Contrail Climate Impacts: Modeling and Mitigation Strategies

Aviation accounts for approximately 3.5 percent of global anthropogenic climate forcing. Of this, less than half is attributed to the CO2 output from fuel combustion. Nearly half of the total climate impact of aviation can be attributed to contrail cirrus - cirrus clouds that have been seeded by the exhaust plumes of the aircraft - though with considerable uncertainty. Given that only around 2-3 percent of all flights were are likely responsible for 80 percent of the global annual contrail climate forcing, a potential contrail mitigation strategy could involve re-routing this subset of flights to minimize the formation of strongly warming contrails. Studies have shown that such strategies would require as little as 0.2 percent additional fuel burn. Implementing such a strategy requires an accurate ability to forecast contrail impacts, which in turn requires accurate modeling of microphysical atmospheric processes at flight levels.
In this talk, Breakthrough Energy's Tom Dean gave an overview of contrail modeling and described the grid-based Contrail Cirrus Prediction model (CoCiP), whose output is designed to be input as a layer in flight planning tools.