<Li> agricultural activities, including the use of fertilizers, that lead to higher nitrous oxide (N O) concentrations . </Li> <P> The seven sources of CO from fossil fuel combustion are (with percentage contributions for 2000--2004): </P> <Table> <Tr> <Th> Seven main fossil fuel combustion sources </Th> <Th> Contribution (%) </Th> </Tr> <Tr> <Td> Liquid fuels (e.g., gasoline, fuel oil) </Td> <Td> 36% </Td> </Tr> <Tr> <Td> Solid fuels (e.g., coal) </Td> <Td> 35% </Td> </Tr> <Tr> <Td> Gaseous fuels (e.g., natural gas) </Td> <Td> 20% </Td> </Tr> <Tr> <Td> Cement production </Td> <Td> 3% </Td> </Tr> <Tr> <Td> Flaring gas industrially and at wells </Td> <Td> <1% </Td> </Tr> <Tr> <Td> Non-fuel hydrocarbons </Td> <Td> <1% </Td> </Tr> <Tr> <Td> "International bunker fuels" of transport not included in national inventories </Td> <Td> 4% </Td> </Tr> </Table> <Tr> <Th> Seven main fossil fuel combustion sources </Th> <Th> Contribution (%) </Th> </Tr>

Most greenhouse gas emissions (44 ) are coming from which type of fossil fuel