CLIMATEWIRE | Ominous clouds rippled overhead, and scientist Jason Field raced to succeed in shelter earlier than the rain hit.
Field, a glaciologist with the Geological Survey of Denmark and Greenland, had been tenting with colleagues on the Greenland ice sheet final Friday when the climate started to show.
Because the group rushed to get off the ice, Field was struck by how heat the air felt on his face. It reminded him of scorching Chinook winds that sweep by means of Colorado within the wintertime, melting snow and ice of their path.
He was proper to search out it foreboding. Over the following few days, the nice and cozy climate triggered a significant melting episode in Greenland — a shocking occasion for September, which generally marks the tip of the ice sheet’s soften season.
Throughout the episode’s peak Saturday, round 12 billion tons of ice melted and ran off into the ocean. Scientists estimate that greater than 200,000 sq. miles of the ice sheet — an space greater than California — had been affected by the melting.
In accordance with Xavier Fettweis, a local weather scientist on the College of Liège in Belgium, the episode seemingly ranks amongst Greenland’s prime 10 highest runoff occasions. And it’s seemingly the strongest September soften occasion on report.
Seeing such a robust soften occasion so late within the yr, Fettweis added in an e-mail, is “distinctive.”
The melting Greenland ice sheet is a prime concern for local weather scientists, and for human society as an entire, because the Earth warms. Greenland presently pours about 250 billion tons of ice into the ocean every year, within the type of each crumbling glaciers and floor melting. It’s the planet’s prime contributor to rising sea ranges.
Summer season is Greenland’s predominant melting season. When ice melts on the floor, a number of the liquid water trickles again into the porous snow on prime of the ice sheet, the place it refreezes. However a few of it runs into the ocean, the place it provides to rising seas. These runoff occasions are a significant preoccupation for scientists maintaining a tally of sea ranges.
Large melting occasions are inclined to exacerbate the runoff drawback — past the issue of further liquid. Previous a sure level, porous snow fills up and there isn’t area for any extra liquid water to trickle in.
And late-season soften occasions can prime the ice sheet for extra runoff the next summer time, Fettweis warned. With winter approaching, the liquid water refreezes sooner and types onerous lenses on the floor of the ice sheet. These lenses could make it tougher for subsequent yr’s meltwater to penetrate the floor, forcing it to run off into the ocean as a substitute.
This yr’s soften season had been comparatively modest till the September episode. It was punctuated by a single “warmth ripple” in July, in response to the Nationwide Snow and Ice Information Heart, which prompted a average soften surge throughout the ice sheet.
However the ice sheet has seen some extraordinary melting in different current summers. The 2019 season introduced a few of its strongest melting, and highest mass losses, on report (Climatewire, Aug. 2, 2019). And 2021 noticed a number of intensive soften occasions in July and August.
Throughout final yr’s August occasion, scientists noticed rain falling at Greenland’s Summit Station — a high-altitude analysis station situated almost 2 miles above sea degree — for the primary time in recorded historical past. Temperatures there hardly ever rise above freezing.
Scientists have warned these sorts of occasions might develop extra frequent and extra extreme because the area retains warming — rising Greenland’s contributions to international sea-level rise.
Sturdy September soften occasions are nonetheless unusual. However which will change within the coming years. In accordance with Fettweis, research counsel that Greenland’s soften season will lengthen in a hotter local weather, and late-season occasions might occur extra usually.
The most recent melting occasion seems to have slowed after peaking over the weekend. However the episode was immortalized by artist Mette Hansgaard, who had adopted Field and the opposite scientists into the sector for just a few days to expertise the ice sheet — and its ongoing response to local weather change — for herself.
As plump raindrops started to fall from the sky final Friday, Hansgaard paused to seize the panorama on her canvas.
“It’s raining right here, so each time the colours get moist, the colours begin to run,” she stated as she painted. “So the rain and the climate impacts the portray the identical means because the climate impacts ice, in a means.”
Reprinted from E&E Information with permission from POLITICO, LLC. Copyright 2022. E&E Information supplies important information for vitality and setting professionals.