Concept of climate-charged airspace areas

Approximately two third of aviation’s climate impact is caused by non-CO2 effects, like the production of ozone and the formation of contrail-cirrus clouds, which can be effectively prevented by re-routing flights around highly climate-sensitive areas. Although climate-optimized re-routing results in slightly longer flight times, increased fuel consumption and higher operating costs, it is up to 60% more climate-friendly. However, if mitigation efforts are associated with a direct increase in costs, this immediately raises the question of the willingness of primarily profit-oriented airlines to act in a more climate-friendly manner and the passengers´ willingness to pay for environmental protection. In order to create an incentive for climate-optimized flying, a climate charge is imposed on airlines when operating in these areas. If climate-charged airspaces (CCAs) are (partly) bypassed, both climate impact and operating costs of a flight can be reduced: a more climate-friendly routing becomes economically attractive (explanation video). By implementing the precautionary and polluter-pays principles of environmental economics, the concept introduces key requirements of a sustainable development into the field of aviation. The proposed extension of the accounting system clearly reduces the discrepancy between the marginal costs estimated by the airlines and the consequential costs for society. Accordingly, this resolves the trade-off between economic viability and environmental compatibility and creates a financial incentive for climate mitigation. The feasibility of this concept is demonstrated on a small route network in the North Atlantic flight corridor (NAFC). If flights are completely re-routed around altered CCAs, on average more than 90 % of the mitigation potential of climate-optimized flying is achieved.Aircraft Noise and Climate Effect

Implementation of eco-efficient procedures to mitigate the climate impact of non-CO2 effects

Within this study, the lack of incentivizing airlines to internalize their climate costs is tried to be closed by the introduction of climate-charged airspaces, as non-CO2 emissions have locationand time-dependent effects upon the climate. In order to create an incentive for airlines to minimize flight time and emissions in highly climatesensitive regions, a climate charge is imposed for airlines when operating in these areas. Costminimizing airlines are expected to re-route their flights to reduce their climate charges and hence cash operating costs. Accordingly, this leads to the desired outcome of incentivizing climate mitigation and even of driving technological innovation towards cleaner technologies. The evaluation of the climate impact mitigation potential of climate-charged airspaces is performed based on optimal control techniques. Climate sensitivities are expressed by climate change functions characterizing the climate impact caused by an emission at a certain location and time. The cost-benefit potential (climate impact mitigation vs. rise in operating costs) is investigated for a Transatlantic route and benchmarked against climate-optimized trajectories.Aircraft Noise and Climate Effect

Cost-Benefit Assessment of Climate and Weather Optimized Trajectories for Different North Atlantic Weather Patterns

Besides CO2, the climate impact of commercial aviation is strongly influenced by non-CO2 effects, which are highly sensitive to meteorological conditions and their spatial variations. To assess the cost-benefit potential (climate impact mitigation vs. cost increase) of climate and weather optimized flight trajectories in the North Atlantic flight corridor, optimal control techniques are applied. However, the execution of multi-criteria route optimizations for an intercontinental route network and various weather patterns is computationally highly intensive. Since computational resources are limited, a reduced surrogate route network is generated and evaluated first with regard to the computational effort, the coverage in terms of available seat kilometers, as well as the accuracy of reproducing the original route network with regard to climate impact. The proposed reduced route network consists of 40 routes (original network: 1,359) and is able to reproduce the climate impact of the original route network with reasonable climate impact deviations of 2.5%. The evaluation of climate and weather optimized trajectories is performed for the top route of the surrogate network. The maximum climate impact reduction potential is differing strongly from 9% up to 60% for varying North Atlantic weather patterns. Averaged over the weather patterns, a maximum climate impact mitigation potential of about 32%, going along with a cost increase of about 8% has been estimated. However, at a cost penalty of 1%, a potential climate impact reduction of 24% has been observedAircraft Noise and Climate Effect

How to efficiently design aircraft with minimum climate impact?

Given the comparably high impact of aircraft emissions, especially their non-CO2 effects, on climate in the order of 5%, aviation stakeholders are required to act to reduce the warming effects of air traffic. Besides new operational procedures, like e.g. climate-optimized routing, this demands the development of completely new global-warming optimized aircraft by aircraft manufacturers. The European Clean Sky 2 project "Global-Warming Optimized Aircraft Design" (GLOWOPT) aims at providing aircraft designers an innovative tool to perform aircraft design studies for minimum climate impact, which we call Climate Functions for Aircraft Design (CFAD). The CFAD will substantially change the way aircraft are designed, while maintaining compatibility to existing Multidisciplinary Design Optimization (MDO) methods. The functions need to integrate a lot of information on the typical aircraft usage, including the routes the aircraft will be operated on. This is because, besides the amount of emissions, the impact of aviation non-CO2 effects, such as NOx, H2O as well as contrails, on climate is highly dependent on location (i.e. latitude, longitude) and altitude. So, the representative operating profile of the aircraft needs to be considered in a characteristic route and fleet model. This work will present the interdisciplinary GLOWOPT approach, which comprises expertise on aircraft design, operations, atmospheric physics and climate. Conceptual thoughts on how the complexity of the operating profile in combination with the geographically variable climate impact of aircraft emissions will be reduced such that it can be used in an aircraft design process are given.Flight Performance and PropulsionAircraft Noise and Climate Effect

Mitigating the Climate Impact from Aviation: Achievements and Results of the DLR WeCare Project

The WeCare project (Utilizing Weather information for Climate efficient and eco efficient future aviation), an internal project of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR), aimed at finding solutions for reducing the climate impact of aviation based on an improved understanding of the atmospheric impact from aviation by making use of measurements and modeling approaches. WeCare made some important contributions to advance the scientific understanding in the area of atmospheric and air transportation research. We characterize contrail properties, show that the aircraft type significantly influences these properties, and how contrail-cirrus interacts with natural cirrus. Aviation NOx emissions lead to ozone formation and we show that the strength of the ozone enhancement varies, depending on where within a weather pattern NOx is emitted. These results, in combination with results on the effects of aerosol emissions on low cloud properties, give a revised view on the total radiative forcing of aviation. The assessment of a fleet of strut-braced wing aircraft with an open rotor is investigated and reveals the potential to significantly reduce the climate impact. Intermediate stop operations have the potential to significantly reduce fuel consumption. However, we find that, if only optimized for fuel use, they will have an increased climate impact, since non-CO2 effects compensate the reduced warming from CO2 savings. Avoiding climate sensitive regions has a large potential in reducing climate impact at relatively low costs. Taking advantage of a full 3D optimization has a much better eco-efficiency than lateral re-routings, only. The implementation of such operational measures requires many more considerations. Non-CO2 aviation effects are not considered in international agreements. We showed that climate-optimal routing could be achieved, if market-based measures were in place, which include these non-CO2 effects. An alternative measure to foster climate-optimal routing is the closing of air spaces, which are very climate-sensitive. Although less effective than an unconstrained optimization with respect to climate, it still has a significant potential to reduce the climate impact of aviation. By combining atmospheric and air transportation research, we assess climate mitigation measures, aiming at providing information to aviation stakeholders and policy-makers to make aviation more climate compatible.Aircraft Noise and Climate Effect