant
source of greenhouse gases.
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UNIT 1: Physical Patterns in a Changing World
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HEROES IN
ACTION
ALEC LOORZ: KIDS VS GLOBAL WARMING
Alec Loorz (Figure 2.26) became a climate
activist at the age of 12. Inspired by the
documentary An Inconvenient Truth, Loorz
wanted to contribute to a solution to
global warming. He tried to join different
organizations but they turned him away,
saying he was too young. So Loorz started
his own organization when he was 13: Kids
vs Global Warming. “I used to play a lot of
video games, and goof off, and get sent
to the office at school,” he
said. “But once I realized it
was my generation that
was going to be the first
to really be affected by
climate change, I made up
my mind to do something
about it.”
Through his organization,
Loorz has spoken all over the world to
hundreds of thousands of people on the
subject of global warming. Through the
iMatter campaign, Kids vs Global Warming
is also empowering young people to take
a leadership role in addressing climate
change. The goal of the campaign is to
create a youth climate movement. Young
people will help create awareness by
educating their peers, politicians, and
the general public through speeches
and presentations, and through the
international iMatter march. Loorz has
done more than give speeches. He also
sued the United States government.
In 2011, Loorz, along with four other
teenagers in the organization, filed a
lawsuit to try to force the U.S. government
to reduce the nation’s CO2
emissions. They wanted
reductions of at least
6 percent per year
beginning in 2013. The
teens also wanted to make
people across the country
aware that the United
States had made little
progress in dealing with climate change. In
an interview about the lawsuit, Loorz said,
“I think a lot of young people realize that
this is an urgent time, and that we’re not
going to solve this problem just by riding
our bikes more.” Although the lawsuit was
dismissed, Kids vs Global Warming filed
an appeal in 2013. They continue to seek a
way to hold the government accountable
for the impact of their decisions on
the climate.
“WE’RE NOT GOING TO
SOLVE THIS PROBLEM
JUST BY RIDING OUR
BIKES MORE.”
FIGURE 2.26 Environmental activist
Alec Loorz
A CALL TO ACTION
1.Think about some environmental
challenges you care about. What are
some ways you can contribute?
2.How can you raise awareness of
global warming in your community?
How would you try to reach a more
global audience?
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CHAPTER 2: Changing Patterns of Climate
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FIGURE 2.27 Greenacre Park in
New York City is an example of a
pocket park. New York City was
one of the first cities to create
pocket parks.
How could a pocket park
benefit my community?
Why might
some people argue
that climate change is
unimportant or that we
should not do anything
about it?
TAKING ACTION AGAINST CLIMATE
CHANGE
How should we deal with climate change? This has been debated by many
scientists, governments, and concerned citizens around the world. Not
everyone agrees that action should be taken. Some people feel that climate
change is a natural process and there is nothing we can do. Others doubt
that climate change is real, or that humans are causing it.
However, most geographers and other scientists agree that human
actions are a cause of climate change. As you learned earlier in the chapter,
we will feel the impacts of climate change in the coming years. People need
to take action now to address the effects of climate change. There are two
ways we can deal with climate change: mitigation and adaptation.
MITIGATION
mitigation action taken to
reduce the consequences of
a problem
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Mitigation means reducing the consequences of a problem. To mitigate
climate change, we must act on its causes. One of the key greenhouse gases
we produce is CO2.
UNIT 1: Physical Patterns in a Changing World
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By making different choices, we can reduce CO2 levels in the atmosphere.
Here are some examples of actions we can take to help mitigate
the problem:
• switch from fossil fuels to other forms of energy such as solar or wind
• drive a fuel-efficient car, ride a bike, or walk instead of driving
• reduce your energy use, such as by turning off the lights when no one is in
the room
• preserve green spaces or plant more trees to absorb greenhouse gases
• use technology to capture CO2 emitted from smokestacks
• consume locally made products instead of products that come from
far away
• reduce, reuse, and recycle to reduce the amount of energy used to
manufacture new products
• conserve water by using less or using it more efficiently
ADAPTATION
adaptation a change or
adjustment made to deal with
a new situation
An adaptation is a change made to deal with a new situation. In the case
of climate change, we must adjust to the effects of climate change to try to
protect ourselves and our planet.
Some adaptations include
• growing crops that will adapt and grow in the new climate
• expanding healthcare to treat or prevent health problems caused by
extreme weather events such as heat waves
• protecting water sources from the effects of warmer temperatures and
extreme weather, for example, by building larger storage places
• building more parks and green spaces in cities where people can cool off
Figure 2.27 shows an example of a pocket park. Pocket parks are smallscale urban parks that can be built in small spaces—in abandoned lots,
in between buildings, or in former parking lots. Cities are adopting these
pocket parks as a way to increase green spaces.
CHECK-IN
1. INTERRELATIONSHIPS In a sentence or two, explain
the differences between mitigating a problem
and adapting to a problem.
2. INTERPRET AND ANALYZE Think about what you
know or have learned about extreme weather.
Identify two actions that people could take to
mitigate the problem and two actions that would
help them adapt to the problem.
NEL
3. COMMUNICATE Suppose you read an ad claiming
that climate change is not a big problem and
so we should do nothing about it. Create an ad
in reply. Be sure to provide evidence to support
your opinion.
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