Atmospheric Gases: How Humans Affect Global Climate
Joseph B. Yavitt

Some atmospheric trace gases that contribute to the so-called “greenhouse effect” originate through biological processes occurring in soil, sediments, and in wetlands. While essential for keeping the Earth’s climate in balance, there is much concern that changes in land use and other human activities might be altering the flux of such gases from sources into the atmosphere. For example, cutting down forest to make agricultural fields can contribute to the increase of carbon dioxide and nitrous oxide in the atmosphere.

This exploration will acquaint students with biosphere-atmosphere exchange of “greenhouse” gases. We will visit local forest, field, and wetland areas and measure gas flux between soil (or sediment) and the atmosphere. We will then go into the laboratory and use a gas chromatograph to analyze the gas samples. The results will be interpreted in an ecological context considering the ramifications of human land-use patterns. We will discuss the uncertainty in such studies and relate the uncertainty to important management and policy decisions concerning the modification of human behavior to prevent abrupt climatic change.