Simulated 2050 aviation radiative forcing

Abstract:

The radiative forcing from aviation is investigated by using a comprehensive general
 circulation model in the present (2006) and the future (2050). Global flight
 distance is projected to increase by a factor of 4 between 2006 and 2050. However,
simulated contrail cirrus radiative forcing can increase by a
 factor of 7, and thus does not scale linearly with fuel emission mass.

Simulations indicate negative radiative forcing induced by the indirect effect of
aviation sulfate aerosols on liquid clouds that increases
by a factor of 4 in 2050. As a result, the net 2050 aviation radiative forcing is a cooling. 
Aviation sulfates emitted at cruise altitude can
be transported down to the lowest troposphere, increasing the aerosol
concentration, thus increasing the cloud drop number concentration and persistence
of low-level clouds. Aviation black carbon aerosols produce a negligible forcing.