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Global Warming

August 2001 - -

One of planet earth's unique characteristics is a warm average temperature of 57ºF that enables it to support the flourishing life that exists today. A phenomenon known as the greenhouse effect is responsible for maintaining this comfortable temperature. Unfortunately, human activities over the last century have disrupted the earth's natural balance by enhancing the greenhouse effect and initiating a frightening trend of global warming.

Under normal conditions, a delicate balance exists between incoming energy from the sun (solar radiation) and outgoing energy from the earth in the form of reflected light and heat (infrared radiation). Some heat is naturally trapped inside the atmosphere by naturally occurring "greenhouse gases" such as carbon dioxide, water vapor, nitrous oxide, methane, and ozone. This natural heat-trapping process is known as the "greenhouse effect," and is essential for maintaining the warm temperatures that support life on this planet. Without it, the earth's temperature would be about 0ºF- too cold for most life forms.

As mentioned above, most greenhouse gases (carbon dioxide, water vapor, nitrous oxide, methane, and ozone) are naturally occurring in certain amounts. Normally these gases are roughly balanced in global cycles; atmospheric gases are emitted by sources such as wetlands or decomposing biomass and absorbed by "sinks" such as forests and oceans. Over the last century, however, human activities have added abnormal amounts of these greenhouse gases into the atmosphere- far more than the earth's sinks are capable of absorbing. As atmospheric concentrations of these gases increase, the natural equilibrium is disrupted and the greenhouse effect is enhanced. The result is global warming, a gradual increase in the earth's overall average temperature.

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