Nice job Kurt. Contest this link? It's not rocket science you know
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http://www.nasa.gov/worldbook/global_warming_worldbook.html
"A majority of climatologists have concluded that human activities are responsible for most of the warming. Human activities contribute to global warming by enhancing Earth's natural greenhouse effect.
The greenhouse effect warms Earth's surface through a complex process involving sunlight, gases, and particles in the atmosphere. Gases that trap heat in the atmosphere are known as greenhouse gases."