The analysis of several scenarios in this study leads to the following insights:

1. The MOF should disclose more detailed plans covering year-by-year financing and fuel utilization measures aligned with its reduction goals. The MOF envisages a much faster reduction trajectory than the IMO’s for the 2030s. This extremely rapid pace of reduction in the initial years necessitates the ecofriendly transition of most vessels within the next decade. However, the USD 6.5 billion required for the next five years significantly dwarfs the ministry’s current investments in ecofriendly ships.

2. It is crucial to accelerate the shift towards ecofriendly vessels, especially those powered by zero carbon fuels. Under Scenario IMO_Net50—the least ambitious policy-driven scenario—can achieve its reduction targets using a fuel blend of methanol, LNG, and LNG-CCS alone. However, the more stringent IMO_Net0 scenario requires a shift to a fuel mix focused on green methanol, green ammonia, and green hydrogen to reach net-zero emissions by 2050. Moreover, gray methanol, blue hydrogen, and blue ammonia—which have higher GHG emission factors (EF) than their greener counterparts—find themselves economically nonviable due to rising carbon prices under the net-zero scenarios. Therefore, a transition to carbon-free fuels must ultimately define the future of maritime shipping.

3. Reduction plans designed specifically for different types of vessels are essential. Among the ten types of vessels considered in this study, it is crucial to formulate more detailed reduction plans for the three key culprits in GHG emissions from ships: bulk carriers, container ships, and crude oil tankers. As the dominant players in maritime logistics, they account for 62.13 percent of the fleet by total deadweight tonnage (DWT) and are responsible for 61.67 percent of the total GHG emissions. Bulk carriers, marked by a higher proportion of older ships compared with other vessel types, face an urgent need for replacement by more efficient new ships. A strong focus on these major ship types is critical to an accelerated transition to an ecofriendly fleet. Moreover, reduction measures must carefully consider the characteristics of each vessel type. For example, retrofitting fuel propulsion systems may be effective for bulk carriers and crude oil tankers. On the other hand, enhancing energy efficiency is paramount for fuel carriers like LNG and LPG ships, where alternative fuel options find limited usage. These targeted approaches will effectively aid the transition to an ecofriendly fleet.

4. Assessment of the existing fossil fuel ships' potential of becoming stranded assets is crucial. As the maritime industry advances towards a net-zero future, carbon costs are expected to rise, foreshadowing the risk of both current and forthcoming fossil fuel-powered ships being reduced to stranded assets. This prospect calls for proactive measures. Attention must also be given to the varying investment requirements across different time slices of reduction pathways. For a transition to an ecofriendly fleet, it is critical to meticulously time and scale the introduction of new low-carbon and zero-carbon ships to strike a strategic balance between old and new vessels and thereby ensure an optimal fleet portfolio. Given these considerations, South Korea must reevaluate its asset structure and new vessel investment strategy from a longer-term perspective than now.