Hundreds of billions of tons of carbon dioxide are absorbed by oceans and living biomass and represent ‘SINKS’ within the global carbon cycle. This carbon dioxide is then emitted back into the atmosphere through natural processes such as respiration and decomposition and are known as ‘SOURCES’.
Approximately 99% of additional carbon dioxide emissions are added to our atmosphere annually from the combustion of fossil fuels such as petroleum, coal and natural gas. These omissions are then reduced by approximately 14% due to the carbon dioxide being absorbed by land use and forest sinks. This gives a net emission of carbon dioxide from the burning of fossil fuels of approximately 85%.
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Sources |
Emission Processes |
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Combustion of Fossil Fuels for residential, commercial, industrial, and transportation uses. 85% of CO2 emissions |
66% of CO2 emissions come from the production of electricity for lighting, heating, cooling, and operating appliances. The rest is from emissions due to the consumption of gasoline, diesel, and jet fuel for transportation. |
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Cement Manufacture 0.7% of CO2 emissions |
Carbon dioxide is created when calcium carbonate (CaCO3) is heated to from lime for later use in cement. |
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Natural Gas Flaring 0.3% of CO2 emissions |
Carbon dioxide is produced when methane (CH4) from oil wells is burned to reduce pressure. |
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Lime Manufacture 0.3% of CO2 emissions |
Carbon dioxide is released when limestone is heated to produce lime for use in steel manufacturing, construction, pulp/paper industry, and water and sewage treatment. |
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Biomass Combustion (The annual planting and growing cycle of biofuel crops offsets most of this source.) |
Carbon dioxide is released when fuel wood and wood waste is burned. This also includes the burning of ethanol blends (gasohol) by vehicles. |
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Limestone and Dolomite Use 0.1% of CO2 emissions |
Carbon dioxide is released as a by-product in a number of industries including: construction, agriculture, and chemical and metal manufacture. |
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Soda Ash Manufacture and Consumption <0.1% of CO2 emissions |
The manufacture of soda ash (sodium carbonate – Na2CO3) releases CO2. Soda is used in producing glass, soaps, paper, textiles, and foods. |
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Carbon Dioxide Manufacture <<0.1% of CO2 emissions |
Carbon dioxide is used directly in the production of carbonated drinks, foods, and some chemical processes. |
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Sinks |
Absorption Processes |
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Land Use Change and Forestry -14% of CO2 emissions |
Carbon dioxide is absorbed from the atmosphere when the following are done: *improved forest management *regeneration of forests *tree-planting programs *soil conservation programs *converting marginal croplands to forests |
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