The global distribution of radiative forcing by persistent linear contrails
has been estimated for 1992 and 2050 using global contrail cover computed
for aircraft fuel consumption scenarios for the two periods, a detailed pre
scription of the radiative properties of the Earth's surface and the cloudy
atmosphere, and flux computations with an established radiative transfer m
odel. The computed global mean radiative forcing by line-shaped contrails i
s similar to 0.02 Wm(-2) in 1992 and similar to 0.1 Wm(-2) in 2050. At nort
hern mid-latitudes, the zonal mean forcing is five times larger than the gl
obal mean. Diffuse contrails and indirect effects of aircraft emissions on
natural cirrus are not included in this study. Thus, the results are consid
ered a minimum estimate of contrail effects.