What does puzzle me though, on the figures quoted, is how you can use an extra 1.6 tonnes of fuel but manage to produce an extra three tonnes of carbon dioxide.
because most of the mass of fuel is carbon (since the rest is mainly hydrogen, which has an atomic mass of 1, compared with 12 for carbon) but So2 is carbon plus oxygen, atomic mass of 16.
So, if you perfectly burned, say, ethanol, C2H6. you'd get IIRC CO2 *2 plus H2O *2.
So for 12*2+1*6=24 units (kg, say) of ethanol, you'd get 12+16*2=44 units (kg) of CO2 plus 2*2*1+16=20 units (kg) of water vapour.
Kerosene isn't ethanol, but the same logic holds. CO2 "mass" includes oxygen that was extracted from the air, not included in the original fuel mass.