Greenhouse Gases

My STEM Lesson Plan

Greenhouse gases

Human-caused global warming occurs when human activity introduces too much of certain types of gas into the atmosphere. More of this gas equals more warming. The atmospheric gases primarily responsible for the greenhouse effect are known as "greenhouse gases" and include water vapor, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). The most prevalent greenhouse gas is CO2.

CARBON DIOXIDE: .
Carbon dioxide (CO2): Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle.

Some atmospheric CO2 is natural. For example, before the Industrial Revolution, therewere about 280 parts per million (ppm) of CO2 in the atmosphere, and during most of the past 800,000 years, CO2 fluctuated between about 180 ppm during ice ages and 280 ppm during interglacial warm periods. Since the Industrial Revolution, though, the amount of CO2 has dramatically increased. Currently, the increase is 100 times faster than that when the last ice age ended, according to the National Oceanic and Atmospheric Administration (NOAA).

In May 2013, scientists reported measuring atmosphericcarbon dioxide levelsas high as 400 ppm. Levels of CO2haven't been that high since the Pliocene Epoch, which was between 3 million and 5 million years ago, according to the Scripps Institution of Oceanography.

In 2012, CO2 accounted for about 82 percent of all U.S. greenhouse gas emissions, according to the EPA. "We know through high-accuracy instrumental measurements thatthere is an unprecedented increase in CO2in the atmosphere.We know that CO2absorbs infrared radiation [heat] and the global mean temperature is increasing," Keith Peterman, a professor of chemistry at York College of Pennsylvania, and his research partner, Gregory Foy, an associate professor of chemistry at York College of Pennsylvania, told Live Science in a joint email message.

CO2 makes its way into the atmosphere through a variety of routes. Burning fossil fuels, for example, releases CO2. Deforestation is also a large contributor to excessive CO2 in the atmosphere. In fact, deforestation is the second largest anthropogenic (human-made) source of carbon dioxide, according to research published by Duke University. When trees are killed, they release the carbon they have stored for photosynthesis. According to the 2010 Global Forest Resources Assessment, deforestation releases nearly a billion tons of carbon into the atmosphere per year.

But fossil fuel combustion is the number one anthropogenic source of carbon dioxide. The EPA lists this source as the cause of 32 percent of total U.S. CO2emissions and 27 percent of total U.S.greenhouse gasemissions in 2012.

METHANE

Methane is the second most common greenhouse gas, but it is much more destructive. In 2012, the gas accounted for about 9 percent of all U.S. greenhouse gas emissions, according to the EPA. There may be less methane in the atmosphere, but this gas is much more efficient at trapping radiation. The EPA reports that methane has 20 times more impact on climate change over a 100-year period.
Methane (CH4): Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.

Methane can come from many natural sources, but humans cause a large portion of methane emissions through mining, the use of natural gas, the mass raising of livestock and the use of landfills, according to the Inventory of U.S. Greenhouse Gas Emissions and Sinks report from 1990 to 2012. In fact, according to the EPA, humans are responsible for more than 60 percent of methane emissions.
Nitrous oxide (N2O): Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.

Fluorinated gases— that is, gases to which the elementfluorinewas added — including hydro fluorocarbons, per fluorocarbons and sulfur hexafluoride, are created during industrial processes and are also considered greenhouse gases. Though they are present in very small concentrations, they trap heat very effectively, making them high "global-warming potential" (GWP) gases. Hydro fluorocarbons, per fluorocarbons, and sulfur hexafluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydro chlorofluorocarbons, and halons). These gases are typically emitted

in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases").

Chlorofluorocarbons (CFCs), once used as refrigerants and aerosol propellants until they were phased out byinternationalagreement, are also greenhouse gases.

Current greenhouse gas concentrations
Gas / Pre-1750
tropospheric
concentration / Recent
tropospheric
concentration / Absolute increase
since 1750 / Percentage
increase
since 1750 / Increased
radiative forcing
(W/m2)
Carbon dioxide (CO2) / 280ppm / 395.4 ppm / 115.4 ppm / 41.2% / 1.88
Methane (CH
4) / 700 ppb / 1893ppb /
1762ppb / 1193ppb /
1062ppb / 170.4% /
151.7% / 0.49
Nitrous oxide (N
2O) / 270 ppb / 326ppb /
324ppb / 56ppb /
54ppb / 20.7% /
20.0% / 0.17
Tropospheric
ozone (O
3) / 237 ppb / 337ppb / 100ppb / 42% / 0.4

How do we know if the temperature increase is caused by anthropogenic emissions?

Computer models strongly suggest that this is the case. The following graphs show that 1) If only natural fluctuations are included in the models (such as the slight increase in solar output that occurred in the first half of the 20th century), then the large warming in the 20th century is not reproduced. 2) If only anthropogenic carbon emissions are included, then the large warming is reproduced, but some of the variations, such as the cooling period in the 1950s, is not reproduced (this cooling trend was thought to be caused by sulfur dioxide emissions from dirty power plants). 3) When both natural and anthropogenic emissions of all

TYPES ARE INCLUDED, THEN THE TEMPERATURE EVOLUTION OF

THE 20TH CENTURY IS WELL REPRODUCED

Effects of global warming

Global Warming Impacts

Many of the following "harbingers" and "fingerprints" are now well under way:

Rising Seas--- inundation of fresh water marshlands (the everglades), low-lying cities, and islands with seawater.
Changes in rainfall patterns --- droughts and fires in some areas, flooding in other areas. See the section above on the recent droughts, for example!
Increased likelihood of extreme events--- such as flooding, hurricanes, etc.
Melting of the ice caps --- loss of habitat near the poles. Polar bears are now thought to be greatly endangered by the shortening of their feeding season due to dwindling ice packs.
Melting glaciers - significant melting of old glaciers is already observed.
Widespread vanishing of animal populations --- following widespread habitat loss.
Spread of disease --- migration of diseases such as malaria to new, now warmer, regions.
Bleaching of Coral Reefs due to warming seas and acidification due to carbonic acid formation --- One third of coral reefs now appear to have been severely damaged by warming seas.
Loss of Plankton due to warming seas --- The enormous (900 mile long) Aleutian island ecosystems of orcas (killer whales), sea lions, sea otters, sea urchins, kelp beds, and fish populations, appears to have collapsed due to loss of plankton, leading to lossof sea lions, leading orcas to eat too many sea otters, leading to urchin explosions, leading to loss of kelp beds and their associated fish populations.

Where do we need to reduce emissions?

In reality, we will need to work on all fronts - 10% here, 5% here, etc, and work to phase in new technologies, such as hydrogen technology, as quickly as possible. To satisfy the Kyoto protocol, developed countries would be required to cut back their emissions by a total of 5.2 % between 2008 and 2012 from 1990 levels. Specifically, the US would have to reduce its presently projected 2010 annual emissions by 400 million tons of CO2. One should keep in mind though, that even Kyoto would only go a little ways towards solving the problem. In reality, much more needs to be done.

ACTIVITY 1
Objective
To use a statistical analysis technique, the moving average, to search for meaningful trends in regional raw temperature data.

copy of the "Temperature Trends" student handouts
Part I
Part II
Temperature Graph
pencil
yellow, blue, green, and red pencils, markers, or crayons
scissors
tape
calculator

Part 1

Divide the class into 10 groups, one for each year of data.
Distribute both Part 1 Temperature Trends and "Temperature Graph" student handouts with the other materials. Ask student to discuss the raw data before graphing.
Record their observations on the board.
Have each group graph its year of data, using the data Monthly Average Temperatures and chart provided on the Part 1 "Temperature Trends" student handouts. After they have graphed their data year, direct students to cut out their graphs and lightly tape them together temporarily, spanning 1989 to 1998.
Display the taped-together graphs on the wall or floor. Have students observe any trends. Add these observations to the initial observations on the board.

Part 2

Students will now plot a 12-month moving average. Distribute the Part 2 "Temperature Trends" student handout. You may need to help students with the instructions in this part.
Demonstrate the algorithm until students are able to calculate the moving averages on their own. Students will realize they can plot only their first seven averages, June to December, on their own graph. They must plot the next five averages on the next year's group's graph, January to May. The previous year's group will fill in averages for January to May on their graph.
The group working on the final year has only enough data to produce one moving average, June.
Once students have finished their moving averages, discuss the results with them. What do they see in the data now? How does that differ from what they inferred from the previous plotting technique? What does each plotting technique tell them? What is the value of the moving average?

The graph students create will show temperatures above and below the average temperature line of the chosen data set. The moving average sums for each month are presented below. Plotting for the January sums begins in June. (Note: Strictly speaking, plotting for a moving average would begin at the exact center point of the data set; however, because 12 months is an even number and a 12-month average can't have a "center month," June was chosen as the starting point for plotting the averages.)2-Month Moving Average for Boston, Jan. 1989 to Dec. 1998*
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec / 1989
50.4
50.5
50.8
51.1
51.2
50.8
50.7 / 1990
50.7
50.9
50.9
51.1
51.6
53.2
52.6
52.8
52.9
53.2
53.9
54.2 / 1991
54.3
54.4
54.3
54.1
65.8
53.5
53.6
53.3
52.8
52.4
51.7
51.5 / 1992
51.1
50.8
50.8
50.5
50.3
50.2
50.3
49.9
50.0
50.1
50.5
50.7 / 1993
51.1
51.4
51.4
51.4
51.7
51.6
50.8
50.7
50.9
51.1
51.0
51.2 / 1994
51.4
51.3
51.3
51.5
51.8
52.2
53.2
53.3
53.4
53.0
52.9
52.6 / 1995
52.4
52.5
52.4
52.6
52.0
51.5
51.1
51.3
51.1
51.3
51.3
51.2 / 1996
50.9
50.7
50.8
50.4
50.3
50.9
50.8
51.2
51.3
51.1
51.0
51.0 / 1997
51.2
51.2
51.2
51.2
51.3
50.9
51.3
51.3
51.7
51.9
52.3
52.0 / 1998
52.1
52.2
52.3
52.5
52.7
53.0

The averages shown in this table were calculated using the common technique of rounding the number 5 by increasing the next higher place value by 1.

The visual result of plotting the monthly average temperature with the 12-month moving average temperature line is impressive. The Boston data set provides some tantalizing hints in the monthly plot that some cyclical temperature changes may be occurring, but they turn out to be inconclusive in the moving average trend. A moving average is a sliding average of whatever is being studied. In this activity, the continuous average of a cluster of data (a 10-year span of temperature records) yields more meaningful information about temperature trends than a single data set (a one-year span of monthly temperature records) provides. A single data set is more likely to contain fluctuations that do not appear in a larger trend analysis.
Most students will conclude that there isn't much of significance when looking at results in the moving average trend. Some may argue for a three- to four-year cycle of small change. The data on this graph alone, however, are not compelling as it only shows 10 years of information. Students may suggest that by looking farther back and creating a moving average for the past 100 years they can verify this trend. However, that opens the question about the past being a reliable predictor of the future

ACTIVITY 2

Purpose: This activity will introduce you to the Global Warming Wheel Card.

This homework requires that you take your Global Warming Wheel Card home with

you and ask your parents or other adult to share their electricity and home heating

bills with you.

1.Look around your house for items that need electricity to operate.

List the first 10 items that you find.

1……………………………………………….

2 ………………………………………………

3 ………………………………………………

4 ………………………………………………

5 ………………………………………………

6 ………………………………………………

7 ………………………………………………

8 ………………………………………………

9 ………………………………………………

10. ……………………………………………..

2.Of those 10 items, which ones do you use every day?

3.How much did your family spend each month for electricity in the past six months?

Total amount: Now divide that number by 6. This will give you an average monthly bill.

Average monthly bill:

4.Using your Global Warming Wheel Card, pick the amount that is closest to the

“average for six months” that you just calculated. How much carbon dioxide

does your household produce every year?

5.Use your Global Warming Wheel Card to find what your household can do to

reduce the amount of carbon dioxide that you generate.

6.Can you think of other things that you can do to reduce the amount of electricity that you use in your home?

ACTIVITY 3

Electricity Use and Carbon Dioxide

Purpose: This activity will allow you to think about what you can do

to help reduce the release of carbon dioxide into the air and

perhaps limit future climate change.

Time required: 40 minutes

Equipment:

•Pencils and paper

•Materials provided in this packet, including responses to

Activity #2 and Global Warming Wheel Card

1.Find three other students with whom you would like to work. You will need

pencils and paper, and you might want to have these things with you:

2. Take the next 20 minutes to discuss the following:

A)The four of you work for your town’s Department of Environmental

Protection. You have learned a great deal about climate change in the past

several months, and you are becoming concerned about the possible effects

it will have on your local community if it continues to get worse. You are

now aware of some of the causes and effects of climate change, and you

would like to do everything you can to make sure that your community

does not contribute more carbon dioxide than is absolutely necessary.

However, you also realize that people in your community enjoy the way

their lives are now, and you do not want to make too many changes that

will upset their lives. Your department has been asked to come up with

some new programs for reducing the amount of carbon dioxide generated

by your community. What three programs would you propose to encourage

your community’s citizens, businesses, and institutions (such as schools) to

change their behavior so they produce less carbon dioxide?

B) What would your community probably like about these programs?

C)What would your community probably NOT like about these programs?

ACTIVITY 4

OBJECTIVE
To compare the thermal properties of carbon dioxide, methane and air.
EQUIPMENT
• 3 identical plastic bottles
• 3 temperature probes
• 3 pre-drilled bungs (optional, helpful)
• Stopwatch
• Carbon dioxide
• Methane
• 3 Clamp stands if you have access to them (not essential)
• Lamp (or other heat source)
METHOD
• Clean and dry the bottles (they should be dry inside as well)
• Remove any labels
• Insert temp probes through the bungs. If you haven’t got bungs then drill holes in the bottle caps and insert the temp probes through the hole, seal the edges of the hole with plastecine or similar.
• Fill one bottle with carbon dioxide. If you’ve got a soda stream use that, if not put some indigestion tablets into a balloon containing some water, hold the neck of the balloon closed and wait for it to fill with carbon dioxide given off by the tablets. Fill the bottle with the carbon dioxide from the balloon.
• Fill one bottle with methane – from the normal domestic gas supply.
• Seal all three bottles with the bung or the cap
• Secure a bottle in each of the clamp stands
• Place all three bottles equidistant from an indirect heat source such as a lamp (don’t switch the lamp on yet)
• Wait until the temp in all three bottles is identical
• Switch on the lamp
• Take temperature readings from all three bottles for the next 30 minutes at one minute intervals
• Plot the results on a graph
RESULTS
This graph shows the results of an experiment we did a few years ago using just carbon dioxide and air, you should be able to achieve similar results in your experiment

CONCLUSION
The experiment should demonstrate that carbon dioxide and methane will retain more heat than air.
LIMITATIONS
The experiment does not explain why the greenhouse gases retain more heat than air, this is explained at the quantum physics level and isn’t something that can be done at home. Here’s an answer I provided a while back which explains the physics