Section 1. Gathering Information
Carbon Cycle and Greenhouse
Gases Web-quest
activity 2
Summary
n subjects
Students visit various Web sites and complete the Web-quest Exploration Guide to gather
information and learn about the carbon cycle, greenhouse gases, and climate change.
Students then create a carbon cycle poster and share with the class.
Science, Language Arts
Background
Global Climate Change
Most scientists agree that our
climate is changing as a result of human
activities, especially burning fossil fuels
to produce energy. When you hear the
phrase “climate change,” what do you
think it means? Climate change includes
long-term changes in temperature,
precipitation, or wind. Climate change
is the result of many factors, including
human-produced greenhouse gases (U.S.
EPA, 2007a).
Greenhouse gases trap heat in the
Earth’s atmosphere. A certain amount of
greenhouse gases are necessary to keep
the Earth warm enough to sustain life.
The temperature of Earth is maintained
by heat radiation from the sun and heat
loss into space. When greenhouse gases
are added to the atmosphere, less heat is
allowed to escape into space, and Earth’s
?
surface warms. This process is called
global warming. Global warming is the
gradual increase in the average global
temperature (U.S. EPA, 2007a). Global
warming contributes to additional and
various changes in the overall climate.
Of all the greenhouse gases, carbon dioxide (CO2) levels have increased the most
in recent years. Carbon dioxide represents
more than 80 percent of total greenhouse
gas emissions in the U.S. (U.S. EPA,
2008). Energy generation and transportation represent the largest sources of CO2
emissions in the U.S. (Figure 1). Reducing
Direct use of fossil fuels in:
Homes, Commercial Buildings,
and Industry
27%
did you know?
Climate change has different impacts to
different locations on Earth. For example,
some areas may have increased precipitation, while others may have decreased
precipitation. Some areas may have
warmer summers, while some areas may
not notice any changes.
Should We Use Wood for Energy? •
Electric
Power
Sector
39%
34%
Figure 1.
Transportation
This graph depicts sources of CO2
emissions in the U.S. (numbers are
metric tons CO2 emitted).
GRAPH COURTESY OF U.S. EIA (2008)
Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
n Key Questions
1.What are the components
of the carbon cycle?
2.How do human activities
influence the carbon cycle and
climate change?
3.What can be done to reduce
greenhouse gas emissions?
n Objectives
By the end of the activity,
students will be able to do the
following:
1.Describe the basic
components of the carbon
cycle (SC.912.E.7.1).
2.Explain how human activities
influence the carbon cycle
(SC.912.E.6.6; SC.912.L.17.16).
3.Explain the greenhouse
effect and various causes
of global climate change
(SC.912.L.17.11; SC.912.E.7.7).
4.Synthesize information
gathered by creating a poster
and presenting this poster to
the class (LA.1112.5.2.3).
n Materials
• C
opies of Carbon Cycle and
Greenhouse Gases Student
Worksheet:Web-quest
Exploration Guide for each
student
• Computers with Internet
access for each student or
pair of students
• Headphones for each student
for video/audio sections
n Time Estimate
1 hour
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Greenhouse
Gases
Greenhouse gases emitted
by the U.S. include the
following:
• Carbon dioxide (CO2)
• Methane (CH4)
• Nitrous oxide (N2O)
• H
ydrofluorocarbons
(HFCs)
• Perfluorocarbons (PFCs)
• Sulfur hexafluoride (SF6)
• Water vapor (H2O) (U.S. EIA, 2008c)
CO2 emissions is an important part of
slowing global climate change.
?
The Carbon Cycle
Carbon is an element that continuously moves through all plants, animals,
soils, oceans, and the atmosphere. The
movement of carbon is referred to as
the carbon cycle (Figure 2). As you read
the following paragraphs, refer to the
figure above to visualize the movement
of carbon through the cycle.
?
did you know?
In 2005, about 21 percent of the world’s
total energy-related carbon dioxide was
emitted by the U.S.
(U.S. EIA, 2008c)
did you know?
Carbon is the building block of life!
Carbon plays a major role in the makeup
and function of all living organisms.
Carbon moves from the atmosphere
to plants through photosynthesis—a
process where green plants grow by
harnessing energy from the sun. During
photosynthesis, plants use sunlight,
carbon dioxide (CO2), and water to produce oxygen and glucose. The glucose
(or sugar) is a form of chemical energy
that is stored in the cells of plants.
Plants release energy in the form of
carbon during plant respiration. The
excess carbon that is not released during
respiration is stored in tree trunks and
CO2 cycle
sunlight
auto &
factory
emissions
photosynthesis
animal & plant
respiration
organic carbon
dead organisms
& waste products
decay organisms
fossils & fossil fuels
root
respiration
ocean uptake
Figure 2. Carbon continuously cycles through living organisms, soils, oceans, and
the atmosphere.
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Should We Use Wood for Energy? • Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
How is Wood
Carbon Neutral?
LARRY KORHNAK
Trees store carbon as they grow, making them an important part of the carbon cycle.
?
did you know?
In the atmosphere, carbon combines
with oxygen to form the gas carbon
dioxide (CO2).
leaves as plants grow. This stored carbon
is transferred to animals when plants
are eaten. When animals breathe, CO2 is
released into the atmosphere.
If plants are burned, for example
in a forest fire or at a power plant, CO2
is released into the atmosphere. When
plants and animals naturally decompose,
carbon is released into the atmosphere
and soil. Some of this carbon gets buried
far beneath the Earth’s surface and will
form fossil fuels in millions of years.
When fossil fuels are extracted from
the earth and burned for energy, CO2 is
released into the atmosphere. However,
this carbon has not been part of the
carbon cycle for millions of years. All of
the CO2 released by burning fossil fuels
cannot be absorbed back into the carbon
cycle by land plants and oceans (Matthews & Robertson, 2005). Therefore, the
overall amount of CO2 in the atmosphere
increases when fossil fuels are burned.
Think of CO2 in the
atmosphere as a bathtub full
of water. Burning wood represents water entering the
tub through the faucet, and
growing trees represents the
drain because combustion
adds CO2 to the atmosphere
and photosynthesis removes
it. Woody biomass is carbon
neutral as long as we do not
burn wood (run the faucet)
faster than we grow trees
(drain the water). On the
other hand, because fossil fuels are not part of the shortterm carbon cycle, burning
fossil fuels is like running the
faucet without opening the
drain. The water level rises
and the tub overflows. The
same thing happens when
CO2 levels in the atmosphere
increase: when atmospheric
carbon rises, average global
temperatures also rise.
LARRY KORHNAK
The Role of Woody Biomass in the
Carbon Cycle
Unlike fossil fuels, woody biomass
is a carbon-neutral energy source. This
means using energy from woody biomass
will not increase the overall amount
of CO2 in the atmosphere (Matthews
& Robertson, 2005). This may sound
surprising to you: how can you burn
something and not add CO2 to the
atmosphere? As we learned, burning
wood releases CO2 into the atmosphere.
However, trees that are growing absorb
and store carbon. Therefore, if trees are
planted at the same rate they are harvested and burned for energy, then the
overall amount of CO2 in the atmosphere
does not increase.
Woody biomass is a carbon neutral source of energy.
Should We Use Wood for Energy? •
Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
29
teacher
Assessment
Suggestions
Objective 1:
Review student answers to
the Web-quest Exploration
Guide, part I. In addition,
student understanding of
carbon cycle processes can
be assessed by reviewing
student posters and the
ability of students to
answer questions about his
or her poster.
Objective 2:
Review student answers to
the Web-quest Exploration
Guide, parts I and II.
Objective 3:
Review student answers to
the Web-quest Exploration
Guide, parts II–VI.
Objective 4:
Score student posters
using the rubric on the
following page.
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Teacher Instructions
Preparation
1. Read the Background Information provided at the beginning of this activity and
make copies if you plan to assign reading before the activity. Additional, more
detailed information is available in the Climate Change and Carbon fact sheets in the
Supplemental Reading section.
2.Go through the Web-quest Exploration Guide on your own to familiarize yourself
with the topic and activity.
3.Ensure that each Web site link is operational and that the video segments upload
correctly.
Procedure
1.When students are at computer stations, pass out copies of the Web-quest
Exploration Guide and provide them with the web address to open the PDF file from
the program Web site (this will enable them to utilize active hyperlinks). Also, pass
out headphones. Ask students to wear headphones during video/audio sections
of the Web-quest or if headphones are unavailable, ask them to lower or mute the
volume.
2.Review instructions with your class and make sure each student completes his or her
own worksheet.
3.When students complete the Web-quest, initiate a class discussion using the
Discussion Questions. If time is limited, you can do the discussion the following day
or assign the questions as student homework.
4.After completing this Web-quest, ask students to create a poster depicting their own
version of the carbon cycle. Encourage students to draw, use magazine clippings, or
photos and to be as creative as possible. Their diagrams should not simply be a copy
of a standard carbon cycle, but instead, have a unique or interesting component that
shows a deeper understanding of the cycle. Have students share their posters with
the class. Posters can be displayed around the classroom, lunchroom, or in school
hallways.
Should We Use Wood for Energy? • Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
teacher
n Student Poster Rubric: Carbon Cycle and Greenhouse Gases Web-quest
4 Above
Standards
Category
3 Meets
Standards
2 Approaching
Standards
1 Below
Standards
Graphics –
Originality
Several of the
graphics used on
the poster reflect
an exceptional
degree of student
creativity in their
creation and/or
display.
One or two
of the graphics used on
the poster reflect student
creativity in
their creation
and/or display.
The graphics
are made by the
student, but are
based on the
designs or ideas
of others.
No graphics made
by the student are
included.
Content –
Accuracy
At least 7 accurate facts are
displayed on the
poster.
5-6 accurate
facts are
displayed on
the poster.
3-4 accurate
facts are displayed on the
poster.
Less than 3 accurate
facts are displayed on
the poster.
Attractiveness The poster is
exceptionally attractive in terms
of design, layout,
and neatness.
The poster
is attractive
in terms of
design, layout,
and neatness.
The poster is
acceptably attractive though
it may be a bit
messy.
The poster is distractingly messy or very
poorly designed. It is
not attractive.
Knowledge
Gained
Student can accurately answer
all questions
related to facts
in the poster and
processes used to
create the poster.
Student can
accurately
answer most
questions
related to facts
in the poster
and processes
used to create
the poster.
Student can accurately answer
about 75% of
questions related
to facts in the
poster and processes used to
create the poster.
Student appears to have
insufficient knowledge
about the facts or
processes used in the
poster.
There are no
grammatical
mistakes on the
poster.
There is 1
grammatical
mistake on
the poster.
There are 2
grammatical
mistakes on the
poster.
There are 3 or more
grammatical mistakes
on the poster.
Grammar
Resources
•
•
•
•
•
•
Koshland Science Museum: http://www.koshland-science-museum.org/exhibitgcc/
NASA Earth Observatory: http://earthobservatory.nasa.gov/Library/CarbonCycle/
U.S. EIA: http://www.eia.doe.gov
U.S. EPA: http://www.epa.gov/climatechange/emissions/index.html
Windows to the Universe: http://windows2universe.org/earth/Water/co2_cycle.html
Woods Hole Research Center: http://www.whrc.org/resources/primer_home.html
Should We Use Wood for Energy? •
Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
Extensions
• Ask each student to calculate
his or her individual emissions.
Go to http://www.epa.gov/
climatechange/wycd/calculator/
ind_calculator.html for more
information.This individual
emissions calculator asks for
detailed information, which
students will need to gather on
their own.Tell students to write
a brief report on the data they
entered and the results. Students
can share their reports with the
class and participate in a class
discussion on ways to reduce
individual emissions.
• Have students calculate their
carbon footprints using a
calculator available online.There
are many versions of the carbon
calculator; one is available at
http://coolclimate.berkeley.edu/.
Next, as a class, compare carbon
footprints and discuss reasons
for differences in figures. Also,
compare the national individual
average to student averages
and compute a class carbon
footprint. Discuss ways to
reduce your carbon footprint.
• Ask students to calculate the
school’s carbon footprint.
Go to http://www.epa.gov/
climatechange/wycd/actionsteps.
html for more information. As a
class, write up a report for the
principal identifying ways for
your school to reduce its carbon
emissions.
• As a class, participate in a climate
change challenge and report
results to your local newspaper.
Visit http://www.carbonrally.
com/ for more information.
• As a class, watch the movie An
Inconvenient Truth and have a class
discussion about what students
learned and their own thoughts.
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Carbon Cycle and Greenhouse Gases
STUDENT
Web-quest Exploration Guide
___________________________________________________________________ NAME
(1 of 6)
________________ date
_________________
period
Carbon sinks, sources, and sequestration, greenhouse gas emissions, and climate change: what does this all
mean, and how in the world are you part of the carbon cycle? This Web-quest Exploration Guide will direct
you to numerous online resources related to the carbon cycle. Follow the instructions and complete the
worksheet to turn in to your teacher.
I.The Global Carbon Cycle
Go to the Pearson/Prentice Hall Biological Science Web site: http://wps.prenhall.com/esm_freeman_
biosci_1/0,6452,501436-,00.html
You
may need to download a plug-in to view the video. Follow instructions to download the plug-in,
and continue with the following steps.
Click on Natural Production.
Put your headphones on or mute the sound.
Maximize the page and watch the video depiction of the carbon cycle.
Describe two processes of the carbon cycle:
4Close the video window.
4Click on Human Activities on the original Web page.
4Watch the video and answer the following questions:
1.What are two most significant ways that humans increase the amount of carbon in the atmosphere?
2. S ince 1950 what has happened to atmospheric CO2 concentrations recorded at a laboratory at
Mona Loa?
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Should We Use Wood for Energy? • Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
STUDENT
Carbon Cycle and Greenhouse Gases Web-quest Exploration Guide (2 of 6)
II.The Greenhouse Effect
Go to the National Geographic Video Web site: http://science.nationalgeographic.com/science/
environment/global-warming/gw-overview-interactive.html
Go
through the animated depiction of the greenhouse effect (start and continue through each
section by clicking on the green buttons).
Answer the following questions:
1.What happens when the sun’s radiation reaches Earth’s atmosphere?
2.How does Earth stay warm enough to sustain life?
3.How do human activities intensify the warming effect?
4.Fill in the following chart about the major greenhouse gases (GHG) (Hint: click on the GHG
inside the pie chart to retrieve more information on each GHG).
GHG
% Contribution to increase in
GHG emissions since 1700
Source(s)
Carbon Dioxide
(CO2)
Nitrous Oxide (N2O)
Methane (CH4)
Other
Should We Use Wood for Energy? •
Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
33
STUDENT
Carbon Cycle and Greenhouse Gases Web-quest Exploration Guide (3 of 6)
III.Greenhouse Gas Maps
Go to the Purdue University Newsroom Web site: http://www.purdue.edu/newsroom/
Type
Vulcan in the Search Purdue News box.
Click on Revolutionary CO2 maps zoom in on greenhouse gas sources in the search results.
Answer
the following questions:
1. What do the Vulcan maps depict?
2. What percentage of global CO2 emissions does the U.S. account for?
Click
on Download image under the map of Where CO2 is being emitted (near the top of the article).
Answer the following questions:
1. Based on this image, what regions of the United States emit the greatest amounts of CO2?
2. Why do you think these areas emit such large amounts of CO2?
IV. International CO2 Emissions
Go to the International Energy Agency Dynamic Maps Web site: http://www.iea.org/country/maps.asp
Click on Go to the Map under Map Energy Indicators.
Click on Map Energy Indicators in the upper left corner and select CO2 Emissions.
Click on North America, click on the United States, and record CO2 emissions in the table below.
Click on Asia (including China), select China, and record CO2 emissions in the table below.
Click on OECD Europe, select a country of your choice, and record CO2 emissions in the table below.
Click on Africa, select Zimbabwe, and record CO2 emissions in the table below.
Country
CO2 emissions (Mt1 of CO2)
U.S.
China
European Country:
Zimbabwe
Mt = Million tonnes (1 million tonnes = 2.05 billion pounds)
1
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Should We Use Wood for Energy? • Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
STUDENT
Carbon Cycle and Greenhouse Gases Web-quest Exploration Guide (4 of 6)
Answer the following questions:
1. How do CO2 emissions of the U.S. and China compare with the European country and Zimbabwe?
2. W
hat might be some similarities and differences that could account for the differences in CO2
emissions of these four countries?
V. What are the utility emissions in my area?
Go to the U.S. Environmental Protection Agency Clean Energy Web site: http://www.epa.gov/
cleanenergy/energy-and-you/how-clean.html
4Enter your five-digit zip code in the box.
4Select the utility company that provides your electricity.
4Review Graph 1: What is my fuel mix?
4Fill in the following chart:
GHG
Nitrogen Oxide
Sulfur Dioxide
Carbon Dioxide
Your region’s utility
emissions rate (lbs/MWh)
National average emissions
rate (lbs/MWh)
Methane (CH4)
VI.Fuel Economy
Go to the U.S. Department of Energy Fuel Economy Web site: http://www.fueleconomy.gov/feg/whyshtml
List four reasons why fuel economy is important:
1.
2.
3.
4.
Click on Find and Compare Cars at the top of the page.
Select the Model Year of your personal car or your family car.
Select the Make of your personal car or your family car.
Select the Model of your personal car or your family car.
Find the model from the list that matches the engine components in your personal car or family’s
car (for example 4, 6, or 8 cylinder engine, automatic or manual transmission, etc.).
Should We Use Wood for Energy? •
Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
35
STUDENT
Carbon Cycle and Greenhouse Gases Web-quest Exploration Guide (5 of 6)
4Click Compare and fill in the table below with the information provided about your personal car or
your family’s car.
Year
Make
Model
City MPG
Hwy MPG
Annual fuel cost ($)
Annual petroleum consumption (barrels/year)
Carbon footprint (tons CO2 emitted/year)
VII. Global Warming Effects
Go to Ben and Jerry’s Lick Global Warming Web site at: http://www.lickglobalwarming.org/map.cfm
Click on two of the icons to choose a category and then click on a dot on the map to learn more about a
specific effect of global warming.
Record the information below:
Category 1:
Location:
Effect:
Category 2:
Location:
Effect:
VIII. What Can I do?
Go to the Union of Concerned Scientists Web site: http://www.ucsusa.org/global_warming/what_you_can_do/
Read
What You Can Do about Global Warming.
Record
five things that you or your family can do:
1.
2.
3.
4.
5.
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Should We Use Wood for Energy? • Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
Carbon Cycle and Greenhouse Gases Web-quest Exploration Guide (6 of 6)
Discussion Questions
1
What
agencies or organizations sponsored the Web sites you collected information
from and what might their bias be?
2
Is
the information presented on the Web sites balanced?
3
What
are some of the reasons there is more carbon dioxide in the atmosphere now
than ever before?
4
Why
do you think the U.S. emits large amounts of CO2 and other greenhouse gases?
5
What
can individuals and families do to reduce carbon emissions?
6
What
can industries, communities, and federal governments do to reduce carbon
emissions?
Should We Use Wood for Energy? •
Section 1 – Activity 2: Carbon Cycle and Greenhouse Gases Web-quest
STUDENT
Conclusion
Carbon cycles continuously
through all plants, animals,
soils, oceans, and the
atmosphere. Carbon is the
building block of life and is
a major part of the makeup
and function of all living organisms. Humans get carbon
from food. Plants absorb
carbon from the atmosphere during photosynthesis, and plants and animals
store carbon as they grow
and release carbon as they
decompose. Some human
actions, particularly burning
fossil fuels to generate energy, cause carbon dioxide
to be released into the atmosphere. Not all of these
emissions can be absorbed
into the carbon cycle by
living organisms. Now that
you’ve learned about the
carbon cycle and greenhouse emissions, review the
following questions and be
prepared to discuss your
answers and thoughts with
the rest of the class.
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