From Terminals to Transformation: The Hidden Climate Role of Airports

When it comes to sustainability in aviation, we tend to look to the skies, focusing on how aircraft themselves can become more eco-friendly through innovations like Sustainable Aviation Fuel (SAF). But one area often overlooked in the public imagination is the airport itself. Many airports function like mini-cities, complete with terminals, shopping areas, restaurants, lounges, internal transit, and support infrastructure. Because of their scale and complexity, airports offer a high-leverage opportunity to reduce the environmental footprint of the entire aviation system.

Measuring What Matters: How the ACA Framework Guides Airport Climate Action

To guide and benchmark climate efforts, the industry uses the Airport Carbon Accreditation (ACA) scheme, administered by Airports Council International (ACI). At Level 1 (Mapping), airports begin by calculating their direct and indirect emissions—Scope 1 and 2—as a foundation for future reductions. At the other end of the spectrum, Level 5 (Net Zero) is awarded to airports that have nearly eliminated these emissions and have plans in place to address Scope 3 emissions, which come from third parties like airlines, ground transport, and tenants. The ACA scale reflects a progression from measuring impact to actively decarbonizing the entire airport ecosystem.

 

7 Levels of Accreditation 

 

There are many ways airports work to improve their ACA rating, and one of them may be less obvious: How do people get to the airport in the first place? After all, even the most ambitious sustainability efforts inside the terminal would be undermined if the majority of passengers arrived by private, fossil-fueled vehicles.

 

For example, Copenhagen Airport benefits from Denmark’s robust train and metro network. To maximize its use, however, the airport was intentionally designed with train and metro stations located at the heart of the terminal complex, making public transport the most convenient option. Today, an average of 60% of travelers arrive by train, metro, or bus. For those who still drive, the airport has installed 400 electric vehicle charging points in partnership with Danish energy firm EWII, collectively saving around 700,000 kWh annually. In 2022, Copenhagen Airport achieved Level 4+ (Transition) in the ACA scheme, reflecting both operational decarbonization and stakeholder engagement. In short, as airports strive for net-zero, they must not only rethink what happens within their boundaries, but also how people get there.

 

Just as transit infrastructure plays a crucial role in shaping an airport’s carbon footprint, so too does how the airport powers itself. Terminals, runways, lighting systems, and ground operations require enormous energy loads, making the shift to renewable energy and efficient infrastructure another critical front in the push toward greener gateways.

There is no one-size-fits-all approach to powering airports sustainably. Instead, leading airports are turning to the energy mix best suited to their local climate, infrastructure, and operational needs. In Incheon, South Korea, the airport has capitalized on both abundant rooftop space and geothermal reserves—installing 23 MW of solar and 10 MW of geothermal capacity—as part of its commitment to run on 100% renewable energy by 2040 under the RE100 initiative. 

In Melbourne, Australia, a region known for its sunlight and seasonal temperature shifts, the airport operates a 12 MW solar farm that supplies a quarter of its energy needs and supplements this with a trigeneration plant, which efficiently produces power, heating, and cooling from a single system. In the United States, Austin-Bergstrom Airport benefits from Texas’ high solar yield, powering its terminal with 100% renewable electricity, supported by a 1.8 MW solar array, and is steadily electrifying its ground service equipment. 

Each of these airports demonstrates how location-specific choices can lead to meaningful progress, showing that sustainability in aviation isn’t about one perfect solution, but many smart ones. A key part of reducing long-term energy consumption is sustainable building design. To this end, many airports are retrofitting existing structures or constructing new ones to meet green building standards, helping to reduce both operational energy use and embodied carbon in materials.

At Oslo Airport, Terminal 3 became the world’s first airport terminal to achieve a BREEAM “Excellent” rating. This wasn’t simply a symbolic win: the terminal was designed with passive ventilation, smart lighting, and real-time energy monitoring, a combination that enables the building to adapt to external conditions and minimize wasted energy. These features not only lower demand but also improve operational efficiency over time. 

Meanwhile, Toronto Pearson Airport, which holds an ACA Level 4 (Transformation) rating, has focused on upgrading its existing infrastructure with high-efficiency lighting, water-cooled chillers, and enhanced insulation throughout its terminals. These improvements help maintain consistent indoor temperatures using less energy, particularly in Canada’s cold climate, while also optimizing how cooling systems respond to daily loads. Both airports show that sustainable architecture isn’t just about certification—it’s about building smarter environments that demand less and deliver more.

While building retrofits are longer-term undertakings, airports are also embracing circular economy principles through smarter water conservation and waste management. These efforts not only reduce emissions tied to on-site operations but also lessen dependence on finite municipal resources. 

At Singapore Changi, a large portion of the airport’s water demand is met through NEWater, a high-grade recycled supply used in toilets and cooling systems. In Latin America, Bogotá El Dorado has created a closed-loop system where 100% of rainwater is treated and reused on site, 80% of waste is recycled, and 14,300 LED lights have been installed to minimize energy consumption. These circular solutions demonstrate that airports can turn even routine utilities into climate-forward systems.

Runway to Resilience: Five Best Practices for Greener Airports

While no two airports are identical, the following best practices offer a practical starting point for any facility aiming to reduce its environmental impact and raise its ACA standing.

• Seek ACA accreditation to benchmark and drive climate action – While voluntary, the Airport Carbon Accreditation (ACA) program provides a globally recognized framework for tracking emissions and aligning with climate goals. Enrolling in the ACA allows airports to benchmark progress, structure their sustainability plans, and signal climate leadership to regulators, investors, and travelers.
• Design public transport access to reduce friction and cognitive load – Promoting public transport isn’t enough, airports must actively reduce the effort required to choose it. Locating train and metro stations at the terminal core, integrating schedules with flight times, and streamlining wayfinding all lower the cognitive and logistical burden of using rail or bus over private cars.
• Build energy strategies around locally available renewable options – Airports should evaluate their geographic, climatic, and infrastructure advantages when deciding how to transition to renewables. Whether it’s geothermal in colder climates, solar in high-irradiance zones, or trigeneration in areas with seasonal temperature swings, a locally optimized mix ensures energy resilience and lower emissions.
• Retrofit and redesign buildings to reduce both operational and embodied carbon
  Airports must take a long-term view toward terminal design and renovation. Energy-efficient lighting, smart HVAC systems, better insulation, and passive ventilation reduce day-to-day energy use, while thoughtful material choices and modular construction techniques help cut the carbon footprint embedded in airport infrastructure itself.
• Expand sustainability beyond energy to include materials, water, and waste cycles  – Airports should adopt a systems view of sustainability that goes beyond carbon accounting. This means integrating circular economy practices—such as water reuse, waste recovery, and material lifecycle planning—into facility operations. These strategies not only cut emissions but also reduce long-term dependence on external resources and infrastructure.

In rethinking airports not just as transit hubs but as climate actors in their own right, we unlock one of aviation’s most grounded, but most powerful, opportunities for change.