Global Warming is an increase in the temperature of the Earth due to the use of fossil fuels and industrial processes that build up to the emission of greenhouse gasses, mostly carbon dioxide and methane ("Global Warming Threatens"). As energy from the sun strikes the surface of the earth, it turns into heat which, in turn, releases the heat as long-wave infrared radiation (Crowe). Gasses in the air, such as carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, and water vapor, trap some of this radiation as it tries to make its way back out to space (Olgesby). These gases trap in heat as do the windows of a greenhouse; therefore, they are called greenhouse gases (Elston). As an excess amount of these gasses are emitted into the Earth's atmosphere by industries and fossil fuels, the temperature of the Earth's atmosphere gradually increases (Oglesby). Humans escalate the amount of greenhouse gasses in the atmosphere by burning fossil fuels and by many manufacturing processes (Crowe). In the U.S., from 1990-1997, carbon dioxide emissions have increased 10.7 percent (Elston). This activity and a warming atmosphere are causing drastic changes around the earth, especially in Florida.
Global warming poses a threat to Florida's beaches and freshwater supplies due to a rise in sea level ("Southeast"). Warming the atmosphere will raise sea levels by expanding ocean water, melting mountain glaciers, and melting parts of the Greenland Ice Sheet ("Beach Erosion"). The Intergovernmental Panel on Climate Change estimates that the local sea levels may rise 8 to 30 inches by the year 2100 ("Global Warming Threatens..."). The horizontal advance can be 150 to 200 times greater than the sea level rise, and even greater in areas with a moderate sloping shoreline (Alvarez et al). Consequently, saltwater will be forced to move landward, which shifts the border between saltwater and freshwater inland and causes the encroachment of saltwater into groundwater aquifers ("Southeast"). Over the longer-term, a three-foot sea level rise could be disastrous for aquifers in Ft. Lauderdale, Miami and Homestead areas, which are located on the low coastal ridge (Alvarez et al).