By Exequiel Sanhueza Yáñez*

Although a lot has been written in recent years about climate change, I can point out that this concept refers to the variation of the climate on earth due, mainly, to the action of human beings who, since the revolution in agriculture, have destroyed their own habitat by burning of forests and other phenomena of an industrial, agricultural and land, air and maritime transport nature. All of this has implied the use of non-renewable resources, annually the release of millions of tons of greenhouse gases (GHG) into the atmosphere. The consequence of this is the heat that is trapped in the Earth’s atmosphere, producing a greenhouse effect that leads to global warming.

It is good to remember that the Swedish scientist Svante Arrhenius was the first to point out, in 1896, that fossil fuels could lead to or accelerate global warming, coining the term “greenhouse effect” when establishing a relationship between concentrations of atmospheric carbon dioxide and temperature.

Time passed until in 1972, when a private association called the Club of Rome, made up of some businessmen, scientists and politicians, asked Donella Meadows, an environmental scientist and biophysicist with experience in system dynamics, to prepare a report whose conclusions were the following: “if the increase in world population, pollution, industrialization, exploitation of natural resources and food production continue to be maintained, without any kind of variation, it is likely that the total limit of growth on earth, at least for the next century, will be reached. A stern warning that is becoming reality.

Despite the fact that the World Meteorological Organization (WMO) urges to intensify measures to mitigate climate change, unfortunately, there is still not full awareness among some governments, businessmen and politicians, that this is a global problem. I say this as even large countries like China, the United States, Australia and India, still produce and export coal with industrial fines.

Likewise, it is also good to remember that our aviation industry has not been exempt from its responsibility for global warming because it has launched into space enormous amounts of carbon dioxide, water vapor, nitric oxide, nitrogen dioxide, oxides of sulfur and soot, thereby contributing to cause condensation trails.

Climate scientists have warned us that we are already past the tipping point. This means that, according to the National Office of Oceanic and Atmospheric Administration (NOAA), “global climate impacts on temperature and precipitation will be more significant and persistent, due to the greater amplitude and greater persistence of (phenomena such as) El Niño in the second half of the 21st century. I must remember that El Niño directly affects precipitation patterns in the tropics, as well as strongly influences the climate around the world.

Recently, WMO Secretary-General Professor Petteri Taalas noted that “greenhouse gas concentrations continue to rise and reach new all-time highs” adding that “fossil fuel emission rates are now above levels before the pandemic; the last seven years were the warmest on record. Cities, which contribute 70% of global emissions, are highly vulnerable to climate impacts.” These latest news are very discouraging and, by the way, they do not help commercial aviation at all.

This will mean that, from now on, meteorological phenomena such as hurricanes, frontal systems, droughts, thaws and turbulence in clear air, will be more intense, more violent and more devastating each year, seriously affecting air operations, passengers and carriers.

How global warming is affecting commercial aviation

In this general analysis, I will include only some of the multiple variables that affect the performance of an airplane as a result of global warming and I will exclude the strict technical and operational protocols that crews must carry out for each particular case.

Thus, while Europe is being hit by great heat waves, in the US, in mid-August 2022, American Airlines indicated that “unexpected and strong” electrical storms had hit operations at its largest hub, Dallas-Fort Worth International Airport (DFW), forcing the cancellation of more than 660 flights. “This was the worst storm we’ve seen in DFW this summer,” said American Airlines Director of Operations, David Seymour. On the other hand, Southwest Airlines also canceled almost 250 flights in the same days “blaming the weather and air traffic control programs.” This situation generated huge losses for carriers and inconvenience a large number of passengers.

Modern aircraft today have anti-icing systems for engines, fuselage and windshield, as well as sophisticated navigation systems that include on-board radars, operated by experienced pilots that allow them to fly safely. However, the presence of much more active frontal systems as a result of global warming makes the operation more complex and requires the flight crews to take extreme precautions, normally diverting the flight to less compromised areas from the meteorological point of view. Despite this, because of flying more active frontal systems than those known to date there have been cases of aircraft with shattered front windshields, damaged radar domes, leading edges of the horizontal and vertical planes as a result of huge hail damage. This has forced, in some cases, the aircraft to go to an alternative aerodrome. It is unfortunate to have to remember that Air France flight 447, when flying a very active frontal system, with severe ice formation, crashed over the South Atlantic Ocean at 00:14 on June 1, 2009. It is therefore understandable why, in highly justified cases, flights and air operations should be canceled or postponed, even if this means higher costs.

From the foregoing, it can be deduced the importance of having, in Flight Dispatch offices, detailed forecasts, satellite photos and up-to-date times of the origin aerodrome, alternate aerodromes and destination aerodrome, for good operational decision-making that lead to operate with a more than acceptable level of security. Why is such rigor so important? Because adverse weather conditions are the main cause of air accidents and incidents, especially during the takeoff and initial climb phases as well as during the descent, initial and final approach and landing phases.

In general, the most adverse weather conditions can further contaminate the runways with snow, sleet or water, which, by affecting the braking action, can compromise the directional control of the aircraft on the ground, making it necessary to restrict the maximum takeoff weight and, as a consequence, the profitability of the operation decreases. Landings can be affected by aquaplaning and takeoffs and landings can be affected by crosswinds, gusts or windshear. For these reasons, the use of contaminated runways is avoided as far as possible and runways with reports of wind shear are not used due to the risk that this entails.

In the same way, the threat of encountering heavy and persistent rain during takeoff will surely force the departure of flights to be delayed. If the problem occurs during the landing phase, the crews will opt for more prudent measures such as diverting a flight to an alternative aerodrome, wait until the rain has diminished in the area or until the runway has been cleared of ice. Why? Because flight safety is above any consideration.

The abnormal heat waves that are being experienced are significantly altering some atmospheric variables. That is why an increase in air temperature, altitude, or water vapor content, either individually or together, will decrease air density. This has an adverse effect on the performance of the aircraft and its engines at takeoff, initial climb and cruise flight, which is why it will mean a decrease in the maximum takeoff weight and consequently will have a direct impact on the payload. (passengers, cargo and mail) to be transported. If we do not want to lower the payment load, a technical scale must be carried out, which will undoubtedly increase variable costs.

I hope I have contributed to understanding why, many times, measures are being adopted that generate delays in itineraries and sometimes flights are canceled, which unfortunately affects passengers, who miss their flights or their connections and cannot meet their business or family commitments, but in the mind of a Commander as in the mind of a Technical Flight Dispatcher and a Cabin Crew, Aviation Safety is always present above any other consideration.

This is one of the great strengths of an airline and the best guarantee for our passengers.

(*) Exequiel Sanhueza Yáñez, a regular contributor to ALA News is a retired Airline Transport Pilot and current Professor at the ICA (Aeronautical Training Institute), in Córdoba, Argentina.