Aeroplanes flying at greater altitudes are producing longer-lasting vapour trails, contributing significantly to global warming. Recent research has highlighted that modern fuel-efficient jets and private jets, which operate at higher altitudes than standard passenger planes, may be exacerbating this issue.
The research indicates that by understanding contrail formation better, airlines could optimize flight routes to minimize contrails, reducing their overall impact on climate change. “If we could predict the contrail-forming regions of the atmosphere accurately, aircraft could be rerouted to avoid them, which would mitigate this effect,” a researcher stated.
Contrails form when the soot particles from jet engine emissions create ice particles at high altitudes. These clouds contribute to the warming effect of aviation, with estimates suggesting that contrails account for up to half of aviation-related warming, surpassing the effects of carbon dioxide emissions.
The persistence of contrails greatly influences their warming potential, yet studying this has proved challenging. The research team utilized advanced flight data and satellite observations to associate specific aircraft with their contrails, examining how aircraft type affects contrail longevity.
Utilizing artificial intelligence, the analysis covered 64,000 flights, revealing that private jets and modern fuel-efficient jets, typically cruising at around 12 kilometers (38,000 feet), are more prone to generating longer-lasting contrails. “This was an unexpected outcome,” noted a researcher involved in the study.
The research also found that not all soot particles emitted by an aircraft convert to ice particles. It appears that at higher altitudes, a greater percentage of soot contributes to ice particle formation, although these particles tend to be smaller in size. Smaller ice particles fall more slowly, leading to prolonged contrail lifespan and increased warming effects.
Despite these findings, quantifying the precise warming impact of these contrails remains difficult, and it is uncertain whether the additional warming from longer-lasting contrails surpasses the benefits of lower fuel consumption in modern aircraft.
It is evident that the environmental toll of private jets is larger than previously assumed. “They have an even greater impact on climate per passenger than we realized,” noted the researcher.
The team’s analysis was limited to flights over the western Atlantic, primarily due to the visibility of contrails over oceans and the constraints of available data. This limitation raises questions about the applicability of these findings to flights in different regions, such as over Greenland and Iceland, where drier air at high altitudes results in lower contrail formation.
This research underlines the significant non-CO2 climate impact caused by aircraft operating at high altitudes, predominantly due to the extensive contrails they generate. Long-haul flights, which commonly operate at these altitudes, are currently excluded from certain environmental initiatives aimed at curtailing non-CO2 warming effects. Furthermore, emphasizing the switch to fuels that produce fewer soot particles could play a pivotal role in addressing this pressing issue.
