Planes and planet-warming pollution

Airplanes could generate 43 gigatonnes of planet-warming pollution through 2050, consuming almost 5 percent of the world’s remaining carbon budget, according to a new Center report.

Aircraft emit staggering amounts of CO2, the most prevalent manmade greenhouse gas. In fact they currently account for some 11 percent of CO2 emissions from U.S. transportation sources and 3 percent of the United States’ total CO2 emissions. All told, the United States is responsible for nearly half of worldwide CO2 emissions from aircraft.

In addition to CO2, aircraft emit nitrogen oxides, known as NOx, which contribute to the formation of ozone, another greenhouse gas. Emissions of NOx at high altitudes result in greater concentrations of ozone than ground-level emissions. Aircraft also emit water vapor at high altitudes, creating condensation trails or “contrails" — visible cloud lines that form in cold, humid atmospheres and contribute to the warming impacts of aircraft emissions. The persistent formation of contrails is associated with increased cirrus cloud cover, which also warms the Earth’s surface. Aircrafts’ high-altitude emissions have a greater global warming impact than they would if the emissions were released at ground level.

Read the Centre for Biological Diversity story - “Aircraft emit staggering amounts of CO2, the most prevalent manmade greenhouse gas.”