● NASA and Boeing are working to understand the impact of aviation on the atmosphere and its possible contribution to climate change
● Disagreement among scientists about the influence of ‘contrails’ on the climate
When an airplane flies through the atmosphere, its engines have a very high temperature and emit water vapor that, upon contact with the cold of altitude, becomes trails of ice. They are the so-called contrails (not to be confused with the hoax of the chemtrails). The same white trail that an observer can see from the balcony of his house looking at the blue sky is now also a cause of concern among the scientific community and industry who doubt the consequences of these aviation clouds for the planet.
For some time now, both environmental activists and other non-profit organizations have been denouncing that white contrails contribute even more to global warming than carbon dioxide from engines.
They are based on a 2021 study, written by David Lee, chair of the aviation working group of the UN Intergovernmental Panel on Climate Change, in which he states that the warming effect of contrails is greater than that of carbon dioxide emitted by engines. The article, whose conclusions have been assumed to be true from the beginning, ensures that the Contrails contribute between 1% and 2% to climate change.
Contrails are sometimes the origin of conspiracy theories
| Agencies
An impact called into question
However, the social consensus that had been reached regarding how harmful these vapor trails are has suffered an unexpected setback. David Lee himself has published a new review of his own conclusionswhere the innumerable scientific uncertainties surrounding the issue are made clear and calls for calm.
The article concludes that “the fundamental premise” that contrails must be mitigated “has not been scientifically established.” And beyond the greenhouse effect that these trails could be generating, Lee points out that no one has taken into account that They may also be having the opposite effect to what is thought, that is, a cooling of the planet.
According to this author, the cirrus clouds left behind by some of these planes, especially when they spread and persist as tall, thin cirrus clouds, could be helping to cool the planet during the day, since they are capable of reflecting sunlight. It is just a theory, but it should not be ignored. However, it is also true that high, cold clouds may also be able to trap surface heat, so they may also play a potential role in the “greenhouse effect.”
And this dilemma is just an example of how “uncertain” it is. and “complex” resulting from the investigation of the impact of contrails on the climate.
An airplane leaving a vapor trail in its wake
| Agencies
Lee has even criticized the misinterpretation of his data. The uncertainty about how aerosols (particles in suspension) interact with clouds is so great – there are numerous studies that show tremendously different results – that the evaluation published in 2021 had not even ventured to make an estimate in this regard.
More tests
Despite the uncertainty, the industry, immersed under media pressure from these groups, has intensified its scientific programs to understand the contribution of this phenomenon to climate change.
In October, the international aviation company Boeing and NASA carried out several flight tests from Everett, one of the cities of Washington. The test consisted of a NASA DC-8 plane flying over the city behind an Airbus 737 MAX 10 to ‘sniff’ its gases and analyze its contrails. The idea was to know if the new sustainable aviation fuel (SAF) can reduce the incidence of aerosols released by these aircraft into the atmosphere.
A plane landing
| Pixabay
In parallel, Google and the Breakthrough Energy researchers association (the climate action research group founded by Bill Gates), carried out a small experiment with American Airlines to test whether commercial pilots could avoid the most prone places in the atmosphere. to generate vapor trails.
For the initial test conducted this year, Google used artificial intelligence to analyze satellite images, weather and flight data, and develop contrail forecast maps on 35 American Airlines routes. Then he asked the pilots to follow different routes: one that did not pass through areas that facilitate the formation of contrails and another following the normal route. The first route reduced the formation of contrails by 54%.
“An exaggeration,” according to some researchers
While Scientists call for calm to try to stop measures that, in the long run, could be more harmful than beneficial, Other voices believe that it is an “exaggeration.” This is the case of Marc Sapiro, director of the Breakthrough Energy project, who in an interview disagreed with Lee’s latest conclusions.
The pressure has also reached politics, especially in Europe. From 2025, European airlines must monitor, report and verify climate effects not related to carbon dioxide emissions on their flights. By 2028, after an impact assessment, the European Commission will have to make a proposal to address these effects, with contrails being the most prominent at the moment.
Reference article: https://phys.org/news/2023-12-nasa-boeing-jet-contrails-science.html
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