Red Snow: Swelling algae incursion is red-lining glacial ice melt

“Watch out where the Huskies go, and don’t you eat that yellow snow!”
F. Zappa (Don’t You Eat the Yellow Snow 1974)

The accuracy of the original set of global warming predictions from more than 40 years ago was shocking when you consider the complexity of the science involved. But there is one caveat: the early researchers now believe they were too conservative in their global warming estimates, both in terms of scale and speed. Global warming has begun and it is going to be worse, sooner, than first predicted.

The primary effects of change are currently found in the polar regions, particularly the Arctic, a region that is warming twice as fast as the rest of the planet. As the ice sheets and ocean ice break apart, they drive related events that serve to reinforce and accelerate global warming. Meanwhile, the melting permafrost is releasing increasing quantities of methane into the atmosphere. Methane is a much more powerful greenhouse gas than CO2.

We have documented those feedback effects here. Bu there are other drivers that are less obvious.

Red snow or watermelon snow is a less well known global warming factor that is both a cause and an effect of the deteriorating situation in the Arctic. The phenomenon is caused by an exploding population of red/pink algae on the snowfields of Alaska and Greenland and elsewhere in the region.

This bizarre phenomenon makes it appear as if someone has sprinkled red dye on the snow fields, but the actual cause is two algae species Chlamydomonas nivalis and C. nivalis. Other than the startling visual effects, the blanket of microbes serves to accelerate ice melt on the glacier by decreasing snow reflectivity and increasing sunlight absorption. Published in a September issue of Nature Geoscience, the latest research shows that the algae cover accounts for 10% – 15% of total snow melt.

In this sense, watermelon snow is related to Frank Zappa’s admonition: “Watch out where the huskies go and don’t you eat that yellow snow.” Different cause, same effect.

Algae blooms are not new to the region, but warming temperatures are causing larger incursions from year to year. This in turn generates another positive feedback loop because more algae grows as the quantity of ice water increases and the range of the algae expands.

When increased algae cover melts the snow off the ice field, it also serves to accelerate  melting because ice reflects less sunlight than clean snow. More warming.

The overall effect is similar to that of black soot deposits, which are also increasing the rate of melt in the Arctic.

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