<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>

Where are the greenhouse gases located in the atmosphere