_IMG_Greenhouse_effect.gif
<strong>Greenhouse effect</strong>

When solar radiation reaches the Earth's surface, its heat (<b>infrared waves</b>) is reflected.

<strong>Greenhouse gases</strong> such as <b>carbon dioxide</b> and <b>methane</b> can absorb the
<b>infrared waves</b>, trapping the heat in the atmosphere.
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Positive feedback can result in a <strong>runaway greenhouse effect</strong>,
leading to <strong>global warming</strong> at the end of the
<b>Permian</b> period as well as on _FIG_Greenhouse_runaway.jpg	Venus.
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