Aviation Braces For Climate Change’s Effect On Operations

aircraft taking off
Takeoff performance degrades as temperature rises, which may translate into reduced passenger capacity during a heat wave.
Credit: Pedro Pardo/AFP/Getty Images

“Takeoff performance calculation will be fun.” This apparently sarcastic comment from a flight dispatcher at a European carrier appeared on Twitter after a weather forecast indicated a severe heat wave in Spain in mid-July. A “heat dome” with record-breaking temperatures also had just hit North America, causing 50 flight cancellations at Las Vegas McCarran International Airport on a single day, the Las Vegas Sun reported.

  • Eurocontrol to release study on operational ramifications
  • Societal changes may affect demand

The headline-grabbing phenomenon signals a new environmental front for aviation, which is accustomed to being described as a culprit of climate change. It is striving to cut its carbon footprint, looking for short-term ways to make aircraft operations more fuel-efficient, researching new technologies and promoting a ramp-up in the production of sustainable fuels.

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Now the industry must also view itself as a potential casualty of global warming and brace accordingly.

Eurocontrol, the organization in charge of air traffic management in Europe for 41 member states, will publish in the coming weeks a report on how climate change will affect the industry. Four French research organizations specializing in aerospace and high-performance computing have also been investigating the subject. In both cases, preliminary results are available—and they are enlightening.

“We, too, are set to be massively impacted over the decades ahead,” says Eurocontrol Director General Eamonn Brennan.

Storms are growing in frequency and intensity, and initial estimates suggest that horizontal flight inefficiency due to major storms could increase to 4.0-4.2% by 2050, from 3.5% now. The trend is already being seen in en route air traffic flow management delays, Eurocontrol says.

Runway flooding is another increasing risk. By 2090, 178 coastal and low-lying airports could be affected around the world, Eurocontrol says. For every one-day closure at an airport due to full flooding, the cost of diverted and canceled flights is estimated to be around €3 million ($3.6 million) for medium-size airports and €18 million for large airports.

“Many airports are in the design phase or assessment phase of performing infrastructure upgrades to mitigate the impacts of climate stressors such as rising temperature, increased storm intensity and changes in precipitation,” says Juliana Scavuzzi, senior director for sustainability, environmental protection and legal affairs at Airports Council International. “Measures such as elevating critical electrical assets and implementing permeable pavement or nature-based solutions to help with stormwater drainage are examples of the measures airports are taking to protect their assets.”

Meanwhile, France’s ISAE-SupAero college of aerospace technology, aerospace research center ONERA, technology maturation institute IRT Saint-Exupery and modeling laboratory Cerfacs are working together on a holistic simulation. They are studying how climate change is going to affect commercial air transport— from aircraft takeoff performance to leisure travel demand. Cerfacs has long contributed to the work of the United Nation’s intergovernmental panel on climate change.

For example, they calculate that an Airbus A320 departing from a city in southern Europe will on average have to leave 30 seats empty during the hottest three months of the year, due to performance degradation as air temperature rises. The number of passengers (or at least airfares) left behind is calculated based on the 5% reduction in maximum takeoff weight the lower thrust and lift will require. This average means some flights will operate normally while others will be canceled.

That scenario will remain relatively exceptional until 2040. It will then become increasingly common, until it turns into a norm in 2100, the French study shows.

Consequences may also be expected in cruise flight, says ISAE researcher Nicolas Gourdain.

Clear-air turbulence (CAT), a hard-to-detect phenomenon causing discomfort for passengers and posing a safety risk to flight attendants, peaks at higher altitudes. One of the sources of CAT is a thermal gradient that is poised to strengthen, Gourdain explains. Current cruise altitudes are close to 30,000 ft. in part because that is higher than the usual level of powerful CAT. But with global warming, the altitude of maximum-power CAT will rise.

In parallel, a warmer atmosphere will cause greater quantities of water vapor to be found in the air at 30,000 ft. Therefore, the risk of icing increases at that flight level, Gourdain says.

Climate change may also generate societal changes. Many tourists may begin to view destinations such as Greece as too hot for summer holidays. It is entirely possible the result could be a drop in demand for such destinations of 20-30% starting in 2030, Gourdain suggests.

All these anticipated consequences could be dealt with in some manner: Runways could be extended, a new peak season for leisure travel could be factored in, and cruise altitudes could be altered. But such measures would come at a cost, and in some cases they may not even be doable.

Gourdain says the first phase of the joint multidisciplinary work, which began in 2019, has been a success because of the synergies created. A key focus is mutual understanding among the specialists—experts in aircraft aerodynamics had to fathom climate models, for instance. And while previous studies of these issues were conducted, none encompassed as many aspects as this new effort. 

The very notion of risk can differ between fields of study. Risk can refer to strong turbulence, economic viability or a society’s resilience to climate change, Gourdain says.

Differences in how time and space are viewed also had to be factored in. While an aircraft aerodynamics expert thinks in micrometers and seconds, a climate scientist will focus on kilometers and years. The tools and methods differ as well, Gourdain points out.

A new, three-year phase for the study is beginning. Models will be refined, notably for lift and engine thrust as functions of humidity and temperature, Gourdain says. Aircraft will be modeled from three standpoints: as an engineered object, a societal artifact and an economic asset.

Thierry Dubois

Thierry Dubois has specialized in aerospace journalism since 1997. An engineer in fluid dynamics from Toulouse-based Enseeiht, he covers the French commercial aviation, defense and space industries. His expertise extends to all things technology in Europe. Thierry is also the editor-in-chief of Aviation Week’s ShowNews. 


What do you think flying lower and slower (read: in-weather) would do to network stability and efficiency?
I despair at articles like this. Storms are not getting more frequent or intense, as can be clearly seen in the NOAA data. Given that the global circulation models (as poor as they are) predict that warming will mostly be higher lows rather than higher highs, the idea that summer will become too hot is neither supported by the data (summers in the US are actually getting colder from a peak in the 1930s) nor by the warming alarmists' own models.

Flooding is also not increasing. As far as sea level rise goes, it varies by location due to the northern hemisphere still rebounding from the ice sheets in the last ice age, but on average, sea levels are increasing 8-12 inches per century and have been for the last 4,000-5,000 years. There is no evidence that sea levels rise is accelerating. Though, to be fair, during the last interglacial sea levels were about 8 meters above their current values without the help of aircraft or SUVs, so it's possible that in the next thousand years or so sea levels will rise that remaining 8 meters. The problem with the alarmist position on rising seas is that no matter how much warming the models say the Earth will experience, the Antarctic ice is *always* well below freezing and so melting there is solely the result of the sun, not "warm" air. And the sun ain't goin' nowhere.

This idea that CO2 will cause more humidity without creating more clouds (and thus rain) is astoundingly ignorant of how the water vapor/cloud/precipitation system works. A tiny increase in the partial pressure of CO2 has absolutely no effect on water vapor, humidity, the dew point, or any other aspect of the water cycle. The claim "a warmer atmosphere will cause greater quantities of water vapor to be found in the air at 30,000 ft" has no basis either in data or theory. The general climate models used by the warming alarmists don't even take the water cycle into account. Nor do they take the drivers of the weather in the Western Hemisphere into account, the Pacific Decadal Oscillation and the Atlantic Multi-Decadal Oscillation. The models are so simplistic that no one should read anything into them, and certainly should not base public policy on them.

Except for puddle jumpers, I've never cruised at or below 30,000 feet. Indeed, lower than flight level 350 is unusual, and is almost always temporary as fuel is burned off so the aircraft can fly at closer to (or with the 767 and 787 exceeding) flight level 400. In the United States, aircraft going east seek out the jet stream to make travel faster, or going west avoid it for the same reason. Higher flying means a more comfortable flight as only the large storms need to be avoided. Clear air turbulence caused by thermal gradients can be detected by sensors, if airlines really want to go to the expense, but again, the weather cycle (including the three fundamental convection cells in each hemisphere) are not affected by CO2 partial pressure increases, because they are physically stable to impulses--they have to be by simple geography. Very small changes in altitude and wind velocity of the cells can occur (making the jet stream more intense) but only with warming comparable to that which occurred at the end of the last ice age and even the most truculent of the warming alarmists does not predict that magnitude.

Face it, all of this study, along with electric motors for aircraft, "biofuels" (the world's least efficient way of capturing solar energy), and all the worrying is just one giant scam. And I'm shocked that AWST falls for it. Even if the Earth warms by the absolute worst case the warming alarmists predict, roughly 8 degrees Celsius in 100 years (a result with no physical mechanism behind it), the temperature at New York's JFK airport, instead of ranging from -2 degrees Fahrenheit to 104 degrees Fahrenheit, will range from 10 degrees Fahrenheit to 116 degrees Fahrenheit. In other words, JFK airport will be a little warmer, but not anything out of the operating range of jetliners today, much less jetliners (if our civilization survives the warmers' deindustrialization policies) a hundred years from now. Europe will not be as warm as New York. It's all a big "who cares?"