• Although aerosol accumulation will grow with aviation fuel use, aerosol mass concentrations from aircraft in 2050 are projected to remain small compared to surface sources.

• Like CFCs, HCFCs are used for refrigeration, aerosol propellants, foam manufacture and air conditioning.

• In this paper, aerosol forcing is presented in terms of global averages so that an impression can be gained of its likely overall magnitude, its effect on global average temperature, and its effect on sea level rise.