Case Study
Deforestation

Well, here we are. You're sitting at the table waiting for your experiments to conclude and you've got some time to kill. Let's use this time to investigate the intricate relationship between vegetation and climate change through an online case study.

By now you've seen that vegetation can have a profound influence on the cycling of carbon, and thereby on the regulation of global climate. The current increases in atmospheric carbon dioxide concentrations are thought to be caused by the combustion of fossil fuels and by the rapid rates of deforestation currently occurring in tropical forests. By adding carbon dioxide to the atmosphere and destroying the ability to remove it through photosynthesis, this combination of fossil fuel combustion and deforestation may be drastically impacting the systems that affect planetary climate.

Slash and burn agriculture

So why are tropical forests declining? These forests are often cleared by peasant farmers with a technique called "slash and burn agriculture" in which the farmers cut all of the vegetation on a plot of land, then burn it to clear the vegetation and fertilize the soil. This process not only removes vegetation that could reduce atmospheric carbon dioxide levels through photosynthesis, but also adds carbon dioxide to the atmosphere when the vegetation is burned.

Land area occupied by tropical forests has been declining since 1800, and deforestation rates have accelerated in recent decades. In this section, you will examine a case study on tropical deforestation that illustrates the complex nature of this issue. Deforestation is influenced by a variety of factors, particularly the elevated rates of poverty in the developing world, and the case study will help you to understand the process.

The case study was created by Phil Camill of Carleton College in Minnesota for the National Center for Case Study Teaching in Science. Read sections I and II, and then complete the questions on the assignment sheet. If you are unable to load or complete the case study while in lab, you should complete it at a later time during the week.

Case study URL: http://ublib.buffalo.edu/libraries/projects/cases/amazon.html

To better understand the factors affecting tropical deforestation, listen to the National Public Radio segment below that discusses the role of roads in accelerating deforestation rates in the Amazon. Listen to the segment prior to coming to lab, or at some point during the week after you have completed the lab. Do not listen to it during lab as the sound could greatly distract those around you.