Q&A: Why shipping needs better emissions monitoring
As shipping faces growing pressure to reduce its environmental impact, the focus is often placed on new regulations and targets. However, regulations can only be effective if they are properly enforced.
In this Q&A, SeaARCTOS CEO Fredrik Fuglesang discusses the shortcomings of current emissions monitoring practices, why more accurate data is needed, and how real-time monitoring technology could transform compliance across the maritime industry.
Why does maritime emissions monitoring need a new approach?
Compliance with emissions regulations should be easier, faster and more transparent for everyone involved. Today, much of the administrative burden and cost associated with enforcing emissions regulations falls on port authorities and Flag States. This can make widespread monitoring and enforcement difficult and expensive.
Direct, real-time and autonomous emissions monitoring offers a different approach. By continuously measuring emissions and automatically reporting results, responsibility can be placed with shipowners and operators without creating significant additional workload.
Beyond regulators, other stakeholders also benefit from more reliable emissions data. Cargo owners, financiers and classification societies increasingly require dependable information to support decision- making, while shipowners gain stronger reporting capabilities, simplified auditing processes and clear evidence of compliance.
Which emissions should the maritime industry be monitoring?
A comprehensive approach to emissions monitoring should include:
- Carbon dioxide (CO₂)
- Methane (CH₄)
- Nitrogen oxides (NOₓ)
- Sulphur oxides (SOₓ)
- Particulate matter (PM), including black carbon
While much of the regulatory focus has been on greenhouse gas emissions such as CO₂ and, increasingly, methane, local pollutants including SOₓ, NOₓ and particulate matter remain a significant environmental and public health concern.
Monitoring all these emissions provides a more complete picture of a vessel's environmental performance.
Why is methane monitoring becoming more important?
Methane has a significantly higher global warming potential than carbon dioxide, making accurate measurement increasingly important. As more LNG-fuelled vessels enter service, regulators and shipowners need a clearer understanding of methane slip, the unburned methane released from engines during operation.
Current estimation methods may either overstate or understate actual emissions. In some cases, operators that have invested in reducing methane slip may still be charged for emissions that are not occurring in practice. Direct measurement can help ensure emissions are accurately reported while creating stronger incentives for investment in cleaner technologies and operational improvements.
Why does local air pollution still matter?
Local air pollutants continue to have a direct impact on human health, particularly for seafarers, port workers, passengers and communities located near ports and shipping corridors. Emissions such as sulphur oxides, nitrogen oxides and particulate matter are linked to respiratory illnesses and can worsen existing health conditions. Long-term exposure has also been associated with more serious health risks, including cardiovascular disease and certain forms of cancer. Reducing these emissions is therefore important not only for environmental protection but also for public health.
What are the current sulphur emissions regulations?
The introduction of the global sulphur cap in 2020 reduced the allowable sulphur content in marine fuel from 3.5% to 0.5%.
Ships operating outside Emission Control Areas (ECAs) must either use compliant low-sulphur fuel or install exhaust gas cleaning systems, commonly known as scrubbers.
Within ECAs, the sulphur limit is stricter at 0.1%. Existing ECAs are now being joined by new regions, including the Mediterranean Sea, which entered into force in 2025. More recently, the International Maritime Organization (IMO) formally adopted the North-East Atlantic as a new Emission Control Area, with a 0.1% sulphur cap due to take effect in 2028. Together with the Baltic Sea, North Sea, Norwegian Sea and Canadian Arctic ECAs, an increasing proportion of the world's busiest shipping routes will soon be subject to stricter sulphur controls.
The regulations themselves are clear and widely supported. The greater challenge lies in ensuring effective and consistent enforcement.
What is wrong with current sulphur compliance testing?
Current sulphur compliance testing relies on a process that can be both slow and expensive.
Typically, a fuel sample is collected by a surveyor and sent to an independent laboratory for analysis. The entire process can cost thousands of dollars and may take up to 10 days to complete.
By the time results become available, the vessel may have departed and travelled far beyond the port where the sample was taken.
If non-compliance is identified, enforcement becomes significantly more complicated. As a result, many port authorities and Flag States face practical and financial barriers to conducting widespread testing programmes.
What other challenges exist for emissions compliance?
Beyond fuel testing, the maritime industry faces growing challenges related to emissions data management.
Large volumes of operational and environmental data must be collected, verified, stored and presented in an audit-ready format. This requires robust data management systems capable of supporting compliance, reporting and verification requirements.
At the same time, many existing Continuous Emissions Monitoring Systems (CEMS) can struggle to provide consistent and accurate results in harsh marine operating environments.
Improving both data quality and accessibility will be critical as emissions regulations continue to evolve.
How can real-time emissions monitoring help?
Real-time emissions monitoring allows emissions to be measured directly at the source and reported automatically.
Rather than relying on periodic sampling and delayed laboratory analysis, continuous monitoring provides immediate visibility into a vessel's emissions performance.
SeaARCTOS' ARCTOS-1™ system, for example, is installed directly on a vessel's exhaust stack and provides continuous emissions measurements in real time. Data is securely transmitted to a cloud-based platform, giving shipowners, operators, port authorities and regulators access to timely and verifiable emissions information.
This approach can help reduce administrative burdens, strengthen compliance processes and provide greater confidence in reported emissions data.
Looking ahead
Shipping emissions regulations can only achieve their objectives if they are supported by effective monitoring and enforcement.
Current compliance methods can be costly, time-consuming and difficult to scale. As environmental requirements continue to expand, the industry will need faster, more transparent and more reliable ways to verify emissions performance.
Real-time emissions monitoring has the potential to close that gap providing regulators, ports and ship operators with the evidence needed to ensure regulations deliver meaningful environmental outcomes.