GREENLAND

Greenland’s dark snow: climate change made visible

Dark grey snow is nothing new in Greenland; it appears when ice melts during the hottest summer months. What’s not so normal, however, are the record-breaking quantities of it found by the scientists taking part in the “Dark Snow” project.

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Photo of "dark snow" taken by Jason Box during summer 2014.

Dark grey snow is nothing new in Greenland; it appears when ice melts during the hottest summer months. What’s not so normal, however, are the record-breaking quantities of it found by the scientists taking part in the “Dark Snow” project.

The crowd funded scientific project is led by American climatologist Jason Box. His goal is to scientifically prove that Greenland’s “albedo” is diminishing. Albedo is a surface’s reflective power. The darker it is, the lower the albedo, meaning that the surface reflects less light and consequently absorbs more of it – just like how wearing a dark shirt in the sun will make you much hotter than wearing a white one. Dark snow has a much lower albedo than white snow.

After spending two months near the Kangerdlugssuaq glacier in southeast Greenland, researchers concluded that the island was covered in a record amount of dark snow. Their preliminary conclusions show that this a direct consequence of climate change. What’s worse, it is in turn speeding up this phenomenon.

In Greenland, between 250 and 400 billion tons of ice melt every year.

Photos of dark snow near Kangerdlugssuaq glacier, summer 2014. Photo by Jason Box.

"Climate change creates dark snow, and dark snow worsens climate change's effects"

Jason Box works for the Geological Survey of Denmark and Greenland in Copenhagen. He heads the Dark Snow project.

 

We spent two months camping in Greenland, and the results of our measurements show that dark snow has increased 5.6 percent compared to last year. Several factors explain this rise: it’s in part due to microbial activity and rises in temperature, but also due to soot particles from forest fires. These factors influence each other, creating a vicious cycle.

In terms of biological phenomena, our studies focused on ice algae, which grows on melting ice and protects itself from the sun’s rays by creating a sort of black pigment. This pigment helps capture sunshine, and makes the ice melt faster.

Another factor is that ice is melting more quickly due to rises in temperature. Each year, the warm season last longer and longer. Today, it’s about a month longer than it was 15 years ago! We also noticed that every year, the ice starts to melt about 15 metres higher up than the year before. In 15 years, that’s 200 metres. All this contributes to the proliferation of the ice algae, creating more dark snow.

Finally, this year’s record can also be explained by the soot that comes from forest fires. Rises in temperature have made the arctic drier, and so forest fires grow bigger every year. There is also soot that comes from factories, which the wind brings up north.

In short, these factors are caused by climate change, and in turn contribute to worsen its effects. The challenge now is to figure out how big of a role each of these factors plays in the rise of dark snow. We can’t claim with 100 percent certainty that the quantity of dark snow will continue to break records every year. But with temperatures rising globally and in particular in the arctic regions, there is a strong chance this trend will continue.

The Arctic is the region of the world worst hit by climate change. Since 1980, temperatures have risen by 2.5 degrees, compared to 0.7 on average for the rest of the planet. Ice is melting on a grand and very visible scale: since 2007, new shipping routes have opened during the summer months.