Ghostly Satellite Image Captures Arctic ‘Losing Its Soul’

“We started to hear a noise, like breaking or falling parts, ”says Marco Tedesco, climatologist at the Lamont-Doherty Earth Observatory at Columbia University. It makes a loud, sustained crackling sound, recreating what he and his team heard years earlier, during fieldwork on the Greenland ice cap. Below the surface of the ice near where they were standing, a flood had started. “The water below is starting to move but there is still snow on top,” Tedesco says of the phenomenon. As the flowing water expands, the snow and ice covering it give way and reveal a stream or river of meltwater.

What Tedesco describes is a small-scale seasonal melting event, one of many that occurs every summer on the lower edges of the Greenland Ice Sheet, an area of ​​over 650,000 square miles that is only surpassed by by the Antarctic ice sheet. This year, however, things were different.

Following a heat wave in mid-August that brought the first ever precipitation on Summit Camp, at the apex of the ice cap, torrents of meltwater flowed over its surface. Climatologists recorded daily melting rates seven times higher than normal. In the above satellite image of the southwestern corner of the ice cap, captured on August 21, the pale blue water carves vast channels around islands of crisp white ice, or collects in slush depressions. The left side of the image is darker, and like storm clouds on the horizon, it’s a warning of what’s to come. The Greenland ice sheet, like the rest of the Arctic, is trapped in a feedback loop caused by climate change: As the ice melts, it creates conditions for even faster and more extreme melt events.

“The Arctic is losing its soul,” says Mark Serreze, director of the National Snow and Ice Data Center. “The Arctic in many ways is defined by its snow and ice, in all their forms. He adds that while low-lying meltwater runoff is a natural process that has occurred every summer for millennia, “what the image really conveys is how this summer melt-down process becomes more and more. in bigger “.

University of Lincoln climatologist Edward Hanna said the “fairly dramatic” surface meltwater shown in the image is a scene that is likely to be repeated as “Greenland is crossing a crucial tipping point brought about by human-induced climate change “.

For Serreze, who has studied the Arctic since 1982, the dramatic events in Greenland come as no surprise. “We had known for a long time that the Arctic would be the place where the red flags would be the first, and that’s exactly what happened,” he says. But it’s still a shock. “To see a rain event at the top of the Greenland ice cap?” He shakes his head in disbelief.

German, author of The Hidden Life of Ice: Dispatches from a Endangered World, sees something else in both the rainy event at Summit Camp and the impressive satellite image taken the following week: an opportunity.

“For me, it’s really important that we had an unprecedented rain event, to show that these things can happen,” Tedesco said. The Summit Camp rain can help spread awareness of something he and his colleagues have known for years. “These events are strongly linked to the changes we are forcing on the planet,” says Tedesco, calling the Earth “such a delicate, but powerful thermodynamic system”.

Thanks to the “fantastic” quality of the satellite image, says Tedesco, “you can really see the story going on here,” including a large pool of meltwater on the right side which is “very likely to be. melted snow ”.

The left side of the satellite image, says Tedesco, is near the west coast of Greenland and is colored by rock, dust and other particles deposited by the wind, as well as bacteria and other micro -organisms. Its darker color accelerates melting due to a phenomenon known as glacial albedo feedback.

“Albedo is a fancy word to describe how reflective the surface is,” says Serreze. As highly reflective snow and ice melt, the darker surface exposed – rock, open water, or older ice, depending on location – absorbs more solar energy and stimulates even more intense melt. “We’re seeing this in the Arctic as we lose sea ice cover and snow cover,” he says.

However, an unexpected wrinkle appears in the darker part of the satellite image. Tedesco studied this particular part of the ice sheet; due to the underlying topography and other factors, he and many colleagues believe that at least some of the ice-staining material was originally deposited elsewhere on the sheet, a long time ago.

“People think this substance could have been buried in ice in other places and, with the flow of the ice and the increase in melting, it is now exposed,” he says, noting that the idea remains largely unexamined. For him, the possibility of ancient materials coming to the surface is poignant.

“This image is essentially a time machine,” he says, studying the swirls and ripples of white, blue and gray on his computer screen with a thoughtful expression. “You have, on the right, the future: an uneven, wet and muddy ice cap. You have in the middle the present, which is essentially your ice now, frozen. And you have a very deep past on the left, which also determines the future because, of course, the darker it gets, the more sunlight it absorbs and the faster it melts.