Part of the Arctic’s largest remaining ice shelf has shattered and – surprise, surprise – it's looking like the main culprits are warming temperatures and climate change.
Scientists at the Geological Survey of Denmark and Greenland (GEUS) and Friedrich-Alexander University in Germany say they’re “very concerned” after optical satellite imagery has shown that part of the Nioghalvfjerdsfjorden glacier called Spalte glacier in northern Greenland has just detached a 113-kilometers-squared (43-mile-squared) area in a dramatic calving event.
The satellite data from the European Space Agency (ESA) has also shown the area had an annual loss of 50 square kilometers (19 square miles) in the past two years. This comes off the bat of 20 years of slow but steady disintegration. Since 1999, it’s estimated the ice shelf has lost 160 square kilometers (61 square miles), an area nearly twice the size of Manhattan Island.
“Using almost 30 years of satellite data, we see speed up in the glacier flow over the past decade. It is not only near the current disintegration, but we measure acceleration 80 kilometers upstream where the ice begins to float, indicating a large-scale change to this huge glacier,” Dr Anne Solgaard, a research scientist at GUES, said in a statement.
Large calving events such as this occur when water drains from the Greenland ice sheet onto the tongue of the glacier each summer, forming rivers and ponds on the surface, which you can just about see in the satellite imagery. When winter comes and the temperature drops, these pools of water freeze once again, which can put extra pressure on the floating tongue and up the risk of parts cracking off.
The last few years have been incredibly warm in northeast Greenland and much of the Arctic. Observations from local weather stations have shown that the average air temperatures have been consistently high for the past two years, creating the ideal circumstances for extended melt conditions.
“The atmosphere in this region has warmed by approximately 3°C since 1980 and record-breaking temperatures have been observed in 2019 and 2020,” said Jenny Turton, a researcher at Friedrich-Alexander University.
On top of this, it’s thought the floating ice shelf is also being gently melted from beneath as well through warmer sea temperatures.
While the recent calving events have been dramatic, the researchers say they aren’t overly surprised given these higher temperatures that have been afflicting the area.
“When you observe large parts of an ice shelf breaking off you do raise an eyebrow, but with current developments in the Arctic there is also the realization that this is to be expected,” explains Dr Niels J Korsgaard, a researcher at GEUS.
“Temperatures in the Arctic are rising faster than the global average. More heat is available from air and ocean to melt away the bottom and surface of ice shelves, and the thinning ice shelves are more susceptible to breaking up. We saw this with Zachariae Glacier, this summer with Milne Ice Shelf in Canada, and now Nioghalvfjerdsfjorden Glacier is losing parts of its ice shelf as well.”