Weather -- Atmosphere

Windows to the Universe
Includes a section on Earth, with information about weather events, the atmosphere, and much more. Features three reading levels: beginner, intermediate, and advanced.

Ozone Depletion Resource Center
A collection of Environmental Protection Agency resources on ozone and its depletion in the atmosphere.

The Weather World 2010 Project: Online Guides
Four online guides from University of Illinois Urbana-Champaign Department of Atmospheric Science provide information and instruction on everything from wind and clouds to weather satellites.

A Hole in the Sky: Understanding Ozone Depletion

Though its effects on our weather might be small, the ozone concentrated in the stratosphere is crucial to a hospitable climate. Ultraviolet radiation from the Sun causes cancer, weakens our immune systems, and has other harmful effects. The ozone layer helps protect us from this damaging radiation.

Ozone in the stratosphere protects us by absorbing ultraviolet radiation from the Sun. It is created when oxygen molecules (O₂) are split by ultraviolet radiation into two separate oxygen atoms (O). These oxygen atoms can collide with oxygen molecules to form ozone (O₃).

Many scientists believe that ozone is being destroyed as a result of some industrial activities: specifically, the use of chlorofluorocarbons (CFCs). CFCs are man-made chemicals used mainly in refrigeration. When they make their way up into the stratosphere, CFCs react with ultraviolet radiation to create chlorine. When chlorine reacts with ozone, it destroys it. Ozone depletion is most severe in the polar regions, particularly over the South Pole. According to NASA, ozone levels over Antarctica have decreased 30 to 50% since the 1970s, causing what is referred to as a "hole" in the ozone layer.

Though most countries have banned or pledged to discontinue the use of ozone-depleting substances like CFCs, their effects may continue to be felt for a number of years to come. CFCs linger in the troposphere for years before reaching the stratosphere and the ozone layer. Scientists project that within the next few decades ozone depletion from CFCs will peak and then gradually dissipate.

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"Weather" is inspired by programs from Planet Earth.