... is also intensified by the process of deforestation, which is the conversion by humans of forest land to other uses (such as farming). Deforestation now takes place on a large scale in tropical areas of the world. When tropical forest is cleared for pasture land, there is an immediate loss of carbon to the atmosphere as carbon dioxide. One current study indicates that as much of 25% of the current level of CO2 emissions can ... initiatives to develop alternative sources employ fossil fuel energy for their efforts. Ozone Layer Another issue of concern is the depletion of the ozone layer ...

• Word Count: 1531
• Approx Pages: 6
• Grade Level: Undergraduate

... of climate across the surface of the planet. An increase in average global temperature of 0.7 C has already been measured, and present rates of emission of greenhouse gases are committing the Earth to an additional warming of about 0.3 C per decade. We are also adding small particles and droplets called aerosols that reflect light back into space and tend to cause some areas to cool. It is because they trap heat like ... are rising into the air over the forest. The desire of developed countries for inexpensive meat and forest products is another major contributor to deforestation. The s...

• Word Count: 2775
• Approx Pages: 11
• Grade Level: Undergraduate

... gas, and many household products give off Volatile organic chemicals. Some of these pollutants also come from natural sources. For example, forest fires emit particulates and Volatile organic chemicals into the atmosphere. Ultrafine dust particles, dislodged by soil erosion when water and weather loosen layers of soil, increase airborne particulate levels. Volcanoes spew out sulfur dioxide and ... more cataracts (clouding of the lens of the eye), and reduced yields of some food crops. Humans are bringing about another global-scale change in the atmosphere: the increase in what are calle...

• Word Count: 6167
• Approx Pages: 25
• Has Bibliography
• Grade Level: Undergraduate