Temperatures soared to record levels in Greenland early this week, up to 50 degrees above normal in some places. Researchers say this early warm spell could make its ice sheet more vulnerable to melt events this summer.
Recent summers have brought record-setting melting of the massive ice sheet, which is the world’s largest contributor to rising sea levels, outpacing the Antarctic ice sheet and mountain glaciers.
“It was certainly a very unusual event, that such a high temperature was reached in the middle of winter,” Ruth Mottram, a climate scientist at the Danish Meteorological Institute, wrote in an email. “There was indeed a March record set this week.”
This latest warm spell in Greenland pushed the temperature in its capital, Nuuk, up to 59.4 degrees (15.2 Celsius) on Sunday, the warmest on record for March or April, according to climate expert Maximiliano Herrera. Researchers at the Danish Meteorological Institute confirmed the record, stating the temperature surpassed the previous March record of 55.7 degrees (13.2 Celsius) in 2016 and previous April record of 58.2 degrees (14.6 Celsius) in 2019.
Martin Stendel, a climate researcher at the Danish Meteorological Institute, said Sunday’s measurement was the warmest on record so early in the year and warmer than Copenhagen at the same time. The average March high in Nuuk, which sits on the southwestern coast of the island, is about 23 degrees (minus-5 Celsius).
Computer model analyses showed even more anomalous temperatures in the far-northern part of Greenland, between 30 and 50 degrees (17 and 28 Celsius) above normal.
The warmth is related to a phenomenon that meteorologists call the “Greenland block,” a stagnant zone of high pressure that causes the air to sink and warm beneath it. The block may have developed in response to a sudden warming at high levels of the atmosphere in February. The “sudden stratospheric warming” disrupted the polar vortex, a pool of frigid air that kept Greenland chilly through the core winter months.
But once the vortex was jostled in late February, it reshuffled weather patterns, allowing more of the cold air lodged over the Arctic to sink toward the mid-latitudes. The development of high pressure over Greenland is a frequent response to sudden stratospheric warming events.
“You really see this high-pressure system sitting right there,” said Marco Tedesco, a researcher at the Lamont-Doherty Earth Observatory at Columbia University. “If you think about the way it spins, it’s basically sucking up all the warm air from northeast Canada and then it’s putting it on the ice sheet.”