Publication Nature Communications Earth and Environment : International maritime regulation decreases sulfur dioxide but increases nitrogen oxide emissions in the North and Baltic Sea

Collaborating with researchers from Germany, the Netherlands, Sweden, and Denmark, researchers from the Institute of Natural Sciences (Ward Van Roy and colleagues) assessed the effectiveness of ship emission regulations that have been in place in the North and Baltic Seas for more than 15 years. The findings of this study were published today, October 26^th, 2023,  in the leading scientific journal Nature Communications Earth and Environment. The study was based on more than 110,000 remote ship plume measurements and on-board inspections. Remote measurements were conducted using various fixed monitoring stations and aerial measurements using drones, helicopters, and fixed-wing aircraft.

The data revealed a substantial improvement in compliance rates for sulfur emission limits since the initiation of these measurements. This positive trend was observed across the Baltic Sea and the North Sea. Nevertheless, it was observed that the introduction of the global cap limit of 0.5% FSC (fuel sulfur content) led to a slight increase in SO₂ emissions in the SECA (Sulfur Emission Control Area) from 2020 onward, possibly due to the increased use of scrubbers and the fuel price inflations.

In contrast to the successful reduction of SO₂ emissions from ships, the international ship emission regulations appeared to have no impact on the nitrogen oxide (NO_x) emissions from ships. In fact, there was even an increase observed of ships’ NOx emissions. This outcome can be attributed to various regulatory gaps in the NO_x regulations, an issue on which the Institute of Natural Sciences and other researchers have published before.

These research findings are of particular importance to policymakers and other stakeholders responsible for environmental regulation and enforcement, as they offer valuable insights for developing more effective regulations and strategies for the implementation of emission regulations and their enforcement at sea and in ports.

The full study can be consulted here, with a ‘Behind the paper’ blog post being accessible here.