The challenge of benchmarking carbon emissions in maritime ports

The carbon footprint of ports is an essential step in understanding the most impactful activities in ports and designing reduction strategies to comply with the ambitious target set up by the International Maritime Organization (IMO) of cutting GHG emissions by 50% until 2050 (compared to 2008 levels). Acknowledging the importance of decarbonization, several ports have started to report their carbon emissions in recent years. However, currently, there is not a commonly acknowledged approach to quantify the carbon footprint of ports, making the benchmarking of ports that is the main goal of this paper, a challenging task. The focus is on the topmost polluting European ports, although other major ports outside Europe are also considered. Results show that considering only GHG emissions controlled by port authorities (Scope 1) and emissions related to purchased electricity by port authorities (Scope 2), the carbon footprint of EU ports ranges from 0.017 kg CO₂ eq./tonne to 1.27 kg CO₂ eq./tonne. When, in addition, indirect emissions from sources not owned or controlled by port authorities (Scope 3) are considered, then the range of values varies from 2.0 to 5.4 kg CO₂ eq./tonne. Moreover, results show that Scope 3 is usually neglected in the inventory of emissions of ports due mainly to the complexity of setting the boundaries and extensive data collection. However, when emissions associated with vessels are considered, the contribution of Scope 3 becomes dominant, with shares higher than 97%. Finally, given the importance of having consistent benchmarks for the carbon footprint of ports, this paper further suggests the need for adopting a standardized approach to calculate the carbon footprint of ports.