Answer
Carbon intensity: a measure for a ship's energy efficiency and is given in grams of CO2 emitted per cargo-carrying capacity and nautical mile.
CO2 Emission: are emissions stemming from the burning of fossil fuels and the manufacture of cement; they include carbon dioxide produced during consumption of solid, liquid, and gas fuels as well as gas flaring.
GHG emissions: Gases that trap heat in the atmosphere are called greenhouse gases. These gases remain in the atmosphere for longer period of time and do not pass the ozone layer, hence contributing to overall global atmospheric temperature increase. Emission of these gases into the atmosphere from human activities is called GHG emissions. Eg: CH4, CO2, N2O, HCFCs, PFCs, SF6, NF3