On analysing key drivers of carbon emissions in maritime transport with focus on carbon intensity indicators

To achieve the ambitious net-zero goal by 2050, the Carbon Intensity Indicator regulation has been implemented in maritime transport, expecting it to significantly impact the industry. However, it remains less clear whether changes in carbon intensity indicators have actually an effect on emission trends. To assess this, we use the Logarithmic Mean Divisia Index method to reveal the primary drivers of carbon emissions in the maritime sector. Using decomposition results, we further perform a decoupling analysis to explore the relationship between carbon emissions and industrial growth. The results show that carbon emissions from five representative ship types increased by 15.7% from 2007 to 2018, primarily due to transport scale and capacity effects. Although carbon and energy intensity effects are the most significant drivers of emissions reduction, their annual impacts vary due to differing supply and demand responses to market shocks. Our analysis shows no noticeable decoupling trend, meaning that shipping emissions are still not decoupled from economic activity. However, the energy intensity effect is most influential in achieving strong decoupling. Our findings highlight the need for targeted carbon policies, which consider various intensity metrics, to effectively mitigate emissions and achieve decoupling in maritime transport.