HOW BIG A THREAT TO CLIMATE DOES AVIATION POSE?

Leading climate scientists agree: If we intend to halt climate change and stave off the catastrophic effects that are sure to accompany it, we must reduce our per capita emissions of CO2 to no more than 2 tons per year. The problem: In 2016 the United States emitted about 15 tons of CO2 per capita—a level of emissions that’s almost 70% higher than Europe’s worst emitter, Germany, and more than three times higher than the world average. Air travel weighs heavily on our personal CO2 emissions burden, though a private car produces about a pound of CO2 per passenger mile while air travel produces half that and commuter rail only a third as much. Nevertheless, airlines have a significant impact on the environment. According to data from the European Union, the Irish low-cost carrier Ryanair is among the 10 biggest polluters in the EU. The airline emitted more than 10 million tons of carbon dioxide in 2018—an increase of nearly 8% over the previous year. It was outstripped only by coal-fired power plants. Among 20 airlines that were studied by the London School of Economics, those that have the best emissions records are Easyjet, Alaska Air, and Qantas. The worst three are Korean Air, Lufthansa, and Singapore Airlines. The report also commended Delta and United for “taking a strategic approach to the problem of climate change.” Among the factors that contribute to airline fuel efficiency are the average age of aircraft (efficiency has improved by around 10% in recent years), the number of passengers who are being transported at once (the more the better), and the balance of long-haul and short-haul flights (long-haul flights burn a bit less fuel per passenger mile). Fortunately, the study has discovered a downward trend in fuel consumption for all the airlines studied.