The earth is about 4.5 billion years old, and during its
life, the climate has changed quite often and the planet has experienced an Ice Age, warming, and everything in between. Scientists agree that the Earth's averge termperature has increased by about 1.8° F over the past 200 years. It may not sound like a big change, but it will influence the earth. The earth is covered like a greenhouse, which is used by some farmers, florists, and others to grow plants. A greenhouse is a glass-covered building that absorbs the heat from the sun it is usually very hot. Of course, the earth is not covered with glass, but the greenhouse effect refers to the retention of the sun's warmth in the earth's lower atmosphere by greenhouse gases. The greenhouse glass include mostly carbon dioxide, methane, and nitrous oxide. These gases (instead of glass) act as a blanket for the earth, helping to keep the earth warm enough to support life at an average temperature of about 50° F. An increase in the greenhouse gases the earth to become warmer. Think of it as a heavier blanket. The 'blanket' is created by the gases released into the atmosphere when fossil fuels-such as oil, coal, and natural gas-are burned.