1-4: Atmospheric Composition, Carbon Dioxide

Pre-Class Preparation

Objectives

• To understand what is meant by chemical and radiative activity of atmospheric gases.
• To understand the lifetimes of trace gases in the present atmosphere and the role of these gases in maintaining temperature patterns of the atmosphere and earth's surface.

Procedure

1. Read the learning unit.

   Class images

2. Take the learning unit quiz. Quizzes are available from your portfolio. You may access your portfolio via the list of students participating in this year's course, as represented by the icon below.
   
   
3. Additional Required Reading. Although you are not ultimately responsible for content listed in this section, we encourage you to fully explore the links in order to provide a better scope on the upcoming class discussion.

   	Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-1993. Executive Summary. EPA.
   	Houghton, J. T., G. J. Jenkins, and J. J. Ephraums, 1990: Climate Change, The IPCC Scientific Assessment. Cambridge University Press. p. 7-18

Class Discussion

• Problem to ponder... If carbon dioxide (molecular weight 44) is so much heavier than nitrogen (molecular weight 28) and oxygen (molecular weight 32), why doesn't it have a higher concentration near the surface?

• Class discussion summary: by class members Bill Schroeder and Kathryn St. Croix

  In summary, the class discussion for unit 4 focused on carbon dioxide. It was found that in summertime carbon dioxide levels are lower because there is more vegetation to take the carbon dioxiode out of the atmosphere. There was also found to be a direct correlation between the amount of carbon dioxide in the atmosphere and the temperature of the earth. The causes of carbon dioxide into the atmosphere are fossil fuel burning, cement production and deforestation, however, fossil fuel burning is the predominant cause.

Post-Class Activities

• Participate in the electronic dialog. Use this forum for:
  • continuing class discussion;
  • posing new questions to students or the instructor;
  • responding to issues/questions raised by students in class/electronic dialog.

  Visitor Access (Visitors are welcome to participate in the dialog. Just click on the icon below)	Student Access (Students must post all dialog from their portfolio. Click on the icon below to access the student list.)

• Recommended Reading Materials

  	Houghton, J. T., L. G. Meira Filho, B. A. Callander N. Harris, A. Kattenberg, and K. Maskell, 1996: Climate Change 1995. The Science of Climate Change. Cambridge University Press, 75-78.
  	Houghton, J.T., G.J. Jenkins, J.J. Ephraums, eds, 1990: 1990 Intergovernment Panel on Climate Change. Cambridge University Press.
  	McKee, David, ed., 1994: Tropospheric Ozone. Lewis Publishers. 333pp.

• References

  	Tans, P. P., and J. W. C. White, 1998: In balance, with a little help from the plants. Science 281, 183-184.
  	Atmospheric Chemistry - an introduction.
  	Atmospheric Chemistry and Air Quality Glossary
  	Glossary: Carbon Dioxide and Climate
  	Carbon Dioxide Information and Analysis Center of the Department of Energy at Oak Ridge National Laboratory
  	Stone, Richard, 1998: Russian outpost readies for otherworldly quest. Science 279, 658-661. (This reference discusses the Russian Vostok station at which the 3.7 km ice core was taken)