2021 marked the 25th year successful a enactment successful which the key Greenland ice sheet mislaid much wide during the melting season, than it gained during the winter, according to a new UN-endorsed report issued connected Friday.
The data from the Danish Arctic monitoring service Polar Portal – which forms portion of the UN upwind bureau WMO’s annual State of the Climate report - shows that early summer was cold and wet, with unusually dense and precocious snowfall successful June, which delayed the onset of the melting season.
After that, however, a heatwave astatine the extremity of July, led to a sizeable nonaccomplishment of ice.
In presumption of “total wide balance” (the sum of aboveground melting and loss of ice chunks from icebergs, successful summation to the melting of glacier “tongues” in interaction with seawater), the ice sheet lost astir 166 cardinal tonnes during the 12-month play ending successful August 2021.
The quality betwixt the yearly suface wide equilibrium for the periods 2010-2021 and 1981-2010 (expressed arsenic mm crystal melt).
These numbers mean the crystal sheet ended the season with a net surface mass balance of approximately 396 cardinal tonnes, making it the 28th lowest level recorded, in the 41-year clip series.
This could beryllium considered an mean year, but Polar Report notes however perspectives person changed, due to rapidly advancing climate change.
At the extremity of the 1990s, for example, these aforesaid figures would person been regarded arsenic a twelvemonth with a precise debased aboveground wide balance.
The report also notes that the origin of the early summertime chill, could be due to conditions over southwest Canada and the northwest United States.
In these territories, an tremendous “blocking" precocious unit strategy was formed, shaped similar the Greek superior missive Omega (Ω).
The representation shows cool, moist summertime upwind implicit Greenland (in the mediate of the map) and the utmost vigor implicit North America.
This travel signifier occurs regularly successful the troposphere, and not conscionable implicit North America, but it had ne'er been observed with specified spot before.
According to the report, an investigation by World Weather Attribution demonstrated that it could lone beryllium explained arsenic a effect of atmospheric warming caused by quality activity.
According to the report, 2021 was notable for respective reasons.
It was the twelvemonth successful which precipitation astatine Summit Station, which is located astatine the apical of the ice sheet astatine an altitude of 3,200 metres supra oversea level, was registered successful the signifier of rain.
The twelvemonth also saw an acceleration of the nonaccomplishment of crystal astatine the Sermeq Kujalleq glacier, where the complaint of nonaccomplishment had different been stagnant for respective years.
Winter snowfall was also close to mean for the period between 1981 and 2010, which was bully news, due to the fact that a operation of debased wintertime snowfall and a lukewarm summertime tin effect successful precise ample losses of ice, arsenic was the lawsuit successful 2019.
© WMO/Karolin Eichier
In Greenland, the melting of crystal sheets is accelerating.