Documentary film brings you along when scientists melt holes in the Greenland Ice Sheet

By now, we’re used to hearing about IT security professionals hacking into programmes to identify and close holes that cybercriminals can use. But melting holes in the Greenland Ice Sheet to learn about the melting of the ice – that is a bit more challenging for one’s logical sense.

But there is a certain logic in William Colgan’s arguments when he explains what the HotRod project is all about. Because what is the fastest and most efficient way to get through a 500-meter-thick layer of ice?

"You melt your way with a very hot metal rod," says William Colgan.

Hence the research project’s rather special name: HotRod. Well, naming research projects doesn’t have to be rocket science. But since it seems logical to melt through the ice, one might wonder what is so special about the HotRod project.

The whole point of going through the Greenland Ice Sheet is to measure the temperatures down at the ice-sheet bed. This is because the temperatures there can be used in models that show the melting of the Greenland Ice Sheet, and these models can give us information about sea-level rise. Temperature is an important parameter to control in the models because ice at 0 degrees Celsius deforms ten times faster than ice at 10 degrees Celsius.

In recent decades, traditional measurements of temperatures under the surface of the Greenland Ice Sheet have typically been done by drilling through the ice with electromechanical drills. This work requires a lot of people, a lot of time and a lot of resources: thousands of litres of petrol, electricity, food for all the participants and much more.

"The depths that it normally takes several months and large amounts of resources to reach with electromechanical drills, could be reached in a week with an electric melt-tip drill and with the efforts of only two people and two pallets of equipment," says Christopher Shields, Engineer and Technician at GEUS.

In the past, melt-tip drills have also been used in the exploration of the Greenland Ice Sheet, but they are not as easy, stable and accessible as electromechanical drills, which have therefore been the preferred tool. But William Colgan believes that the technological development has now reached a point where it is time to give the melt-tip drill another chance.

Hopefully, an efficient electric melt-tip drill can make the exploration of the deep ice cheaper, faster and more resource-friendly.

The deep ice consists of ice from the Pleistocene, which is the geological term for a period that extended from 2.6 million years ago to approximately 17,500 years ago. The ice above that is from the Holocene, which lasted from approximately 17,500 years ago till now. The two types of ice behave differently, and we know very little about the temperature at the bottom because it is so demanding to get down there.

"If we want to know more precisely how much the ice melts, and how, we need to know more about the deep ice. What we know now is that it deforms about three times as fast as the ice from the Holocene, but the temperature also affects how fast the ice melts. Therefore, we need to know how much of this kind of ice there is, where it is, and what the temperature at the bottom is, so that we can make accurate models of when and how much the sea rises," says William Colgan.

In other words, we have to drill boreholes in the ice to cover the gaps in our knowledge about the melting of the Greenland Ice Sheet. If an efficient melt-tip drill can make the acquisition of new data cheaper and easier, we can speed up the knowledge acquisition we need to be able to prioritise efforts for climate adaptation.

Since 2012, Greenland has lost approximately 225 gigatons of ice per year. For every gigaton of ice melting, oceans worldwide rise approximately 0.0028 millimetres. This means that melting from the Greenland Ice Sheet has caused the world’s oceans to rise by approximately 6.3 millimetres since 2012.

Read more about melting and mass balance on promice.org

And now it’s time to hold on to your hat and reading glasses, because your logical sense may be challenged once again. You might think that when the Greenland Ice Sheet melts, the sea around Greenland rises. But it doesn't. On the contrary, the sea level around Greenland falls when the ice melts.

"When the ice melts, Greenland loses mass, and thus Greenland becomes lighter and is even lifted a little, and its gravity becomes weaker. Therefore, the water moves towards the equator, where the force of gravity does not change,” William Colgan explains.

The melting of the Greenland Ice Sheet can therefore cause floods, especially around the equator, as the water level rises. This makes climate research on the Greenland Ice Sheet an area of great international attention.

William Colgan and Christopher Shields consider the test of the electromechanical melt-tip drill a success. During the test in May 2022, they reached a maximum drilling speed of 4.5 metres per hour. Now they are attempting to improve the system so that they can reach 20 metres per hour.

"Until now, the HotRod project has focused on developing the technology. Now we want to implement the technology in our scientific work with data collection,” William Colgan says.

William Colgan received 2 million DKK from VILLUM FONDEN for ’HotRod: Prototype for Rapid Sampling of Ice-Sheet Basal Temperatures’ i 2018.