Climate change up in the air

German scientists have published a forecast of carbon dioxide and nitrogen oxide (NOx) emission from global air travel up to the year 2030 using a more sophisticated computer model than has been used previously that takes into account changes in engine technology.

Writing in the International Journal Aviation Management, Martin Schaefer of the German Aerospace Center (DLR), Institute of Propulsion Technology, in Cologne, Germany, explains that International Civil Aviation Organization (ICAO) data from 2010 suggest that passenger kilometres would double every 15 years. Aircraft manufacturers Airbus and Boeing forecast a similar increase as well as similar growth for freight. This could be made news for our atmosphere and climate. Greenhouse gas emissions of carbon dioxide are proportional to fuel consumption and contribute directly to global warming. By contrast, noxious NOx indirectly affect climate by influencing atmospheric ozone and methane concentrations. In addition, sooty carbon microparticles in aircraft contrails contribute to climate affects.

Schaefer points out that goals have been set by policymakers and by the aircraft and airline industries in order to address the problem of aviation’s growing environmental footprint. The Advisory Council for Aeronautics Research in Europe (ACARE) aims at a 50% reduction of fuel consumption and an 80% reduction of NOx emissions for new aircraft between 2000 and 2020.While the European Commission’s “Flight Path 2050” hopes to see a 75% reduction of carbon dioxide and a 90% reduction of NOx emissions per passenger-kilometre by 2050. In addition the International Air Transport Association (IATA) expects aviation to have reduced absolute greenhouse gas emissions by 2050 to half what they were in 2005.

Schaefer’s forecast suggests that these hopes are massively ambitious and are unlikely to be on-target by 2030 even with the advent of leaner engines and biofuels. Indeed, the only likely way that the industry will reach such targets is through emissions trading with other industries that can more effectively reduce the size of their environmental footprint.

Schaefer, M. (2015) ‘Forecast of air traffic’s CO2 and NOx emissions until 2030‘, Int. J. Aviation Management, Vol. 2, Nos. 3/4, pp.256-273.

Author: David Bradley

Award-winning, freelance science writer based in Cambridge, England.