A gradual increase in the overall temperature of the earth’s atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants.
Climate change is any substantial change in Earth’s climate that lasts for an extended period of time. Global warming refers to climate change that causes an increase in the average temperature of the lower atmosphere. Global warming can have many different causes, but it is most commonly associated with human interference, specifically the release of excessive amounts of greenhouse gases. (EPA, 2006)
Greenhouse gases, such as carbon dioxide (CO2), methane (CH4), water vapor, and fluorinated gases, act like a greenhouse around the earth. This means that they let the heat from the Sun into the atmosphere, but do not allow the heat to escape back into space. The more greenhouse gases there are, the larger the percentage of heat that is trapped inside the earth’s atmosphere. The earth could not exist in its present state (that is, with life) without the presence of some naturally occurring greenhouse gases, such as CO2, CH4, and water vapor. Without any greenhouse gases no heat would be trapped in atmosphere, so the earth would be extremely cold. (NASA, 2002)
Naturally occurring greenhouse gases (not fluorinated gases) are good in naturally occurring amounts; it’s when people start contributing excessive amounts of them that greenhouse gases become a problem. With excessive greenhouse gas buildup, the earth’s atmosphere warms to unnatural temperatures which causes, among other things, sea level to rise. Global warming also causes sea surface temperatures to rise, precipitation patterns to change, etc.. (NASA, 2002)
In February 2007, the United Nations released a scientific report that concludes that global warming is happening and will continue to happen for centuries. The report also stated with 90% certainty that the activity of