Rain falls at Greenland's summit for the first time in recorded history
As well as the rain, the same site marked above-zero temperatures for nine hours, for the third time in less than a decade.
If it rains in your neighbourhood in August, that’s just a normal summer shower. When the same thing happens at the frozen summit of the world’s largest island, that’s a record-breaker — and yet another warning sign of the ramping-up of the effects of climate change.
On August 14th, rain was observed at the summit of the Greenland Ice Sheet for several hours, according to the U.S. National Snow and Ice Data Center (NSIDC), which said no rain had ever been recorded there before. The elevation of the site is 3,216 metres above sea-level, about as high as Mount Charleston in Jasper National Park.
In all, temperatures at the summit were above zero for nine hours.
“This was the third time in less than a decade, and the latest date in the year on record, that the National Science Foundation’s Summit Station had above-freezing temperatures and wet snow,” the NSIDC said in a release.
The rain observed at the summit station on August 14th was the first ever recorded at that site. (NASA Earth Observatory)
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The rain was part of a larger melting event ushered in by the interplay between low pressure system near Baffin Island and an area of high pressure to the southeast that pushed warm air and moisture over much of Greenland, which is a self-governing realm of the Danish crown.
The warm air, abetted by rainfall elsewhere in the summit region, triggered an enormous melt event that peaked over an extent of 872,000 square kilometres on August 14th. Large-scale melt events are becoming more common in Greenland, but the NSIDC says 2021 is only the second year to have more than one exceeding 800,000 square kilometres.
"That is happening more frequently with climate change, and it's bad for the ice sheet," William Colgan, a senior researcher with the Geological Survey of Denmark and Greenland, told CBC News.
In the long-term, the melting of the Greenland Ice Sheet has major implications for climate change.
Should it suffer a complete melt, there is enough water frozen in the sheet to raise global sea levels by as much as 7 metres. It’s also worth noting that the kind of global temperatures that would trigger even a partial melt would also affect other ice sheets, such as those in Antarctica, further compounding the problem.
The Greenland Ice Sheet covers around four-fifths of the island, and is the world's largest outside Antarctica. (Hannes Grobe/Wikimedia Commons/Creative Commons CC-BY-SA-2.5)
Second, the loss of polar ice has the potential to trigger what climatologists call a positive feedback loop: warming leads to less ice, which makes Earth less reflective of sunlight. If less sunlight is reflected, more is absorbed, leading to more warming, which hastens the melting of remaining polar ice and starts the cycle anew. Already, around 40 per cent of the Arctic is greener than in 1986.
The world has warmed around 1.09°C since the Industrial Revolution, according to the latest report from the Intergovernmental Panel on Climate Change (IPCC), released earlier this month. The IPCC says temperatures will continue to rise until at least 2050, in even the best-case scenarios, with hotter and more frequent extreme-heat events expected in the coming decades.
However, that figure is an average, and the Arctic has been warming faster than the global average – in Canada, the warming is twice the global average.
2021 has already marked a few unhappy climate milestones along that path. In recent days, the U.S. National Oceanic and Atmospheric Administration announced that July was likely the hottest month in recorded human history, and a weather station in Sicily marked a daytime high of 48.8°C, Europe’s warmest on record, though pending confirmation from the World Meteorological Organization.
Canada reached that pinnacle in the last days of June, with the Interior B.C. village of Lytton shattered Canada’s all-time heat record three days running, finally peaking at 49.6°C.
