The Greenland Ice sheet is currently a record-breaking melting rate due to high temperature observed. This past May just broke a record for sea ice loss in Arctic. The role of red pigmented snow algae in melting Arctic glaciers has been strongly underestimated, suggests this study.
White areas covered with snow and ice reflect sunlight; the effect is called albedo, a simple climate-altering process cooling our planet by reflecting sunlight. It has been known for quite some time that red-pigmented snow algae blooming on ice surfaces darken the surface which in turn leads to less albedo and this causes the Earth to absorb more sunlight and heat up even more. The new study found that the presence of the algae reduced the albedo or reflectivity of the snow by as much as 13 percent over the course of one melting season. The blooming leads to a runaway effect: The more glaciers and snow fields thaw the more algae bloom which in turn results in a darkening of the surface which again accelerates melting.
“Our results point out that the “bio-albedo” effect is important and has to be considered in future climate models,” says lead author Stefanie Luz, postdoc at the German Research Center for Geosciences GFZ. While it is still unclear just how large these blooms can get, they can be quite widespread in the Arctic by summertime. “Based on personal observations, a conservative estimate would be 50 percent of the snow surface on a glacier at the end of a melt season. But this can potentially be even higher”, she said.
Researchers plan to return to the Greenland Ice Sheet this summer to study the relationship between the algae and glaciers more closely. (Floro Mercene)