Rising temperatures in the Arctic are causing glaciers to retreat onto land, exposing thousands of kilometres of coastline in Greenland and other areas 鈥� with potential geopolitical consequences.
at the University of South Bohemia in the Czech Republic and his colleagues used satellite imagery taken in 2000 and 2020 to track changes in marine-terminating glaciers across the northern hemisphere. They found that almost 2500 kilometres of new coastline had emerged over this period due to glaciers retreating onto land, with two-thirds of this 鈥� over 1600 kilometres 鈥� appearing in Greenland, where temperatures are rising far faster than the global average.
Geopolitical tensions are rising as nations compete to control Arctic resources, which are becoming more accessible as the ice melts. US President Donald Trump has threatened to forcibly annex Greenland, which is rich in critical minerals, deposits of rare-earth elements and unexplored oil and gas reserves. But the new coastlines in Greenland are precarious, warns Kavan, as they are vulnerable to landslides that can trigger huge tsunamis, threatening communities and economic activity across the Arctic region.
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鈥淭he coastline that is newly exposed is unconsolidated,鈥� he says. 鈥淚t is not cemented with ice, the permafrost is not there, so it is really easy to erode it. These coastlines are probably the most dynamic coastlines in the world.鈥�
In narrow fjords, for example, glacier ice fixes the sloping cliffs in place. 鈥淲hen that glacier is gone, the slopes become unstable because they are no longer supported by the mass of the ice,鈥� he says. 鈥淭hese slopes are sensitive to landslides or rockfalls, or these kind of catastrophic events, which can then trigger tsunamis.鈥�
This happened听in September 2023, when a landslide in a narrow fjord in Greenland caused a 200-metre-high听tsunami, triggering a seismic signal picked up by sensors around the world.
Such events, which are becoming increasingly frequent, can be dangerous for nearby communities. In June 2017, Nuugaatsiaq and Illorsuit, two settlements in north-western Greenland, were hit by a tsunami sparked by a landslide in a nearby fjord. The tsunami washed away 11 homes and killed four people.
Such events mean efforts to exploit natural resources in the Arctic may be risky. 鈥淥n the one hand, there鈥檚 new land to be exposed with these potential natural resources,鈥� says Kavan. 鈥淏ut at the same time, these natural hazards with landslides and tsunamis can threaten the infrastructure, which is usually located on the coast.鈥�
Alongside economic consequences, there are severe environmental issues caused by melting glaciers. The retreating ice disrupts light and nutrient circulation in the fjords and the coastal ocean, says at Aarhus University in Denmark. 鈥淭hat has implications from the bottom of the food web, all the way to the top.鈥�
Nature Climate Change
