Climate impact mitigation potential of european air traffic

Air traffic contributes to anthropogenic global warming by about 5% due to CO2 emissions (about 1/3) and non-CO2 effects (about 2/3) primarily caused by emissions of NOx and water vapour as well as the formation of contrails. Since aviation is expected to maintain its trend to grow over the next decades, mitigation measures are required counteracting its negative effects upon the environment. One of the promising operational mitigation measures which has been subject of the EU project ATM4E, is climate-optimized flight planning using algorithmic climate change functions describing the climate sensitivity as a function of emission location and time. The methodology developed for the use of algorithmic climate change functions in trajectory optimization is described and results of its application to the planning of about 13,000 intra-European flights on one specific day are presented. The optimization problem is formulated as bi-objective continuous optimal control problem with climate impact and fuel burn being the two objectives. Results on individual flight basis indicate that there are three major classes of different routes which are characterized by different shapes of the corresponding Pareto-fronts. For the investigated scenario, results show a climate impact mitigation potential of about 73% which is related with a fuel penalty of 14.5%. However, a climate impact reduction of 50% can already be achieved with 0.75% additional fuel burn.