Aerosol Radiative Forcing

The long term global temperature rise caused by increased greenhouse gas radiative forcing is partially masked by temporary aerosol radiative cooling, which remains poorly known.

I present a new purely observation based estimate of Aerosol Radiative Forcing (ARF) due solely to the direct radiative effect of aerosols over clear sky ocean, and its time variation over the period 2003-20204 from combined MODIS and CERES aerosol, cloud, and radiation measurements. The resulting mean 2003-2020 ARF is -1.16 +/- 0.39 W/m2 , with no significant trend within an uncertainty of +/- 0.025 W/m2dec.

Combining this ARF with the best estimate of the greenhouse gas and solar radiative forcing, and the most likely value of the Equilibrium Climate Sensitivity, produces a plausible Earth Energy Imbalance as a residual of the energy balance equation at the top of the atmosphere.