One largely unnoticed consequence of the Covid-19 pandemic has been the interruption of many scientific missions in the Arctic. Remote field trips to the northernmost regions of the globe have been canceled or postponed due to travel restrictions, quarantines and other logistical measures implemented to protect local Inuit communities.
One of the affected expeditions is the field season of the East Greenland Ice Core Project (EGRIP). Since 2015, EGRIP has measured the movements of glaciers in Greenland – the world’s largest island, more than eighty percent of which is covered with ice, and a recent target of former US president Donald Trump’s expansionist plans. The EastGrip is an international science facility 2,700m above sea level, where an international team of scientists – technically up to 30 people, but typically more than 35 – study how fast-moving glaciers known as ice streams will contribute to future sea-level change.
In Greenland, the question is an urgent one:according to the Centre for Polar Observation and modelling, its ice sheet is currently shrinking by 270 billion tonnes per year, as melting ice makes an intricate journey via ice streams all the way to the ocean. According to Nasa, if the island’s entire ice sheet melted, the global sea level would rise by 7.4 metres, leaving many coastal areas under water.
The pandemic prevented EGRIP’s international science team from reaching the facility at all during 2020 – which has caused the scientists concern. Even if EGRIP was designed to be crewless for several years, what worries the researchers is the underground drilling and caves the team has made within the ice sheet.
The caves were created using a method called balloon construction: snowblowers excavated seven metres of snow and then filled it with inflated balloons to give them shape. Once the snow hardened, the balloons were removed, leaving behind tunnel-like structures. Now, without maintenance, the tunnels are sagging under the weight of compressed snow.
“The ceiling is getting lower and lower, due to the flow of the snow and gravity, and could crush any vital equipment,” explains professor Jørgen Steffensen, a glaciologist and EGRIP’s station manager. “This year, the camp will have to brace for a lot of underground excavation to cut away and remove the low ceiling, which will slow down the drilling process.” Early plans to deploy staff on the ground on April 22, 2021 were scrapped after the emergence of several aggressive coronavirus variants meant that travel restrictions were imposed in many countries. The new provisional date for EGRIP staff’s comeback to the camp is mid-June 2021.
Most of the work done at EGRIP – which the pandemic is now putting in jeopardy – has to do with drilling out so-called “deep ice cores”. These are long, cylindrical samples extracted from the ice sheet, from which researchers can glean insights about the planet’s climate history.
The ice cores are drilled through a hole in Greenland’s 1.5-km-thick ice sheet to reach the bedrock, and are logged in a fridge room with temperatures at -35°C. Then, in the mission’s “science trench” – situated 9.5m under the ice sheet’s surface – the cores are processed and cut into different sections, which scientists probe, scan and examine for volcanic ash, acid and particular ice crystal properties. Some cores sections are sent to laboratories around the world for further measurements.
The study of ice cores conducted at EGRIP and elsewhere is revolutionising our understanding of climate history. Ice – especially old ice like that found in Greenland – provides an archive of past atmospheric conditions: it includes information on historic temperature evolution, volcanic eruptions, greenhouse gas concentrations and many other parameters that determine environmental conditions.
And ice sheets in Greenland and Antarctica are unique. Unlike other ice fields, their interior temperatures rarely reached melting point during the summer. As a consequence, they consist of layer upon layer of compressed snow (not frozen water). In this compression, small bubbles of air between the snowflakes get trapped in the ice. These bubbles are our only source of knowledge about the atmosphere and greenhouse gases for hundreds of thousands of years.
In Greenland, Steffensen and his team have counted 60,000 annual layers, while in Antarctica, their American colleagues have measured about 45,000 layers. (EGRIP is also the first research outfit ever to have drilled an ice core through an ice stream – one of the rogue glaciers that are stripping Greenland of tonnes of ice.) “Ice cores from these two ice sheets hold a timeline of information which can be measured with each annual layer identified,” Steffensen says. “Much in the way that the evolution of a tree can be identified in its rings.”
The production of this story was supported by a grant from the IJ4EU fund
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This article was originally published by WIRED UK
