Ports play a key role in the decarbonization programme. Global transport is responsible for about 24% of all CO2 emissions, 10% of which are from shipping.
Despite all the efforts to get to NET-Zero, little progress has really been made by the world’s major ports in terms of environmental sustainability.
On the contrary, in some cases, direct and indirect Greenhouse Gas emissions produced during port or logistics operations (inland transportation of cargo from quay to warehouse) have even increased.
These are the findings that emerge from a study conducted by VesselBot, the leader in Scope3 emissions monitoring and optimization technology (which includes all other indirect emissions that occur in a company’s value chain and include instances of carbon emissions outside the company’s direct physical footprint).
Their report examines the Greenhouse Gas emissions in the first quarter of 2025 from some of the world’s top container ports. They include the North American ports of Long Beach, Los Angeles, Norfolk, Houston and Savannah, the European ports of Rotterdam, Valencia and Algeciras, and the Asian ports of Shanghai, Singapore and Laem Chabang, Thailand.
Vesselbot analysts stated that overall, compared to 2024, they have observed an increase in emissions for most ports, particularly for the ports of Shanghai (CNSHA) and Singapore (SGSIN).
Shanghai is the port with the highest emissions. In the reporting period, the Asian port was responsible for directly and indirectly generating 140,000 tonnes of Greenhouse Gases.
This is a record figure, which can be explained by the increase in shipping activities in and around the port, which is now much more congested than it was in the previous year.
In its analysis Vesselbot considered the efficiency of port operations, the layout of the port and the number of terminals capable of handling ships. Overall, there was an almost linear relationship between the number of ships departing/arriving at a port and the quantity of emissions it produces.
Vessel congestion can also lead to increased emissions and waiting times. From this point of view, efficient, even automated terminals (such as the Tuas Terminal in Singapore) can simplify operations and significantly reduce waiting times, thus speeding up loading and unloading processes.
The pollution caused by ships at berth is significant. Although they switch off their main engine when alongside the quay, containerships keep their auxiliary engine running to support necessary operations and vital functions. These emissions are always the highest, which means that if a port is not able to speed up loading and unloading operations, they are very likely to increase rapidly.
In March 2025, 8.4% of the global container fleet was stranded for days in the harbour before quayside vessel handling operations could begin, with a devastating effect on port pollution levels.
Geopolitical unrest, extreme weather conditions and strikes clearly contributed to longer waiting times, which sometimes exceeded 3 – 4 days. For example, compared to 2024, congestion and port delays have reached critical levels in Northern European ports, like Rotterdam. According to Vesselbot analysts the gradual introduction of new networks, high TEU volumes and delayed ship arrivals outside berthing windows have caused severe congestion and delays in port operations. They also point out that port layouts also contribute to emission levels.
In this respect, the report highlights how the port of Houston in the US and Rotterdam in the Netherlands require ships to travel at reduced speed on rivers and canals for several kilometres before reaching their terminals. Increased congestion at these ports may not only lead to longer waiting times, but also to greater emissions. In February 2025, the Port of Houston experienced delays due to heavy fog, which prevented ships from sailing along its waterway.
Vesselbot’s analysis shows that Singapore is, after Shanghai, the port of call with the highest level of pollution. Between January and March, the port was responsible for over 80,000 tonnes of emissions.
Rotterdam is the European port with the largest amount of emissions with almost 50,000 tonnes in the reporting period. US ports also recorded significant levels of pollution. They handled record volumes between January and March due to frenzied front-loading by US importers, tormented by the need to get as much goods from China as possible before the introduction of Trump’s announced tariffs.
“This report reveals the complex relationship between port activity and emissions,” said Constantine Komodromos, CEO and founder of VesselBot. “Our data shows that while more vessels generally mean more emissions, performance and operational efficiency are crucial mitigating factors.”
However, the decarbonization of the shipping sector requires a multifaceted approach. The report concludes that ports have to acquire real-time data to optimize operations, reduce idle emissions and better manage vessel flows. Policies, technology and collaborative international logistics strategies will be key to realising a low-carbon future for shipping.
Translation by Giles Foster
