Since the dawn of commercial jet travel, the uninformed masses have looked up at the skies and assumed the vapor trailing off of airliners was the government covertly spraying chemicals over the country. Contrails will be a topic of discussion at this month’s COP29 summit in OPEC+ member-state Azerbaijan. A recent study found that airlines could alter flight paths to cut contrail warming by over 50 percent for just $5 per ticket.
Contrails are simply water vapor condensing into ice crystals particulates blown out the back of a jet turbine engine. Typically, these vapor trails vanish in a matter of minutes but they will linger on for longer 10 percent of the time and actively damage the environment. Persistent contrails act as a blanket, trapping heat in the atmosphere and preventing it from radiating out into space.
European climate advocacy group Transport & Environment found that 80 percent of contrail warming is generated by only three percent of flights. The flight rerouting to eliminate that same amount of warming would burn five percent more fuel. The extra fuel might not sound worth it, but reduced contrail warming is 40 times more impactful than the extra CO2 emissions. The BBC explained how researchers tweak flight paths to reduce contrails:
Geography and a flight’s latitude have a strong influence on whether a contrail is warming. Flights over North America, Europe and the North Atlantic region accounted for more than half of global contrail warming in 2019, the report said.
Time of day also influences the climate effects of contrails. Those formed by evening and night flights have the largest warming contribution. Seasonality is also important – the most warming contrails tend to occur in winter.
Delta Air Lines and Etihad Airways are developing their own solutions to prevent persistent contrails. The practice is also in the carriers’ best interest because avoiding the particulates that cause contrails also increases the longevity of jet turbine engines. I assume skeptics are now going to claim that this is a conspiracy theory for oil producers to sell more jet fuel and prop up the price of crude amid the shift to electric vehicles.
