Contrail and cirrus cloud avoidance technology

Civil aviation, providing transport to connect people, cultures and economies, is situated at the heart of globalisation. Since its earliest days, it has grown along with every other part of the industrialised society and experienced growth rates exceeding that of global GDP. Projections suggest that future air traffic emissions will play an increasingly important role in the contribution to global warming, which is regarded to be a serious threat to earth’s socio-ecological systems. Air traffic contributes to the overall anthropogenic radiative forcing, a metric denoting perturbations in the earth’s radiation budget, by the emission of greenhouse gases and aerosols, and also by the generation of high ice clouds, commonly known as contrails. Recent studies suggest that the radiative forcing resulting from contrails is potentially higher than that of all other air-traffic pollutants combined. In light of this, contrail avoidance is attracting increasing interest from the aeronautical community. An important contribution to the understanding of the problem in a wider context is made in this thesis, alongside proposals for short, mid and long term strategies for contrail avoidance. These are in particular the optimisation of the aircraft for contrail avoidance, the application of remotely induced heat to suppress contrail formation, and a novel engine concept that exhibits the potential for a reduction of all emissions simultaneously. Aircraft optimisation deals with the adaptation of existing technology for more environmentally compatible air transport, whereas the latter two approaches are breakthrough technologies of a more disruptive character covered by several patents resulting from this research. Short and mid term strategies are accompanied by an increase in carbon dioxide emissions. A study examining the long-term impact of aviation carbon dioxide emissions relative to that of contrails suggests that in order to achieve more sustainable air transport, the avoidance of contrails is inevitable. However, as the short-term impact of contrails is less severe, postponing contrail avoidance until the associated increase in carbon dioxide emissions is less significant could be a better way to deal with the problem.