Adapting aviation to a changing climate

Climate change-induced phenomena are a tangible and growing risk to the European aviation sector, with stakeholders already experiencing its impacts in the form of higher temperatures; changes in rain, snow, wind, and storm patterns; more frequent and persistent droughts and wildfires; sea level rises and thawing permafrost ( Figure 2.6. ).

According to the ACI World 2020 stakeholder survey, 53% of the European respondents representing airports stated that they have already been affected by adverse weather [38] . However, the IPCC 6th Assessment Report of Working Group II on Impacts, Adaptation and Vulnerabilities notes that the sector is still in the earlier stages of adaptation [25]

By the end of the century, under a high warming scenario, up to 200 airports across the EU could face the risk of inundation due to sea level rise and extreme weather events. The majority of these are small airports with less than 10,000 air traffic movements per year. Nonetheless, many are important for connectivity and economic reasons. The cost of diverted and cancelled flights from a one-day closure at an airport due to full flooding is estimated to be around €3 million for medium-size airports and €18 million for large airports [39] [40]

In addition, higher temperatures will also impact aircraft performance, potentially necessitating a reduction in maximum take-off weight at airports with shorter runways [41] . As such, stakeholders need to further adapt and build resilience to these impacts by integrating climate change considerations into their planning processes and future investments.

At the international level, ICAO has published a Climate Change Adaptation Synthesis and guidance material on climate change risk assessment and adaptation planning [42] . Within the EU, the Climate Adaptation Strategy [43] , in agreement with the Sustainable and Smart Mobility Strategy [44]  and ongoing policy review of the Trans-European Transport Network, commits to actively mainstream climate resilience considerations in all relevant policy fields. This is to be done by integrating climate resilience considerations into the criteria applicable to construction and renovation of critical infrastructure. At the national level, according to a 2018 EEA survey, 17 out of the surveyed 23 European states responded that transport was covered in their national climate change vulnerability and risk assessments [45] .

While climate-proofing critical infrastructure may add an additional upfront cost of around 3% to a project, resilience investments have a cost-benefit-ratio of about 1:4 [46] . European Standardisation Organisations have updated standards governing the safety and performance of infrastructure in a changing climate.

Knowledge gaps in the understanding of the links between long-term climate change and risks to the aviation sector need to be addressed, so as to inform a coherent strategy and short-term decision-making. This can be facilitated by greater coordination across the sector [47] .