Priyanka+C.

TOPIC 5: Describe how climate can be influenced by human activities (eg. Greenhouse gasses, depletion of ozone layer)  The climate is definitely influenced by human activities. The activities that we contribute to the climate cause changes in the atmosphere. The largest known contribution to the climate is burning of fossil fuels; burning fossil fuels releases carbon dioxide in the air. Greenhouse gases and aerosols also affect the climate; they affect the atmosphere by altering incoming solar radiation and out-going infrared radiation that are part of Earth’s energy balance.  __Greenhouse Gases __  Our activities result in emission of four main greenhouse gases: carbon dioxide, methane, nitrous oxide, and halocarbons. These gases come together in the atmosphere and creates concentration.  · Carbon dioxide (CO2) has increased from fossil fuel and it is used for transportation, building heating, and the manufacture of cement and other goods. Carbon dioxide is released in natural processes such as the decay of plant matter · Methane (CH4) has increased from human activities by agriculture, natural gas distribution and landfills. Methane is also released from natural processes. · Nitrous oxide (N2O) is emitted by human activities such as fertilizer use and fossil fuel burning. Natural processes in soils and the ocean also releases nitrous oxide. · Halocarbon gas has increased due to human activities; halocarbon gas includes the chlorofluorocarbons. The enormous amount of chlorofluorocarbon gases is decreasing due to international regulations; designed to protect the ozone layer. · Ozone is a greenhouse gas that is continually produced and destroyed by chemical reaction. In the troposphere, the human activities have increased due to release of gases such as carbon monoxide, hydrocarbons, and nitrogen oxide; which chemically reacts to produce ozone. · Water vapour is the most abundant and important greenhouse gas in the atmosphere. However, human activities have very small affect in the atmosphere. Human have the potential to affect this greenhouse gas by changing the climate. · Aerosols are small particles in the atmosphere with concentration and chemical composition. Aerosols have both naturally occurring compounds and emitted due to human activities such as: fossil fuel and biomass burning. Also surface mining and industrial processes increased dust in the atmosphere.  <span style="font-family: 'Calibri','sans-serif'; font-size: 12.5pt;"><span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">                <span style="font-family: 'Arial','sans-serif'; font-size: 10pt;">                <span style="font-family: 'Calibri','sans-serif'; font-size: 12.5pt;"> <span style="font-family: 'Calibri','sans-serif'; font-size: 12.5pt;"> <span style="font-family: 'Calibri','sans-serif'; font-size: 12.5pt;">(This diagram shows that human activities really changed the climate and the natural systems.)

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