Aviation Footprint in a Warming Future Climate

There are two distinct, but expected, impacts of a warming climate on the aviation industry. One impact is the change in aircraft maximum take-off weight (MTOW), which is a near-surface effect. Another impact, which is the focus of this talk, and is most prominent during aircraft cruising, is the influence of changes in atmospheric properties (density, temperature and viscosity) on aircraft engine fuel burning efficiency. Aviation jet engines are sensitive to changes in ambient atmospheric conditions because they are “breathing” thermal engines that inhale air and expel it at much higher speeds. The magnitudes of the effects of climate warming on fuel efficiency are assessed using 27 climate models from Phase 5 of the Coupled Model Intercomparison Project (CMIP5) archive. Unlike the MTOW, where only the airport level air density plays a decisive role, the ambient temperature, air density and cruising altitude winds all are important factors in aircraft engine fuel efficiency. This study focusses on the reduction of fuel efficiency in a warming climate, using publicly available flight inventory data. Fuel efficiency is directly related to the environmental footprint of the aviation sector of industry. Major finding of this study is that aircraft will cruise in a sticker atmosphere and a benign cycling only is possible with reduced anthropogenic emissions.

Susan's pioneering research on atmospheric composition and stratospheric structure are very relevant for this study.