Will Loss of Arctic Sea Ice Cause More ‘Snow on Ice’ in Greenland?
Scientists are collecting lake sediment, rock, water and plant samples to tease apart linkages between Arctic sea ice, atmospheric uptake, and changes in snowfall on the Greenland Ice Sheet.
Nicolás Young (LDEO), Jason Briner (UB) and an assortment of fellow scientists and graduate students are gearing up to spend a third summer camping along the Greenland ice margin. As part of an ambitious multi-institutional and cross-disciplinary project, NSF-funded Snow on Ice, Young and Briner are collecting lake sediment, rock, water and plant samples that will be used to tease apart linkages between reductions in sea ice on the Arctic Ocean, atmospheric uptake through increased evaporation from the exposed ocean surface and changes in snowfall on the Greenland Ice Sheet. The fieldwork will be centered in southwest Greenland where climate sensitivity during past interglacials was the greatest. The resulting data will be combined with new isotopic ice core work (UW) and updated subglacial topography (UCI), for delivery to two sets of modelers on the project team (UM and NASA JPL) to feed into a set of nested models. Canada's Geotop and Denmark's GEUS fill out the partner list.
Explore the photo essay below and read more below to learn about the exciting work of the Snow on Ice Project.
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Slide 1: Traveling to remote study sites means loading people and gear into a helicopter. This Sikorsky is delivering the science team and their equipment right up to the edge of the ice. Some more remote campsites, with their proximity to the ice, are locati
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Slide 2: After setting up camp, the first order of business is to get out onto the lake in a small zodiac and collect depth measurements, creating a benthic map. A handheld sonar device is mounted on the zodiac and a survey of the lake undertaken. A map is cr
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Slide 3: The coring setup involves a zodiac acting as a small tugboat pulling the coring platform behind it as it pulls it into position. The coring platform is a pontoon with a wooden platform workspace and a large A-frame in the center for suspension of the
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Slide 4: Lakes included in the field study were selected along the edges of the ice with drainage basins extending back beneath the present day Greenland Ice Sheet. This provides a continuous sediment record from silt-rich glacial sediments collecting under i
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Slide 5: A series of âpearl dropâ lakes extends from the ice edge, each connected to the next, providing a continuous line of ice sheet drainage collecting and carrying sediment as the water flows. The lake closest to the ice will receive too much s
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Slide 6: When the weather was too windy to core on the lake, scouting was undertaken for the best glacial erratic locations. Here Nicolás Young takes stock of the area, hiking up the ridgeline to look for locations to collect rock samples for exposure dati
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Slide 7: As the Greenland ice moved over the landscape it reworked the surface, entraining, pushing and repositioning rocks as it traveled, leaving behind large boulders, or glacial erratics. These rocks appear across the bedrock, dotting the surface just whe
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Slide 8: Nicolás Young collects a surface rock sample from a glacial erratic at camp site JB2. Erratics sitting unshielded on the Greenland bedrock are selected for sampling. Using a multi-cosmogenic technique, isotopes beryllium-10 (half life of 1.39 Ma)
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Slide 9: Collecting field samples has an established protocol. Rock samples are carefully bagged and labeled, compass locations recorded, photographs taken of the location and recorded with the sampleâs unique ID for future reference. Photo: Nicolas Youn
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Slide 10: Nicolás Young and Ole Bennike hike up to the ridgeline to look out over the ice sheet and the wider drainage area. Along the left edge they noted a moraine that appears to have been deposited during the Little Ice Age (~1400-1850). In this area th
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Slide 11: At our first campsite, JB1, the terrain was steep, rocky and extremely windy. Arctic hare blended in to the rocks and caribou roamed the area, appearing out of nowhere to survey the region and then move off. The caribou were majestic with their mount
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Slide 12: Our camp was located along the ice margin where the Greenland Ice Sheet edge transitioned into the surrounding terrain. Heidi Roop (l) and Michele Koppes (r) look over the ice from the hilltop. A hike onto the ice sheet showed groups of erratics push
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Slide 13: Ole Bennike from GEUS, Denmark stops to collect a s surface water samples from a small isolated ponds in the sampling area. Pond water is collected to use the water isotopic signature to determine water residence time. If the water is fully meteoric
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Slide 14: This caribou antler is resting in the short scrubby plant material covering much of the area in our camp site, material that will be collected for biomarker analysis. The plant with the small rounded leaves with round toothed edges is Betula nana<
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Slide 15: Large fields of cottongrass Eriophorum sp. covered the region of our second campsite jB2. This site was further south than the first campsite, with musk ox and caribou wandering the landscape and loons calling regularly from the lake. Cottongr
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Slide 16: At camp JB2, a series of lakes separated our campsite from the edge of the ice sheet. The water was an extraordinary aquamarine, colored with a milky tint from the glacial till. Here the coring team is motoring to a site to collect their first core f
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Slide 17: This full length lake cores has been split for a visual description prior to returning to the lab for a more comprehensive analysis. It shows a clear layering in the sediment. At the front of the image wet grey glacially sourced sediments are seen in
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Slide 18: The winds next to the ice sheet rise up quickly and with an intensity that can be surprising. Called katabatic winds, they push down from the ice sheet into the lower valleys. Around the edges of the ice there are wide areas of water-deposited sedime
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Slide 19: The ice sheet has worked over the landscape in the past but in the present day there is ground cover, flowering plants, blueberry and crowberry bushes, and plenty of musk ox and caribou grazing on the plants. In every direction, ridgelines are visibl
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Slide 20: From the top of the ridgeline, the far reaches of the ice sheet are visible, trailing off into the clouds that blend with the white coloring. One lake in a series of drainage lakes sits in the center of our view and in the foreground are rocks scatte
The project goal is to look at the last 8000 years in Western Greenland, spanning back into the last Thermal Maximum when temperatures were approximated at 1-2°C warmer than today and the ice sheet was smaller. It is difficult to constrain the dimensions of an ice sheet that is smaller than present as the traditional markers that are used for evidence are covered over but we will tackle it with the multiple instrument approach described above. The data will be used as a proxy for what might happen in Greenland's future, addressing with increased certainty whether reductions in Arctic sea ice in the past triggered a feedback loop that caused increased precipitation falling as snow, and resulted in stabilizing the Greenland ice Sheet even in a warming climate.
For more on this project see the Snow On Ice website.