“2021 is the 25th year in a row in which Greenland’s ice sheet lost more mass during the course of the melting season than it gained during the winter.”
That’s according to the latest report from Polar Portal, a website featuring observations from Danish research institutions that monitor the Greenland Ice Sheet and the sea ice in the Arctic.
The report explains that while “the early part of the summer was cold and wet with unusually heavy and late snowfall in June, which delayed the onset of the melting season,” July saw a heatwave that “led to a considerable loss of ice.”
The Greenland Ice Sheet experienced a loss of about 166 million tonnes of ice in the 12-month period ended August. This is almost the annual average since around the mid-1980s, according to the report. Between September 1986 and August 2021 it has lost approximately 5,500billion tonnes. This contributes 1.5 centimeters towards the global sea level rise of 12 centimeters.
This season, the ice sheet had a net surface balance of 396 billion tonnes. Although that “makes the current season the 28th lowest in the 41-year time series,” or a “somewhat average year,” the report highlights “how our perspective changes in line with climate change,” explaining that in the late 1990s, “the same figure would have been regarded as a year with a very low surface mass balance in the climate picture at that time.”
2021: 25th consecutive year #Greenland’s Ice Sheet lost more mass during melting season than it gained in winter
Although melting season delayed by cold, wet spring, heatwaves at the end July caused significant melting.@PolarPortal report: https://t.co/Q86TBy1KM6 pic.twitter.com/fJGW1vyskb
— World Meteorological Organization (@WMO) January 7, 2022
The report includes detailed observations on unusual weather in the 2021 Arctic summer, extreme melting times despite average temperatures, as well as sea ice falling to its second-lowest level since July 2017.
Last year was also “notable,” the report says, because “precipitation at Summit Station, which is located at the ‘top’ of the ice sheet at an altitude of 3,200 meters above sea level, was registered in the form of rain.”
The U.S. National Snow and Ice Data Center was notified that August rainfall was recorded. noted that “there is no previous report of rainfall at this location (72.58°N 38.46°W), which reaches 3,216 meters (10,551 feet) in elevation.”
Michelle McCrystall was also a postdoctoral fellow at University of Manitoba and was a leader of the team. publishedArctic rainfall research in October
“The fact that we’re getting rainfall on the summit of Greenland right now, and that we’re maybe going to get more rainfall into the future — it kind of staggers me,” she said.
McCrystall’s team wrote that “the transition from a snow- to rain-dominated Arctic in the summer and autumn is projected to occur decades earlier and at a lower level of global warming, potentially under 1.5°C, with profound climatic, ecosystem, and socioeconomic impacts.”
Their paper was just months after Niklas Borers of the Potsdam Institute for Climate Impact Research. said that a research team he led “found evidence that the central-western part of the Greenland Ice Sheet has been destabilizing and is now close to a critical transition.”
“We’re at the brink, and every year with CO2 emissions continuing as usual exponentially increases the probability of crossing the tipping point,” Boers warned. “It might have passed [the tipping point], but it’s not clear. However, our results suggest there will be substantially enhanced melting in the near future, which is worrying.”