Introduction
Carbon Cycle

The biogeochemical cycle that seems to be getting the most press these days is the carbon cycle. Everywhere that you turn in the environmental news business, you see articles about global warming and the greenhouse effect. Inevitably, these articles discuss the amount of carbon dioxide that is being released by various nations and processes. A good example of this is the recent controversy over the Bush Administration's plan to not sign the Kyoto Protocols. One of the points that is being debated is whether a nation can offset the limits on the amount of carbon dioxide that it can release by processes that remove carbon dioxide.

The carbon cycle involves more than just carbon dioxide. Other compounds, such as methane and carbon monoxide, are also involved in the carbon cycle. They are also examples of greenhouse gases that are important to the proposed mechanisms that cause global warming. The reason that carbon dioxide gets a lot of the coverage is because it is the most important greenhouse gas in the atmosphere next to water vapor.

Carbon Sequestering

One of the controversies surrounding the Kyoto Protocols is the concept of carbon credits and carbon sequestering. Natural processes, such as tree growth, remove carbon dioxide from the air and sequester carbon in the plant fibers. As long as the tree is growing, this process will continue to remove greenhouse gases from the atmosphere at a fairly regular rate. Some governments, such as the U.S., want to use this sequestered carbon as a credit that will offset the some of the carbon dioxide that is released by the burning of fossil fuels. However, some people have raised objections to this plan because of some unintended consequences it might have. They argue that using trees as an offset will promote countries cutting down slow growth, indigenous trees in favor of quick growing, foreign species. They also point out that using trees to sequester carbon is only a short-term solution. When the trees decay and rot, the carbon is put back into the atmosphere in the form of carbon dioxide.

The sites below provide some information about the carbon cycle and methods for sequestering carbon.

Carbon Cycle Information

Woods Hole Research Center
Fundamentals of Physical Geography
US Global Change Research Information Office

Carbon Sequestration

Department of Energy
Carbon in a Tree
American Forests

After reading through these and any other sites that you might find, answer the following questions

• Where are the largest reservoirs of carbon on Earth? Is mankind affecting these reservoirs so as to increase the rate of change in carbon stored in them?
• Is using tree growth a valid method for sequestering carbon? Should countries be allowed to use this method for offsetting the amount of carbon dioxide they produce?
• In your opinion, which would be a better use of funding: researching methods for sequestering more carbon, or researching methods for creating energy sources that do not use carbon like wind and solar?