The depletion of the stratospheric ozone layer via CFCs and and global warming due to CO₂ deposition into the atmosphere are:

Let's end the confusion now and remember this for the second exam.

Global Warming: This is caused by the build up of CO₂ and CH₄ in the lower atmosphere of the earth. These gases increase the infrared absorption potential of the lower atomsphere and hence increases its ability to retain heat.

Ozone Depletion: This occurs in the stratosphere at a height of about 15 km above the surface. The depletion of Ozone means that more UV radiation from the sun reaches the surface. This does not make the surface hotter, as only a small percentage of sunlight is in the form of Ultraviolet radiation.

The ozone layer itself does not reduce the overall amount of visible radiation which reaches the surface and does most of the heating. Hence removal of the ozone layer does not make the earth substantially warmer.

The Current Status of the Ozone Problem (as of 10/96):

Ozone Depeletion
Oct 30, 1996 Hole size

Long Term Evolution:

Latest Results (9/1/96 - 10/14/96)

Overview:

• Location of Ozone Layer

• Ozone Destruction Mechanism

• Balance in the Stratosphere

• Annual Data on Ozone Levels

• Oct. 15 Annual Data on Ozone Levels

• Annual Ozone Hole Size Data

• Annual Minimum Levels

• Switzerland Annual Data

• MPEG Animation of 1994 Hole

• A Bigger Animation

• Ozone Mythology

1995 Hole data:

Why do we see the hole in the Antarctic Spring?

Chlorine from CFCs is stored on stratospheric cloud surfaces during the long polar night and then released to attack ozone when the sun returns in spring. The process involves a series of unusual chemical reactions taking place at temperatures as low as -85 degrees C (188K). Normal ozone levels are restored in the summer when the Antarctic atmosphere, isolated during the winter inside a cold "polar vortex", becomes mixed with ozone-rich air from other latitudes.

Expectations for this Spring (i.e. right now)

The Antarctic spring of this year is arriving, and with it the annual depletion of ozone within the south polar vortex. In recent years, the destruction of ozone within the lower stratospheric region from 14 to 20 km has been virtually total.

Where are we Now?

Internet Resources Relevant to the Ozone Problem:

• Ozone Hole Image Archive
• Frequently Asked Questions
• Canadian Weekly Ozone Watch
• Ozone Page from Sweden; nice collection of references
• NASA Fact Sheet
• EPA Straospheric Ozone Page
• What about Bromides?
• Ozone Reality Check

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