UN NEWS—The data from the Danish Arctic monitoring service Polar Portal – which forms part of the UN weather agency WMO’s annual State of the Climate report – shows that early summer was cold and wet, with unusually heavy and late snowfall in June, which delayed the onset of the melting season.
After that, however, a heatwave at the end of July, led to a considerable loss of ice.
In terms of “total mass balance” (the sum of surface melting and loss of ice chunks from icebergs, in addition to the melting of glacier “tongues” in contact with seawater), the ice sheet lost around 166 billion tonnes during the 12-month period ending in August 2021.
Climate Change
These numbers mean the ice sheet ended the season with a net surface mass balance of approximately 396 billion tonnes, making it the 28th lowest level recorded, in the 41-year time series.
This could be considered an average year, but Polar Report notes how perspectives have changed, due to rapidly advancing climate change.
At the end of the 1990s, for example, these same figures would have been regarded as a year with a very low surface mass balance.
The report also notes that the cause of the early summer chill, could be due to conditions over southwest Canada and the northwest United States.
In these territories, an enormous “blocking” high pressure system was formed, shaped like the Greek capital letter Omega (Ω).