Additionality in a nutshell
In the world of maritime sustainability, "additionality" is a key concept, but it often sounds more complicated than it actually is. At its core, additionality asks a simple question: Would this environmental benefit have happened without intervention or investment from the customer? If the answer is no, then the action is considered "additional" - meaning it truly contributes something new to the fight against climate change.
Taking an example from the real world, if a shipping company did not purchase Sustainable Maritime Fuel (SMF), would this fuel still be used? If the answer is no, then it means that your company was responsible for the additional use of SMF.
Current debate around additionality
While additionality is a crucial step in verifying impact, it can lead to debates and confusion regarding its implementation. How can we determine if a company’s actions actually led to the use of SMF?
Fortunately, there is a consensus on how you can determine this:
SMF is not additional if its use is required by regulation. The threat of penalties from legal authorities drives the decision to use SMF, not the actions of customers.
SMF is additional if its use is not required by regulation. When a shipping company uses more sustainable fuel than required by regulation, it is the company’s desire to decarbonise, rather than legal penalties, that leads them to use this fuel.
Why It Matters for Maritime Decarbonization
The decarbonization of the maritime sector is a challenging endeavour, and progress must be both measurable and meaningful.
Additionality has been introduced to ensure that companies are making an actual difference and that the efforts and the money they put into book and claim is driving real change.
Additionality and Book & Claim
One of the most promising tools for accelerating sustainability in shipping is the book & claim system. This model allows companies to support the use of SMF even if they can’t physically access it. Instead of buying the fuel directly, they purchase the “booked” environmental attributes and claim the climate benefit. This system helps scale demand for sustainable fuels across the industry, making it easier for fuel producers to invest in low-emission alternatives.
But here’s the catch: for book & claim to be credible, the climate benefits must be additional. That means the SMF wouldn’t have been produced or used without the support of the book & claim buyer. If the fuel was going to be used anyway then the buyer isn’t actually influencing the trajectory of decarbonization. Ensuring additionality helps builds trust in the system.
Making Additionality Transparent and Verifiable
To safeguard additionality, book & claim systems require robust tracking and verification mechanisms, as well as clear guidelines on how to assess additionality. This includes clear documentation of fuel production, lifecycle emissions, and understanding the influence of regulations on the use of the fuel. Third-party verification and independent registries help ensure that each claim is backed by real, additional impact. Without these safeguards, book and claim risks losing credibility - and its power to drive real change. One such example of clear guidelines on assessing additionality is the paper jointly published by the Global Maritime Forum and the Maersk Mc-Kinney Møller Center for Zero Carbon Shipping, available here.
In Summary: Additionality for Impact, Not Just Optics
Additionality isn’t just a technical term - it’s a safeguard for integrity. In the maritime sector, where sustainability is both urgent and complex, it ensures that every climate claim reflects real progress. As book & claim systems gain traction, understanding and enforcing additionality will be key to turning good intentions into lasting impact.
Do you want to know more about Katalist or see the platform in action?