Future Of Greenland: ‘Dark Ice’ Speeds Up Melting

Ever wanted to explore Greenland? If so, do it fast. For years, strips of “dark ice” are revealed every summer on the otherwise white, frozen landscape of Greenland. Today, research suggests these bands could expose how climate change will affect – and melt – the world’s largest island in area, of which three-quarters is covered in ice.

Climate scientists Johnny Ryan, from Aberystwyth University in the United Kingdom, and Jason Box, from the Geological Survey of Denmark and Greenland, set up camp for a large portion of the summer in southwest Greenland in order to gauge the level of accuracy that dark ice – which is rich with impurities like dust, algae, and soot from ancient wildfires – reflects sunlight. The team’s work is affiliated with the ongoing Dark Snow Project, which aims to uncover more about the effects of climate change on the melting of Greenland’s ice sheet.

In August, a drone captured images – released by NASA’s Earth Observatory – of Ryan and Box’s tents, revealing a patch of dark ice to the right of the campsite. A close-up of the images also showed their equipment, including spectrometers used to measure the reflectivity of the ice.

The Greenland Ice Sheet stretches an estimated 660,000 square miles (1.7 million square kilometers), making it equivalent to the size of the United States east of the Mississippi River. Seemingly, the giant ice layer covers most of Greenland year round, with only a narrow strip of land near the coast ever thawing out and melting into the ocean. A few streams and melt ponds are located further inland, along with ribbons of dark ice.

The strips of dark ice in the images belong to Greenland’s permanent ice sheet that doesn’t melt even during the summer. When a large amount of snow hits the island, the ice sheet can reflect about 86 percent of the sunlight that hits it. However, the strip of dark ice that gets exposed during the summer can reflect as little as 30 percent of incoming sunlight. So what does this mean? The dark ice takes in more heat, warms up the surface much faster and thus, speeds up melting.

As a result, melting on the island could be a grave problem, with even graver consequences.

Typically, Greenland’s massive ice sheet is 1.4 miles (2.3 km) thick, holding 8 percent of the planet’s fresh water. If all of it melted, sea levels would rise an astronomic 24 feet (7.4 meters).

“So what happened in the past is having a direct effect on how the ice sheet behaves today,” Ryan told NASA.

Attaining more knowledge about the reflectivity of ice will offer insight into just how fast climate change will impact Greenland’s ice sheet melts. Most scientists believe considerable melting won’t occur for several hundred years, though very little is known about how melting will happen and how quickly.

“There’s still a great deal we don’t understand about the materials that darken the underlying ice sheet and how their presence will affect how the ice sheet behaves,” Box said in a statement. “We don’t, for instance, have good measurements of the relative abundance of dust, algae, and black carbon (soot) that we find in the areas with dark snow.”