32. The Ozone Layer
The Atmosphere, the Ocean and Environmental Change (GG 140) Stratospheric ozone is important as protection from harmful ultraviolet solar radiation. Ozone in the stratosphere blocks almost all UVC radiation, which is extremely energetic and harmful. Ozone within the ozone layer is destroyed through chemical reactions involving chlorine atoms and the ozone molecules. The main anthropogenic source of chlorine in the atmosphere is chlorofluorocarbons (CFCs). Emissions of CFCs began to increase after 1960 and continued to increase until the 1990s. The 1987 Montreal Protocol banned the emission of CFCs as of 1994, and currently CFC emissions are nearly zero. 00:00 - Chapter 1. Terminology for Stratospheric Ozone 00:01 - Chapter 2. The Ozone Layer 11:06 - Chapter 3. The Dobson Unit 15:05 - Chapter 4. Origin and Maintenance of Ozone in the Stratosphere 26:22 - Chapter 5. The Ozone Hole 37:51 - Chapter 6. The Montreal Protocol Complete course materials are available at the Open Yale Courses website: http://oyc.yale.edu This course was recorded in Fall 2011.