Taking flight with Airport Carbon Accreditation Level 5

Making an effective, measurable impact on airport carbon emissions is no easy task without expert support.

Airports face multiple challenges due to their complex operation and many moving interrelated functions. One of the most fundamental is the takeoff and landing of aircraft—a major contributor to scope 3 emissions, which are outside of the direct control of the airport—but also the reason for the airport to exist in the first place. Although airport emissions require a complex, well-planned process of measurement and reduction, solutions are comparatively easier to implement for scope 1 and 2 reductions than for scope 3 emissions.

To assist airports, the Airport Carbon Accreditation (ACA) is a global program that independently assesses and recognizes their efforts to manage carbon emissions. With more than 500 participating airports worldwide, the ACA program signifies substantial progress towards sustainability and environmental responsibility.

The unique demands of ACA Level 5

Some have already reached Level 5, the highest level possible, and we expect more to do the same in the next year or so as industry focus switches to scope 3 emissions reductions.

ACA's Level 5 requires airports to maintain a zero balance on scope 1 and 2 emissions. They also need to address scope 3 emissions, by actively engaging with third parties to drive emissions reductions, and utilize carbon removals for any residual emissions.

Airport Carbon Accreditation level 5 differs from level 4+ in several ways:

• The scope 1 and 2 carbon footprints need to be independently verified as reaching and maintaining ≥ 90% absolute CO₂ emissions reductions.
• Including scope 3 categories should be more detailed.
• Scope 1 and 2 reduction targets need to be stronger.
• A scope 3 emission reduction target of zero by 2050 must be included.
• Relevant organizations within the value chain must be included in the stakeholder partnership plan.
• Airports must use credible carbon removals instead of offsets.

An integrated approach to airport scope 3 emissions

Scope 3 emissions, primarily tied to aircraft takeoff and landing, pose a significant challenge for airports. Yet there are still opportunities to influence emission reductions, despite the lack of direct airport control over this area of operations.

The key is to recognize the interconnectedness of all the emissions-contributing elements of an airport—an understanding that becomes the foundation upon which a roadmap can then be built. This acts as a guide for airports and supports their efforts to achieve emissions reductions.

Crucially, a practical roadmap involves setting milestones. This sets out a realistic framework of achievable targets and is a useful tool against any greenwashing claims by providing more focus points for accountability. It also empowers airports to allocate resources efficiently, focusing on areas that will yield the most significant carbon reduction. Stakeholder partnership plans are also an ACA Level 5 requirement and ensure that all emissions-contributing parties understand that efforts require a unified, holistic approach and that they are actively involved in the process.

An approach needed by airports to address the complexity and range of challenges also requires a multidisciplinary, collaborative team with experience from multiple sectors to support it.

From offsets to carbon removals

ACA Level 5 mandates a shift from traditional offsets to carbon removals. Unlike offsets, removals actively extract carbon from the atmosphere, and are important for a few reasons:

• CDR includes both nature-based removals—for example, wetland restoration, blue carbon management (carbon storage in the ocean), reforestation, and others - as well as technology-based removals such as bioenergy with carbon capture and storage and direct air capture and storage.
• Current obstacles include high costs and technical challenges. Uncertain regulatory requirements also make this market hard to navigate.
• Early investors in CDR will support market development, accelerate growth (including developing business models and financing mechanisms), and become climate leaders.

Strength in collaboration

Level 5 accreditation presents many complex challenges. The intricacies of scope 3 reductions, particularly those associated with aircraft takeoff and landing, demand innovative solutions. The nascent carbon removal landscape also presents its own set of challenges such as prohibitive costs, technical obstacles, and regulatory uncertainties.

However, Level 5 accreditation is not without opportunity. Beyond the environmental benefits, developing an achievable roadmap can also support the airport in securing government funding and advocating for government and utility support.

Our Climate Resilience, Electrification, Energy, and Aviation teams regularly work together to support airports in assessing and addressing emissions from various sources. This collaborative approach allows us to identify strategic areas for intervention on optimal resource allocation and time investment.