Thrilling descent into the dangerous Maw of the Greenland Ice Sheet reveals alarming secrets

Vertical ice caves in Greenland drain water from the ice to the sea and are believed to hide messages critical to understanding climate change, energy and the environment.

Scientists have taken a thrilling descent into the pit of a Greenland ice sheet by drilling deep into the ice to explore aspects of the area that hold secrets crucial to climate change research, reports The Washington Post.

The team created two intersecting holes in the bottom of a now frozen ice river, anchored their lines by pulling a rope through them, and dropped into the vertical cave, a “ moulin, ” which published their findings.Moulin volumes control the subglacial water pressure on the Greenland ice sheet‘, in the journal Geophysical Research Letters.

Cave explorer Matt Covington, a professor of geology at the University of Arkansas, and his colleague Jason Gulley, an ice cave expert at the University of South Florida, began to sink into the hole that fills in the summer with flowing melt water.

The hole, scientists believe, eventually penetrates more than half a kilometer into the ice and joins a network of channels that extend all the way to the base of the ice sheet.

“If you dangle from the wall of this deep shaft and hear ice breaking and falling, your heart will go into your throat,” recalled Covington.

While the scientists dangled from the rope, they took measurements using a device called a laser rangefinder, which reflects a laser beam to measure distance.

Massive scientific implications

Covington and his colleague Gulley were motivated to attempt the dangerous descent by a scientific question that is believed to have enormous implications for global warming climate research.

First, there was the issue of the size of the ice caves that have been found by the thousands across the surface of Greenland. There are concerns that they could undermine the integrity of the world’s second largest ice sheet as the melting continues and the moulins expand further into central Greenland.

In summer, Greenland’s moulins absorb a growing volume of meltwater, as the complicated topography of the Greenland ice sheet, which extends high in the sky, doesn’t just let the water flow from the edge to the sea. Accordingly, it floats under the ice through the ice caves to the ocean. At the end of that journey, the sea level rises.

“These are big giant scary holes in the ice … Places that historically humans have avoided. During the summer you have entire lakes that disappear along these things, sometimes at night. Almost every river on the Greenland ice sheet disappears into these holes, ”said Gulley.

Amid global fears of the effects of a warming climate, the North Pole is registering the fastest warming.
In summer, more of Greenland’s surface is melting, with lakes forming at higher and colder heights on the ice sheet, which has shed some 4 trillion tons of mass since 1992.

While they agree that surface melting accounts for about half of the losses, the rest is thought to be caused by massive icebergs breaking off in the sea.

Greenland’s meltwater escapes through thousands of these ice caves. However, scientists had to determine whether these holes should be the surface entrance to an under-ice network of channels, which drain the meltwater. Accordingly, they were suspected to be responsible for the destabilization of the Greenland ice sheet.

“If you keep the crevasse full of water, the water is denser, it can exert a force, and it basically rips the crack all the way to the base of the ice sheet,” Gulley said.

Concerns have grown that with this “network” that is taking up more and more water, the ice sheet itself can move faster to the sea.

The suspicions were supported by the fact that each summer melting season accelerates the movement of the Greenland ice towards the sea. Some of these fears were allayed by the theory that as more water flows into the ice caves, it will form deeper channels in the ice, relieving some of the hydraulic pressure and reducing sliding to the sea.

The team of scientists first traveled to a western part of the Greenland Ice Sheet to study the ice caves, along with Will Gadd, a famous ice climber.

According to Gulley, human exploration is vital because it’s extremely difficult to navigate drones in such small spaces, while under the ice sheet you can’t use GPS to guide them.

The groundbreaking results of the moulin descents, for example at Phobos moulin in western Greenland, provide observations of the size of the caves with scientific models of the water levels in them. The team calculated that the surface of the cave at the water surface was about 5,000 square feet, much larger than had been assumed in previous models.

The results of those studies also offer possible future implications, as water in the ice caves can put more pressure on the surrounding ice and cause it to slide faster, accelerating sea-level rise and potentially dangerous for Greenland’s future.

Understanding how moulins work in supplying water to the sea and affect the speed of ice movement is critical, scientists argue.

“The finding that there are moulins in Greenland that are larger than expected is significant, as these moulins form a buffer between the surface melting and the subglacial runoff,” added Ádam Ignéczi, who studies moulins at Sheffield University in The United Kingdom. involved in the latest study.