Modern airplanes are worse for the environment

A recent study has revealed that modern commercial aircraft flying at higher altitudes produce longer-lasting contrails that contribute more to global warming than those generated by older planes. 

This finding suggests that although modern airplanes emit less carbon, their overall impact on climate change may be greater due to the contrails they create.

Environmental footprint of the aviation industry 

Conducted by scientists at the Imperial College London (ICL), the study sheds light on the significant challenges the aviation industry faces in its efforts to reduce its environmental footprint. 

The study also found that private jets, contrary to previous assumptions, produce more contrails than previously thought, potentially leading to a disproportionately large impact on climate warming.

Contrails, or condensation trails, are thin streaks of cloud formed by aircraft exhaust fumes that contribute to global warming by trapping heat in the atmosphere. 

While the exact warming effect of contrails is uncertain, scientists believe it is greater than warming caused by carbon emissions from jet fuel.

Modern airplanes create more contrails 

The study, published in Environmental Research Letters, employed machine learning to analyze satellite data on more than 64,000 contrails from a variety of aircraft flying over the North Atlantic Ocean. 

The researchers found that modern aircraft, such as the Airbus A350 and Boeing 787, which fly at altitudes above 38,000 feet (about 12 km), create more contrails than older commercial aircraft.

Modern aircraft are designed to fly at higher altitudes where the air is thinner, which reduces aerodynamic drag and consequently lowers carbon emissions per passenger. 

However, this also means that these aircraft produce contrails that persist longer, extending their warming effect. This presents a complex trade-off for the aviation industry, as efforts to improve fuel efficiency inadvertently increase the climate impact of contrails.

Double whammy for climate warming 

Edward Gryspeerdt is the lead author of the study and a Royal Society University Research Fellow at the Grantham Institute – Climate Change and the Environment at ICL. 

“It’s common knowledge that flying is not good for the climate. However, most people do not appreciate that contrails and jet fuel carbon emissions cause a double whammy warming of the climate. This study throws a spanner in the works for the aviation industry,” said Gryspeerdt.

“Newer aircraft are flying higher and higher in the atmosphere to increase fuel efficiency and reduce carbon emissions. The unintended consequence of this is that these aircraft flying over the North Atlantic are now creating more, longer-lived, contrails, trapping additional heat in the atmosphere and increasing the climate impact of aviation.”

According to Gryspeerdt, this doesn’t mean that more efficient aircraft are a bad thing – far from it, as they have lower carbon emissions per passenger-mile. “However, our finding reflects the challenges the aviation industry faces when reducing its climate impact,” he added.

Reducing contrails from modern airplanes

The study also confirmed a straightforward measure that can reduce the lifespan of contrails: decreasing the amount of soot emitted from aircraft engines. 

Modern aircraft engines, which are designed to be cleaner, typically emit fewer soot particles, thereby reducing the lifetime of contrails. While previous studies using models predicted this phenomenon, the current study is the first to confirm it through real-world observations.

Study co-author Dr. Marc Stettler is a Reader in Transport and the Environment in the Department of Civil and Environmental Engineering at ICL.

“From other studies, we know that the number of soot particles in aircraft exhaust plays a key role in the properties of newly formed contrails. We suspected that this would also affect how long contrails live for,” noted Dr. Stettler.

“Our study provides the first evidence that emitting fewer soot particles results in contrails that fall out of the sky faster compared to contrails formed on more numerous soot particles from older, dirtier engines.”

Climate impact of private jets

The research also revealed that private jets, which fly at even higher altitudes, produce contrails more frequently than previously thought, raising concerns about their climate impact. 

Despite being smaller and using less fuel, private jets create contrails similar to those generated by much larger commercial aircraft, which surprised the researchers.

“Despite their smaller size, private jets create contrails as often as much larger aircraft. We already know that these aircraft create a huge amount of carbon emissions per passenger so the super-rich can fly in comfort,” said Gryspeerdt.

“Our finding adds to concerns about the climate impact caused by private jets as poor countries continue to get battered by extreme weather events.”

This study highlights the complex and often contradictory effects of modern aviation on climate change, suggesting that even as the industry reduces carbon emissions, other factors like contrail formation may undermine these efforts.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–