1. Introduce the greenhouse effect. What is the greenhouse effect? Ask students to define the “greenhouse effect.” [A natural process where water vapor, carbon dioxide and other gases in the atmosphere “trap” heat and warm the Earth’s surface.] Explain to the students that without a balanced greenhouse effect on Earth, life, as they know it, would not exist. Why? [Temperature fluctuations between day and night would be too great to tolerate.]

Safety Note: Wear safety glasses and

be careful of gases under pressure.

Demonstrate the greenhouse effect by creating a “mini greenhouse” in a gallon size plastic bag. Place a thermometer in each of two plastic bags. Mark one bag as the control and seal it. Place two teaspoons of baking soda in a 100-mL beaker or similar container and place the beaker in the other (experimental) bag. Place the plastic bags in the sun or under a light bulb. Place the bags next to each other. Record the starting temperature inside the bags. Add about 20 mL of vinegar to the beaker and seal the experimental bag. Record the temperature each minute for 5 minutes. After five minutes, there should be more of an increase in temperature in the bag with added gases (CO2 and water vapor) than in the control.

The reaction is:

NaHCO3 + HC2H3O2 g NaC2H3O2 + CO2 + H2O

Review the gases that are implicated in the greenhouse effect [water vapor, carbon dioxide, methane, nitrous oxide, hydrofluorcarbons, etc.]. Explain that these gases absorb energy from the sun and emit it back into the atmosphere as thermal infrared radiation (heat). Without the natural greenhouse effect, the Earth’s surface temperature would be much colder, but there can be too much of a “good” thing.

2. Distinguish between global warming and global climate change. 

Is the Earth getting warmer because of increases in greenhouse gases? Is the climate of the Earth changing? Provide each student with an index card (or small piece of paper). Have them write down what they think global climate change is and what causes it. Collect the cards. Use students’ ideas and the teacher transparencies, A Simplistic View of Climate Change and A More Realistic View of Climate Change, to begin a discussion about global warming (increase in the temperature of the Earth’s troposphere) and global climate change (changes in long-term patterns). Explain that there is a natural “greenhouse effect” on Earth, but increases in greenhouse gas (GHG) emissions and particulate black carbon through human activities have affected the Earth’s climate. Some of these gases will never be controlled by government regulations (water vapor) and some are high on the list for control (carbon dioxide).

3. Compare changes in carbon dioxide with temperature trends. Show the Carbon Dioxide Concentrations transparency. The rise of carbon dioxide gas in our atmosphere has been measured continuously since 1958 at Mauna Loa Observatory in Hawaii. The rise follows an oscillating line known as the  “Keeling Curve,” named after Dr. Charles David Keeling, a professor at Scripps Institution of Oceanography. As a renowned expert on the way carbon moves through our planet’s environment, Keeling was the first to measure carbon dioxide in the atmosphere on a continuous basis. (Note: He passed away of a heart attack on June 22, 2005.)

Follow up with the Global Temperature Changes transparency showing an increase in global temperature over time. Have students draw conclusions from these two charts. Additional charts and graphs on the MEECS Air Quality CD relate to global climate change or you can access online resources if your group is in the computer lab.

4. Explore trends in Michigan’s climate. What is happening to Michigan’s climate? After insuring that students understand the difference between weather and climate, have them graph the average temperature and precipitation over time in Michigan on the interactive site of the National Climatic Data Center. Graphs of temperature and precipitation over time are generated online at this site (http://www.ncdc.noaa.gov/oa/climate/research/cag3/cag3.html). The Michigan Climate Example illustrates the appearance of these graphs. The data at this site can be downloaded in tabular form if you want the students to plot the data by hand or using a computer. Use the Climate at a Glance student activity page to guide their research. The data suggest that some seasons of the year show warming trends and others show cooling trends. Annual precipitation is increasing in Michigan. These are indications of climate change. Have students speculate what will happen in the next 50 years if the trends continue. [More precipitation, some seasons are hotter and others are cooler].

Note: If computer access is limited, there are graphs in a PowerPoint and tables of Michigan’s temperature and precipitation trends on the MEECS Air Quality CD.

5. Research how global climate change could affect Michigan.

What could the future bring for Michigan? Divide students into groups and have them read Climate Change and Michigan. They should work through the impacts on the Michigan Climate Change student activity page together. Lead a discussion about what students discovered about what could happen to the climate of Michigan if the present trends continue. An important point is that although sea levels are predicted to rise, the levels of the Great Lakes are predicted to fall.

Additional material for the discussion can be found in a report on the web site of the Union of Concerned Scientists: Findings from Confronting Climate Change in the Great Lakes Region: Michigan. (http://www.ucsusa.org/greatlakes/pdf/michigan.pdf).

6. Tying it all together—taking action.

What can we do about global climate change? Show the Distribution of Michigan Greenhouse Gas Emissions by Economic Sector and Distribution of Michigan Greenhouse Gases by Gas Type transparencies, reviewing the relative contribution from each sector and the relative proportion of types of greenhouse gases. Review some of the actions that Michigan automobile manufacturers and utilities are doing to mitigate global climate change (see Background Information for this lesson).

In the computer lab, have students explore their impacts on greenhouse gas emissions and what individuals can do about global climate change using the EPA and other web sites (see suggestions below). Students can calculate their greenhouse gas contributions at the EPA GHC calculator web site as well as sites by other organizations. Have them prepare a chart on the amount of their greenhouse gas contributions using different online calculators.

Upon completion of the research, have students write an essay about their greenhouse gas emissions and how they can reduce them. Use the teacher resource, Ten Easy Ways to Cool Global Warming, as a guide to evaluating the essay.