Greenland, Canadian and Icelandic land-ice albedo grids (2000–2016)

Albedo, Latin for ‘whiteness’, is a term used to describe the amount of sunlight reflected by the ground. Fresh snow albedo can exceed 85%, making it among the most reflective natural substances. Warm conditions promote snow crystal metamorphosis that, like the presence of liquid water, bring snow albedo down below 65%. With the darkening, caused by the metamorphosis, absorbed solar energy thus increases by roughly a factor of two. Seasonal snow melts over the lower reaches of a glacier leading to the exposure of bare ice with albedo below 55%. Impurities such as dust, black carbon or microbes can bring glacier-ice albedo below 30%, meaning that snow ablation gives way to impurity-rich, bare glacier ice which increases absorbed sunlight by more than a factor of three.