Contrails and Climate Change

When you look up in the sky at aircraft contrails, they appear as white puffy lines, sometimes forming interesting patterns. They look harmless, right? But they are not.

Until about five years ago, it was believed that carbon dioxide (CO2) emissions from commercial aircraft operations were the primary contributor to climate change. A study published in 2021 by a group of U.S., European, and Chinese environmental scientists suggests aircraft contrails may contribute significantly more to global warming than CO2.

The effect of contrails is not obvious, because they don’t appear to occupy much of the sky. It is the cirrus clouds that are formed from contrails that make the biggest contribution. During the day, direct reflection of the sun’s rays offset some of the heat-trapping effect, but at night, the cirrus clouds act only as a thermal blanket.

Further research indicates that cleaner-burning fuels can reduce contrail cirrus cloud formation.

This can be achieved using aviation fuel produced from plants and animal

CITIZENS’ CLIMATE EDUCATION

BY TONY HAYS

fats, which results in fewer soot particles than fuel refined from oil. Another promising method is by rerouting aircraft both in direction and altitude to spaces in the sky where contrail formation is less likely to occur.

The French company Thales Avionics has developed a software tool that can estimate the probable climate impact of a given flight route considering the current meteorological conditions, and then suggest a modified flight route that would reduce the probability of contrail formation.

The difficulty is that predicting both the level of atmospheric humidity and location at altitude is still an emerging science, and more research is needed. This software is still in the testing phase.

Within the next 25 years, it is probable that most aircraft engines will be fueled by hydrogen. These engines will produce no CO2, nor soot particles, but over twice as much water vapor, and water vapor itself also contributes to contrail formation.

The German Aerospace Center (DLR) and Airbus are involved in a joint study to compare emissions of a jet engine at altitude using either kerosene fuel or hydrogen.

CO2 will remain in the atmosphere for hundreds of years to come, while water vapor will remain for only hours. Comparing their effects on global warming is not straightforward.

Tony Hays has worked in aircraft design and operations in the UK, Canada, and the U.S. since 1962, and currently teaches classes in aircraft design, primarily in Asia. He has a special interest in the design of aircraft and their propulsion systems to reduce carbon emissions. He is an active member of the south Orange County chapter of the Citizens’ Climate Education.

She states, “Horses have brought me so much pleasure and enjoyment in owning and riding, but also I have formed lifelong friendships through horses.”

For those looking to get involved with the equestrian community, Carter encourages you to volunteer at the local equestrian competitions.

“It is a great way to meet horse owners and others with the same interests,” says Carter.

Carter states the key to protecting the equestrian lifestyle is to help the public learn and interact with horses and riders.

“When on trails that are shared with hikers, bikers and dog owners, it is key to be friendly, open and willing to instruct them on proper interaction,” she says. “We leave a lasting impression with our words and actions.”

Jessica DiCostanzo is a San Juan Capistrano Equestrian Coalition Board Member, lifelong equestrian, and co-founder of equivont.com.

PLEASE NOTE: In an effort to provide our readers with a wide variety of opinions from our community, The Capistrano Dispatch provides Guest Opinion opportunities in which selected columnists’ opinions are shared. The opinions expressed in these columns are entirely those of the columnist alone and do not reflect those of The Capistrano Dispatch or Picket Fence Media. If you would like to respond to this column, please email us at editorial@thecapistranodispatch .com.

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