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= **//How Climate can be influenced by Human Activities//** =

**//Human activities contribute to climate change by causing changes in Earth’s atmosphere. The biggest known cause of this is due to fossil fuels, which release carbon dioxide into the atmosphere. Other causes also are greenhouse gasses and the ozone layer. These changes by human activities have caused a warming change in the climate system. The human impact on climate this era has also noticed changes in natural processes such as, solar changes and volcanic eruptions. //**

= = = = = // __ Green House Gasses: __ // // Human activities result in releasing four greenhouse gasses: Carbon Dioxide //// (CO2), methane (CH4), nitrous oxide (N2O) and the halocarbons. Also all these gasses contribute to the greenhouse effect. // = = = = Ø // Carbon dioxide has increased due to human activities from fossil fuel in transportation, building heat/cooling, and etc. Carbon dioxide is also released in natural processes // = = Ø // Methane has increased by human activities because of agriculture, natural gas distribution and landfills. Methane is also released from natural resources such as wet lands. But this has not been released in the atmosphere recently because in the last two decades growth rates have decreased. // = = Ø // Nitrous Oxide is also transmitted by human activities such as fertilize use and fuel burning. Natural processes in the oceans and soil also release nitrous oxide. // = = Ø // Halocarbon gas concentrations have increased a lot because of human activities. Principal Halocarbons include the chlorofluorocarbons which were used greatly as refrigeration agents and in other industrial processes. They are not used as much now because before they found out that the presence of this in the atmosphere was found to cause stratospheric ozone depletion. Now the use of this gas is decreasing because we want to protect our ozone layer // = = =

**//__The Greenhouse Effect & Ozone Depletion: __//**

**//Greenhouse gasses are made up of many gasses but the major natural greenhouse gases are water vapour, which causes about 36-70% of the greenhouse effect on earth, carbon dioxide, which causes 9-26%; methane, which causes 4-9%, and ozone, which causes 3-7%. //** **//The ozone layer is a layer in the earth atmosphere which absorbs 97-99% of the suns high frequency which is destroying life on earth. It is located at the lower portion of the stratosphere. Human activity is by far the most destructive source of ozone depletion. Human activity such as releasing various compounds containing chlorine, or bromine accounts to 75-85% of ozone damage. //**



**//__Bibliography: __//** **//http://www.solarnavigator.net/greenhouse_gases.htm//** [|**//http://oceanservice.noaa.gov/education/pd/climate/factsheets/howhuman.pdf//**] [|**//http://www.umich.edu/~gs265/society/ozone.htm//**]