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Impact of Modern Aircraft Contrails on Climate Change

A recent study indicates that contemporary commercial aircraft, operating at higher altitudes, produce contrails that contribute more significantly to global warming than those generated by older models. This finding suggests that despite emitting lower levels of carbon, modern planes may exacerbate climate change through their contrails.

Conducted by researchers at Imperial College London, the study sheds light on the considerable hurdles the aviation sector faces in mitigating its environmental footprint. In addition, the research revealed that private jets also generate more contrails than previously recognized, which could have a disproportionate impact on global warming.

Contrails, which are condensation trails created from aircraft exhaust, play a role in global warming by capturing heat in the atmosphere. Although the precise warming impact of contrails is still being studied, experts believe it surpasses the warming effects associated with the carbon pollution from jet fuel.

The research, published in Environmental Research Letters, utilized machine learning techniques to evaluate satellite data tracking over 64,000 contrails produced by various aircraft types over the North Atlantic.

The analysis found that modern aircraft, such as the Airbus A350 and Boeing 787, commonly cruising above 38,000 feet, tend to create more persistent contrails compared to older airliners that typically operate at about 35,000 feet. The design of newer aircraft allows them to fly higher, promoting fuel efficiency and reducing carbon emissions per passenger. However, this altitude also results in contrails that last longer in the atmosphere, leading to a complex dilemma for the aviation industry.

Double Whammy of Climate Impact

Dr. Edward Gryspeerdt, the study’s lead author and a researcher at the Grantham Institute—Climate Change and the Environment, noted, “It is well-known that flying contributes negatively to climate change, though many may not fully grasp that both contrails and carbon emissions can result in a compounded warming effect.” He emphasized that increasing the altitude of newer aircraft to enhance fuel efficiency has an unintended consequence: the generation of more enduring contrails that trap additional heat.

While the findings do not imply that newer, more efficient aircraft are detrimental—indeed, they exhibit lower carbon emissions for each passenger-mile—the research highlights the intricate challenges inherent in the aviation sector’s climate response strategies.

The study also identified a straightforward measure to help shorten the lifespan of contrails: reducing soot emissions from aircraft engines, which is prevalent when fuel combustion is inefficient. Modern engine designs emit fewer soot particles, helping to minimize the duration of contrails.

Co-author Dr. Marc Stettler, an expert in transport and environmental engineering at Imperial College London, reiterated that the concentration of soot particles in aircraft emissions significantly influences the formation and longevity of contrails. The study provides concrete evidence that fewer soot emissions correlate to contrails that dissipate more quickly compared to those formed by older engines with higher soot output.

Private Jets: Significant Contributors to Contrail Formation

Further findings highlighted that private jets, which can fly at altitudes exceeding 40,000 feet, produce contrails more frequently than was previously believed, raising concerns regarding the environmental toll of these aircraft used by the wealthy. Despite their smaller size and lower fuel consumption, the research found that private jets generate contrails comparable to those of larger commercial planes.

Dr. Gryspeerdt pointed out, “Though less massive, private jets create contrails as frequently as larger aircraft. Given their substantial carbon emissions per passenger, their environmental impact is concerning, particularly in light of the extreme weather that poorer nations face as a result of climate change.” This emphasizes the disproportionate burden private aviation places on global climate health.

More information: Operational differences lead to longer lifetimes of satellite detectable contrails from more fuel efficient aircraft, Environmental Research Letters (2024). DOI: 10.1088/1748-9326/ad5b78

Source
phys.org