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Understanding the impact of climate change on aviation

7 March 2023

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EUROCONTROL is working to understand the many ways in which climate change is disrupting aviation operations and how stakeholders can develop new levels of resilience, writes Rachel Burbidge, the Agency's Environment Policy Officer.

In recent years the aviation sector has ramped up its decarbonisation efforts. Airports, airlines and States have implemented ambitious decarbonisation strategies and, in October 2021, the International Civil Aviation Organization's (ICAO) General Assembly's historic agreement set a goal of net zero carbon emissions by 2050 for the global civil aviation sector.

But that is just one side of the story. Climate change is also having an impact on the aviation sector. Disruptive weather has increasingly caused delays over the last few years. The Network Manager and its European aviation stakeholder partners have progressively introduced measures to counter this problem, such as integrating cross-border weather forecasts into network operations. But at the same time, Europe has been experiencing unprecedented weather events such as devastating floods in Belgium and Germany, wildfires and extreme temperatures across the continent.

In 2022 temperatures were so hot in summer that some runways melted. Storms caused delayed, diverted and cancelled flights and damaged communications equipment. Extreme precipitation caused a control tower to flood, temporarily closing an airport. At the end of 2022, we saw heavy winter weather impacting airport operations, causing many more flights to be delayed and cancelled.

According to the United Nations Intergovernmental Panel on Climate Change, such impacts will increase as climate change accelerates. So the aviation industry needs to take action to adapt and build resilience. In fact, as traffic recovers this will increase pressure on the network – because impacts are exacerbated when capacity is constrained. Our latest EUROCONTROL long-term forecast predicts 16 million flights a year by 2050, an increase of 40% on 2019 levels. So we have a double challenge ahead.

Storms are one of our biggest problems: they cause delays, rerouting and reductions in horizontal flight efficiency, all of which impact fuel burn and CO₂ emissions. They can also damage infrastructure; one impact of climate change can be an increase in lightning strikes.

To support the European aviation sector in adapting to climate change in 2021 EUROCONTROL produced a study (carried out for EUROCONTROL by Egis Aviation and the UK Met Office) "Climate Change Risks for European Aviation" to better quantify the potential impacts.

Publication

6 September 2021

Climate Change Risks for European Aviation

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Graph showing change in extreme rainfall days by 2050 - showing a decrease in the Mediterranian and Southern Europe, and an increase in Scandinavia

Projected change in extreme rainfall days by 2050

From 2013 to 2019, on average, storms were responsible for up to 7.5% of total en-route air traffic flow management (ATFM) delays at network level, and the trend was increasing. During this period, if a flight was affected by a storm, then the average en-route ATFM delay was around 17-18 minutes.

"It is therefore expected that the impacts of climate change will increase across the century. It is not just rising temperatures, but also the secondary impacts that are cause for concern. Higher temperatures are associated with increasingly unpredictable or severe weather events, whilst the melting of land ice and the warming of the oceans threatens coastlines around the world due to sea level rise. These impacts pose threats to infrastructure, transport, supply chains, communities and the resilience of the global economy" (Climate Change Risks for European Aviation).

We wanted the study to provide an understanding of how the frequency and intensity of storms might change in the future. We found that by 2050, while in northern Europe the number of days with the potential for convective weather conditions and major storms might increase, in the south they would decrease, leading to an overall reduction. But when major storms do occur, they will be more intense.

In 2019, over 1 million km were flown as a result of avoiding a major storm. This corresponds to over 6,000t of extra fuel consumed, or over 19,000t of CO₂ produced

So, although overall delays due to major storms might decrease, if a flight were to be delayed by a major storm, the delay would be greater – an average of 20-22 minutes per flight up from 17-18 minutes in 2019, although with some geographic differences. Regions around the Alps, southern Germany, western Czech Republic, northern parts of the UK and most of northern Europe are likely to experience an increase in the number of days with significant convective activity.

We also looked at the potential impacts of sea-level rises for European airports. We looked at 270 coastal and low-lying airports in the European Civil Aviation Conference (ECAC) region and we found that, by the end of the century, over twothirds of them would be at risk of some coastal or marine flooding. This has an operational and economic impact.

If a large airport with over 100,000 movements per year is closed for a full day due to flooding, then around 2-3% of overall air traffic movements in the ECAC region might be impacted with delays, cancellations and reroutings. From an economic point of view, if a large airport were closed for a full day then we estimate costs of about EUR 18 million and, for a mediumsized airport, costs of around EUR 3 million (although that is an average so it could vary considerably). Moreover, if one airport were closed this would have a ripple effect across the network.

A one-day closure of an airport due to full or partial/severe flooding, could potentially impact 0.5% (medium airports) and 2-3% (large airports) of all air traffic movements per day in the ECAC area

Changes in wind patterns can have several different impacts. Very strong winds can halt operations; changes to the prevailing wind direction can also impact operations if there is no crosswind runway, and changes to high-altitude winds can impact flight times and potentially cause issues for airport slot management.

Another aim of the study was to analyse how changes to high-altitude winds might impact flight times. We studied three route groups – Europe to North Asia, Europe to North America and North Europe to the Canary Islands, in both directions and for both summer and winter. We found that for all routes, except from Europe to the Canaries in winter, average flight times decrease.

Although the average impact of changing wind patterns on a single flight may look negligible, the combined impact (which considers all flights operating on the traffic flows considered in this study) is much more substantial. The overall reduction in flight times, as a result of stronger jet streams, is likely to bring savings of more than 55,000 tonnes of aviation fuel per year, which corresponds to roughly 175,000t of CO₂ saved each year, with the greatest reduction expected on routes to and from Asia (although this must be taken in the context of potential increases in traffic and changes to fuel supply).

Fuel and CO₂ saved per year as a result of changing wind patterns
Fuel and CO₂ saved (1,000 tonnes)	2050 traffic (= 2019 traffic)		Expected 2050 traffic levels (+47%)		Expected 2050 traffic levels (+65%)
Fuel and CO₂ saved (1,000 tonnes)	Fuel burn	CO₂	Fuel burn	CO₂	Fuel burn	CO₂
Europe to North America	9	28	13	42	15	47
North America to Europe	12	38	18	56	20	63
Europe to Asia	23	72	33	105	37	118
Asia to Europe	10	32	15	47	17	53
Northern Europe to Canaries	<1	<1	<1	<1	<1	<1
Canaries to Northern Europe	1	5	2	7	2	8
Total	55	175	81	256	91	289

Another major impact to consider arises from higher average and extreme temperatures. This can impact operational performance, because warmer air is less dense so more thrust will be required for take- off; more runway length or reduced payloads might be needed during the hottest parts of the day.

20 to 22 minutes

Forecast average en-route ATFM delay due to weather per flight delayed by a major storm in 2050

There might also be climate-change-induced impacts on tourism demand. For example, some locations may become uncomfortably hot for tourism in the summer months, which may see tourists moving their holidays to the Spring or Autumn, or to relatively cooler locations. Conversely, new locations might start to have a more pleasant climate throughout the year, leading to an increase in tourism. This can all have an impact on the number of passengers passing through airports, and the number of flights, infrastructure and personnel required. And although we expect such changes to be gradual, it is something for airports to think about in their longer-term planning.

The European aviation sector has the potential to adapt to future climate conditions if it starts building resilience now so as not to be caught unawares further down the line. It will never be possible to be 100% resilient to every single event but taking proportionate and timely action can reduce future operational impacts, damages and costs.

It is essential for all aviation organisations to carry out a climate change risk assessment and implement adaptation measures to build resilience for their own passengers, personnel, infrastructure and operations. But it is also important to recognise the interconnectedness of the wider European and global aviation system and that an impact in one location can have knock-on effects across the network. Therefore, a coordinated approach is also essential to ensure that our response is timely and impacts are reduced for all. In response, EUROCONTROL and ACI EUROPE have established the European Aviation Climate Change Adaptation Working Group to support operational stakeholders in adapting to the impacts of climate change. The group is developing guidance, providing peer-topeer support and identifying good practices to contribute to building a climate-resilient aviation sector. EUROCONTROL will continue to support European aviation in this collaborative effort.