Emissions from air freight have increased by 25% since 2019, according to a 2024 analysis by Stand.Earth, an environmental advocacy organization. The increase, attributed to the expansion of cargo-only fleets during the pandemic and disruptions to slower freight modes, has resulted in a yearly increase of almost 20 million tons of carbon dioxide, bringing the total emissions from air freight to 93.8 million tons.

While fleet modernization and operational improvements have contributed to decarbonization efforts, sustainable aviation fuel (SAF) is seen as a key component in reducing the sector's environmental footprint. SAF, when used neat, can reduce the life cycle of greenhouse gas emissions from aviation by as much as 80% compared to conventional fuel. The International Air Transport Association (IATA) estimates that SAF could account for as much as 65% of the total reduction of emissions.

Christoph Wolff, CEO of the Smart Freight Centre, considers SAF the main pathway to decarbonization. The challenge, however, lies in the limited availability and higher cost of SAF compared to traditional jet fuel. This is where the "book and claim" system emerges as a potential solution.

Book and claim is a chain of custody model that separates the physical flow of SAF from its environmental benefits. An airline can "book" SAF by purchasing its environmental attributes, even if the fuel is not physically used on their specific flight. The SAF is then "claimed" by another airline or entity that can utilize the physical fuel. This allows companies to invest in SAF production and claim the emissions reductions, regardless of their location or operational constraints.

The system relies on a robust tracking and verification system, often leveraging blockchain technology, to ensure transparency and prevent double-counting of emissions reductions. Blockchain, a decentralized and immutable ledger, provides a secure and auditable record of SAF transactions, from production to consumption. This helps to build trust and credibility in the book and claim system.

The adoption of book and claim systems could incentivize the production and uptake of SAF by making it more accessible to a wider range of companies. By decoupling the physical fuel from its environmental benefits, companies can contribute to decarbonization efforts even if they do not have direct access to SAF. However, the success of book and claim hinges on the development of standardized methodologies for calculating emissions reductions and ensuring the integrity of the tracking system. Industry stakeholders, including airlines, fuel producers, and regulatory bodies, are currently working to establish these standards and promote the widespread adoption of book and claim.