Uncertainties in radiative forcing due to surface albedo changes caused by land-use changes

A radiative transfer model has been used for estimating the radiative forcing due to land-use changes. Five global datasets for current vegetation cover and three datasets of preagriculture vegetation have been adopted. The vegetation datasets have been combined with three datasets for surface albedo values. A distinct feature in all the calculations is the negative radiative forcing at the northern midlatitudes due to the conversion of forest to cropland. Regionally the radiative forcing is likely to be among the strongest of the climate forcing mechanisms. A wider range is estimated for the global mean radiative forcing due to land-use changes than previously reported. The single most important factor yielding the large range in estimated forcing is the cropland surface albedo values. This underlines the importance of characterizing surface albedo correctly.