... alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. 2.2 What Is Global Warming? Global warming is the increased heat trapped in the earth's atmosphere resulting from excess greenhouse gases such as Carbon Dioxide (CO2). These naturally occurring gases including Methane (CH4)  & Nitrous Oxide (N20) form a layer ... surface. In turn, the earth radiates energy back into space and some atmospheric gases (water vapour, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat so...

• Word Count: 1933
• Approx Pages: 8
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• Grade Level: High School