Between traffic growth and environmental imperatives, what transformations for airports?

Connecting continents and ensuring rapid domestic connections: these are the main advantages of air transport. In the current context of climate and environmental change, however, this mode of transport is being criticized for its greenhouse gas (GHG) emissions, its elitist nature and the recreational dimension of some of its flights: pressure that is prompting it to undergo major transformations.

As an essential land-based infrastructure, airports are at the heart of this transformation, which some of them have been engaged in for several years. Claire Mazelet and Didier Wellenreiter, two of Artelia’s airport experts, provide an overview of current issues and achievements.

What is the current state of the airline industry and airports?

Claire Mazelet: “This sector has been turned upside down by Covid. In 2020, most passenger flights were halted and investment put on hold. Today, this traffic is more or less back to its pre-crisis level, and investments are resuming, but with a much greater awareness of the urgency of climate change. Against this backdrop, the airline industry is not getting a good press. If it is to continue to grow, it must evolve. This applies not only to aircraft, which are the main source of greenhouse gas emissions, but also to airports, which have to show themselves to be environmentally virtuous. Today, decarbonization is a central issue for all players in the sector.”

Didier Wellenreiter: “This worldwide revival in passenger traffic is particularly marked in Asia and the Middle East[1], where the affluent categories, who aspire to travel, are gaining in importance. In Europe, the situation is more nuanced, as the desire to reduce the carbon footprint of transport is prompting authorities and companies to favor rail for domestic travel. The increase in air freight is another very important issue, driven by the globalization of trade and the massive growth in online, or “dematerialized”, commerce.
The return of traffic to 2019 levels has been faster than expected, and growth is set to continue according to some projections. This is both a source of satisfaction and concern for airport operators, who must adapt by launching various operations to renew and modernize facilities, optimize and expand reception capacity, and take action to decarbonize construction and operation.”

[1] In a January 2024 CP, IATA (International Air Transport Association), reports that total (global) revenue passenger kilometers have returned to 99.6% of 2019 levels, with particularly strong momentum in domestic flights (boosted by China). Asia-Pacific is playing a leading role.

How can we welcome more passengers, in better conditions, while reducing the airport's carbon and environmental footprint?

Claire Mazelet: “Airports are highly complex infrastructures, combining runways and parking stands for aircraft, passenger terminals, logistics zones, energy systems, numerous roadways, often rail connections, lots of green spaces… There is therefore a wide variety of installations, a very important functional and technical dimension, with a central imperative of safety. Investments have always been made to improve functionality, and we have been working alongside airports in these various technical fields for many years, from the project planning phase through to construction management. For example, we have been working with Copenhagen airport for many years, and have participated in its successive transformations (terminal extensions, modernization of facilities, runway drainage, etc.).

Today, with the upturn in traffic and the urgency of climate change, improving this functionality is part of an ambition for sustainability that requires us to rethink the way we design and build these facilities. Many airport operators are adopting a highly voluntary environmental approach with a view to achieving carbon neutrality by 2030-2050, with the help of ACA (Airport Carbon Accreditation) certification. This is the case of ADP (Paris Aéroport), which has drawn up a highly ambitious program for its Charles de Gaulle and Orly hubs (new energy sources, optimized taxiing of aircraft, multimodal connections, etc.). We assisted them in obtaining HQE (high environmental quality) certification for Paris-Orly, and we are now helping other platforms with their carbon footprint, regulations and environmental labeling initiatives”

What are the main levers used to improve an airport's carbon footprint?

Didier Wellenreiter: “There is, of course, the optimization of energy consumption, for which we offer both comprehensive studies and targeted interventions. For Marseille airport, for example, we are improving the lighting control of the parking stands, so as to reduce it to a minimum when they are not in use. We are also replacing lighting with new-generation LEDs, which are less energy-hungry. We also support other platforms in implementing low-carbon energy sources and electrifying their equipment. For example, we are studying the creation of a photovoltaic power plant for Nice airport and the installation of 140 electricity distribution points at the Basel-Mulhouse hub to power buses and other equipment. Some of our colleagues in Artelia’s Industry sector are also working on biofuels, electrofuels and hydrogen, which are being considered as “sustainable aviation fuels”, capable of contributing to the decarbonization of flights.

Claire Mazelet: “Another important lever is to act on travel from and to the airport. Increasingly, airports are defining themselves as multimodal mobility hubs, seeking to improve their connections with other transport infrastructures (railway lines, tramways, metros, etc.). The aim is to limit car use and thus reduce indirect emissions. For example we piloted the construction of a tramway line in Bordeaux linking the city to its airport. [We are participating in other initiatives of this type, and are assisting the ADP group with preliminary studies for the creation of an automated transport system in public and reserved areas between the various terminals at Paris-Charles de Gaulle (Paris-CDG).”

Beyond the energy dimension, what other actions are being taken to reduce the environmental impact?

Didier Wellenreiter: “Project owners want to have a global vision and a choice of scenarios that integrates the various environmental impacts. We are therefore increasingly thinking in terms of “life cycle” and “global cost”. We take into account initial investments, operating costs and impacts, and deconstruction-reuse costs. Artelia has also developed an eco-design approach to take design studies a step further, optimizing the surfaces and materials to be used to minimize impacts.

In the case of airports, we are studying various solutions, drawing on the experience we have acquired in other sectors. These involve, for example, desilting certain areas, improving stormwater management on the platform, optimizing the use of materials and reusing some of them from deconstruction… The particularity of air infrastructures is that high safety and performance objectives must always be met. Marseille airport, for example, is studying the desilting of shoulders on which there are no aircraft taxiways, while at the same time ensuring that there is no risk of material being projected into aircraft engines.

The upkeep of green spaces is also much more carefully considered, both in terms of the use of natural weedkillers and the preservation of protected species. In Marseille, we come across bustards (a bird), in Ajaccio a endemic species of snail, and in the Solenzara valley, huge carpets of orchids…”

Claire Mazelet: “Making progress on the environment and carbon footprint really means reconsidering a multitude of aspects. It’s essential to keep an open mind. For example, we are taking part in an innovative study aimed at assessing the conditions under which single-engine aircraft could be used to move around the tarmac… another lever for limiting impacts. Reducing noise and nuisance for local residents is also an important issue for urban and regional development.

And what about the risks posed by climate change to airport operations?

Claire Mazelet: “The resilience of territories and infrastructures to climate change, and in particular to flooding and submersion, is one of Artelia’s key areas of expertise. We put this know-how to work for airports, which are often located in coastal areas. For example, we took part in the creation of a new runway protection dike for Hong Kong airport. We are currently studying the reinforcement of the runway threshold at Ajaccio airport, affected by the retreat of the coastline. More broadly, we are beginning to look at the overall resilience of airports. In Togo, Gnassingbé Eyadema International Airport has commissioned a vulnerability and resilience study as part of its extension/rehabilitation project. It’s still rare, but this type of request will certainly increase with the growing frequency and intensity of extreme climatic events.”