Global warming
...e depleting substances such as CFCs, also known as Chlorofluorocarbons, hydrofluorocarbons, and perfluorocarbons. These gases are generated by a number of human activities such as fossil fuel combustion, waste disposal in landfills, the use of a refrigerator, numerous agricultural and industrial activities, and the cutting down of numerous forests. These human practices have already changed the chemical make up of the atmosphere. Between the pre-industrial times and today, we have seen the concentration of carbon dioxide rise 30% in some regions, in particular the northern hemisphere, human practices have increased concentrations of aerosols in atmosphere, which is a traditional form of air pollution), which tends to cool the atmosphere. With all these gases in the air, it is starting to change the EarthÆs climate. The temperature of the EarthÆs surface is as warm, if not warmer than it has been in any other century since at least 1400 AD. The temperature over the past century has risen one degree Fahrenheit over the last century. These last few decades have been the warmest this century. The sea level has risen 4 to 10 inches, and mountain glaciers world-wide have begun to retreat. It is important to recognize that with the recent warming and the other climatic changes that have been going on have not been related to one another. For example, warming has been greatest over the mid-latitude continents in the winter and spring, with some area of cooling, such as over the North Atlantic Ocean. Local and regional climate variation are not inconsistent with the existence of global warming. One recent study by the IPCC (Intergovernmental Panel on Climate Change) said that unless governments do something to restrict the emissions of greenhouse gases to a lower level, global temperatures could rise 1.6 to 6.3 degrees Fahrenheit by the year 2100. This would represent the fastest rate of global warming since the end of the last ice age more than 10,000 years ago. With the increased warming of the Earth it could lead to catastrophic events that could endanger living things on our planet. One event is major drought all around the world. With the warming of the planet, the water on the ground would quickly evaporate causing the rivers and lakes to quickly dry up. This would lead to crops dying from lack of rain, which would lead to food pr...