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[]
[]
[]
["Natural and anthropogenic sources"]
["Gas ","Preindustrial level ","Current level   ","Increase since 1750   ","Radiative forcing (W/m2)"]
["Carbon dioxide ","280 ppm "," 387 ppm ","107 ppm ",1.46]
["Methane ","700 ppb ","1745 ppb ","1045 ppb  ",0.48]
["Nitrous oxide ","270 ppb "," 314 ppb "," 44 ppb ",0.15]
["CFC-12 ",0," 533 ppt ","533 ppt ",0.17]
[]
[]
[]
["Anthropogenic greenhouse gases"]
["Seven main fossil fuel combustion sources ","Contribution"]
["(%)"]
["Liquid fuels (e.g., gasoline, fuel oil) ","36 %"]
["Solid fuels (e.g., coal) ","35 %"]
["Gaseous fuels (e.g., natural gas) ","20 %"]
["Cement production "," 3 %"]
["Flaring gas industrially and at wells ","< 1 %  "]
["Non-fuel hydrocarbons ","< 1 %  "]
["International bunker fuels of transport"]
["not included in national inventories "," 4 %"]
[]
["source: http://en.wikipedia.org/wiki/Greenhouse_gas"]