Albedo is a fancy way of saying that you will feel cooler on a hot day if you wear a white t-shirt instead of a dark t-shirt. Anyone from Miami certainly knows that. But Alaskan glaciers know that too. Albedo refers to the amount of light that is reflected off a surface, relative to how much light hits the surface. For glaciers, the white is the ice, and the dark is the earth. White is more reflective than darker colors, so the white ice of glaciers do a good job of reflecting sunlight, helping to keep them cool. As glaciers melt with changing climate and environmental conditions, the exposed darker ground absorbs more sunlight, which further warms the surface, which can lead to further melting, which can expose more dark ground… and the cycle continues. This is one of the reasons why glacier melting is both an indicator of a changing climate, and why it is something that is globally important, because as more ice melts, it affects sea level and coastal areas, communities’ freshwater sources, etc.
That’s the big picture, but as we trekked along the glacier, we saw this same effect on tiny scale as well. The tiny holes of a couple inches diameter that you see in the surface of the glacier are called cryoconite holes. Cryoconite is windblown rock and dirt, and as this dark material is deposited on the white glacier surface, that area warms, locally melting the ice underneath, and the dirt and rock sink into cylindrical holes of melted ice. So these tiny holes on this Alaskan glacier are signs of a phenomenon that has global effects, even in Miami.
