Aviation has a smaller impact on climate change than previously thought but it’s also growing rapidly and its effects are more complex than other contributors according to a new study. A team of European climate scientists has recrunched the numbers and determined that aviation is responsible for 3.5 percent of the global warming effect that results from human activities. Previous estimates pegged the aviation contribution at about 5 percent. The new data takes into account some balancing factors in the ways that aircraft pollute.
For instance, nitrogen oxides emitted in aircraft exhaust increase the production of ozone, a major greenhouse gas, but they also destroy methane, a big contributor to atmospheric warming. Also contrails heat and cool the planet at the same time by trapping atmospheric heat while reflecting sunlight. The net result is that contrails are only about half as bad as previously thought. The scientists say that despite the findings, aviation still needs to clean up its act and the COVID-created hiatus in aviation activity isn’t going to help much. “It’s not going to make much difference in the long term,” said researcher David Lee at Manchester Metropolitan University in the U.K.