The proposed amendments to the MARPOL convention would require ships to combine a technical and an operational approach to reduce their carbon intensity, and would add further requirements to the energy efficiency measures in MARPOL Annex VI chapter 4. Current requirements are based on the Energy Efficiency Design Index (EEDI), for newbuild ships, which means they have to be built and designed to be more energy efficient than the baseline; and the mandatory Ship Energy Efficiency Management Plan (SEEMP), for all ships. The SEEMP provides for ship operators to have in place a plan to improve energy efficiency through a variety of ship specific measures.

It was reported the IMO initial strategy’s ambition to improve carbon efficiency of the fleet by 40% by 2030 compared to 2008 is silent on how carbon efficiency shall be measured. Thus the 2030 ambition may, or may not, result in lower total emissions from the fleet, dependent upon the metric chosen and resulting change in operational behaviour of ships.