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Desert Diary
Climate/Greenhouse Warming


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Think it's hot now?—Just wait. There's a lot we don't know yet about global warming and the greenhouse effect, but we also understand a great deal. What is the greenhouse effect? Everyone has heard the term; few understand it.

First, you need to know that radiation varies greatly in frequency, and the transparency of a substance depends in part on that frequency. Think of X-rays, which pass easily through objects that block visible light.

You're well aware that it's a lot hotter inside a greenhouse than out. This is because incoming radiation from the sun can pass easily through the glass, but much is absorbed by things inside. These items then re-emit radiation at a lower frequency—as heat. The glass, fully transparent to visible light, blocks much of the heat radiation, trapping it inside.

So-called greenhouse gases, such as carbon dioxide, act like glass. Incoming radiation from the sun passes through the gases easily, but passage of heat re-emitted from the earth's surface is impeded. We add constantly to the carbon dioxide of the atmosphere by burning fossil fuels—and thus global warming.
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Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest. rule

Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.



Web Resources

USA Today links to websites on climatic change. rule