Snow darkening, increased solar radiation. Northern hemisphere globe projection showing how the reduced albedo of snow from dust (black carbon and organic carbon) causes a net increase in solar radiation absorbed at the surface. This albedo change is known as the 'snow darkening effect' (SDE). The heat change (3 to 6 degrees Celsius) caused by increased solar radiation flux is colour-coded from mild (green), to higher (yellow) to high (orange and then red). The data was modelled for spring (March to May) in the northern hemisphere, using the the GOddard SnoW Impurity Module (GOSWIM). The results were published in 2015.